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a aThis document provides an overview of four lectures on space debris that will examine the current state of the orbital debris environment. It will look at the number and mass of objects in orbit, as well as their distribution, using data from NASA, ESA and other sources. The lectures will also explore the history of space launches and fragmentations and how the debris population has evolved over time. Current estimates indicate there are over 34,000 pieces of debris larger than 10 cm in size, around 900,000 pieces between 1 cm and 10 cm, and approximately 128 million pieces between 1 mm and 1 cm. The total mass of all orbital debris is around 9,200 tonnes.
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21.pdf
This lecture discusses the current state of the space environment in terms of orbital populations and space debris. Graphs and data from NASA, ESA, and other sources show the growth of objects in low Earth orbit over time, with a steep rise in the number of tracked objects since 2000. Charts depict the spatial density distributions of debris of different sizes in LEO according to the ESA MASTER model. Additional graphics present information on worldwide space activity and launch trends in recent years.
22.pdf
This document discusses the history and effects of space debris fragmentation events. It examines data from NASA and ESA on past fragmentation events and how they increased the amount of orbital debris and collision risk over time. Examples of fragmentation simulations are provided, showing the dispersion of debris clouds from broken satellites and rocket bodies. The risks that orbital debris poses to important spacecraft like the International Space Station and Space Shuttle are also reviewed, including historical near-collisions and the shielding used to protect these vehicles.
26.pdf
This lecture discusses in-situ measurements of space debris. It describes missions like LDEF, Hubble, the International Space Station, and Space Shuttle that have enabled the collection of in-situ data on space debris. Examples are provided of impacts on these structures from debris. Estimates of small debris, like micrometer-sized particles, are also presented.
32.pdf
The lecture discusses a simulation study conducted for ESA that aimed to understand how the space debris environment is affected by key satellite and constellation parameters. The study used three evolutionary debris models to project the debris environment out to 2213 under different scenarios. A baseline case examined the impact of a 1080-satellite constellation in 20 orbital planes at 1100km altitude, with a 5-year lifetime and 90% post-mission disposal. The results of the simulation study would be covered in the next lecture.
29.pdf
This lecture discusses the impacts of space debris on spacecraft operations. It provides data on historical close approaches and collision avoidance maneuvers performed by NASA, ESA, CNES, and private company Capella Space spacecraft. The number of close approaches requiring maneuvers has grown over time, particularly following major breakup events. For example, the number of high-risk conjunctions for ESA spacecraft doubled on average after the 2009 Iridium-Cosmos collision. Even small satellites like Capella-1 have performed maneuvers to avoid debris.
28.pdf
This document summarizes a lecture on space debris and the increasing risk of collisions. It discusses how the number of predicted close approaches between debris fragments is rising even as the number of fragments decreases over time. Data is presented on close approaches related to debris from the 2007 Fengyun-1C anti-satellite test and the 2009 Iridium-Cosmos collision. While around 27,000 close approaches under 5km were predicted per week in 2019, by 2021 that number had risen to around 46,000 per week. Similarly, close approaches under 1km rose from 1,100 to 2,400 per week. This increasing risk is likely due to the dispersing and expanding cloud of fragments over time.
27.pdf
This lecture discusses space debris, focusing on three significant hypervelocity collision events - the Fengyun 1C ASAT test in 2007, the Iridium 33-Cosmos 2251 collision in 2009, and the Microsat-R ASAT test in 2019. The consequences of these events in increasing space debris in low Earth orbit are examined. The lecture also reviews the top 50 debris-producing objects in history and how these high-profile collisions have impacted the space environment.
31.pdf
The lecture discussed recent data from the SOCRATES conjunction analysis program regarding CubeSats and the Starlink constellation. The data showed that the number of conjunctions predicted for CubeSats has remained stable compared to 2014 levels, accounting for about 1 in 20 to 1 in 25 conjunctions. For Starlink, conjunction predictions have increased dramatically, with Starlink objects accounting for about 1 in 4 of all conjunctions within 5 km and 1 in 2 to 1 in 3 of conjunctions within 1 km. The growing Starlink constellation has increased the total number of conjunctions reported by SOCRATES by 50% and highlights the need for autonomous collision avoidance systems to manage the growing risks.
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21.pdf
This lecture discusses the current state of the space environment in terms of orbital populations and space debris. Graphs and data from NASA, ESA, and other sources show the growth of objects in low Earth orbit over time, with a steep rise in the number of tracked objects since 2000. Charts depict the spatial density distributions of debris of different sizes in LEO according to the ESA MASTER model. Additional graphics present information on worldwide space activity and launch trends in recent years.
22.pdf
This document discusses the history and effects of space debris fragmentation events. It examines data from NASA and ESA on past fragmentation events and how they increased the amount of orbital debris and collision risk over time. Examples of fragmentation simulations are provided, showing the dispersion of debris clouds from broken satellites and rocket bodies. The risks that orbital debris poses to important spacecraft like the International Space Station and Space Shuttle are also reviewed, including historical near-collisions and the shielding used to protect these vehicles.
26.pdf
This lecture discusses in-situ measurements of space debris. It describes missions like LDEF, Hubble, the International Space Station, and Space Shuttle that have enabled the collection of in-situ data on space debris. Examples are provided of impacts on these structures from debris. Estimates of small debris, like micrometer-sized particles, are also presented.
32.pdf
The lecture discusses a simulation study conducted for ESA that aimed to understand how the space debris environment is affected by key satellite and constellation parameters. The study used three evolutionary debris models to project the debris environment out to 2213 under different scenarios. A baseline case examined the impact of a 1080-satellite constellation in 20 orbital planes at 1100km altitude, with a 5-year lifetime and 90% post-mission disposal. The results of the simulation study would be covered in the next lecture.
29.pdf
This lecture discusses the impacts of space debris on spacecraft operations. It provides data on historical close approaches and collision avoidance maneuvers performed by NASA, ESA, CNES, and private company Capella Space spacecraft. The number of close approaches requiring maneuvers has grown over time, particularly following major breakup events. For example, the number of high-risk conjunctions for ESA spacecraft doubled on average after the 2009 Iridium-Cosmos collision. Even small satellites like Capella-1 have performed maneuvers to avoid debris.
28.pdf
This document summarizes a lecture on space debris and the increasing risk of collisions. It discusses how the number of predicted close approaches between debris fragments is rising even as the number of fragments decreases over time. Data is presented on close approaches related to debris from the 2007 Fengyun-1C anti-satellite test and the 2009 Iridium-Cosmos collision. While around 27,000 close approaches under 5km were predicted per week in 2019, by 2021 that number had risen to around 46,000 per week. Similarly, close approaches under 1km rose from 1,100 to 2,400 per week. This increasing risk is likely due to the dispersing and expanding cloud of fragments over time.
27.pdf
This lecture discusses space debris, focusing on three significant hypervelocity collision events - the Fengyun 1C ASAT test in 2007, the Iridium 33-Cosmos 2251 collision in 2009, and the Microsat-R ASAT test in 2019. The consequences of these events in increasing space debris in low Earth orbit are examined. The lecture also reviews the top 50 debris-producing objects in history and how these high-profile collisions have impacted the space environment.
31.pdf
The lecture discussed recent data from the SOCRATES conjunction analysis program regarding CubeSats and the Starlink constellation. The data showed that the number of conjunctions predicted for CubeSats has remained stable compared to 2014 levels, accounting for about 1 in 20 to 1 in 25 conjunctions. For Starlink, conjunction predictions have increased dramatically, with Starlink objects accounting for about 1 in 4 of all conjunctions within 5 km and 1 in 2 to 1 in 3 of conjunctions within 1 km. The growing Starlink constellation has increased the total number of conjunctions reported by SOCRATES by 50% and highlights the need for autonomous collision avoidance systems to manage the growing risks.
Space Debris Project
The document discusses the growing issue of space debris and meteoroids in Earth's orbit. It provides background on where space debris comes from, including derelict spacecraft and rocket parts. Models like ORDEM and MEM are used to track and predict the movement of debris. Mitigation efforts aim to minimize new debris, but the issue continues growing as the amount of objects in space increases each year. Shields help protect satellites from impacts, but more must be done to curb the problem to ensure safe space travel.
33.pdf
The document summarizes key results from a simulation study conducted by Professor Hugh Lewis for ESA on the sensitivity of the space debris environment to satellite constellation parameters. The study found that post-mission disposal success, constellation size, satellite area, and launch vehicle behavior were among the most important parameters that affected the debris environment. Having a high post-mission disposal success rate and smaller constellations can help limit the impact on the debris environment, but may not eliminate impacts entirely. The results of this study informed guidelines from the IADC on the development of large satellite constellations.
On the possibility of through passage of asteroid bodies across the Earth’s a...
We have studied the conditions of through passage of asteroids with diameters 200, 100, and
50 m, consisting of three types of materials – iron, stone, and water ice, across the Earth’s
atmosphere with a minimum trajectory altitude in the range 10–15 km. The conditions of this
passage with a subsequent exit into outer space with the preservation of a substantial fraction
of the initial mass have been found. The results obtained support our idea explaining one of the
long-standing problems of astronomy – the Tunguska phenomenon, which has not received
reasonable and comprehensive interpretations to date. We argue that the Tunguska event was
caused by an iron asteroid body, which passed through the Earth’s atmosphere and continued
to the near-solar orbit.
The Dynamical Consequences of a Super-Earth in the Solar System
Placing the architecture of the solar system within the broader context of planetary architectures is one of the
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Space debris refers to nonfunctional human-made objects in orbit around Earth, such as broken satellites, rocket stages, and other fragments. It poses a growing risk of collisions in popular orbital regions. Approximately 29,000 objects larger than 10 cm and over 166 million smaller than 1 cm have been tracked orbiting Earth. Left unchecked, collisions between objects could trigger the Kessler Syndrome where the amount of debris renders regions of space unusable for generations. Detection methods for debris include laser ranging and high-sensitivity radar sensors.
Heterogeneous delivery of silicate and metal to the Earth by large planetesimals
After the Moon’s formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during
this stage of late accretion has been estimated to be approximately 0.5% of Earth’s present mass, based on highly siderophile
element concentrations in the Earth’s mantle and the assumption that all highly siderophile elements delivered by impacts
were retained in the mantle. However, late accretion may have involved mostly large (≥ 1,500 km in diameter)—and therefore
differentiated—projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present
smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal’s core may
descend to the Earth’s core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to
the Earth’s mantle and imply a late accretion mass that may be two to five times greater than previously thought. Further, we
demonstrate that projectile material can be concentrated within localized domains of Earth’s mantle, producing both positive
and negative 182W isotopic anomalies of the order of 10 to 100 ppm. In this scenario, some isotopic anomalies observed in terrestrial
rocks can be explained as products of collisions after Moon formation.
Seminar report on GPS based Space Debris Removal System
Space debris refers to defunct objects in orbit around Earth, including spent rocket stages, old satellites, and fragments. As the number of satellites increases, space debris poses a hazard to operational spacecraft through collisions. Effective measures are needed to mitigate space debris, such as de-orbiting satellites at end-of-life and actively removing existing debris. The 2009 collision between an Iridium satellite and a Russian satellite created over 200,000 pieces of debris and challenged assumptions about collision risks. The US Space Surveillance Network tracks and catalogs artificial objects in orbit to monitor and predict space debris.
Martian soil as revealed by ground-penetrating radar at the Tianwen-1 landing...
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heterogeneous and geologically complex and characterized by structures that resemble partial
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comparable radar data from the Lunar far side are rather uniform, despite the two surfaces
being geologically contemporary. The close-to-surface crater presented in this study shows
no detectable surface expression, which suggests an accelerated occultation rate for small
craters on the surface of Mars as compared to the rate on the Moon. This is probably due to
the relentless eolian processes on the Martian surface that led to the burial of the crater and
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Tianwen-1 landing site is not dominated by water ice.
Debris-growth-pictures-5-16-09.ppt
The document summarizes the growth of space debris in Earth's orbit over time. It shows how the amount of debris has increased dramatically since the first satellite was launched in 1957. Space debris can remain in orbit for decades and includes non-functional objects as well as fragments from collisions. Charts from NASA illustrate the rise in the number of catalogued debris objects, with over 14,000 tracked pieces of debris currently in orbit, posing a threat to active satellites.
30.pdf
This lecture discusses a 2014 study of collision risk for CubeSats conducted using conjunction data from SOCRATES and the DAMAGE model. The study found over 360,000 conjunctions involving CubeSats since 2005, with millions more predicted over the next 30 years even with relatively low launch rates. Few collisions are predicted, but the increasing CubeSat activity may not be sustainable without engagement and guidelines to mitigate risks to the space environment. The next lecture will review more recent conjunction data from SOCRATES.
Knowledge Evolution in Distributed Geoscience Datasets and the Role of Semant...
Knowledge Evolution in Distributed Geoscience Datasets and the Role of Semant...Xiaogang (Marshall) Ma
Knowledge evolves in geoscience, and the evolution is reflected in datasets. In a context with distributed data sources, the evolution of knowledge may cause considerable challenges to data management and re-use. For example, a short news published in 2009 (Mascarelli, 2009) revealed the geoscience community’s concern that the International Commission on Stratigraphy’s change to the definition of Quaternary may bring heavy reworking of geologic maps. Now we are in the era of the World Wide Web, and geoscience knowledge is increasingly modeled and encoded in the form of ontologies and vocabularies by using semantic technologies. Accordingly, knowledge evolution leads to a consequence called ontology dynamics. Flouris et al. (2008) summarized 10 topics of general ontology changes/dynamics such as: ontology mapping, morphism, evolution, debugging and versioning, etc. Ontology dynamics makes impacts at several stages of a data life cycle and causes challenges, such as: the request for reworking of the extant data in a data center, semantic mismatch among data sources, differentiated understanding of a same piece of dataset between data providers and data users, as well as error propagation in cross-discipline data discovery and re-use (Ma et al., 2014). This presentation will analyze the best practices in the geoscience community so far and summarize a few recommendations to reduce the negative impacts of ontology dynamics in a data life cycle, including: communities of practice and collaboration on ontology and vocabulary building, link data records to standardized terms, and methods for (semi-)automatic reworking of datasets using semantic technologies.
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Flouris, G., Manakanatas, D., Kondylakis, H., Plexousakis, D., Antoniou, G., 2008. Ontology change: classification and survey. The Knowledge Engineering Review 23 (2), 117-152.
Ma, X., Fox, P., Rozell, E., West, P., Zednik, S., 2014. Ontology dynamics in a data life cycle: Challenges and recommendations from a Geoscience Perspective. Journal of Earth Science 25 (2), 407-412.
Mascarelli, A.L., 2009. Quaternary geologists win timescale vote. Nature 459, 624.KGrothe-AIAA-ASAT-SpaceDebris
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24.pdf
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25.pdf
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Placing the architecture of the solar system within the broader context of planetary architectures is one of the
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presenting a challenge to modeling their interiors and atmospheres. Here we present the results of a large suite of
dynamical simulations that insert a hypothetical planet in the mass range 1–10 M⊕ within the semimajor axis range
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unaffected when the additional planet is placed near 3 au, Mercury experiences substantial instability when the
additional planet lies in the range 3.1–4.0 au, and perturbations to the Martian orbit primarily result when the
additional planet lies in the range 2.0–2.7 au. We further show that, although Jupiter and Saturn experience
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the architecture of the inner and outer solar system planets, and for exoplanetary systems
space debris management
Space debris refers to nonfunctional human-made objects in orbit around Earth, such as broken satellites, rocket stages, and other fragments. It poses a growing risk of collisions in popular orbital regions. Approximately 29,000 objects larger than 10 cm and over 166 million smaller than 1 cm have been tracked orbiting Earth. Left unchecked, collisions between objects could trigger the Kessler Syndrome where the amount of debris renders regions of space unusable for generations. Detection methods for debris include laser ranging and high-sensitivity radar sensors.
Heterogeneous delivery of silicate and metal to the Earth by large planetesimals
After the Moon’s formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during
this stage of late accretion has been estimated to be approximately 0.5% of Earth’s present mass, based on highly siderophile
element concentrations in the Earth’s mantle and the assumption that all highly siderophile elements delivered by impacts
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differentiated—projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present
smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal’s core may
descend to the Earth’s core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to
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by long-term surface processes such as impact gardening, eolian erosion, water weathering,
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assess its loss tangent. The RoPeR radargram revealed the local regolith layer to be highly
heterogeneous and geologically complex and characterized by structures that resemble partial
or complete crater walls and near-surface impact lenses at a very shallow depth. However,
comparable radar data from the Lunar far side are rather uniform, despite the two surfaces
being geologically contemporary. The close-to-surface crater presented in this study shows
no detectable surface expression, which suggests an accelerated occultation rate for small
craters on the surface of Mars as compared to the rate on the Moon. This is probably due to
the relentless eolian processes on the Martian surface that led to the burial of the crater and
thus shielded it from further erosion. The high loss tangent indicates that the regolith at the
Tianwen-1 landing site is not dominated by water ice.
Debris-growth-pictures-5-16-09.ppt
The document summarizes the growth of space debris in Earth's orbit over time. It shows how the amount of debris has increased dramatically since the first satellite was launched in 1957. Space debris can remain in orbit for decades and includes non-functional objects as well as fragments from collisions. Charts from NASA illustrate the rise in the number of catalogued debris objects, with over 14,000 tracked pieces of debris currently in orbit, posing a threat to active satellites.
30.pdf
This lecture discusses a 2014 study of collision risk for CubeSats conducted using conjunction data from SOCRATES and the DAMAGE model. The study found over 360,000 conjunctions involving CubeSats since 2005, with millions more predicted over the next 30 years even with relatively low launch rates. Few collisions are predicted, but the increasing CubeSat activity may not be sustainable without engagement and guidelines to mitigate risks to the space environment. The next lecture will review more recent conjunction data from SOCRATES.
Knowledge Evolution in Distributed Geoscience Datasets and the Role of Semant...
Knowledge Evolution in Distributed Geoscience Datasets and the Role of Semant...Xiaogang (Marshall) Ma
Knowledge evolves in geoscience, and the evolution is reflected in datasets. In a context with distributed data sources, the evolution of knowledge may cause considerable challenges to data management and re-use. For example, a short news published in 2009 (Mascarelli, 2009) revealed the geoscience community’s concern that the International Commission on Stratigraphy’s change to the definition of Quaternary may bring heavy reworking of geologic maps. Now we are in the era of the World Wide Web, and geoscience knowledge is increasingly modeled and encoded in the form of ontologies and vocabularies by using semantic technologies. Accordingly, knowledge evolution leads to a consequence called ontology dynamics. Flouris et al. (2008) summarized 10 topics of general ontology changes/dynamics such as: ontology mapping, morphism, evolution, debugging and versioning, etc. Ontology dynamics makes impacts at several stages of a data life cycle and causes challenges, such as: the request for reworking of the extant data in a data center, semantic mismatch among data sources, differentiated understanding of a same piece of dataset between data providers and data users, as well as error propagation in cross-discipline data discovery and re-use (Ma et al., 2014). This presentation will analyze the best practices in the geoscience community so far and summarize a few recommendations to reduce the negative impacts of ontology dynamics in a data life cycle, including: communities of practice and collaboration on ontology and vocabulary building, link data records to standardized terms, and methods for (semi-)automatic reworking of datasets using semantic technologies.
References:
Flouris, G., Manakanatas, D., Kondylakis, H., Plexousakis, D., Antoniou, G., 2008. Ontology change: classification and survey. The Knowledge Engineering Review 23 (2), 117-152.
Ma, X., Fox, P., Rozell, E., West, P., Zednik, S., 2014. Ontology dynamics in a data life cycle: Challenges and recommendations from a Geoscience Perspective. Journal of Earth Science 25 (2), 407-412.
Mascarelli, A.L., 2009. Quaternary geologists win timescale vote. Nature 459, 624.KGrothe-AIAA-ASAT-SpaceDebris
This document discusses the growing problem of space debris orbiting Earth. It defines space debris as nonfunctional human-made objects in space including defunct spacecraft and fragments from explosions. The amount of space debris is increasing and will likely be dominated by collision fragments in the future, posing a hazard to operational satellites and human spaceflight. Several proposals for active debris removal are presented, including using nets, lasers, and momentum to capture debris and deorbit them to burn up in Earth's atmosphere. International guidelines call for passive mitigation efforts but active debris removal may be necessary to reduce risks to space activities and prevent the space environment from becoming too polluted.
Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-...
The main scientific goal of TESS is to find planets smaller than Neptune around stars bright enough to allow further characterization studies. Given
our current instrumentation and detection biases, M dwarfs are prime targets to search for small planets that are in (or nearby) the habitable zone
of their host star. Here we use photometric observations and CARMENES radial velocity measurements to validate a pair of transiting planet
candidates found by TESS. The data was fitted simultaneously using a Bayesian MCMC procedure taking into account the stellar variability
present in the photometric and spectroscopic time series. We confirm the planetary origin of the two transiting candidates orbiting around TOI-
2095 (TIC 235678745). The star is a nearby M dwarf (d = 41:90 0:03 pc, Te = 3759 87 K, V = 12:6 mag) with a stellar mass and radius
of M? = 0:44 0:02 M and R? = 0:44 0:02 R , respectively. The planetary system is composed of two transiting planets: TOI-2095b with an
orbital period of Pb = 17:66484 (7 105) days and TOI-2095c with Pc = 28:17232 (14 105) days. Both planets have similar sizes with
Rb = 1:250:07 R and Rc = 1:330:08 R for planet b and c, respectively.We put upper limits on the masses of these objects with Mb < 4:1 M
for the inner and Mc < 7:4 M for the outer planet (95% confidence level). These two planets present equilibrium temperatures in the range of 300
- 350 K and are close to the inner edge of the habitable zone of their star.
Class 1
This document provides an introduction to geology, outlining key concepts and topics covered in the field. It defines geology as the study of Earth and discusses its division into physical geology and historical geology. Major sections address geological concepts, the origin and structure of Earth, and its composition. Geology is presented as important for understanding natural resources, hazards, and problems facing modern society.
P1 P2 mock quiz
The document contains a 10 question quiz about the electromagnetic spectrum and related topics like radiation, global warming, and the greenhouse effect. The questions cover topics such as the different types of radiation, how they are used and their effects, how food is cooked in microwaves, what gases cause global warming, and what the greenhouse effect has on Earth.
Space Debris And SSA 20032012
Space debris poses threats from Earth to space, space to space, and space to earth. Current systems track but do not prevent collisions, and accidents have occurred. The issue risks a cascade effect that increases debris. Both the US and Europe recognize the need for space situational awareness to support space operations, but the US focuses more on strategic capabilities while Europe emphasizes open access. Active measures are needed now to address the problem before it worsens further.
51.pdf
This lecture introduces the NASA standard breakup model, which was developed using data from the SOCIT series of HVI experiments and other sources. The model can be used to calculate the number, mass, area-to-mass ratio, and velocity of fragments resulting from explosions or collisions in space. It provides empirical equations to estimate these values as a function of fragment size and other parameters based on historical data from events like satellite breakups and hypervelocity impact tests. The model is implemented in simulations to analyze and predict the evolution of space debris populations over time.
Solar Dynamics Observatory_June 2010
The document summarizes information about NASA's Solar Dynamics Observatory (SDO) satellite mission to study the sun. SDO was launched in 2010 and uses high-resolution instruments to observe the sun's atmosphere, magnetic field, and irradiance. It aims to improve understanding of the sun's influence on space weather and the solar cycle. SDO provides images every minute that are 10 times clearer than previous satellites and help scientists monitor solar activity and eruptions.
24.pdf
The lecture discusses space surveillance networks and space situational awareness. It introduces the US Space Surveillance Network, which tracks objects 10 cm and larger in low Earth orbit and 1 m and larger in geosynchronous orbit. Commercial networks like LeoLabs and ExoAnalytic Solutions are also discussed. Data from these networks is used for important services like conjunction predictions to ensure space safety. The next lecture will focus on systems used to measure and characterize space objects.
25.pdf
Radar and optical telescopes are used to gather data on space objects. Radar, like the Haystack radar, can track and image objects in geosynchronous orbit with the highest resolution. Optical telescopes measure sunlight reflected by objects, but are limited to periods when the object and telescope have line of sight. The MMT optical telescope system has tracked over 300,000 objects, including Starlink satellites, and analyzed their brightness over time to characterize them.
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12 Perterbations.pdf
This document provides an overview of orbital perturbations and methods for modeling them. It introduces Cowell's method and Encke's method for numerically integrating the equations of motion with perturbations. It then discusses atmospheric drag as a perturbation, describing how drag causes orbits to decay over time. It provides the US Standard Atmosphere 1976 model for atmospheric density with altitude.
4 3d orbits.pdf
This document discusses coordinate systems for describing orbits in three dimensions. It introduces the geocentric equatorial frame, which uses a right-handed Cartesian coordinate system centered on Earth with axes defined by the vernal equinox and Earth's rotation. The state vector specifies an object's position and velocity in this frame using six components. Orbital elements also uniquely define orbits using six parameters and the location of the object. Coordinate transformations allow changing between the state vector and orbital element representations.
9 rigid body dynamics.pdf
This chapter discusses rigid body dynamics and provides the foundation for developing equations of satellite attitude dynamics. It first covers the kinematics of rigid bodies using Chasles' theorem, which states that rigid body motion can be described by the displacement of any point plus a rotation about a unique axis through that point. It then discusses the equations of translational and rotational motion by analyzing the interaction between rigid body motion and applied forces. Key concepts covered include moments of inertia, Euler's equations, kinetic energy, and different methods for describing rigid body orientation including Euler angles, yaw/pitch/roll angles, and quaternions. The chapter serves as a basis for understanding satellite attitude dynamics.
10 Sat attitude.pdf
This document discusses the torque-free motion of satellites. It shows that a spinning satellite will have stable motion only if it is oblate in shape, with the equatorial radius greater than the polar radius. Oblate spinners will have prograde precession and spin, while prolate spinners will have retrograde precession and spin. The components of angular velocity and angular momentum are derived in terms of the satellite's principal moments of inertia and Euler angles.
8 Interplanetary traj.pdf
This document discusses interplanetary trajectories and Hohmann transfers between planets. It begins by outlining Hohmann transfers, which provide the most energy-efficient method of transferring between nearly circular, coplanar orbits. It then discusses the timing of opportunities for planetary rendezvous using Hohmann transfers, which depend on the relative positions and velocities of the planets. The document covers methods for calculating delta-v requirements at planetary departure and arrival points to achieve the Hohmann transfer orbit. It also introduces non-Hohmann transfer trajectories when planetary orbits are not coplanar.
6 maneuvres.pdf
This document discusses orbital maneuvers, beginning with an introduction to impulsive maneuvers where brief rocket firings instantaneously change a spacecraft's velocity vector. It then focuses on the Hohmann transfer, the most energy-efficient maneuver for transferring between two coplanar circular orbits. A Hohmann transfer uses an elliptical orbit tangent to the two circles, requiring burns at periapsis and apoapsis to place the spacecraft onto the transfer orbit and then the target orbit. An equation is provided for calculating the angular momentum of the Hohmann transfer ellipse based on the radii of the source and target orbits.
7 relative motion.pdf
This document discusses relative motion between two orbiting spacecraft, a target and chaser. It defines a local vertical/local horizontal (LVLH) coordinate frame attached to the target spacecraft, with axes along the radial direction, local horizontal, and angular momentum direction. Equations are provided to calculate the relative position, velocity, and acceleration of the chaser in this frame based on the states of both spacecraft in an inertial frame. An example problem applies these equations to calculate the relative motion between two spacecraft in slightly different elliptical orbits.
3 position by time.pdf
This document discusses how to determine the position of an orbiting body as a function of time for different orbit types. It introduces Kepler's equation, which relates the true anomaly to time through integrals that must be solved iteratively. For elliptical orbits, Kepler's equation leads to the definition of mean anomaly as a function of true anomaly. The mean anomaly is directly proportional to time through the mean motion. Eccentric anomaly is also introduced to simplify expressions relating true anomaly to time.
5 prelim determination.pdf
- The Gibbs method determines orbital elements from three position vectors of an object.
- It utilizes the fact that the position vectors must lie in the same orbital plane, defined by the angular momentum vector.
- Equations relating the position vectors and angular momentum allow solving for the angular momentum magnitude.
- Knowing the angular momentum vector and magnitude allows determining the velocities at the three observation times from the position vectors using basic orbital mechanics equations.
11 rocket dyanmics.pdf
This document discusses rocket vehicle dynamics and performance. It begins with the equations of motion for a rocket during powered ascent, accounting for thrust, drag, and gravity. It then derives the thrust equation from momentum considerations, relating thrust to propellant mass flow rate and exhaust velocity. Finally, it combines the thrust equation and equations of motion to obtain the rocket equation, which relates propellant expenditure to changes in rocket velocity (delta-v).
3 EDL.pdf
The document discusses entry, descent, and landing (EDL) for spacecraft. It covers:
1) The dynamics of atmospheric entry and re-entry, including key equations of motion.
2) Issues during EDL like deceleration, heating, and communication blackouts.
3) Methods for testing and simulating EDL, including ground and simulation testing.
The document aims to explain the EDL phase and prepare the reader to understand and analyze challenges of atmospheric entry for spacecraft.
1 Power Sys.pdf
1. The power requirements of the spacecraft loads and batteries that need to be supplied by the solar array.
2. The effects of the orbital parameters on the intensity and duration of sunlight, such as eclipse periods.
3. The degradation of the solar cell efficiency over time due to radiation damage and high temperatures in space. Accounting for this ensures the array can still produce enough power at the end of the mission lifetime.
2 Thermal Control.pdf
The document provides an overview of thermal control systems for spacecraft. It discusses passive and active thermal control systems, with passive relying on components like surface coatings and active using powered mechanisms. The document covers thermal analysis methods like conduction, convection, and radiation. It describes modeling the thermal environment from heat sources like solar radiation, planetary radiation, and albedo. Design of passive thermal control uses appropriate surface coatings to control absorptance and emittance.
59.pdf
This document discusses a lecture on space sustainability given by Professor Hugh Lewis at the University of Southampton. The lecture focuses on taking a long term view of ensuring the space environment remains usable by future generations. It includes repeated tags asking the reader to connect with the university and view a film about being connected.
48.pdf
This lecture discusses hypervelocity impacts in space. It focuses on the impact process, computational models used to simulate impacts, and ensuring the accuracy of models. Experimental facilities like light gas guns are used to test impacts and calibrate models. Results from experiments help develop empirical break-up models to better understand and predict how objects break apart during high-speed collisions in space.
50.pdf
This lecture discusses three experiments - SOCIT, DebriSat, and DebrisLV - that studied the effects of hypervelocity impacts on satellites using the light gas gun at Arnold Air Force Base. SOCIT targeted a Navy Transit satellite bus with an aluminum sphere projectile traveling at 6.1 km/s. DebriSat used a custom-built satellite and aluminum cylinder projectile impacting at 6.8 km/s. DebrisLV represented a launch vehicle stage. Diagnostic equipment measured the impact effects, and the results will be used to develop models of hypervelocity impact damage to satellites.
52.pdf
This lecture discusses re-entry predictions and risks from space debris. It covers:
1) How uncertainties in satellite characteristics and the atmosphere lead to uncertainties in re-entry predictions. Predictions are most accurate within 10 days and least accurate beyond that.
2) Methods for calculating risks to humans, including equivalent casualty cross-section and modeling debris footprint as a 2D Gaussian.
3) Long-term risks are low, estimated at 1 casualty every 45 years based on historical re-entries.
56.pdf
The lecture discusses common misconceptions about the Kessler Syndrome, a concept developed by NASA scientist Donald Kessler warning of the risk of increasing amounts of space debris. Some of the misconceptions addressed are that it would be a quick collision chain reaction, that there would be no way to stop it once started, and that it would mean an end to all space travel. The lecture presents examples of these misconceptions in media reports and research articles and aims to explain in upcoming lectures why these ideas are likely incorrect.
57.pdf
This lecture discusses techniques for calculating probabilities using combinatorics, and applies them to scenarios involving satellite collisions and drawing playing cards. Two scenarios are presented:
1) Calculating probabilities of different outcomes from 10 satellite conjunctions each with a 5% chance of collision.
2) Drawing 10 cards from a deck and calculating probabilities of different numbers of hearts. The chance of a heart on each draw is 1/4. Probabilities are calculated using combinations, multiplication of probabilities, and subtraction of complementary events.
55.pdf
(1) Donald Kessler introduced the idea of a "critical population density" of space debris in 1978 and 1991, where above this density collisions would produce debris faster than it decays.
(2) In 2001, Kessler introduced the concept of a "critical number of objects" and applied a stability model showing regions of low Earth orbit have exceeded the critical level and become unstable.
(3) Kessler's work showed the space debris population could exponentially increase without further launches if the critical threshold is surpassed, known as the "Kessler Syndrome," though this was sometimes misunderstood to mean an immediate effect rather than gradual increase.
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哪里购买(ucr毕业证书)美国加州大学河滨分校毕业证研究生文凭证书原版一模一样
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留信网认证的作用:
1:该专业认证可证明留学生真实身份
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3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
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【业务选择办理准则】
一、工作未确定，回国需先给父母、亲戚朋友看下文凭的情况，办理一份就读学校的毕业证【微信bwp0011】文凭即可
二、回国进私企、外企、自己做生意的情况，这些单位是不查询毕业证真伪的，而且国内没有渠道去查询国外文凭的真假，也不需要提供真实教育部认证。鉴于此，办理一份毕业证【微信bwp0011】即可
三、进国企，银行，事业单位，考公务员等等，这些单位是必需要提供真实教育部认证的，办理教育部认证所需资料众多且烦琐，所有材料您都必须提供原件，我们凭借丰富的经验，快捷的绿色通道帮您快速整合材料，让您少走弯路。
留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
【关于价格问题（保证一手价格）】
我们所定的价格是非常合理的，而且我们现在做得单子大多数都是代理和回头客户介绍的所以一般现在有新的单子 我给客户的都是第一手的代理价格，因为我想坦诚对待大家 不想跟大家在价格方面浪费时间
对于老客户或者被老客户介绍过来的朋友，我们都会适当给一些优惠。
哪里购买美国乔治城大学毕业证硕士学位证书原版一模一样
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留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
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20.pdf
- 1. Space Environment Lecture 20 – Space Debris (Vol. 1) Environment status (part 1) Professor Hugh Lewis SESA3038 Space Environment
- 2. Overview of lectures 20 to 23 • In these four lectures we introduce the space debris topics we will be looking at over the next few weeks, before focusing on the current state of the environment, in terms of the orbital population: – We use data and graphics from NASA, ESA and other sources to understand the current situation and the history that has led to it – We consider the number of objects in orbit, their mass and their distribution (for the latter, concentrating on LEO only) – We look at the history of space launches and fragmentations, before seeing what the environment now looks like Space Environment – Space Debris (Vol. 1)
- 3. Space debris Space Environment – Space Debris (Vol. 1) • The space debris environment: update • Space surveillance/measurement of space debris • Impacts on space operations • Modelling of space debris • Environment/evolutionary modelling • Impact modelling • Breakup modelling • Re-entry modelling • On-ground risk modelling • Clean Space Volume 1 (Week 5)
- 4. Growth of the orbital population Space Environment – Space Debris (Vol. 1) Data from NASA Orbital Debris Quarterly Newsletter (April 2020) https://orbitaldebris.jsc.nasa.gov/quarterly-news/
- 5. Growth of the orbital population Space Environment – Space Debris (Vol. 1) Data from Celestrak BOXSCORE (February 2021) https://celestrak.com/satcat/boxscore.php
- 6. Growth of the orbital population Space Environment – Space Debris (Vol. 1) Data from ESA’s Annual Space Environment Report (September 2020)
- 7. Space debris population Space Environment – Space Debris (Vol. 1) 7 Softball size or larger (≥ 10 cm) ~34,000 ~900,000 ~128,000,000 Total mass: ~9,200 tonnes Marble size or larger (1 cm to 10 cm) Ball-point pen tip (1 mm to 1 cm)
- 8. Size distribution Space Environment – Space Debris (Vol. 1) Graphic from “Orbital Debris: A Technical Assessment” (1995)
- 9. Growth of cross-sectional area Space Environment – Space Debris (Vol. 1) Data from ESA’s Annual Space Environment Report (September 2020)
- 10. Growth of mass in orbit Space Environment – Space Debris (Vol. 1) Data from ESA’s Annual Space Environment Report (September 2020)
- 11. Mass in context Forth Road Bridge: 39,000 tonnes of steel Space Environment – Space Debris (Vol. 1)
- 12. Space Environment – Space Debris (Vol. 1) Mass in context The Shard: 12,500 tonnes
- 13. Activities: • Look back at SESA3041/6079: • Outer Space Treaty • Introduction to space debris • Introduction to space debris mitigation guidelines and standards • IADC space debris mitigation guidelines • ESA’s Annual Space Environment Report: • Read the report (available in the “Course Content” folder on Blackboard) Space Environment – Space Debris (Vol. 1)