This report outlines the rationale, procedures, technical feasibility, risk assessment, and cost-benefit analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an interplanetary spacecraft. The planet Mars is the target body in this study and the outbound Trans-Mars injection in the years between 2175 and 2199 will be analyzed (within this timeframe Bennu’s orbit is predicted to approach Earth within two Earth radii on at least 80 occasions). The Mars orbit insertion burn, Trans-Earth injection burn, and Earth orbit insertion burn are assumed to be achieved with propulsive maneuvers outlined in standard manned interplanetary mission architectures. To accomplish this mission, two methods of transferring kinetic energy are examined: direct capture and release of the asteroid by a spacecraft using a Kevlar net and an inertial reel, and indirect capture by establishing a station on the asteroid to manufacture compressed material from the carbonaceous regolith in order to fire a mass stream to be captured by the spacecraft. This mission architecture analysis takes into account the associated safety risks of perturbations within Bennu’s orbit (which could result in inaccurate rendezvous location predictions), the implications of altering the orbit of 101955 Bennu after transferring a portion of its energy (since there is a possibility of collision with Earth in the late 22nd century if the asteroid is slowed too significantly), g-limit restrictions of the spacecraft and its occupants during an acceleration by the asteroid, and the possibility of a collision between Bennu and the spacecraft. In addition, the cost-benefit considerations of this mission architecture are weighed. This examination concludes that a direct capture Net and Reel system aboard the spacecraft is not a viable capture method due to an insufficient maximum ΔV available through a best-case perfectly elastic collision (capture) with the asteroid, as well as a prohibitive weight penalty aboard the spacecraft due to the Net and Reel system. However, this report finds that the method of establishing a station on Bennu with the capability to separate mass from the asteroid and fire it at a spacecraft is a plausible (if costly) means of transferring a significant ΔV. A KETNEO-FIMM Asteroid Station mission architecture could also be used in subsequent interplanetary missions providing cost-sharing over many decades for future interplanetary missions.
Kinetic Energy Transfer of Near-Earth Objects for Interplanetary Manned Missi...Winston Sanks
This report outlines the rationale, procedures, technical feasibility, risk assessment, and cost-benefit
analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of
the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an
interplanetary spacecraft. The planet Mars is the target body in this study and the outbound Trans-Mars
injection in the years between 2175 and 2199 will be analyzed (within this timeframe Bennu’s orbit is
predicted to approach Earth within two Earth radii on at least 80 occasions). The Mars orbit insertion burn,
Trans-Earth injection burn, and Earth orbit insertion burn are assumed to be achieved with propulsive
maneuvers outlined in standard manned interplanetary mission architectures. To accomplish this mission,
two methods of transferring kinetic energy are examined: direct capture and release of the asteroid by a
spacecraft using a Kevlar net and an inertial reel, and indirect capture by establishing a station on the
asteroid to manufacture compressed material from the carbonaceous regolith in order to fire a mass stream
to be captured by the spacecraft. This mission architecture analysis takes into account the associated safety
risks of perturbations within Bennu’s orbit (which could result in inaccurate rendezvous location
predictions), the implications of altering the orbit of 101955 Bennu after transferring a portion of its energy
(since there is a possibility of collision with Earth in the late 22nd century if the asteroid is slowed too
significantly), g-limit restrictions of the spacecraft and its occupants during an acceleration by the asteroid,
and the possibility of a collision between Bennu and the spacecraft. In addition, the cost-benefit
considerations of this mission architecture are weighed. This examination concludes that a direct capture Net
and Reel system aboard the spacecraft is not a viable capture method due to an insufficient maximum ΔV
available through a best-case perfectly elastic collision (capture) with the asteroid, as well as a prohibitive
weight penalty aboard the spacecraft due to the Net and Reel system. However, this report finds that the
method of establishing a station on Bennu with the capability to separate mass from the asteroid and fire it at
a spacecraft is a plausible (if costly) means of transferring a significant ΔV. A KETNEO-FIMM Asteroid
Station mission architecture could also be used in subsequent interplanetary missions providing cost-sharing
over many decades for future interplanetary missions.
Options and uncertainties in planetary defense: Mission planning and vehicle ...Sérgio Sacani
This paper is part of an integrated study by NASA and the NNSA to quantitatively understand the response timeframe should a threatening Earth-impacting near-Earth
object (NEO) be identified. The two realistic responses considered are the use of a spacecraft functioning as either a kinetic impactor or a nuclear explosive carrier to
deflect the approaching NEO. The choice depends on the NEO size and mass, the available response time prior to Earth impact, and the various uncertainties.
Whenever practical, the kinetic impactor is the preferred approach, but various factors, such as large uncertainties or short available response time, reduce the kinetic
impactor's suitability and, ultimately, eliminate its sufficiency.
Herein we examine response time and the activities that occur between the time when an NEO is recognized as being a sufficient threat to require a deflection and
the time when the deflection impulse is applied to the NEO. To use a kinetic impactor for successful deflection of an NEO, it is essential to minimize the reaction time
and maximize the time available for the impulse delivered to the NEO by the kinetic impactor to integrate forward in time to the eventual deflection of the NEO away
from Earth impact.
To shorten the response time, we develop tools to survey the profile of needed spacecraft launches and the possible mission payloads. We further present a vehicle
design capable of either serving as a kinetic impactor, or, if the need arises, serving as a system to transport a nuclear explosive to the NEO. These results are generated
by analyzing a specific case study in which the simulated Earth-impacting NEO is modeled very closely after the real NEO known as 101955 Bennu (1999 RQ36). Bennu
was selected for our case study in part because it is the best-studied of the known NEOs. It is also the destination of NASA's OSIRIS-REx sample return mission, which
is, at the time of this writing, enroute to Bennu following a September 2016 launch.
Extensive Noachian fluvial systems in Arabia Terra: Implications for early Ma...Sérgio Sacani
Valley networks are some of the strongest lines of evidence for
extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However,
their purported absence on certain ancient terrains, such as
Arabia Terra, is at variance with patterns of precipitation as predicted
by “warm and wet” climate models. This disagreement has contributed
to the development of an alternative “icy highlands” scenario,
whereby valley networks were formed by the melting of highland ice
sheets. Here, we show through regional mapping that Arabia Terra
shows evidence for extensive networks of sinuous ridges. We interpret
these ridge features as inverted fluvial channels that formed in
the Noachian, before being subject to burial and exhumation. The
inverted channels developed on extensive aggrading flood plains. As
the inverted channels are both sourced in, and traverse across, Arabia
Terra, their formation is inconsistent with discrete, localized sources
of water, such as meltwater from highland ice sheets. Our results are
instead more consistent with an early Mars that supported widespread
precipitation and runoff.
Solar system exploration with space resources - Aiaa asm 2014_bp_9 final paperBryan Palaszewski
Solar System Exploration Augmented by
Lunar and Outer Planet Resource Utilization:
Historical Perspectives and Future Possibilities
Bryan Palaszewski 1
NASA John H. Glenn Research Center
Lewis Field
Cleveland, OH 44135
(216) 977-7493 Voice
(216) 433-5802 FAX
bryan.a.palaszewski@nasa.gov
Fuels and Space Propellants Web Site:
http://www.grc.nasa.gov/WWW/Fuels-And-Space-Propellants/foctopsb.htm
Establishing a lunar presence and creating an industrial capability on the Moon may lead to important new discoveries for all of human kind. Historical studies of lunar exploration, in-situ resource utilization (ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and robotic exploration. In the historical work, a broad range of technological innovations are described and analyzed. These studies depict program planning for future human missions throughout the solar system, lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated analyses based on the visions presented are presented. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal propulsion, nuclear surface power, as well as advanced chemical propulsion can significantly enhance these scenarios.
Robotic and human outer planet exploration options are described in many detailed and extensive studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such vehicles, atmospheric mining in the outer solar system has also been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses have investigated resource capturing aspects of atmospheric mining in the outer solar system. These analyses included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists.
Kinetic Energy Transfer of Near-Earth Objects for Interplanetary Manned Missi...Winston Sanks
This report outlines the rationale, procedures, technical feasibility, risk assessment, and cost-benefit
analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of
the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an
interplanetary spacecraft. The planet Mars is the target body in this study and the outbound Trans-Mars
injection in the years between 2175 and 2199 will be analyzed (within this timeframe Bennu’s orbit is
predicted to approach Earth within two Earth radii on at least 80 occasions). The Mars orbit insertion burn,
Trans-Earth injection burn, and Earth orbit insertion burn are assumed to be achieved with propulsive
maneuvers outlined in standard manned interplanetary mission architectures. To accomplish this mission,
two methods of transferring kinetic energy are examined: direct capture and release of the asteroid by a
spacecraft using a Kevlar net and an inertial reel, and indirect capture by establishing a station on the
asteroid to manufacture compressed material from the carbonaceous regolith in order to fire a mass stream
to be captured by the spacecraft. This mission architecture analysis takes into account the associated safety
risks of perturbations within Bennu’s orbit (which could result in inaccurate rendezvous location
predictions), the implications of altering the orbit of 101955 Bennu after transferring a portion of its energy
(since there is a possibility of collision with Earth in the late 22nd century if the asteroid is slowed too
significantly), g-limit restrictions of the spacecraft and its occupants during an acceleration by the asteroid,
and the possibility of a collision between Bennu and the spacecraft. In addition, the cost-benefit
considerations of this mission architecture are weighed. This examination concludes that a direct capture Net
and Reel system aboard the spacecraft is not a viable capture method due to an insufficient maximum ΔV
available through a best-case perfectly elastic collision (capture) with the asteroid, as well as a prohibitive
weight penalty aboard the spacecraft due to the Net and Reel system. However, this report finds that the
method of establishing a station on Bennu with the capability to separate mass from the asteroid and fire it at
a spacecraft is a plausible (if costly) means of transferring a significant ΔV. A KETNEO-FIMM Asteroid
Station mission architecture could also be used in subsequent interplanetary missions providing cost-sharing
over many decades for future interplanetary missions.
Options and uncertainties in planetary defense: Mission planning and vehicle ...Sérgio Sacani
This paper is part of an integrated study by NASA and the NNSA to quantitatively understand the response timeframe should a threatening Earth-impacting near-Earth
object (NEO) be identified. The two realistic responses considered are the use of a spacecraft functioning as either a kinetic impactor or a nuclear explosive carrier to
deflect the approaching NEO. The choice depends on the NEO size and mass, the available response time prior to Earth impact, and the various uncertainties.
Whenever practical, the kinetic impactor is the preferred approach, but various factors, such as large uncertainties or short available response time, reduce the kinetic
impactor's suitability and, ultimately, eliminate its sufficiency.
Herein we examine response time and the activities that occur between the time when an NEO is recognized as being a sufficient threat to require a deflection and
the time when the deflection impulse is applied to the NEO. To use a kinetic impactor for successful deflection of an NEO, it is essential to minimize the reaction time
and maximize the time available for the impulse delivered to the NEO by the kinetic impactor to integrate forward in time to the eventual deflection of the NEO away
from Earth impact.
To shorten the response time, we develop tools to survey the profile of needed spacecraft launches and the possible mission payloads. We further present a vehicle
design capable of either serving as a kinetic impactor, or, if the need arises, serving as a system to transport a nuclear explosive to the NEO. These results are generated
by analyzing a specific case study in which the simulated Earth-impacting NEO is modeled very closely after the real NEO known as 101955 Bennu (1999 RQ36). Bennu
was selected for our case study in part because it is the best-studied of the known NEOs. It is also the destination of NASA's OSIRIS-REx sample return mission, which
is, at the time of this writing, enroute to Bennu following a September 2016 launch.
Extensive Noachian fluvial systems in Arabia Terra: Implications for early Ma...Sérgio Sacani
Valley networks are some of the strongest lines of evidence for
extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However,
their purported absence on certain ancient terrains, such as
Arabia Terra, is at variance with patterns of precipitation as predicted
by “warm and wet” climate models. This disagreement has contributed
to the development of an alternative “icy highlands” scenario,
whereby valley networks were formed by the melting of highland ice
sheets. Here, we show through regional mapping that Arabia Terra
shows evidence for extensive networks of sinuous ridges. We interpret
these ridge features as inverted fluvial channels that formed in
the Noachian, before being subject to burial and exhumation. The
inverted channels developed on extensive aggrading flood plains. As
the inverted channels are both sourced in, and traverse across, Arabia
Terra, their formation is inconsistent with discrete, localized sources
of water, such as meltwater from highland ice sheets. Our results are
instead more consistent with an early Mars that supported widespread
precipitation and runoff.
Solar system exploration with space resources - Aiaa asm 2014_bp_9 final paperBryan Palaszewski
Solar System Exploration Augmented by
Lunar and Outer Planet Resource Utilization:
Historical Perspectives and Future Possibilities
Bryan Palaszewski 1
NASA John H. Glenn Research Center
Lewis Field
Cleveland, OH 44135
(216) 977-7493 Voice
(216) 433-5802 FAX
bryan.a.palaszewski@nasa.gov
Fuels and Space Propellants Web Site:
http://www.grc.nasa.gov/WWW/Fuels-And-Space-Propellants/foctopsb.htm
Establishing a lunar presence and creating an industrial capability on the Moon may lead to important new discoveries for all of human kind. Historical studies of lunar exploration, in-situ resource utilization (ISRU) and industrialization all point to the vast resources on the Moon and its links to future human and robotic exploration. In the historical work, a broad range of technological innovations are described and analyzed. These studies depict program planning for future human missions throughout the solar system, lunar launched nuclear rockets, and future human settlements on the Moon, respectively. Updated analyses based on the visions presented are presented. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal propulsion, nuclear surface power, as well as advanced chemical propulsion can significantly enhance these scenarios.
Robotic and human outer planet exploration options are described in many detailed and extensive studies. Nuclear propulsion options for fast trips to the outer planets are discussed. To refuel such vehicles, atmospheric mining in the outer solar system has also been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses have investigated resource capturing aspects of atmospheric mining in the outer solar system. These analyses included the gas capturing rate, storage options, and different methods of direct use of the captured gases. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists.
T he effect_of_orbital_configuration)_on_the_possible_climates_and_habitabili...Sérgio Sacani
As lower-mass stars often host multiple rocky planets, gravitational interactions among planets can have significant
effects on climate and habitability over long timescales. Here we explore a specific case, Kepler-62f (Borucki et al.,
2013), a potentially habitable planet in a five-planet system with a K2V host star. N-body integrations reveal the
stable range of initial eccentricities for Kepler-62f is 0.00 £ e £ 0.32, absent the effect of additional, undetected
planets. We simulate the tidal evolution of Kepler-62f in this range and find that, for certain assumptions, the planet
can be locked in a synchronous rotation state. Simulations using the 3-D Laboratoire de Me´te´orologie Dynamique
(LMD) Generic global climate model (GCM) indicate that the surface habitability of this planet is sensitive to
orbital configuration.With 3 bar of CO2 in its atmosphere, we find that Kepler-62f would only be warm enough for
surface liquid water at the upper limit of this eccentricity range, providing it has a high planetary obliquity
(between 60 and 90). A climate similar to that of modern-day Earth is possible for the entire range of stable
eccentricities if atmospheric CO2 is increased to 5 bar levels. In a low-CO2 case (Earth-like levels), simulations
with version 4 of the Community Climate System Model (CCSM4) GCM and LMD Generic GCM indicate that
increases in planetary obliquity and orbital eccentricity coupled with an orbital configuration that places the
summer solstice at or near pericenter permit regions of the planet with above-freezing surface temperatures. This
may melt ice sheets formed during colder seasons. If Kepler-62f is synchronously rotating and has an ocean, CO2
levels above 3 bar would be required to distribute enough heat to the nightside of the planet to avoid atmospheric
freeze-out and permit a large enough region of open water at the planet’s substellar point to remain stable. Overall,
we find multiple plausible combinations of orbital and atmospheric properties that permit surface liquid water on
Kepler-62f. Key Words: Extrasolar planets—Habitability—Planetary environments. Astrobiology 16, xxx–xxx.
The habitability of Proxima Centauri b - I. Irradiation, rotation and volatil...Sérgio Sacani
Proxima b is a planet with a minimum mass of 1.3 M⊕ orbiting within the habitable zone (HZ) of Proxima Centauri, a very low-mass,
active star and the Sun’s closest neighbor. Here we investigate a number of factors related to the potential habitability of Proxima b
and its ability to maintain liquid water on its surface. We set the stage by estimating the current high-energy irradiance of the planet
and show that the planet currently receives 30 times more EUV radiation than Earth and 250 times more X-rays. We compute the time
evolution of the star’s spectrum, which is essential for modeling the flux received over Proxima b’s lifetime. We also show that Proxima
b’s obliquity is likely null and its spin is either synchronous or in a 3:2 spin-orbit resonance, depending on the planet’s eccentricity and
level of triaxiality. Next we consider the evolution of Proxima b’s water inventory. We use our spectral energy distribution to compute
the hydrogen loss from the planet with an improved energy-limited escape formalism. Despite the high level of stellar activity we find
that Proxima b is likely to have lost less than an Earth ocean’s worth of hydrogen (EOH) before it reached the HZ 100–200 Myr after
its formation. The largest uncertainty in our work is the initial water budget, which is not constrained by planet formation models. We
conclude that Proxima b is a viable candidate habitable planet.
Is there an_exoplanet_in_the_solar_systemSérgio Sacani
We investigate the prospects for the capture of the proposed Planet 9 from other
stars in the Sun’s birth cluster. Any capture scenario must satisfy three conditions:
the encounter must be more distant than ∼ 150 au to avoid perturbing the Kuiper
belt; the other star must have a wide-orbit planet (a & 100 au); the planet must be
captured onto an appropriate orbit to sculpt the orbital distribution of wide-orbit
Solar System bodies. Here we use N-body simulations to show that these criteria may
be simultaneously satisfied. In a few percent of slow close encounters in a cluster,
bodies are captured onto heliocentric, Planet 9-like orbits. During the ∼ 100 Myr
cluster phase, many stars are likely to host planets on highly-eccentric orbits with
apastron distances beyond 100 au if Neptune-sized planets are common and susceptible
to planet–planet scattering. While the existence of Planet 9 remains unproven, we
consider capture from one of the Sun’s young brethren a plausible route to explain such
an object’s orbit. Capture appears to predict a large population of Trans-Neptunian
Objects (TNOs) whose orbits are aligned with the captured planet, and we propose
that different formation mechanisms will be distinguishable based on their imprint on
the distribution of TNOs
Solar system as a radio telescope by the formation of virtual lenses above an...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Artigo relata como a Terra sofreu com os impactos de ateroides a 4 bilhões de anos atrás, e como a superfície do planeta foi remodelada e os oceanos formados.
The asteroid belt contains less than a thousandth of Earth’s mass and is radially segregated, with S-types
dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more
mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having
formed empty, without any planetesimals between Mars and Jupiter’s present-day orbits. This is consistent with
models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational
scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside
1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a
preference for the inner main belt. C-types are implanted from the outside, as the giant planets’ gas accretion
destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main
belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid
belt may thus represent a repository for planetary leftovers that accreted across the solar system but not
in the belt itself.
Ultrafast transfer of low-mass payloads to Mars and beyond using aerographite...Sérgio Sacani
With interstellar mission concepts now being under study by various space agencies and institutions,
a feasible and worthy interstellar precursor mission concept will be key to the success of the long
shot. Here we investigate interstellar-bound trajectories of solar sails made of the ultra lightweight
material aerographite. Due to its extremely low density (0.18 kgm−3) and high absorptivity (∼1), a
thin shell can pick up an enormous acceleration from the solar irradiation. Payloads of up to 1 kg can
be transported rapidly throughout the solar system, e.g. to Mars and beyond. Our simulations consider
various launch scenarios from a polar orbit around Earth including directly outbound launches as well
as Sun diver launches towards the Sun with subsequent outward acceleration. We use the poliastro
Python library for astrodynamic calculations. For a spacecraft with a total mass of 1 kg (including
720 g aerographite) and a cross-sectional area of 104 m2, corresponding to a shell with a radius of 56m,
we calculate the positions, velocities, and accelerations based on the combination of gravitational and
radiation forces on the sail. We find that the direct outward transfer to Mars near opposition to Earth
results in a relative velocity of 65 kms−1 with a minimum required transfer time of 26 d. Using an
inward transfer with solar sail deployment at 0.6AU from the Sun, the sail’s velocity relative to Mars
is 118 kms−1 with a transfer time of 126 d, whereMars is required to be in one of the nodes of the two
orbital planes upon sail arrival. Transfer times and relative velocities can vary substantially depending
on the constellation between Earth andMars and the requirements on the injection trajectory to the Sun
diving orbit. The direct interstellar trajectory has a final velocity of 109 kms−1. Assuming a distance
to the heliopause of 120AU, the spacecraft reaches interstellar space after 5.3 yr. When using an
initial Sun dive to 0.6AU instead, the solar sail obtains an escape velocity of 148 kms−1 from the
solar system with a transfer time of 4.2 yr to the heliopause. Values may differ depending on the
rapidity of the Sun dive and the minimum distance to the Sun. The mission concepts presented in this
paper are extensions of the 0.5 kg tip mass and 196m2 design of the successful IKAROS mission to
Venus towards an interstellar solar sail mission. They allow fast flybys atMars and into the deep solar
system. For delivery (rather than fly-by) missions of a sub-kg payload the biggest obstacle remains in
the deceleration upon arrival.
T he effect_of_orbital_configuration)_on_the_possible_climates_and_habitabili...Sérgio Sacani
As lower-mass stars often host multiple rocky planets, gravitational interactions among planets can have significant
effects on climate and habitability over long timescales. Here we explore a specific case, Kepler-62f (Borucki et al.,
2013), a potentially habitable planet in a five-planet system with a K2V host star. N-body integrations reveal the
stable range of initial eccentricities for Kepler-62f is 0.00 £ e £ 0.32, absent the effect of additional, undetected
planets. We simulate the tidal evolution of Kepler-62f in this range and find that, for certain assumptions, the planet
can be locked in a synchronous rotation state. Simulations using the 3-D Laboratoire de Me´te´orologie Dynamique
(LMD) Generic global climate model (GCM) indicate that the surface habitability of this planet is sensitive to
orbital configuration.With 3 bar of CO2 in its atmosphere, we find that Kepler-62f would only be warm enough for
surface liquid water at the upper limit of this eccentricity range, providing it has a high planetary obliquity
(between 60 and 90). A climate similar to that of modern-day Earth is possible for the entire range of stable
eccentricities if atmospheric CO2 is increased to 5 bar levels. In a low-CO2 case (Earth-like levels), simulations
with version 4 of the Community Climate System Model (CCSM4) GCM and LMD Generic GCM indicate that
increases in planetary obliquity and orbital eccentricity coupled with an orbital configuration that places the
summer solstice at or near pericenter permit regions of the planet with above-freezing surface temperatures. This
may melt ice sheets formed during colder seasons. If Kepler-62f is synchronously rotating and has an ocean, CO2
levels above 3 bar would be required to distribute enough heat to the nightside of the planet to avoid atmospheric
freeze-out and permit a large enough region of open water at the planet’s substellar point to remain stable. Overall,
we find multiple plausible combinations of orbital and atmospheric properties that permit surface liquid water on
Kepler-62f. Key Words: Extrasolar planets—Habitability—Planetary environments. Astrobiology 16, xxx–xxx.
The habitability of Proxima Centauri b - I. Irradiation, rotation and volatil...Sérgio Sacani
Proxima b is a planet with a minimum mass of 1.3 M⊕ orbiting within the habitable zone (HZ) of Proxima Centauri, a very low-mass,
active star and the Sun’s closest neighbor. Here we investigate a number of factors related to the potential habitability of Proxima b
and its ability to maintain liquid water on its surface. We set the stage by estimating the current high-energy irradiance of the planet
and show that the planet currently receives 30 times more EUV radiation than Earth and 250 times more X-rays. We compute the time
evolution of the star’s spectrum, which is essential for modeling the flux received over Proxima b’s lifetime. We also show that Proxima
b’s obliquity is likely null and its spin is either synchronous or in a 3:2 spin-orbit resonance, depending on the planet’s eccentricity and
level of triaxiality. Next we consider the evolution of Proxima b’s water inventory. We use our spectral energy distribution to compute
the hydrogen loss from the planet with an improved energy-limited escape formalism. Despite the high level of stellar activity we find
that Proxima b is likely to have lost less than an Earth ocean’s worth of hydrogen (EOH) before it reached the HZ 100–200 Myr after
its formation. The largest uncertainty in our work is the initial water budget, which is not constrained by planet formation models. We
conclude that Proxima b is a viable candidate habitable planet.
Is there an_exoplanet_in_the_solar_systemSérgio Sacani
We investigate the prospects for the capture of the proposed Planet 9 from other
stars in the Sun’s birth cluster. Any capture scenario must satisfy three conditions:
the encounter must be more distant than ∼ 150 au to avoid perturbing the Kuiper
belt; the other star must have a wide-orbit planet (a & 100 au); the planet must be
captured onto an appropriate orbit to sculpt the orbital distribution of wide-orbit
Solar System bodies. Here we use N-body simulations to show that these criteria may
be simultaneously satisfied. In a few percent of slow close encounters in a cluster,
bodies are captured onto heliocentric, Planet 9-like orbits. During the ∼ 100 Myr
cluster phase, many stars are likely to host planets on highly-eccentric orbits with
apastron distances beyond 100 au if Neptune-sized planets are common and susceptible
to planet–planet scattering. While the existence of Planet 9 remains unproven, we
consider capture from one of the Sun’s young brethren a plausible route to explain such
an object’s orbit. Capture appears to predict a large population of Trans-Neptunian
Objects (TNOs) whose orbits are aligned with the captured planet, and we propose
that different formation mechanisms will be distinguishable based on their imprint on
the distribution of TNOs
Solar system as a radio telescope by the formation of virtual lenses above an...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Artigo relata como a Terra sofreu com os impactos de ateroides a 4 bilhões de anos atrás, e como a superfície do planeta foi remodelada e os oceanos formados.
The asteroid belt contains less than a thousandth of Earth’s mass and is radially segregated, with S-types
dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more
mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having
formed empty, without any planetesimals between Mars and Jupiter’s present-day orbits. This is consistent with
models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational
scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside
1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a
preference for the inner main belt. C-types are implanted from the outside, as the giant planets’ gas accretion
destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main
belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid
belt may thus represent a repository for planetary leftovers that accreted across the solar system but not
in the belt itself.
Ultrafast transfer of low-mass payloads to Mars and beyond using aerographite...Sérgio Sacani
With interstellar mission concepts now being under study by various space agencies and institutions,
a feasible and worthy interstellar precursor mission concept will be key to the success of the long
shot. Here we investigate interstellar-bound trajectories of solar sails made of the ultra lightweight
material aerographite. Due to its extremely low density (0.18 kgm−3) and high absorptivity (∼1), a
thin shell can pick up an enormous acceleration from the solar irradiation. Payloads of up to 1 kg can
be transported rapidly throughout the solar system, e.g. to Mars and beyond. Our simulations consider
various launch scenarios from a polar orbit around Earth including directly outbound launches as well
as Sun diver launches towards the Sun with subsequent outward acceleration. We use the poliastro
Python library for astrodynamic calculations. For a spacecraft with a total mass of 1 kg (including
720 g aerographite) and a cross-sectional area of 104 m2, corresponding to a shell with a radius of 56m,
we calculate the positions, velocities, and accelerations based on the combination of gravitational and
radiation forces on the sail. We find that the direct outward transfer to Mars near opposition to Earth
results in a relative velocity of 65 kms−1 with a minimum required transfer time of 26 d. Using an
inward transfer with solar sail deployment at 0.6AU from the Sun, the sail’s velocity relative to Mars
is 118 kms−1 with a transfer time of 126 d, whereMars is required to be in one of the nodes of the two
orbital planes upon sail arrival. Transfer times and relative velocities can vary substantially depending
on the constellation between Earth andMars and the requirements on the injection trajectory to the Sun
diving orbit. The direct interstellar trajectory has a final velocity of 109 kms−1. Assuming a distance
to the heliopause of 120AU, the spacecraft reaches interstellar space after 5.3 yr. When using an
initial Sun dive to 0.6AU instead, the solar sail obtains an escape velocity of 148 kms−1 from the
solar system with a transfer time of 4.2 yr to the heliopause. Values may differ depending on the
rapidity of the Sun dive and the minimum distance to the Sun. The mission concepts presented in this
paper are extensions of the 0.5 kg tip mass and 196m2 design of the successful IKAROS mission to
Venus towards an interstellar solar sail mission. They allow fast flybys atMars and into the deep solar
system. For delivery (rather than fly-by) missions of a sub-kg payload the biggest obstacle remains in
the deceleration upon arrival.
Kinetic Energy Transfer of Near-Earth Objects for Interplanetary Manned Missi...Winston Sanks
This report outlines the rationale, procedures, technical feasibility, risk assessment, and cost-benefit
analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of
the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an
interplanetary spacecraft. The planet Mars is the target body in this study and the outbound Trans-Mars
injection in the years between 2175 and 2199 will be analyzed (within this timeframe Bennu’s orbit is
predicted to approach Earth within two Earth radii on at least 80 occasions). The Mars orbit insertion burn,
Trans-Earth injection burn, and Earth orbit insertion burn are assumed to be achieved with propulsive
maneuvers outlined in standard manned interplanetary mission architectures. To accomplish this mission,
two methods of transferring kinetic energy are examined: direct capture and release of the asteroid by a
spacecraft using a Kevlar net and an inertial reel, and indirect capture by establishing a station on the
asteroid to manufacture compressed material from the carbonaceous regolith in order to fire a mass stream
to be captured by the spacecraft. This mission architecture analysis takes into account the associated safety
risks of perturbations within Bennu’s orbit (which could result in inaccurate rendezvous location
predictions), the implications of altering the orbit of 101955 Bennu after transferring a portion of its energy
(since there is a possibility of collision with Earth in the late 22nd century if the asteroid is slowed too
significantly), g-limit restrictions of the spacecraft and its occupants during an acceleration by the asteroid,
and the possibility of a collision between Bennu and the spacecraft. In addition, the cost-benefit
considerations of this mission architecture are weighed. This examination concludes that a direct capture Net
and Reel system aboard the spacecraft is not a viable capture method due to an insufficient maximum ΔV
available through a best-case perfectly elastic collision (capture) with the asteroid, as well as a prohibitive
weight penalty aboard the spacecraft due to the Net and Reel system. However, this report finds that the
method of establishing a station on Bennu with the capability to separate mass from the asteroid and fire it at
a spacecraft is a plausible (if costly) means of transferring a significant ΔV. A KETNEO-FIMM Asteroid
Station mission architecture could also be used in subsequent interplanetary missions providing cost-sharing
over many decades for future interplanetary missions.
Orbit design for exoplanet discovery spacecraft dr dora musielak 1 april 2019Dora Musielak, Ph.D.
Most exoplanets have been discovered with space telescopes. Starting with an overview of rocket propulsion, this presentation introduces spacecraft trajectories in the Sun-Earth-Moon System, focusing especially on those appropriate for exoplanet detection spacecraft. It reviews past, present, and future exoplanet discovery missions.
Laser melting manufacturing of large elements of lunar regolith simulant for ...Sérgio Sacani
The next steps for the expansion of the human presence in the solar system will be taken on the Moon.
However, due to the low lunar gravity, the suspended dust generated when lunar rovers move across
the lunar soil is a signifcant risk for lunar missions as it can afect the systems of the exploration
vehicles. One solution to mitigate this problem is the construction of roads and landing pads on the
Moon. In addition, to increase the sustainability of future lunar missions, in-situ resource utilization
(ISRU) techniques must be developed. In this paper, the use of concentrated light for paving on the
Moon by melting the lunar regolith is investigated. As a substitute of the concentrated sunlight, a
high-power CO2 laser is used in the experiments. With this set-up, a maximum laser spot diameter of
100 mm can be achieved, which translates in high thicknesses of the consolidated layers. Furthermore,
the lunar regolith simulant EAC-1A is used as a substitute of the actual lunar soil. At the end of the
study, large samples (approximately 250 × 250 mm) with interlocking capabilities were fabricated by
melting the lunar simulant with the laser directly on the powder bed. Large areas of lunar soil can be
covered with these samples and serve as roads and landing pads, decreasing the propagation of lunar
dust. These manufactured samples were analysed regarding their mineralogical composition, internal
structure and mechanical properties.
The Possible Tidal Demise of Kepler’s First Planetary SystemSérgio Sacani
We present evidence of tidally-driven inspiral in the Kepler-1658 (KOI-4) system, which consists of a giant planet
(1.1RJ, 5.9MJ) orbiting an evolved host star (2.9Re, 1.5Me). Using transit timing measurements from Kepler,
Palomar/WIRC, and TESS, we show that the orbital period of Kepler-1658b appears to be decreasing at a rate = -
+ P 131 22
20 ms yr−1
, corresponding to an infall timescale P P » 2.5 Myr. We consider other explanations for the
data including line-of-sight acceleration and orbital precession, but find them to be implausible. The observed
period derivative implies a tidal quality factor
¢ = ´ -
+ Q 2.50 10 0.62
0.85 4, in good agreement with theoretical
predictions for inertial wave dissipation in subgiant stars. Additionally, while it probably cannot explain the entire
inspiral rate, a small amount of planetary dissipation could naturally explain the deep optical eclipse observed for
the planet via enhanced thermal emission. As the first evolved system with detected inspiral, Kepler-1658 is a new
benchmark for understanding tidal physics at the end of the planetary life cycle
WASP-69b’s Escaping Envelope Is Confined to a Tail Extending at Least 7 RpSérgio Sacani
Studying the escaping atmospheres of highly irradiated exoplanets is critical for understanding the physical
mechanisms that shape the demographics of close-in planets. A number of planetary outflows have been observed
as excess H/He absorption during/after transit. Such an outflow has been observed for WASP-69b by multiple
groups that disagree on the geometry and velocity structure of the outflow. Here, we report the detection of this
planet’s outflow using Keck/NIRSPEC for the first time. We observed the outflow 1.28 hr after egress until the
target set, demonstrating the outflow extends at least 5.8 × 105 km or 7.5 Rp This detection is significantly longer
than previous observations, which report an outflow extending ∼2.2 planet radii just 1 yr prior. The outflow is
blueshifted by −23 km s−1 in the planetary rest frame. We estimate a current mass-loss rate of 1 M⊕ Gyr−1
. Our
observations are most consistent with an outflow that is strongly sculpted by ram pressure from the stellar wind.
However, potential variability in the outflow could be due to time-varying interactions with the stellar wind or
differences in instrumental precision.
The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx mea...Sérgio Sacani
The top-shaped morphology characteristic of asteroid (101955) Bennu, often found among fast-spinning asteroids and binary
asteroid primaries, may have contributed substantially to binary asteroid formation. Yet a detailed geophysical analysis of
this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource
Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained
during the Preliminary Survey phase of the OSIRIS-REx mission, we find a notable transition in Bennu’s surface slopes within
its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of
the rotational Roche lobe with Bennu’s surface has been most recently migrating towards its equator (given Bennu’s increasing
spin rate), we infer that Bennu’s surface slopes have been changing across its surface within the last million years. We also find
evidence for substantial density heterogeneity within this body, suggesting that its interior is a mixture of voids and boulders.
The presence of such heterogeneity and Bennu’s top shape are consistent with spin-induced failure at some point in its past,
although the manner of its failure cannot yet be determined. Future measurements by the OSIRIS-REx spacecraft will provide
insight into and may resolve questions regarding the formation and evolution of Bennu’s top-shape morphology and its link to
the formation of binary asteroids.
SpaceX’s 22nd contracted cargo resupply mission (CRS) to the International Space
Station for NASA will deliver more than 7,300 pounds of science and research, crew
supplies and vehicle hardware to the orbital laboratory and its crew.
Launch is targeted for 1:29 p.m. EDT Thursday, June 3, 2021
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERSveerababupersonal22
It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
block diagram and signal flow graph representation
Kinetic Energy Transfer of Near-Earth Objects for Interplanetary Manned Missions Report
1. Sanks 1
Kinetic Energy Transfer of Near-Earth Objects for Interplanetary Manned Missions
(KETNEO-FIMM)
C1C Winston A. Sanks
Department of Astronautics, 2354 Vandenberg Drive, Suite 5B57,PO Box 4303, U.S. Air Force Academy, CO 80841
C15Winston.Sanks@Usafa.edu
This report outlines the rationale, procedures, technical feasibility, risk assessment, and cost-benefit
analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of
the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an
interplanetary spacecraft. The planet Mars is the target body in this study and the outbound Trans-Mars
injection in the years between 2175 and 2199 will be analyzed (within this timeframe Bennu’s orbit is
predicted to approach Earth within two Earth radii on at least 80 occasions). The Mars orbit insertion burn,
Trans-Earth injection burn, and Earth orbit insertion burn are assumed to be achieved with propulsive
maneuvers outlined in standard manned interplanetary mission architectures. To accomplish this mission,
two methods of transferring kinetic energy are examined: direct capture and release of the asteroid by a
spacecraft using a Kevlar net and an inertial reel, and indirect capture by establishing a station on the
asteroid to manufacture compressed material from the carbonaceous regolith in order to fire a mass stream
to be captured by the spacecraft. This mission architecture analysis takes into account the associated safety
risks of perturbations within Bennu’s orbit (which could result in inaccurate rendezvous location
predictions), the implications of altering the orbit of 101955 Bennu after transferring a portion of its energy
(since there is a possibility of collision with Earth in the late 22nd
century if the asteroid is slowed too
significantly), g-limit restrictions of the spacecraft and its occupants during an acceleration by the asteroid,
and the possibility of a collision between Bennu and the spacecraft. In addition, the cost-benefit
considerations of this mission architecture are weighed. This examination concludes that a direct capture Net
and Reel system aboard the spacecraft is not a viable capture method due to an insufficient maximum ∆V
available through a best-case perfectly elastic collision (capture) with the asteroid, as well as a prohibitive
weight penalty aboard the spacecraft due to the Net and Reel system. However, this report finds that the
method of establishing a station on Bennu with the capability to separate mass from the asteroid and fire it at
a spacecraft is a plausible (if costly) means of transferring a significant ∆V. A KETNEO-FIMM Asteroid
Station mission architecture could also be used in subsequent interplanetary missions providing cost-sharing
over many decades for future interplanetary missions.
I. Nomenclature and Acronyms
a = Semi-major axis (km)
ε = Specific mechanical energy (km2
/s2
)
Isp = Specific impulse (s)
g0 = Earth’s gravitational acceleration (m/s2
)
KE = Kinetic energy (Joules)
σ = Normal stress (Pascal)
∆V = Change in velocity (km/s)
μ = Universal gravitational constant times the mass of the central body (km2
/s2
)
ADACS - Attitude Determination and Control System
ECLSS - Environmental Control and Life Support System
EOI - Earth Orbit Insertion
MOI -Mars Orbit Insertion
SSME – Space Shuttle Main Engine
TEI - Trans-Earth Injection
TOF – Time of Flight
TMI – Trans-Mars Injection
2. Sanks 2
II. Introduction
The ability to travel to large distances within the solar system is a high priority for the global community
due to available opportunities for scientific development, extraterrestrial resource utilization, and the sustainment of
the human race on other celestial bodies. However, manned efforts to reach Mars or other superlunary destinations
are severely impeded by the hostile environment that interplanetary space offers: high energy radiation exposure, the
psychosocial impact of the prolonged isolation of a crew, and in particular, the ECLSS requirements of a long-
duration interplanetary transfer. All of these factors conspire to create a mission requirement of a heavy spacecraft
and a large ∆V. Manned interplanetary missions are examined in this study specifically because these constraints are
much less demanding (or nonexistent) for unmanned missions and a kinetic energy assist by an asteroid may not be
necessary. However, this mission architecture could potentially be applied to an unmanned interplanetary mission as
well. The technical feasibility of designing a spacecraft capable of supporting a manned trans-Martian (or beyond)
mission is limited due to the above requirements. Even using mitigating techniques such as in-situ resource
utilization to manufacture fuel for a return trip, the total mass for a crewed interplanetary vehicle and cargo could
measure upwards of 500 metric tons, based on the most recent NASA Mars Design Reference Architecture1
. This
study will use the best case scenario of a Class B manned spacecraft with a mass of 500,000kg (this mass is the total
spacecraft mass following Earth launch, reaching the rendezvous point, and prior to the TMI ∆V) utilizing the Ares
V cargo vehicle equipped with SSMEs2
as the launch element (this is the same launch configuration used in
NASA’s Mars Design Reference Architecture).
III. 101955 Bennu (1999 RQ36)
101955 Bennu, an Apollo class carbonaceous asteroid roughly 550 meters in diameter at its widest point,
has a synodic period of roughly six years in relation to Earth3
(every six years, Bennu’s orbit takes it near the Earth).
Bennu has a stable and predictable orbit making it a suitable choice for an asteroid sampling mission as well as the
KETNEO-FIMM mission architecture. 101955 Bennu is the target of the Origins Spectral Interpretation Resource
Identification Security - Regolith Explorer (OSIRIS-REx) asteroid sample return mission led by the University of
Arizona, NASA's Goddard Space Flight Center, Lockheed Martin Space Systems of Denver, and NASA's Marshall
Space Flight Center4
. According to OSIRIS-REx team member Steven Chesley of the Jet Propulsion Laboratory,
“The new orbit for … 1999 RQ36 is the most precise asteroid orbit ever obtained.”5
Important orbital and physical
characteristics of Bennu are outlined in Figure 1 and 2 below.
Figure 1: Properties of 101955 Bennu6 7
1
Drake, Bret. "NASA Mars Design Reference Architecture 5.0." NASA, July 2009. Web. Apr 2014. Page 27.
<http://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf>.
2
"Return to SSME – Ares V undergoes evaluation into potential switch." NASASpaceFlight.com, July 2009. Web.
Apr 2014.
<http://www.nasaspaceflight.com/2008/12/ssme-ares-v-undergoes-evaluation-potential-switch/>.
3
"JPL Small-Body Database Browser." Apr 2013. Web. Apr 2014.
<http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=bennu&orb=1>.
4
"OSIRIS-REx." Web. Apr 2014. <http://www.asteroidmission.org/>.
5
Dunbar, Brian. "Asteroid Nudged by Sunlight: Most Precise Measurement of Yarkovsky Effect." NASA, 24 May
2012. Web. Apr. 2014. <http://www.nasa.gov/topics/universe/features/yarkosky-asteroid_prt.htm>.
6
"OSIRIS-REx Fact Sheet." Web. Apr. 2014.
<http://www.nasa.gov/centers/goddard/pdf/552572main_OSIRIS_REx_Factsheet.pdf>.
7
Chelsey, Steven, and David Farnocchia. "Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955)
Bennu." Cornell University Library. 23 Feb. 2014. Web. Apr. 2014. <http://arxiv.org/abs/1402.5573>.
Orbital Period
(days)
Semi-Major Axis
(AU)
Mean Orbital Velocity
(km/s)
Estimated Mass
(kg)
Estimated Density
(g/cm3
)
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Figure 3: Conjunction Class Trajectory Example (Courtesy NASA)12
Figure 4: Opposition Class Trajectory with an Inbound Venus Flyby Example (Courtesy NASA)13
However, the KETNEO-FIMM architecture requires a date of departure with the conditions of both a
desirable Earth-Mars transfer phasing and a Bennu-Earth close approach. The orbits of Bennu, Earth, and Mars can
be extrapolated to the desired dates of departure in the late 22nd
century with only a modicum of accuracy; therefore
in order to accomplish an accurate concept study, three suitable dates of departure that occur within the next decade
will be examined:
12
Williams, David. "A Crewed Mission to Mars...." 25 Apr. 2005. Web. Apr. 2014.
<http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html>.
13
Williams, David. "A Crewed Mission to Mars...." 25 Apr. 2005. Web. Apr. 2014.
<http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html>.
5. Sanks 5
Figure 5: Table of Spacecraft-Bennu Rendevous Opportunity ∆V Requirements17 18
The most important consideration for this study is the outbound ∆V needed and the relative velocities of
Earth and Bennu on the date of departure. These factors will drive the technical feasibility of a KETNEO-FIMM
mission architecture. Multiple considerations must be weighed in selecting a suitable departure date for the mission
as a whole – the total mission ∆V needed incorporating MOI, TEI, and EOI burns is a driving requirement due to the
corresponding propellant mass required to satisfy the total change in velocity (although, propellant mass
requirements can be mitigated through the use of in-situ resource utilization on Mars to manufacture fuel for the
return trip). In addition, the TOF and surface stay durations will dominate ECLSS mass requirements of the
spacecraft, making total mission length an extremely important consideration as well.
Figure 6: Table of Spacecraft-Bennu Rendevous Opportunity TOF Requirements
This study focuses only on the suitability of a kinetic energy transfer to be used on the TMI; therefore, no
single date of departure will be selected for this report and all three dates of departure will be analyzed. However, in
addition to the findings and recommendations made in the remainder of this mission architecture analysis, the
considerations stated above would need to be synthesized at a systems engineering level to determine the best date
of departure.
14
Using the tangential velocities approximation stated in the assumptions section
15
Assuming an atmospheric deceleration upon return to Earth
16
During the 11 May 2018 approach Bennu has a Sun-relative velocity that is lower than the Earth’s – making it
suitable only for the Mass Cannon energy transfer method, see figures 5 and 7
17
Larson, Wiley J. Human spaceflight: mission analysis and design. New York: McGraw-Hill, 2000. Print. Pages
257-264
18
Ishimatsu, Takuto , Jeffrey Hoffman, and Olivier de Weck. "Interplanetary Trajectory Analysis for 2020-2040
Mars Missions including Venus Flyby Opportunities." 14 Sept. 2009. Web. Apr. 2014. Pages 7-8.
<http://www.enu.kz/repository/2009/AIAA-2009-6470.pdf>.
Date Bennu Approach
Distance (AU)
Relative Earth-Bennu
Velocity14
(km/s)
Class ∆V Outbound
(km/s)
∆V MOI
(km/s)
∆V TEI
(km/s)
∆V EOI15
(km/s)
∆V Total
(km/s)
4-September-2017 0.317 1.486 Opposition 7.488 4.454 4.556 0 16.498
11-May-201816
0.35 -6.686 Conjunction 3.507 2.230 2.466 0 8.203
12-September-2023 0.471 2.812
Opposition-
Outbound
Venus Flyby 4.397 4.454 2.234 0 11.085
Date Time of Flight
Outbound (days)
Surface Stay (days) Time of Flight
Return (days)
Total Mission
Duration (days)
4-September-2017 260 40 170 470
11-May-2018 204 553 190 947
12-September-2023 300 14 290 604
6. Sanks 6
IV. Assumptions
To carry out this analysis, several assumptions were made to simplify calculations and to provide a baseline
from which a more detailed study could be carried out. A two body assumption was made for all orbits (suitable as
the orbits of the bodies in question are being considered for short periods of time); the orbits of Mars, Bennu, and
Earth are approximated as tangential and coplanar (all orbits are assumed to lie on the plane of the ecliptic) at the
time of momentum exchange in order to forego vector analysis (which would yield minimally increased accuracy -
all orbit velocities are dominated in a direction within the plane of the ecliptic); a best-case perfectly elastic collision
is assumed for the Net and Reel capture method (i.e. no energy is lost to heat or light in the momentum exchange);
all changes in velocity are assumed instantaneous and tangential (except for the Mass Driver architecture, which
cannot transfer momentum all at once, see section V.b.); Bennu is approximated as a spherical body; the Asteroid
Station is assumed to be nuclear powered and capable of manufacturing dense slugs from Bennu’s carbonaceous
regolith - the mass and power requirements of this system will be approximated to a modern tunnel boring system19
(9.25x105
kg and 3.4 x106
Volt-Amperes); the density of slugs in the Mass Driver architecture is assumed to be made
roughly that of limestone (2.0 g/cm3
); the Mars orbit insertion burn, Trans-Earth injection burn, and Earth orbit
insertion burn are assumed to be achieved with propulsive maneuvers outlined in standard manned interplanetary
mission architectures (such as the NASA Mars Design Reference Architecture 5.0); the ∆V needed from Earth
launch is dominated by burnout velocity, therefore the velocity contributions from the rotation of the Earth and the
velocity penalties due to drag and gravity are not incorporated into calculations; Earth is a point mass during the
spacecraft’s rendezvous with Bennu (i.e. J2, drag, and other perturbations will not affect the spacecraft’s orbit
through its rendezvous with the asteroid); and the time of flight from launch to the rendezvous location is assumed
to be 2 hours for all scenarios (this assumption uses the very close predicted approach of 2 Earth Radii on 9
September 218820
) – this assumption is due to the lack of accuracy in orbital prediction over several decades.
In the late 22nd
century, when very close Earth-Bennu approaches will take place, the ∆V required for
interplanetary transfer, relative velocities between the Earth and Bennu, and other parameters will be similar to the
values that are used in this report for the upcoming dates of departure in the next decade. Therefore in order to
accomplish an accurate concept study, even though the true date of departure would occur between 2175 and 2199,
the three suitable dates of departure that occur within the next decade will be examined
V. Transfer Methodologies Data Reduction and Math Techniques
Two transfer methodologies were examined in this study: utilizing a Kevlar net and an inertial reel attached
to the spacecraft to directly capture the Bennu (or a portion of it) thereby decelerating the asteroid and accelerating
the spacecraft, and establishing a nuclear powered station on the asteroid to manufacture compressed material from
the carbonaceous regolith in order to fire mass from the asteroid to be captured by the spacecraft - similarly
decelerating the asteroid and accelerating the spacecraft due to the mass transfer. Both of these methods would also
allow the extraction of chemical energy from the asteroid depending on the suitability of the asteroid material as a
fuel - the composition of which will be accurately determined in the upcoming OSIRIS-REx mission21
.
The following calculations are outlined in Appendices A, B, and C. First, the specific mechanical energy of
Bennu, Earth, and a 500,000kg Spacecraft orbiting Earth was determined using equation 1 and the given values for
semi-major axis of the bodies being examined using the JPL HORIZONS Database22
. The radius of perigee for the
spacecraft was chosen to be 6878.137km (500km altitude) and the radius of apogee was used as the Earth-Bennu
approach distance on the date of departure23
. Using the orbital energy of each body, the relative velocities of the
bodies in relation to the Sun were calculated using the orbital velocity equation.
19
"Tunnel Boring Machine Fact Sheet." Web. Page 2.
<http://media.metro.net/projects_studies/eastside/images/ee_factsheet_03_tunnelboring.pdf>, and appendix A
20
"101955 Bennu (1999 RQ36) Impact Risk." 3 Mar. 2014. Web. Apr 2014.
<http://neo.jpl.nasa.gov/risk/a101955.html>, and appendix A
21
"OSIRIS-REx Fact Sheet." Web. Apr. 2014.
22
"HORIZONS Web-Interface." Web. <http://ssd.jpl.nasa.gov/horizons.cgi#top>.
23
"JPL Small-Body Database Browser." Apr 2013. Web. Apr 2014.
<http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=bennu&orb=1>.
7. Sanks 7
a2
(1)
Equation 1: Specific Mechanical Energy Equation
)(2
R
V Sun
(2)
Equation 2: Orbital Velocity Equation
Where R is the distance from the Sun to the body in question. Next, the kinetic energies for Bennu and the
spacecraft were calculated using the Kinetic Energy Equation, and the kinetic energy needed for the spacecraft to
achieve the transfer ∆V was computed.
2
2
mv
KE (3)
Equation 3: Kinetic Energy Equation
The ideal rocket equation was used to determine the maximum amount of fuel that could be saved through
kinetic energy transfer with the required interplanetary transfer ∆V using current rocket technology (SSMEs) where
mf is the spacecraft mass after the TMI burn (500,000kg). Figure 7 outlines Kinetic energy and velocity exchange
data yielded through these calculations.
)ln(0
f
i
sp
m
m
gIV (4)
Equation 4: Ideal Rocket Equation
Figure 7: Table of Spacecraft-Bennu KE available, KE needed, ∆V needed, and fuel savings data
24
Assuming the spacecraft would otherwise use SSME engines for interplanetary ∆V, see appendices A, B, and C
25
During the 11 May 2018 approach Bennu has a Sun-relative velocity that is lower than the Earth’s – making it
suitable only for the Mass Cannon energy transfer method, see figures 5 and 7
Date Class Relative KE available
from Bennu (Joules)
∆KE needed for
Transfer (Joules)
∆V needed
Outbound (km/s)
Maximum fuel saved
due to transfer (kg)24
4-September-2017 Opposition 2.93x1019
1.25x1014
7.49 2.69x106
11-May-201825
Conjunction 1.60x1019
5.53x1013
3.51 1.10x106
12-September-2023
Opposition-
Outbound
Venus Flyby 3.19x1019
7.03x1013
4.40 1.34x106
8. Sanks 8
Bennu’s kinetic energy (and thus its velocity) is not significantly reduced in a momentum exchange due to
its mass that is much greater than the spacecraft mass. The trajectory of Bennu is likewise infinitesimally altered26
and will likely not have Earth-impact implications in the late 22nd
century. This possibility will be discussed in detail
in section VI, Safety. Using the rocket equation once again, the maximum fuel saved due to energy transfer was
calculated. This value was based on the assumption of current rocket technology, and represents a significant mass
savings. An interplanetary transfer ∆V achieved through a momentum exchange avoids a mass penalty that would
have otherwise required a spacecraft design orders of magnitude larger and heavier to accommodate the extra fuel –
adding significant complexity and cost to the launch element of the interplanetary mission.
V.a Direct Capture –Net and Inertial Reel
In the Direct Capture methodology, a Kevlar net connected to an inertial reel will provide the means to
accomplish the kinetic energy exchange. The inertial reel would be a hydraulically or electromagnetically damped
reel around which the Kevlar would spool. The reel would control the rate of unreeling to ensure the acceleration of
the spacecraft remained within calculated parameters during the capture of Bennu. Kevlar was chosen as the Net and
Reel material due to its high tensile strength, low density, and ability to be produced in mass quantities27
. A
conceptual design of the Net and Inertial Reel capture system is outlined in figure 8.
Figure 8: Conceptual design of Net and Inertial Reel capture system (Courtesy Space Junk 3D, LLC)28
The force of the spacecraft being accelerated by the asteroid at a chosen maximum of 10g was calculated to
find the mass of an inertial reel system capable of sustaining the momentum transfer. 10g was chosen as the
acceleration limit based on experimental data of human horizontal g-load tolerances (“eyeballs in”) over the length
of time of the anticipated acceleration29
(30.29s to 44.82s, see figure 9). An analysis of a perfectly elastic collision
was carried out using equations 5 and 6 to determine if utilizing the Net and Reel capture architecture could deliver
the required ∆V. For the departures in 2017 and 2018, the Net and Reel capture system cannot provide the ∆V
needed for the interplanetary transfer in full (in 2018, this mission architecture cannot be used at all due to the
negative relative velocity of Bennu to Earth30
).
26
See appendices A, B, and C
27
"Technical Guide, Kevlar, Aramid Fiber." Dupont. Web. Apr. 2014. Page II-1 and II-2.
<http://www2.dupont.com/Kevlar/en_US/assets/downloads/KEVLAR_Technical_Guide.pdf>.
28
<http://i.space.com/images/i/000/025/507/i02/space-fishing-net.jpg?1359135870>
29
Creer, Brent, Harald Smedal, and Rodney Wingrove. "CENTRIFUGE STUDY OF PILOT TOLERANCE TO
ACCELERATION PILOT PERFORMANCE." 1 Nov. 1960. Web. Apr. 2014. Figure 10.
<http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980223621.pdf>.
30
See figure 5
9. Sanks 9
iif
v
mm
m
v
mm
mm
v 2
21
2
1
21
21
1
2
(5)
Equation 5: Perfectly Elastic Collision Equation - Velocity of Body 1
iif
v
mm
m
v
mm
mm
v 1
21
1
2
21
12
2
2
(6)
Equation 6: Perfectly Elastic Collision Equation - Velocity of Body 2
The necessary cross sectional area of the Kevlar reel was determined using the tension force provided by an
accelerating spacecraft, and the tensile yield strength of Kevlar (a factor of safety under the Class B manned mission
assumption was applied - the Kevlar yield tensile strength used was 1.5 times weaker than the true Kevlar yield
tensile strength), and equation 7.
F
A
A
F
; (7)
Equation 7: Normal Stress Equation
Next, the length of the reel was calculated through a work-energy analysis. The force of the spacecraft on
the inertial reel is assumed to be constant and in the same direction of the velocity of the spacecraft. Therefore the
work done on the spacecraft is equal to the total kinetic energy transfer during the capture, which is also equal to the
constant force multiplied by the distance traveled during the 10g acceleration of the spacecraft. This distance is the
length that the inertial reel must accommodate.
Fxdxf
mv
KE
2
2
(8)
Equation 8: Kinetic Energy and Work Equations (constant force)
Using this length of the reel, the calculated cross sectional area of the reel, and the density of the material in
question (1.44 gram/cm2
for Kevlar31
) a mass estimate for a Net and Reel system could be generated. The Net and
Reel system total mass is estimated as 1.5 times the mass of the reel itself.
Figure 9: Table of Direct Capture Net and Reel Architecture Properties
As can be seen in the table above, the mass of the reel system is very heavy – two orders of magnitude
heavier than the spacecraft mass budget - even in the 4 September 2017 scenario with a reduced mission ∆V (less
than the total needed for the interplanetary transfer).
31
"Technical Guide, Kevlar, Aramid Fiber." Dupont. Web. Apr. 2014. Page II-1 and II-2.
<http://www2.dupont.com/Kevlar/en_US/assets/downloads/KEVLAR_Technical_Guide.pdf>.
Date ∆V needed
Outbound (km/s)
∆V Max Net and
Reel Capture (km/s)
∆t Capture
at 10g (s)
Cross Sectional
Area of Reel (cm2
)
Length of Reel
(km)
Total Net and Reel
System Mass (kg)
4-September-2017 7.49 2.97 30.29 203.25 947 4.16x107
12-September-2023 4.40 5.62 44.82 203.25 1433 6.29x107
10. Fi
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11. Sanks 11
to the spacecraft37
. The slugs would be decelerated in the mass collection system apparatus similar in design to the
Net and Reel concept – however the acceleration involved38
would be so minimal that no inertial reel would be
necessary, and thus the mass penalty would be negligible. A conceptual design of the Asteroid Mass Driver Station
and the Spacecraft Mass Collector system is outlined in figures 11 and 12.
Figure 11: Conceptual design of Asteroid Station and Mass Driver
(Courtesy Bryan Versteeg / Spacehabs.com)39
Figure 12: Conceptual design of Spacecraft Mass Collector (Courtesy NASA)40
The Asteroid Station would need to encapsulate at least half of the asteroid surface area in order to restrict
the loosely packed material of Bennu from shifting during the operation of the station. This can be achieved by the
use of a thin, flexible, reinforced plastic sheeting similar to the spacecraft mass collection system. This sheeting
would blanket half of Bennu and be secured into the station – disallowing the escape of any asteroid mass during
slug manufacturing (compression) or firing. This mass restriction system would contribute a significant mass
penalty41
(1.09x106
kg) bringing the total Asteroid Station system mass42
to 2.02x106
kg. The impact of this penalty
37
Appendix A, B, and C
38
See figure 13
39
http://www.spacehabs.com/357373/asteroid-mining-gallery/
40
Kaufman, Marc "NASA Announces Plan for Capturing Asteroid." National Geographic, Apr. 2013. Web. 1 Apr.
2014. <http://news.nationalgeographic.com/news/2013/04/130410-asteroid-recovery-nasa-space-budget-science/>
41
See appendix A
12. Sanks 12
on the mission will be discussed in section VII, conclusion. In order to find the total mass that a Mass Driver system
would need to fire to achieve the desired spacecraft interplanetary ∆V, a slug firing velocity of 1 km/s was chosen
based on power capabilities of modern nuclear reactors43
and achievable velocities of modern naval-based rail
guns44
(while the intended projectile in this study is non-ferrous, and a carriage would need to be utilized to propel a
slug, the power usage and achievable velocity values are assumed to be roughly equivalent). By the year 2175 these
technologies can be anticipated to grow even more powerful while weighing less and consuming less power. Using
the Kinetic Energy Equation, the chosen slug ∆V of 1 km/s, and the ∆V needed for the interplanetary transfer, the
total mass needed to transfer from Bennu to the spacecraft was calculated (1.25x105
kg to 2.41x105
kg – between
roughly half of and equal to the mass of the first Space Launch System rocket45
). With the total mass of the
momentum exchange determined, the volume of the mass collector on the spacecraft could then be found using the
relation for the definition of density and the assumption that the density of the slugs are made to be slightly less than
that of limestone46
(2.0 g/cm3
). The mass of each slug was found using the achievable muzzle energy of current rail
guns47
(about 32 mega joules) and the chosen firing velocity of the Mass Driver - once again using kinetic energy
relations. The number of total firings was then found using the mass of each slug and the total mass needed for the
energy exchange. The data yielded through this analysis is presented in figure 13 below.
Figure 13: Table of Indirect Capture Mass Driver Architecture Properties
Since the mass transfer between Bennu and the spacecraft must happen in multiple firings, the
instantaneous and tangential ∆V assumption being used throughout this study cannot apply in this mission
architecture case. Therefore, a more complex analysis to determine the astrodynamic specifications of the kinetic
energy transfer would need to be conducted – which is beyond the scope of this study (for example, the relative
velocities, distances, and trajectories of each body will change after each slug firing and capture – thereby changing
the net kinetic energy needed for the transfer and creating a new problem to be solved through iteration). This
method would require an extremely accurate attitude determination and control system (ADACS) on both the
spacecraft and the Asteroid Station with precise pointing stability acting in conjunction with a highly dynamic (and
equally accurate) telemetry, tracking, and command (TT&C) network. These systems must be able to precisely
adjust the attitude of the two bodies for the correct firing and capture orientation as well as predict the new trajectory
of the spacecraft and Asteroid Station after each mass transfer.
42
See appendix A
43
"How much electricity does a typical nuclear power plant generate?" U.S. Energy Information Administration, 3
Dec 2013. Web. Apr 2014. <http://www.eia.gov/tools/faqs/faq.cfm?id=104&t=3>.
44
Ellis, Roger. "Electromagnetic Railgun." Office of Naval Research. Web. Apr. 2014.
<http://www.onr.navy.mil/media-center/fact-sheets/electromagnetic-railgun.aspx>.
45
Gerbis, Nicholas. "How the Space Launch System Will Work." HowStuffWorks. HowStuffWorks.com, 11 Oct
2011. Web. Apr 2014. <http://science.howstuffworks.com/space-launch-system1.htm>.
46
"Rock Types and Specific Gravity." Rock Types and Specific Gravity. Web. Apr 2014.
<http://www.edumine.com/xtoolkit/tables/sgtables.htm>.
47
Ellis, Roger. "Electromagnetic Railgun." Office of Naval Research. Web. Apr. 2014.
<http://www.onr.navy.mil/media-center/fact-sheets/electromagnetic-railgun.aspx>.
48
Assuming a capture ∆t of 1s, see appendices A, B, and C
Date Firing Velocity
(km/s)
Slug Mass
(kg)
Muzzle Energy
(Joules)
Total Mass Transfer
(kg)
Acceleration of SC per
Slug Capture (m/s2
)48
Mass of SC Mass
Collector (kg)
Number of
Firings
4-September-2017 1.0 64 3.2x107
2.41x105
1.18 1480 3767
11-May-2018 1.0 64 3.2x107
1.91x105
1.99 1261 2976
12-September-2023 1.0 64 3.2x107
1.25x105
2.26 952 1947
13. Sanks 13
VI. Safety
Safety is a priority in this mission architecture as the already grave risks of manned spaceflight are
compounded by the risks inherent in a momentum transfer. The risk of inaccurate rendezvous location predictions
due to perturbations within Bennu’s orbit is a concern as there is a possibility of mass collision with the spacecraft in
an area not designed to withstand an impact. This safety concern is addressed by the extremely accurate TT&C
systems outlined in the Mass Driver architecture that would characterize Bennu’s orbit for years before a transfer
attempt was made in addition to the selection of Bennu as the source of kinetic energy. As stated above in section II,
Bennu has a stable and predictable orbit making it a suitable choice for the KETNEO-FIMM mission architecture.
According to the report Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955) Bennu by the OSIRIS-
Rex research team49
, Bennu has a well-determined orbit due primarily to 12 years of radar ranging – the accuracy of
the orbit determined for Bennu will increase dramatically by the planned departure dates in the late 22nd
century.
In this same timeframe – the late 22nd
century – Bennu’s orbit becomes a potential hazard to Earth.
Between 2175 and 2199 Bennu’s orbit is predicted to approach Earth within two Earth radii on at least 80
occasions50
making the date range of these close approaches an excellent time to pursue a KETNEO-FIMM
interplanetary mission. However, it is possible that if the energy of Bennu’s orbit was lowered to a certain degree its
orbit could potentially collide with the Earth. In the analysis found through this study, the kinetic energy transfer to
accelerate one 500,000kg spacecraft would not be enough to alter its trajectory such that an Earth collision (that
wasn’t going to happen otherwise) would occur. However, if multiple missions of this sort were undertaken, it
would be possible to have a degree of control over Bennu’s trajectory – if Bennu’s energy was lowered significantly
enough through the KETNEO-FIMM architecture, its trajectory could be brought under the Earth (relative to the
Sun) during the 2175-2199 close approaches, mitigating Bennu’s collision potential. The mass required to effect this
change would need to be analyzed closer to the dates of departure in order to accurately determine a trajectory offset
plan (as it stands, Bennu is predicted to have a 1 in 2700 chance of an impact with Earth in the late 22nd
century51
-
the lines of variance predicting Bennu’s and Earth’s orbit 170 years from now are not yet precise enough).
The G-limit restrictions of the spacecraft and its occupants during acceleration by the asteroid have been
addressed in this study by limiting the maximum spacecraft acceleration to 10g. This is ensured in the Net and
Inertial Reel architecture through the inertial reel itself – this would be a hydraulically or electromagnetically
damped reel which would control the rate of unreeling to ensure the acceleration of the spacecraft remained within
the calculated parameters during the capture of Bennu. In the Mass Driver architecture, each 64kg slug capture by
the spacecraft contributes an acceleration of roughly52
1m/s to 2 m/s (assuming a capture ∆t of 1s), far below the
safe acceleration value that the astronauts and spacecraft could be designed for.
VII. Conclusion
This report aimed to analyze the rationale, procedures, technical feasibility, risk assessment, and cost-
benefit analysis of utilizing a Near-Earth Object, 101955 Bennu (provisional designation 1999 RQ36 - the target of
the OSIRIS-REx mission), as a source of energy to minimize the propulsion requirements of an interplanetary
spacecraft. The planet Mars was the target body in this study and only the outbound Trans-Mars injection in the
years between 2175 and 2199 was examined. The Mars orbit insertion burn, Trans-Earth injection burn, and Earth
orbit insertion burn were assumed to be achieved with propulsive maneuvers outlined in standard manned
interplanetary mission architectures (such as the NASA Mars Design Reference Architecture 5.0). Two methods of
transferring kinetic energy were considered: direct capture and release of the asteroid by a spacecraft using a Kevlar
net and an inertial reel, and establishing a station on the asteroid to manufacture compressed material from the
carbonaceous regolith in order to fire a mass stream to be captured by the spacecraft.
This examination concludes that a direct capture Net and Reel system aboard the spacecraft is not a viable
capture method due to an insufficient maximum ∆V available through a best-case perfectly elastic collision with
(capture of) the asteroid, as well as a prohibitive weight penalty aboard the spacecraft due to the Net and Reel
49
Chelsey, Steven, and David Farnocchia. "Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955)
Bennu." Cornell University Library. 23 Feb. 2014. Web. Apr. 2014. Page 22. <http://arxiv.org/abs/1402.5573>.
50
"101955 Bennu (1999 RQ36) Impact Risk." 3 Mar. 2014. Web. Apr 2014.
<http://neo.jpl.nasa.gov/risk/a101955.html>.
51
Chelsey, Steven, and David Farnocchia. "Orbit and Bulk Density of the OSIRIS-REx Target Asteroid (101955)
Bennu." Cornell University Library. 23 Feb. 2014. Web. Apr. 2014. Page 2. <http://arxiv.org/abs/1402.5573>.
52
See figure 13 and appendices A, B, and C
14. Sanks 14
system. As well, the Net and Reel system is unsuitable to be applied to an unmanned mission - even if an unmanned
5000kg space system was capable of sustaining 100g, the mass of the corresponding inertial reel system would
measure 415,800kg53
. The mass of an inertial reel system would still outweigh the total spacecraft mass several
times. Unfortunately, the Net and Inertial Reel mission architecture would not be suitable for any interplanetary
mission architecture.
However, this report finds that the method of establishing a station on Bennu with the capability to separate
mass from the asteroid and fire it at a spacecraft is a plausible means of transferring a significant ∆V to a spacecraft.
The fuel savings per mission could measure up to 2.7x106
kg of propellant54
depending on the ∆V required and the
relative velocities of Earth and Bennu at the time of transfer. To accomplish this mission, a station with an estimated
mass55
of at least 2.02x106
kg (due to the polyethylene mass restriction system, nuclear reactor, regolith tunnel
boring machine, mass compactor, and the mass driver) would be rendezvoused with the asteroid at significant ∆V
using a standard propulsion system – enough to match Bennu’s velocity on the date of departure (as stated above, a
Net and Reel capture method could not be used to provide the ∆V to rendezvous the station with the asteroid).
Effectively, the launch of the Asteroid Station mission would be capable of reaching Mars on its own. Therefore, the
KETNEO-FIMM Asteroid Station mission architecture would require three times the amount of mass (and the
according amount of propellant) that a standard non-kinetic energy transferring interplanetary mission architecture
would require. However, the KETNEO-FIMM Asteroid Station and Mass Driver mission architecture could also be
used in subsequent interplanetary missions providing cost-sharing over many decades. Based on the available kinetic
energy of Bennu on the dates of departure used in this study, between 200,000 and 450,000 missions could be
propelled through a KETNEO-FIMM architecture before Bennu’s orbit decayed to the point of being unusable56
.
This opportunity to provide ∆V for future missions could provide low cost access to Mars very frequently over the
entirety of the close approach time frame from 2175 to 2199 with a return on investment that could measure
hundreds of the initial station cost (depending on the number of missions carried out).
VIII. Acknowledgements
I would like to express my deep gratitude to the following individuals for their help in fact-checking,
reviewing, and revising this report – without their help this project would have not been possible. Colonel (ret) Gary
Payton, Lieutenant Colonel Sean Londrigan, and Lieutenant Colonel Thomas Joslyn - professors at the U.S. Air
Force Academy assisted me in the formative ideas of this report and kept me tempered in its technical feasibility.
Mr. Russ Anarde and Mr. Jim Przybysz of Northrop Grumman vetted the foundational concepts involved in the
momentum transfer proposal. Mr. Todd Merrill and Major Marc Fulson of the Space and Missile Systems Center
thoroughly assisted in the grammatical and stylistic format of the report. Dr. Dante Lauretta (OSIRIS-Rex principal
investigator) and Ms. Evelyn Hunten of the University of Arizona discussed with me the proper phasing required to
accomplish the mission as well as the suitability of Bennu as an energy transfer target. Ms. Rachel Weiss, Mr.
Wayne Hallman, and Mr. David Garza of Aerospace Corporation and the Jet Propulsion Laboratory reviewed
trajectory options and provided the JPL HORIZONS tool which was pivotal in the completion of the research. The
following professors, scientists, students, and mentors were likewise invaluable in their contributions to the analysis:
Col (ret.) Jack Anthony, Col James Dutton, Col Robert Kraus, Lt Col David French, Lt Col David Barnhart, Lt Col
David Richie, Lt Col Scott Putnam, Major Douglas Kaupa, Captain Jason Christopher, Capt Brian Crouse, Capt
Joseph Robinson, Capt Pamela Wheeler, Capt Blythe Andrews, Dr. James Solti, Dr. Robert Brown, Michael
Schmidhuber (AIAA), Supreet Vijay, C1C Miguel Barrios, C1C Julian Rojas, C1C Ryan Good, and C2C David
Emanuel. Finally, I wish to thank my Mother, Deatrice Angela Sanks; my Grandmother, Rosemary Sanks; my
Grandfather, Royce Sanks; my Uncle, Royce Sanks Jr, and my cousin, Starr Sanks or their support and
encouragement throughout my studies.
53
Appendix F
54
See figure 7
55
Appendix A and "Tunnel Boring Machine Fact Sheet." Web. Page 2.
<http://media.metro.net/projects_studies/eastside/images/ee_factsheet_03_tunnelboring.pdf>.
56
Appendices A, B, and C
15. Sanks 15
Appendices:
A – Energy Transfer Calculations for 4 September 2017 Date of Departure and Asteroid Station Mass Restriction
System Calculations
B – Energy Transfer Calculations for 11 May 2018 Date of Departure
C – Energy Transfer Calculations for 12 September 2023 Date of Departure
D – Rendezvous Time of Flight and Fuel Calculations for 4 September 2017 and 9 September 2188 Dates of
Departure
E – Net and Inertial Reel Mass Calculations for minimized ∆V options on 4 September 2017 Date of Departure
F – Energy Transfer Calculations for 4 September 2017 Date of Departure for Unmanned System