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.
Predictions of the_atmospheric_composition_of_gj_1132_bSérgio Sacani
GJ 1132 b is a nearby Earth-sized exoplanet transiting an M dwarf, and is amongst the most highly
characterizable small exoplanets currently known. In this paper we study the interaction of a magma
ocean with a water-rich atmosphere on GJ 1132b and determine that it must have begun with more
than 5 wt% initial water in order to still retain a water-based atmosphere. We also determine the
amount of O2
that can build up in the atmosphere as a result of hydrogen dissociation and loss.
We find that the magma ocean absorbs at most ∼ 10% of the O2 produced, whereas more than
90% is lost to space through hydrodynamic drag. The most common outcome for GJ 1132 b from our
simulations is a tenuous atmosphere dominated by O2
, although for very large initial water abundances
atmospheres with several thousands of bars of O2
are possible. A substantial steam envelope would
indicate either the existence of an earlier H2
envelope or low XUV flux over the system’s lifetime. A
steam atmosphere would also imply the continued existence of a magma ocean on GJ 1132 b. Further
modeling is needed to study the evolution of CO2
or N2
-rich atmospheres on GJ 1132 b.
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.
Radial velocity monitoring has found the signature of a Msin i = 1:3 M planet located within the Habitable Zone of Proxima
Centauri, the Sun’s closest neighbor (Anglada-Escudé et al. 2016). Despite a hotter past and an active host star the planet Proxima b
could have retained enough volatiles to sustain surface habitability (Ribas et al. 2016). Here we use a 3D Global Climate Model (GCM)
to simulate Proxima b’s atmosphere and water cycle for its two likely rotation modes (the 1:1 and 3:2 spin-orbit resonances) while
varying the unconstrained surface water inventory and atmospheric greenhouse eect (represented here with a CO2-N2 atmosphere.)
We find that a broad range of atmospheric compositions can allow surface liquid water. On a tidally-locked planet with a surface water
inventory larger than 0.6 Earth ocean, liquid water is always present (assuming 1 bar of N2), at least in the substellar region. Liquid
water covers the whole planet for CO2 partial pressures & 1 bar. For smaller water inventories, water can be trapped on the night side,
forming either glaciers or lakes, depending on the amount of greenhouse gases. With a non-synchronous rotation, a minimum CO2
pressure of 10 mbar (assuming 1 bar of N2) is required to avoid falling into a completely frozen snowball state if water is abundant.
If the planet is dryer, 0.5 bar of CO2 would suce to prevent the trapping of any arbitrary small water inventory into polar ice
caps. More generally, any low-obliquity planet within the classical habitable zone of its star should be in one of the climate regimes
discussed here.
We use our GCM to produce reflection/emission spectra and phase curves for the dierent rotations and surface volatile inventories.
We find that atmospheric characterization will be possible by direct imaging with forthcoming large telescopes thanks to an angular
separation of 7=D at 1 m (with the E-ELT) and a contrast of 10 7. The magnitude of the planet will allow for high-resolution
spectroscopy and the search for molecular signatures, including H2O, O2, and CO2.
The observation of thermal phase curves, although challenging, can be attempted with JWST, thanks to a contrast of 210 5 at 10 m.
Proxima b will also be an exceptional target for future IR interferometers. Within a decade it will be possible to image Proxima b and
possibly determine whether this exoplanet’s surface is habitable.
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 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.
Predictions of the_atmospheric_composition_of_gj_1132_bSérgio Sacani
GJ 1132 b is a nearby Earth-sized exoplanet transiting an M dwarf, and is amongst the most highly
characterizable small exoplanets currently known. In this paper we study the interaction of a magma
ocean with a water-rich atmosphere on GJ 1132b and determine that it must have begun with more
than 5 wt% initial water in order to still retain a water-based atmosphere. We also determine the
amount of O2
that can build up in the atmosphere as a result of hydrogen dissociation and loss.
We find that the magma ocean absorbs at most ∼ 10% of the O2 produced, whereas more than
90% is lost to space through hydrodynamic drag. The most common outcome for GJ 1132 b from our
simulations is a tenuous atmosphere dominated by O2
, although for very large initial water abundances
atmospheres with several thousands of bars of O2
are possible. A substantial steam envelope would
indicate either the existence of an earlier H2
envelope or low XUV flux over the system’s lifetime. A
steam atmosphere would also imply the continued existence of a magma ocean on GJ 1132 b. Further
modeling is needed to study the evolution of CO2
or N2
-rich atmospheres on GJ 1132 b.
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.
Radial velocity monitoring has found the signature of a Msin i = 1:3 M planet located within the Habitable Zone of Proxima
Centauri, the Sun’s closest neighbor (Anglada-Escudé et al. 2016). Despite a hotter past and an active host star the planet Proxima b
could have retained enough volatiles to sustain surface habitability (Ribas et al. 2016). Here we use a 3D Global Climate Model (GCM)
to simulate Proxima b’s atmosphere and water cycle for its two likely rotation modes (the 1:1 and 3:2 spin-orbit resonances) while
varying the unconstrained surface water inventory and atmospheric greenhouse eect (represented here with a CO2-N2 atmosphere.)
We find that a broad range of atmospheric compositions can allow surface liquid water. On a tidally-locked planet with a surface water
inventory larger than 0.6 Earth ocean, liquid water is always present (assuming 1 bar of N2), at least in the substellar region. Liquid
water covers the whole planet for CO2 partial pressures & 1 bar. For smaller water inventories, water can be trapped on the night side,
forming either glaciers or lakes, depending on the amount of greenhouse gases. With a non-synchronous rotation, a minimum CO2
pressure of 10 mbar (assuming 1 bar of N2) is required to avoid falling into a completely frozen snowball state if water is abundant.
If the planet is dryer, 0.5 bar of CO2 would suce to prevent the trapping of any arbitrary small water inventory into polar ice
caps. More generally, any low-obliquity planet within the classical habitable zone of its star should be in one of the climate regimes
discussed here.
We use our GCM to produce reflection/emission spectra and phase curves for the dierent rotations and surface volatile inventories.
We find that atmospheric characterization will be possible by direct imaging with forthcoming large telescopes thanks to an angular
separation of 7=D at 1 m (with the E-ELT) and a contrast of 10 7. The magnitude of the planet will allow for high-resolution
spectroscopy and the search for molecular signatures, including H2O, O2, and CO2.
The observation of thermal phase curves, although challenging, can be attempted with JWST, thanks to a contrast of 210 5 at 10 m.
Proxima b will also be an exceptional target for future IR interferometers. Within a decade it will be possible to image Proxima b and
possibly determine whether this exoplanet’s surface is habitable.
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 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.
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.
SPECTROSCOPIC CONFIRMATION OF THE EXISTENCE OF LARGE, DIFFUSE GALAXIES IN THE...Sérgio Sacani
We recently identified a population of low surface brightness objects in the field of the z = 0.023 Coma cluster,
using the Dragonfly Telephoto Array. Here we present Keck spectroscopy of one of the largest of these “ultradiffuse
galaxies” (UDGs), confirming that it is a member of the cluster. The galaxy has prominent absorption
features, including the Ca II H+K lines and the G-band, and no detected emission lines. Its radial velocity of
cz=6280±120 km s−1 is within the 1σ velocity dispersion of the Coma cluster. The galaxy has an effective
radius of 4.3 ± 0.3 kpc and a Sérsic index of 0.89 ± 0.06, as measured from Keck imaging. We find no indications
of tidal tails or other distortions, at least out to a radius of ∼2re. We show that UDGs are located in a previously
sparsely populated region of the size—magnitude plane of quiescent stellar systems, as they are ∼6 mag fainter
than normal early-type galaxies of the same size. It appears that the luminosity distribution of large quiescent
galaxies is not continuous, although this could largely be due to selection effects. Dynamical measurements are
needed to determine whether the dark matter halos of UDGs are similar to those of galaxies with the same
luminosity or to those of galaxies with the same size.
Solar System Education Presentation Template
If you want to buy this presentation template, please visit http://madlis.com
Good design gets out of the way of the content you are sharing. It helps your audience focus on the content itself instead of the design.
But, it's no secret that most people dislike giving presentations. The dread of public speaking consistently ranks among the greatest fears in public surveys.
This presentation slides can help you reduce the anxiety involved with giving a presentation. Well-designed slides not only build your own confidence, they make your key points clearer to the audience.
Solar System Education Presentation Template
If you want to buy this presentation template, please visit http://madlis.com
Good design gets out of the way of the content you are sharing. It helps your audience focus on the content itself instead of the design.
But, it's no secret that most people dislike giving presentations. The dread of public speaking consistently ranks among the greatest fears in public surveys.
This presentation slides can help you reduce the anxiety involved with giving a presentation. Well-designed slides not only build your own confidence, they make your key points clearer to the audience.
It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered
most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the
lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in
the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with
numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide
impacts, resulting in craters ~30km in diameter and occurring perhaps a few million years apart. The
tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes,
which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered
highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces.
The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement
took place following a transition into a colder global climatic regime that occurred after the older
tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and
resurfacing coastal terrains.
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.
SPECTROSCOPIC CONFIRMATION OF THE EXISTENCE OF LARGE, DIFFUSE GALAXIES IN THE...Sérgio Sacani
We recently identified a population of low surface brightness objects in the field of the z = 0.023 Coma cluster,
using the Dragonfly Telephoto Array. Here we present Keck spectroscopy of one of the largest of these “ultradiffuse
galaxies” (UDGs), confirming that it is a member of the cluster. The galaxy has prominent absorption
features, including the Ca II H+K lines and the G-band, and no detected emission lines. Its radial velocity of
cz=6280±120 km s−1 is within the 1σ velocity dispersion of the Coma cluster. The galaxy has an effective
radius of 4.3 ± 0.3 kpc and a Sérsic index of 0.89 ± 0.06, as measured from Keck imaging. We find no indications
of tidal tails or other distortions, at least out to a radius of ∼2re. We show that UDGs are located in a previously
sparsely populated region of the size—magnitude plane of quiescent stellar systems, as they are ∼6 mag fainter
than normal early-type galaxies of the same size. It appears that the luminosity distribution of large quiescent
galaxies is not continuous, although this could largely be due to selection effects. Dynamical measurements are
needed to determine whether the dark matter halos of UDGs are similar to those of galaxies with the same
luminosity or to those of galaxies with the same size.
Solar System Education Presentation Template
If you want to buy this presentation template, please visit http://madlis.com
Good design gets out of the way of the content you are sharing. It helps your audience focus on the content itself instead of the design.
But, it's no secret that most people dislike giving presentations. The dread of public speaking consistently ranks among the greatest fears in public surveys.
This presentation slides can help you reduce the anxiety involved with giving a presentation. Well-designed slides not only build your own confidence, they make your key points clearer to the audience.
Solar System Education Presentation Template
If you want to buy this presentation template, please visit http://madlis.com
Good design gets out of the way of the content you are sharing. It helps your audience focus on the content itself instead of the design.
But, it's no secret that most people dislike giving presentations. The dread of public speaking consistently ranks among the greatest fears in public surveys.
This presentation slides can help you reduce the anxiety involved with giving a presentation. Well-designed slides not only build your own confidence, they make your key points clearer to the audience.
It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered
most of the Martian northern lowlands. However, a persistent problem with this hypothesis is the
lack of definitive paleoshoreline features. Here, based on geomorphic and thermal image mapping in
the circum-Chryse and northwestern Arabia Terra regions of the northern plains, in combination with
numerical analyses, we show evidence for two enormous tsunami events possibly triggered by bolide
impacts, resulting in craters ~30km in diameter and occurring perhaps a few million years apart. The
tsunamis produced widespread littoral landforms, including run-up water-ice-rich and bouldery lobes,
which extended tens to hundreds of kilometers over gently sloping plains and boundary cratered
highlands, as well as backwash channels where wave retreat occurred on highland-boundary surfaces.
The ice-rich lobes formed in association with the younger tsunami, showing that their emplacement
took place following a transition into a colder global climatic regime that occurred after the older
tsunami event. We conclude that, on early Mars, tsunamis played a major role in generating and
resurfacing coastal terrains.
Solar thermal power generation systems use mirrors to collect sunlight and produce steam by solar heat to drive turbines for generating power. This system generates power by rotating turbines like thermal and nuclear power plants, and therefore, is suitable for large-scale power generation.
One of the biggest question at present in Astronomy is whether colonization possible in Mars or not! We are deeply attracted to Mars!
Why?
That's because we are all martians. At least some theories are saying this. It has also been told that river once ran though this planet and few days ago, salty water was discovered in Mars!
Really an exciting news! :)
But how can you colonize there? To find out some important facts related to this question, go through my presentation. Hope you will like it! Enjoy!
John A Chapman mining the moon 20060723John Chapman
NASA has announced a schedule and plan for the creation of a lunar base within 16 years as a precursor to establishing a base on Mars. Space agencies from Europe, Japan, India and China have expressed support for the NASA plan and/or their separate plans for a lunar base. This plan to explore and inhabit the Moon and then Mars is driven by the triple goals of scientific research, lunar/asteroid resource extraction and saving the earthbound human species from eventual extinction by asteroid/comet impact or super-volcano eruption. This paper proposes the application, on the Moon, of equipment and mining methods already well proven on Earth in very cold and dusty environments. The authors present an innovative combination of existing technologies for exploration and mining, including: mobile equipment, spare parts, sample analysis, remote controls, semi-autonomous controls, remote equipment "health" monitoring, real-time precision location and guidance, and the use of broadband WiMAX for communication to and from the proposed lunar base and Earth's Internet.
Pesquisa mostra que as exoluas podem ser os corpos mais comuns no universo onde se pode encontrar vida. As exoluar aumentam o número de corpos presentes na chamada zona habitável dos exoplanetas.
Hot Earth or Young Venus? A nearby transiting rocky planet mysterySérgio Sacani
Venus and Earth provide astonishingly different views of the evolution of a rocky planet, raising the question of why these two rock y worlds evolv ed so differently. The recently disco v ered transiting Super-Earth LP 890-9c (TOI-4306c, SPECULOOS-2c) is a key to the question. It circles a nearby M6V star in 8.46 d. LP890-9c receives similar flux as modern Earth, which puts it very close to the inner edge of the Habitable Zone (HZ), where models differ strongly in their prediction of how long rocky planets can hold onto their water. We model the atmosphere of a hot LP890-9c at the inner edge of the HZ, where the planet could sustain several very different environments. The resulting transmission spectra differ considerably between a hot, wet exo-Earth, a steamy planet caught in a runaway greenhouse, and an exo-Venus. Distinguishing these scenarios from the planet’s spectra will provide critical new insights into the evolution of hot terrestrial planets into exo-Venus. Our model and spectra are available online as a tool to plan observations. They show that observing LP890-9c can provide key insights into the evolution of a rocky planet at the inner edge of the HZ as well as the long-term future of Earth.
Astronomy - State of the Art is a course covering the hottest topics in astronomy. In this section, the Solar System is explored, including place where biology might exist.
Microbial habitability of Europa sustained by radioactive sources Sérgio Sacani
There is an increasing interest in the icy moons of the Solar System due to their potential habitability and as targets for future exploratory missions, which include astrobiological goals. Several studies have reported new results describing the details of these moons’ geological settings; however, there is still a lack of information regarding the deep subsurface environment of the moons. The purpose of this article is to evaluate the microbial habitability of Europa constrained by terrestrial analogue environments and sustained by radioactive energy provided by natural unstable isotopes. The geological scenarios are based on known deep environments on Earth, and the bacterial ecosystem is based on a sulfatereducing bacterial ecosystem found 2.8 km below the surface in a basin in South Africa. The results show the possibility of maintaining the modeled ecosystem based on the proposed scenarios and provides directions for future models and exploration missions for a more complete evaluation of the habitability of Europa and of icy moons in general.
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
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Solar system exploration with space resources - Aiaa asm 2014_bp_9 final paper
1. 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.
Nomenclature
3He Helium 3
4He Helium (or Helium 4)
AMOSS Atmospheric mining in the outer solar system
CC Closed cycle
delta-V Change in velocity (km/s)
________________________________________________________________________
1
Leader of Advanced Fuels, MS 5-10, AIAA Associate Fellow
2. GCNR Gas core nuclear rocket
GCR Galactic Cosmic Rays
GTOW Gross Takeoff Weight
H2 Hydrogen
He Helium 4
ISRU In Situ Resource Utilization
Isp Specific impulse (s)
K Kelvin
kT Kilotons of explosive power
kWe Kilowatts of electric power
LEO Low Earth Orbit
M dry, stage Stage dry mass (kg)
M, dry coefficient Stage dry mass coefficient, B
M p Propellant mass (kg)
MT Metric tons
MWe Megawatt electric (power level)
NEP Nuclear Electric Propulsion
NPP Nuclear Pulse Propulsion
NTP Nuclear Thermal Propulsion
NTR Nuclear Thermal Rocket
OC Open cycle
O2 Oxygen
PPB Parts per billion
UAV Uninhabited Aerial Vehicle
________________________________________________________________________
I. Introduction
Human and robotic missions have been planned for targets throughout the solar system. Both
types of missions can benefit greatly from the resources available from the planets and /or their moons.
These benefits include water on many of the outer planet moons and large asteroids. With this water,
oxygen / hydrogen rocket propulsion systems can be fueled, breathing oxygen can be extracted, and other
life support functions (cooling fluids, etc.) can be facilitated. In addition, the atmospheres of many
planets have ready reserves of gases for propellant production. Carbon dioxide on Mars can be separated
into oxygen and carbon monoxide or methane. The outer planets offer enormous amounts of energetic
gases such as hydrogen, helium 3, methane, and ammonia. By using these in-situ resources, robotic
precursor missions can double or triple their payloads to the surface and return double or triple the
samples from the solar system targets. Without in-situ resource utilization (ISRU), solar system
exploration will be exceedingly limited. For future large scale human missions, the possibilities of ISRU
for of human exploration and finally settlement offer the best opportunities for sustainability and success.
II. Human Exploration Options
In the 1950’s, 1960’s, 1970’s, and 1980’s, ambitious robotic and human mission were planned,
spanning from Mercury to the outermost reaches of the solar system (Refs. 1-10). While investments in
robotic missions have continued, human exploration of the solar system has awaited new invigorating
steps. While lunar and Mars missions are in the early step-wise planning stages, many cost barriers have
3. prevented their implementation. Future human missions to other destinations such as Mercury and
Saturn will also require long-term investments. Currently, Mercury and Saturn have robotic missions
returning invaluable data on those planets and their environs (Refs. 11 and 12). These data have provided
insights that will ensure the success of future missions. With its proximity to the Sun, Mercury has
extremely high temperatures and requires special high heat flux considerations for long-term human visits
or bases. In contrast, temperatures at Saturn and its moons require designs for cryogenic environments.
The possibilities for in-situ resource utilization (ISRU) may allow more effective robotic missions and
human visits to these planetary targets.
A. Mercury
Mercury is the closest planet to the Sun; ranging from a perihelion of 46 million km to an
aphelion of nearly 70 million km. The high temperature, high heat flux environment at Mercury and the
tenuous surface emanations of several major chemical species (sodium, etc.) surrounding it will likely
pose challenges to long term human visits. Permanently shadowed craters offer a valuable niche for
longer term human visits and planetary bases. Such craters offer cryogenic temperatures while the sun
facing surface is at a temperature of 590 to 725 degrees K. The north polar regions of Mercury have
been identified as a likely location for such permanently shadowed craters (Ref. 11, 12, and 13). Water
ice is also likely to be in these craters, further aiding and assisting any human explorations. Short
exploratory missions can be accomplished with hopping ascent-descent vehicles from the base at the
shadowed crater.
Figure 1 shows the locations of the shadowed craters (Ref. 12). Figure 2 depicts the
temperatures that would exist in and near the craters (Ref. 13). The crater could accommodate a small
base or at least an initial landing site. The lander’s temperature could stay within the nominal operating
temperatures of traditional spacecraft. The temperature distribution in the crater would allow
construction of the base at the warmer side of the crater and then the frozen volatiles would be extracted
with cryogenic mining machines.
B. Saturn and its moons
Saturn is one of the outer planets. Its orbit has a perihelion 1,352.6 million km and an aphelion
1,514.50 million km. An extensive series of flybys of the Saturnian moons have been conducted by the
Cassini spacecraft. During these flybys, cameras and instruments capture and data on the moons’
composition, atmosphere and cloud cover (on the moon Titan), volcanos, plumes, rotation, and gravity.
Titan is the largest moon of Saturn. Its intriguing nature includes a nitrogen and methane
atmosphere and a subsurface ocean (Ref. 4). Recent flybys of the Cassini spacecraft have shown direct
visual evidence of the northern lakes which are likely composed of methane. Based on measurements and
theories of the evolution of Titan, a large ocean of water and ammonia may exist below the icy surface.
Large lakes in the north polar regions have been seen on Titan’s surface, and they are likely composed of
liquid methane. Figure 3 shows the possible nature of Titan’s interior, surface, and atmosphere. While
methane can be used as an effective rocket propellant, its nitrogen could be used in cold gas propulsion or
electric propulsion (resistojet, arcjet or magneto-plasma-dynamic (MPD) thrusters).
4. C. Enceladus
The moon Enceladus is producing a large plume of water that is escaping into space.
Speculation on the production of that water varies. The south polar region has several hot spots (a
cryogenic, volcanic area), known as the tiger stripes, matching the location of the plume of water exiting
Enceladus (Ref. 15).
In-situ resources from the Titan water ocean can be used for rocket propellants. Access to the
ocean may only require drilling a short (or km long) distance into the icy crust. At Enceladus, the water
plume may be captured, or the ocean of reservoir feeding the plume will be tapped. Capturing this water
may prove difficult, however, and additional research is needed to find the best manner of fluid capturing.
D. Asteroids
An excellent additional target may be Ceres, the largest asteroid in our solar system. Ceres may
provide substantial water from its water ice and the potential ocean below the ice (Ref. 16). As with
Enceladus, drilling through many km of ice may be required and finding sufficiently deep crevasses will
no doubt be useful in easing the drilling requirements.
III. Mission studies
A. Mercury Missions
A human round trip mission to Mercury was assessed. The mission delta-V values for the round
trip Mercury missions were derived from Refs. 17 to 20. The highest delta-V case was selected from this
data: an Earth departure delta-V of 5.2 km/s, a Mercury arrival delta-V 0f 10.9 km/s and a Mercury
departure delta-V of 8.7 km/s (Ref. 17). Each delta-V was delivered by a separate single stage; thus a 3
stage vehicle is used. At Earth, a capsule enters the atmosphere to return the crew directly to Earth. The
capsule’s mass is 4,350 kg (Ref. 17). The round trip time is 585 days with a 40 day stay time at Mercury
(Ref. 15). In this case, the vehicle does not land on Mercury. The LEO masses of both chemical
propulsion and nuclear thermal propulsion vehicles were estimated. Figure 4 compares the LEO masses
for 2 types of chemical propulsion systems and 2 nuclear thermal propulsion (NTP) systems. The
interplanetary chemical propulsion systems used tankage dry mass coefficients of 3% and 5% of the total
propellant mass in the tankage. In many cases, these dry masses may be deemed to be optimistically low;
however, they allow some relative comparison of the chemical propulsion and the nuclear mission cases.
The NTP vehicles dry mass was 15% of the propellant mass. In current NTP designs, an Isp of
900 seconds is nominally used (Refs. 23 and 24). Somewhat lower Isp values were used for these
missions: 800 and 850 seconds, respectively. These lower Isp values were assumed given the high heat
flux environment of Mercury and the degraded Isp values would reflect the added propellant used for
propellant cooling and/or refrigeration. The chemical propulsion systems required between 17,150 MT
and 27,000 MT to accomplish the mission. The NTP vehicles required approximately an order of
magnitude less mass in LEO: 1,700 MT to 2,300 MT.
5. Table I. Space vehicle dry mass coefficient and rocket engine specific impulse (Isp)
Based on Ref. 21, the stage and lander mass was estimated with the following mass scaling
equation:
M dry,stage (kg) = M, dry coefficient * M p (kg)
A Mercury landing vehicle mass was also estimated. The one-way delta-V for the lander was 3.5
km/s (Ref. 22). The ascent delta-V was also 3.5 km/s. These delta-V values accommodate
approximately 19% for gravity losses for each maneuver; this gravity loss delta-V is added to the orbital
velocity for a 100 km orbit which is 2.945 km/s. The lander Isp was 480 seconds. The higher Isp was
chosen for the lander as the engine used a higher engine expansion ratio that the interplanetary transfer
vehicle (Ref. 21). The smaller engine size would allow a higher expansion ratio, given the typical volume
constraints for space vehicles. The dry mass coefficient was 20% of the total propellant load. While the
Mercury missions will likely require more aggressive thermal control (propellant shielding, cooling, etc.),
that thermal control system mass is accommodated in the payload mass of the vehicle. The payload
delivered to the surface was 10 MT. Figure 5 compares the mass in LEO of a one-way lander and a round
trip lander. The masses were 140 MT for the round trip lander and 27 MT for the one way lander. Thus,
using ISRU on the surface of Mercury to replenish the lander’s propellant would allow a savings of 113
MT on this mission. Additional analyses are needed to investigate the mass reductions for the
interplanetary transfer vehicle to carry the lander to Mercury. Another option would be to carry 5 landers
to Mercury rather than carry simply one lander; many more permanently shadowed craters could then be
visited on one mission. The interplanetary vehicle carrying the 5 landers could be sent on a lower energy
trajectory than the human flights, thus saving additional mass launched into LEO in the overall Mercury
architecture.
Additional summary data on mission design is summarized in Ref. 20. Figure 6 provides map of
the one-way delta-V and trip time for a wide range of planetary targets (Ref. 20). Fast missions to Jupiter
and Mercury are possible with delta-V values of 80 to 100 km/s. Nuclear propulsion systems may
6. someday allow such ambitious missions and if augmented by ISRU, such mission will be within our
technological reach
B. Atmospheric Mining in the Outer Solar System (AMOSS)
Atmospheric mining in the outer solar system can be a powerful ISRU tool in extracting fuels
from the outer planets and allow fast human and robotic exploration of the solar system. Preliminary
designs of aerospacecraft with gas core rocket nuclear engines for mining the outer planets were
developed (Refs. 23 and 24). Helium 3 (3He), a nuclear fusion fuel, would be extracted from the
atmosphere and stored for final delivery to orbital assets. Analyses showed that gas core nuclear rocket
(GCNR) engines can reduce the mass of such aerospacecraft mining vehicles very significantly: from 72
to 80 percent reduction over nuclear thermal propulsion (NTP) solid core powered aerospacecraft mining
vehicles. While this mass reduction is important in reducing the mass of the overall mining system, the
complexity of a fissioning plasma gas core rocket is much higher than the more traditional solid core NTP
engines. Additional analyses were conducted to calculate the capture rates of 3He hydrogen and helium 4
during the mining process. Very large masses of hydrogen and helium 4 are produced every day during
the often lengthy process (multi-day) of helium 3 capture and gas separation. Figure 7 shows the mass of
hydrogen needed for the gas core rocket and the potentially excess hydrogen captured every day (Ref.
23). Typically, these very large (excess) additional fuel masses can dwarf the requirements needed for
hydrogen captured for ascent to orbit. Thus, the potential for fueling small and large fleets of additional
exploration and exploitation vehicles exists. Aerial vehicle designs can take on many configurations.
Additional aerospacecraft or other uninhabited aerial vehicles (UAVs), or balloons, rockets, etc., could fly
through the outer planet atmospheres, for global weather observations, localized storm or other
disturbance investigations, wind speed measurements, polar observations, etc. Deep-diving aircraft (built
with the strength to withstand many atmospheres of pressure) powered by the excess hydrogen or helium
4 may be designed to probe the higher density regions of the gas giants.
Based on these past analyses, there will likely be several possible future avenues for effective use
of the gases of the outer planets for exciting and scientifically important atmospheric exploration
missions. The analyses focused on Uranus and Neptune, as these planets offer vast reservoirs of fuels that
are more readily accessible than those from Jupiter and Saturn (as these latter planets require lower
energies needed to attain orbit and present less danger from powerful atmospheric lightning) and, with the
advent of nuclear fusion propulsion, may offer us the best option for fast interplanetary travel and the first
practical interstellar flight.
C. Nuclear Underground Explosions
Based on recent measurements and simulations of the lunar radiation environment, it appears that
long term occupancy of the lunar surface may be detrimental to human beings. In addition to the long
term exposure to natural radiation sources (galactic cosmic rays, solar flares, etc.), there is additional
scattered radiation on the lunar surface (Ref. 25). Based on these most recent measurements and the past
work in lunar bases, it seems reasonable to assess living and working in underground facilities on the
Moon. Using small of large nuclear devices on the Moon may provide an option for creating a series of
large habitable underground spaces. Project Plowshare in the 1960s’ (Refs. 26 to 33) addressed some of
the issues with using nuclear devices to complete large scale redirection of rivers, building canals, and
many other massive civil engineering projects.
Past Earth based nuclear weapons testing often was done underground due to the Nuclear Test
Ban Treaty of 1963. The tests often left sizable craters on the surface. When a nuclear device is
sufficiently deeply buried, the explosive force can be completely contained underground (Ref. 26, Figure
7. 8). The blast vaporizes some of the surrounding rocky material which then expands and creates an
underground cavity, as shown in Figure 8. In most cases the weight of overhead rock soon crumbles the
roof of the void chamber and a vertical column (or chimney) is created by the successively falling loose
rocky layers. The material in the chimney undergoes compaction after the roof collapse but the initial
amount of void space created by the blast just after detonation is distributed in this broken rocky debris.
Small robotic mining systems could be used to manage the debris. Based on historical data, such a space
can also be spherical if the blast size is sufficiently small. After the radiation has fallen to acceptable
levels, people could potentially create comfortable living spaces.
In Ref. 7, this technique was proposed for not only living spaces, but for large scale ISRU.
Nuclear explosions would be used to melt and vaporize lunar regolith. Figure 9 illustrates four different
processes using nuclear detonations (Ref. 7). There are 2 chambers: one for the nuclear explosion, and
one for the reaction product capturing. This processing would essentially chemically reacting oxygen,
hydrogen, or other species. The processes range from creating oxygen and metal oxides to producing
water and metal carbides. From Ref. 7:
“A nuclear charge of one kiloton, detonated underground, fractures approximately
80,000 cubic meters or 330,000 tons of lunar rock, containing 130,000 MT
of oxygen. At least 1%, or 33,000 MT, of the rock is fully evaporated. The silicon
and metals condense quickly. But, since they are in an essentially pure oxygen
atmosphere, they also reoxidize vigorously. Estimating, very conservatively, that
only 20 to 30% of the liberated oxygen can be extracted and stored, this means that
through the underground detonation of a one-kiloton nuclear charge, of a systems mass
of a few hundred pounds, 6,000 to 10,000 MT (Earth weight) of oxygen can be
provided.”
Certainly, extensive processing will require maintenance of the nearly spherical cavities and
effective pumping schemes to introduce the gases into the underground chambers for the planned
reactions. However the rates of production may be high enough to warrant the use of nuclear detonations.
D. Lunar Slide Lander
The lunar slide lander uses friction between a descending tubular spacecraft and a
prepared runway of lunar regolith. The operations of the slide lander are in 8 phases (Ref. 8):
1) Elliptical orbit descent.
2) Perilune maneuver (pre-landing retro-thrust).
3) Approach to touchdown (cut in supporting (vertical) thrust at the end of Phase 3).
4) Touchdown with harenodynamic tail brake. A positive angle of attack is maintained by
the supporting thrust.
5) Initiation of main drag phase. Touchdown of harenodynamic side brakes.
6) Main drag slide phase with supporting thrust.
7) Main drag slide phase without supporting thrust.
8) Final braking by means of additional braking devices, or brief retro-thrust, for a
controlled stop.
8. The slide lander was an attempt to reduce the total propellant load required for lunar
landings. While the approach velocity of the lander is over 1,500 m/s, the long slide process may
reduce the total delta-V required to 200 to 450 m/s. This is in comparison to the 2,000 m/s
typically used for lunar landing (Ref. 34). Precise landing control is required and the length of
the landing strip area is approximately 80 km. Additional studies have identified that the dust
from the initial phase of the slide landing may attain an attitude of 1,300 of km (Ref. 8). Thus,
while the landing methods saves much precious propellant, the implications of the flying dust on
other lunar surface and orbital operations must be addressed.
E. Nuclear Pulse Propulsion
Using nuclear devices for propulsion is another product of the creativity of the 1960’s
engineering and physics community (Refs. 35 to 38). The nuclear pulse propulsion (NPP)
systems were seriously considered for fast transportation throughout the solar system. Small
nuclear devices would be detonated behind a large piloted spacecraft, and the detonation would
power the vehicle. Many 1000’s of such pulses were required for outer planet missions. The
predicted specific impulse for these vehicles is between 1,800 and 6,000 seconds (Ref. 34). The
NPP vehicles were considered a logical precursor to the pulsed fusion propulsion systems, noted
in many of the AMOSS studies (where 3He and deuterium nuclear fuels are mined from the gas
giant planets).
Nuclear pulse propulsion freighters were conceived to return 3,000 MT payloads of raw
or processed materials from many targets in the solar system. Figure 10 shows the mission
energies, the transportation and propellant costs for such a large nuclear freighter (Ref. 7).
These analyses noted NPP Isp values from 6,000 to 10,000 seconds (Ref. 7). To support such
operations perhaps nuclear bomblet factories would be constructed all through the solar system. While
constructing large nuclear facilities on every location of human exploration may be optimistic, certainly
several locations for extended exploration should be chosen for such nuclear sites. Smaller nuclear
facilities will be a first step, using smaller reactors.
III. Observations
While human missions to Mercury and Saturn and all of the other planets will be challenging and
require long-term investments, the results from these missions and their development will no doubt have
great influences on our economy and improve our technological prowess.
Krafft Ehricke envisioned a poly-global civilization, with branches of humanity in many far flung
places in our solar system (Ref. 1). His vision was uniquely expressed in Ref. 36. Here is a short excerpt
from that work:
“Our helionauts, as these men who fly our large interplanetary vehicles call themselves
in this era of continuing specialization, have covered the solar system from the sun
scorched shores of Mercury to the icy cliffs of the Saturn moon, Titan. They have
crossed, and some have died doing so, the vast asteroid belt between Mars and Jupiter
9. and have passed through the heads of comets. Owing to the pioneer spirit, the courage
and the knowledge of our helionauts and of those engineers, scientists, and technicians
behind them, astrophysicists today work in a solar physics station on Mercury; biologists
experiment on Mars, backed by a well-supplied research and supply station on the Mars
moon, Phobos; planetologists have landed on Venus; and teams of scientists right now
study what have turned out to be the two most fascinating of our solar system, Jupiter
and Saturn, from research stations on Callisto and Titan.”
These helionaut flights would be the precursors of human outposts and then colonies all through
the solar system. Multiple systems employing planetary ISRU could enable all of these ideas and
concepts. Krafft Ehricke envisioned an entire extensive lunar economy, producing power, finished and
raw materials, and NPP launching bases for extensive exploration of the solar system. The poly-global
civilization was considered a natural expansion of the human experience, pioneering new frontiers and
using technology in the best interests of all humanity.
IV. Concluding Remarks
A wide range of space exploration technologies have been assessed in many studies from the
1960’s to today. In an optimistic future, lunar exploration will lead to base construction and, with time,
lead to extensive lunar industrial investments. There are a wide range of potential lunar industries: raw
materials processing, oxygen and other propellant production, nuclear and solar power, etc. These
industries may lead to small scale devices and large scale products: from microchip production to the
creation of completely new space vehicles. Many of the suggested industries were related to power
production to be transmitted to Earth or other attractive locales in the Earth-Moon space.
The need for safe lunar bases may lead to creating underground structures. If extended visits or
permanent colonization of the Moon is needed, humans will require protection from long term radiation
exposure as well as intense solar events such as coronal mass ejection, galactic cosmic rays, and lunar
surface scattering of radiation. Using explosive forming of underground cavities may lead to an attractive
lunar base or colony. Additional industrialization options include nuclear explosion based processing of
raw lunar materials. Large scale mining of lunar raw materials and gas production and capture from
underground nuclear processing of the in-situ materials has been suggested.
Missions to several planetary targets in the solar system were considered: Mercury, Saturn, and
its moon, Titan and Enceladus, as well as the asteroid, Ceres. The LEO masses were estimated for the
Mercury mission scenarios. Lander (ascent/descent) vehicles for Mercury were also assessed. The mass
of the lander vehicles for Mercury was 140.1 MT for the round trip lander and 27 MT for a one-way
deliver lander to the surface. Each carried a 10 MT payload. With ISRU, five landers could be delivered
to Mercury’s surface rather than one. The LEO masses for the human round trip Mercury missions was
reduced by an order of magnitude, from 27,000 MT to 2,300 or 1,700 MT, using nuclear thermal
propulsion over chemical oxygen /hydrogen propulsion systems. Using ISRU at Mercury would likely
further benefit a range of such missions.
10. Atmospheric mining in the outer solar system can produce nuclear fusion fuels such as 3He
which are rare on Earth. In addition, while extracting the small fraction of 3He in the gas giant
atmospheres, each day enormous amounts of hydrogen and helium are produced. These amounts can far
outstrip the needed for propellants to return the mining aerospacecraft to orbit. These additional hydrogen
and helium gases can augment many additional UAVs and probes for extended exploration of those
planets’ atmospheres and local environs.
Solar system exploration using in-situ resource utilization can allow higher quality missions with
much large data return. Larger more effective research and sample return missions are possible. Faster
missions are possible by using the local planetary resources to return to Earth. By not carrying all of the
return propellants, larger propellant loads in LEO can enable shorter mission flight times. Truly
impressive interplanetary missions can be within our reach with focused investments.
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2
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11
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14. Figure 1. Permanently shadowed craters in Mercury’s north polar region (Ref. 12).
Figure 2. Temperature ranges outside and inside permanently shadowed craters (Ref. 13).
15. Figure 3. Possible present day cross section of Titan (Ref. 14).
Figure 4. LEO masses of human round trip missions to Mercury.
16. Figure 5. LEO masses of lander vehicles for missions to Mercury.
Figure 6. One-way interplanetary mission delta-V versus trip time for various targets (Ref. 20).
17. 0.01
0.10
1.00
10.00
100.00
1,000.00
10,000.00
100,000.00
1,000,000.00
10,000,000.00
0 10 20 30 40
Timefor3Hecapturing(days),hydrogenproduced
andrequired(kg)
Atmospheric gas capture rate (kg/s)
AMOSS 3He mining time and hydrogen capturing requirements,
3He = 1.9e^-5, Mdry = 1,000,000 kg
Time needed for
capturing3He (days)
Massof hydrogen
producedper day
Gas core, 2500 s
Gas core Mp loads
per day, 2500 s
Figure 7. Helium 3 mining time and hydrogen capture (mass per day) versus atmospheric gas capture rate
for Neptune AMOSS (Ref. 23).
Figure 8. Schematic cross section of a hard rock medium after contained nuclear explosion (Ref. 25).
19. Appendix A (Ref. 17; Manning, L. “Comparison of Several Trajectory Modes for Manned and
Unmanned Missions to Mercury 1980-2000,” AIAA 67-28, 1967).