Dissertations / Theses on the topic 'Aeronautics and Space Engineering Board'

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 273-292).
Communications satellite operators maintain archives of component telemetry to monitor system function. Operators generally do not typically use the telemetry data for scientific analysis of the space radiation environment effects on component anomalies or performance. We partnered with four geostationary (GEO) operators, acquired >1 million hours of telemetry, and combined these data with space weather observations to investigate relationships between space weather and hardware performance. We focused on the effects of space weather on two component types: solar cells and high power amplifiers. For solar cells, by augmenting >20 years of GEO telemetry with separate GEO space weather measurements, we calculated both on-orbit degradation of Si and GaAs solar cells in an annual average sense, and also quantified the degradation of cells during severe solar proton events (SPEs) of 10 MeV protons > 10,000 pfu. A functional relationship between the amount of degradation and proton fluence is also considered. We used the calculated degradation to evaluate several combinations of space weather environment models with solar cell degradation models and found that predicted performance is within 1% of the observed degradation. These models had not previously been validated using multiple on-orbit GEO datasets. We did not find a model pairing that consistently outperformed the others over all of the datasets. For high power amplifiers, through the use of statistical analysis, simulations, and electron beam experiments we conducted a root-cause analysis of solid state power amplifier (SSPA) anomalies on-board eight GEO satellites. From the statistical analysis, we identified that the occurrence of anomalies was not random with respect to the space weather environment, but that there appeared to be a relationship to high-energy electron fluence for periods of time between 10 - 21 days before the anomalies. From the simulations and electron beam lab tests, we demonstrated that internal charging occurs in the amplifier chain, potentially identifying a cause for the observed anomalies. We substantiated an approach toward understanding space weather effects on space components by obtaining and using long-duration archives of standard commercial telemetry for scientific analysis. The analysis of large telemetry data sets of similar components over long periods of time improves our ability to assess the role of different types of space weather events in causing anomalies and helps to validate models. The findings in this work that relate deep dielectric charging to component anomalies and solar proton events to solar cell degradation make use of only a small fraction of the potentially available commercial geostationary satellite telemetry. Expansion of this work would provide additional insights on the role of space weather to the science community and to the satellite design and operator community.
by Whitney Quinne Lohmeyer.
Ph. D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.
Includes bibliographical references (leaves 81-84).
Future space structures such as solar power stations and telescopes are expected to be very large. These structures will require on-orbit construction. Due to the risks and costs of human extravehicular work, teams of robots will be essential for the on-orbit assembly of the large space structures. There are a number of technical challenges presented by such robotic construction. The structures will need to be made of lightweight materials and will be very flexible. Autonomous robots will require information about the vibrations of the flexible structures and their dynamic parameters in order to perform the construction efficiently. Often models of the structures are imperfect, therefore the magnitude of the vibrations of the structure must be estimated on-orbit. This thesis presents a method for estimating the shape and dynamic parameters of a vibrating large space structure. This technique is a cooperative sensing approach using remote free-flying robot observers equipped with vision sensors and structure-mounted accelerometers. This approach exploits the complementary nature of the two types of sensors.
(cont.) Vision sensors are able to measure structure deflections at a high spatial frequency but are bandwidth limited. Accelerometers are able to make measurements at high temporal frequency, but are sparsely located on the structure. The fused estimation occurs in three steps. First, the vision data is condensed in a modal decomposition that results in coarse estimates of modal coefficients. In the second step, the coarse estimates of the modal coefficients obtained from vision data are fused with the accelerometer measurements in a multi-rate nonlinear Kalman filter, resulting in a refined estimate of the modal coefficients and dynamic properties of the structure. In the final step, the estimated modal coefficients are combined with the mode shapes to provide a shape estimate of the entire structure. Simulation and experimental results demonstrate that the performance of this fused estimation approach is superior to the performance achieved when using only a single type of sensor.
by Amy M. Bilton.
S.M.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 177-181).
Novel methods for assessing space suit designs and human performance capabilities are needed as NASA prepares for manned missions beyond low Earth orbit. Current human performance tests and training are conducted in space suits that are heavy and expensive, characteristics that constrain possible testing environments and reduce suit availability to researchers. Space suit mock-ups used in planetary exploration simulations are light and relatively inexpensive but do not accurately simulate the joint stiffness inherent to space suits, a key factor impacting extravehicular activity performance. The MIT Man-Vehicle Laboratory and Aurora Flight Sciences designed and built an actively controlled exoskeleton for space suit simulation called the Extravehicular Activity Space Suit Simulator (EVA S3), which can be programmed to simulate the joint torques recorded from various space suits. The goal of this research is to create a simulator that is lighter and cheaper than a traditional space suit so that it can be used in a variety of testing and training environments. The EVA S3 employs pneumatic actuators to vary joint stiffness and a pre-programmed controller to allow the experimenter to apply torque profiles to mimic various space suit designs in the field. The focus of this thesis is the design, construction, integration, and testing of the hip joint and backpack for the EVA S3. The final designs of the other joints are also described. Results from robotic testing to validate the mechanical design and control system are discussed along with the planned improvements for the next iteration of the EVA S3. The fianl EVA S3 consists of a metal and composite exoskeleton frame with pneumatic actuators that control the resistance of motion in the ankle, knee, and hip joints, and an upper body brace that resists shoulder and elbow motions with passive spring elements. The EVA S3 is lighter (26 kg excluding the tethered components) and less expensive (under $600,000 including research, design, and personnel) than a modem space suit. Design adjustments and control system improvements are still needed to achieve a desired space suit torque simulation fidelity within 10% root-mean-square error.
by Forrest Edward Meyen.
S.M.

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
Includes bibliographical references (leaves 68-69).
by John G. Tilly.
M.Eng.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2010.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 189-193).
This thesis addresses two challenges associated with advanced space and planetary exploration: characterizing and improving the mobility of current and future gas pressurized space suits; and developing effective domestic Planetary Protection policies for the emerging private space industry. Gas-pressurized space suits are known to be highly resistive to astronaut movement. As NASA seeks to return to planetary exploration, there is a critical need to improve full body space suit mobility for planetary exploration. Volume effects (the torque required to displace gas due to internal volume change during movement) and structural effects (the additional torque required to bend the suit materials in their pressurized state) are cited as the primary contributors to suit rigidity. Constant volume soft joints have become the design goal of space suit engineers, and simple joints like the elbow are believed to have nearly achieved such performance. However, more complex joints like the shoulder and waist have not yet achieved comparable optimization. As a result, it is hypothesized that joints like the shoulder and waist introduce a third, and not well studied, contributor to space suit rigidity: pressure effects (the additional work required to compress gas in the closed operating volume of the suit during movement). This thesis quantifies the individual contributors to space suit rigidity through modeling and experimentation. An Extravehicular Mobility Unit (EMU) space suit arm was mounted in a -30kPa hypobaric chamber, and both volume and torque measurements were taken versus elbow angle. The arm was tested with both open and closed operating volumes to determine the contribution of pressure effects to total elbow rigidity. These tests were then repeated using a full EMU volume to determine the actual impact of elbow pressure effects on rigidity when connected to the full suit. In both cases, structural and volume effects were found to be primary contributors to elbow joint rigidity, with structural effects dominating at low flexion angles and volume effects dominating at high flexion angles; pressure effects were detected in the tests that used only the volume of the arm, but were found to be a secondary contributor to total rigidity (on average < 5%). These pressure effects were not detected in the tests that used the volume representative of a full EMU. Unexpected structural effects behavior was also measured at high (> 75°) flexion angles, suggesting that the underlying mechanisms of these effects are not yet fully understood, and that current models predicting structural effects behavior do not fully represent the actual mechanisms at work. The detection of pressure effects in the well-optimized elbow joint, even if only in a limited volume, suggests that these effects may prove significant for sub-optimized, larger, multi-axis space suit joints. A novel, fast-acting pressure control system, developed in response to these findings, was found to be capable of mitigating pressure spikes due to volume change (and thus, pressure effects). Implementation of a similar system in future space suit designs could lead to improvements in overall suit mobility. A second study, which focused on the implications of the development of the US private space industry on domestic Planetary Protection policy, is also presented. As signatories of the 1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space (commonly known as the Outer Space Treaty), the United States is responsible for implementing Planetary Protection procedures designed to prevent biological contamination of the Solar System, as well as contamination of the Earth by any samples returned from extra-terrestrial bodies. NASA has established policies and procedures to comply with this treaty, and has successfully policed itself independently and autonomously since the signing of the treaty. However, for the first time in the history of the American space program, private entities outside of NASA have developed the capability and interest to send objects into space and beyond Earth orbit, and no current protocol exists to guarantee these profit-minded entities comply with US Planetary Protection obligations (a costly and time-consuming process). This thesis presents a review of US Planetary Protection obligations, including NASA's procedures and infrastructure related to Planetary Protection, and based on these current protocols provides policy architecture recommendations for the emerging commercial spaceflight industry. It was determined that the most effective policy architecture for ensuring public and private compliance with Planetary Protection places NASA in control of all domestic Planetary Protection matters, and in this role NASA is charged with overseeing, supporting, and regulating the private spaceflight industry. The underlying analysis and architecture tradeoffs that led to this recommendation are presented and discussed.
by Bradley Thomas Holschuh.
S.M.in Technology and Policy
S.M.

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1993, and Thesis (E.A.A.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993.
Includes bibliographical references (leaves 237-245).
by Charles Martin Reynerson.
E.A.A.
Nav.E.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, and Dept. of Electrical Engineering and Computer Science, 1988.
Bibliography: leaf 197.
by Herbert E. M. Viggh.
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, and Dept. of Electrical Engineering and Computer Science, 1988.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2009.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 237-238).
The Earth Science and Applications decadal survey released by the National Research Council in 2007 presents both an ambitious engineering challenge and a challenge for the entire Earth science community to come together to reach a consensus on priorities that cross conventional disciplinary boundaries. The vision established by the decadal survey requires a paradigm shift for Earth system science: Societal benefits must be considered equally with purely scientific benefits to guide the development of the future NASA and NOAA Earth Observations Program. The decadal survey focused heavily on the needs and objectives of the Earth science community, while providing much less thorough treatment of the other relevant stakeholders. To address this, I conducted a stakeholder value network analysis for the Earth Observations Program that includes the development of a comprehensive qualitative and quantitative stakeholder model. The qualitative model includes a rigorous articulation of the needs and objectives of 13 major stakeholders; the development of a three-level stakeholder map including a baseline map, higher-level map, and lower-level map; and a complete stakeholder value network model with 190 individual value flows that capture the interactions between all the stakeholders. The quantitative model includes a method for assigning numeric scores to each value flow; the calculation of 1880 unique and valid "value loops" within the stakeholder value network; and an analysis of the value loops that yields useful insights about the Earth Observations Program. The value loop analysis reveals the most important stakeholders, value flows, and value loops within the stakeholder value network; as well as the most important outputs from and inputs to NASA and NOAA. The analysis also reveals the relative important of each of the six science categories representing the six science-themed panels of the decadal survey. The results from the stakeholder value network analysis provide insights regarding the value produced by the Earth Observations Program, as well as the value-added roles of each stakeholder within the network. The most important value loops and Program outputs are used to derive a set of high-level program goals, including goals that suggest what NASA and NOAA should do, as well as how they should conduct business. Finally, the insights and results from the analysis provide the foundation for a set of recommendations for the Earth Observations Program, which complement the recommendations put forth in the decadal survey.
by Timothy A. Sutherland.
S.M.in Technology and Policy
S.M.

Atomic Oxygen is the dominant atmospheric specie at low earth orbit altitudes for spacecraft orbiting the earth. This altitude range of atomic oxygen dominance extends from 120 km to 900 km. Other species such as helium, molecular oxygen and nitrogen make up the bulk of the rest with the densities corresponding to high to ultrahigh vacuum levels. Spacecraft orbiting at this altitude need to travel at a velocity of 8 km/sec to maintain orbit and therefore spacecraft encounter a high fluence of impinging rarefied atmosphere in a short time period. This gas-surface interaction has several effects which affect the space vehicle. They include aerodynamic drag, surface reaction and surface glow. The need to model these effects on spacecraft surfaces has resulted in the design, development and construction of an advanced facility to simulate these L.E.O. atmospheric effects. This facility utilizing an arc heated source can produce high energy species of the common atmospheric species at a velocity of up to 4.5 km/sec with fluxes comparable to orbit. This particular type of source is unique in Europe with two similar types reported in the U.S.A. Considerable effort was expended in optimizing the source for atomic oxygen production via beam characterization and stagnation condition measurement. This has enabled the radial and axial temperature profiles in the source to be deduced, thus providing a clearer idea of the processes in the source and therefore benefits future users of this technique. In addition, alternative routes of producing atomic oxygen were pursued via nitrous oxide and nitrous oxide/nitrogen seeding. Extensive work on developing reliable beam characterization equipment resulted in the comparison of two methods of beam analysis. This involved the development of a new method of beam mass/energy analysis, which has several advantages over current instruments. Conclusions are made on the suitability of mass spectroscopic detection of reactive specie beams. Finally, atomic oxygen degradation tests were pursued on a variety of surfaces including the polyimide Kapton-H. It was concluded from these tests that Kapton-H erosion has a form of energy dependence, with an energy threshold to erosion of approximately 0.5 eV. The erosion rate above this energy rises rapidly to rates comparable to those of orbit. The Southampton results agree reasonably with the very few results on Kapton-H in this energy range. This has important implications on spacecraft material design.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 155-161).
Extravehicular activity (EVA), or spacewalks allows astronauts to accomplish some of the most important endeavors in space history. The importance of EVA will continue to increase as people venture further into our solar system. The spacesuit, used to protect the astronaut during EVA, is an anthropomorphic spacecraft that provides the physical environment a person needs to survive in the harsh environment of space. Although the suits are safe and effective, the pressurized suit becomes rigid in the vacuum of space, causing the astronaut to waste energy. Mechanical counterpressure (MCP) suits offer an alternative to gas pressurized suits by using elastic garments to provide pressure against the skin. Despite their many advantages, MCP suits are very difficult to put on, or don, making them infeasible for use today. A network of gas pressurized tubes is proposed as a solution to the donning problem. When pressurized, the tubes expand to become rigid, opening the MCP garment in the process. The system was modeled and a functional prototype was developed using a novel construction process. The model can be used as a design tool for future designs and the prototype serves as a proof-of-concept for this solution to the donning problem. The spectacular feats accomplish through spacewalks and space exploration inspire students to pursue an interest and career in science, technology, engineering, and math (STEM). Since its inception, the National Aeronautics and Space Administration (NASA) has been dedicated to educating the public about its compelling mission, fascinating discoveries, and the complicated technologies it develops. However, as the United States slips in indicators of student performance in STEM subjects, many look toward informal education, or education that occurs outside the classroom, to spur interest in STEM subjects. To maximize educational outcomes, NASA has developed a strategic framework to guide its educational programs. This framework is analyzed in the context of strategic management literature and suggests that the framework could be more easily implemented if NASA were to refine its education structure using the strengths of each of its directorates. The proposed framework was implemented in an informal education project and evaluated to determine if a projects implemented under the framework achieves the intended learning objectives. Students showed an increased understanding of NASA's mission and the complicated nature of space exploration. Suggestions to improve future projects are also given.
by Allison P. Anderson.
S.M.in Technology and Policy
S.M.

Recent development in electronics for mobile devices has led to the decrease in sizes and cost of autonomous complex embedded systems such as satellites. It is now possible to build a satellite quicker and only for a fraction of previous costs by using Commercial Off The Shelf (COTS) components. Yet, there are some obstacles that need to be overcome before a successful small satellite can be designed. Among these are the radiation environment, thermal issues, the overall system complexity and tight schedules. This thesis addresses these issues and proposes an overall approach for designing small satellites’ electronics. This approach can be summarised in 6 recommendations: Keep it simple Use fast hardware iterations Do not use space grade components Use a single string design on the system level (no redundancy) Design with limited trust in the software Use simple, accessible and easy updatable documentation With respect to those recommendations an on board data processing system, the Processing Board, has been designed for the ICEYE-1 satellite. The ICEYE-1 satellite is a fully commercial Synthetic Aperture Radar (SAR) satellite that will be launched in December 2017. The designed board has been manufactured and verified during airborne test campaigns.
Nya elektronikutvecklingar för mobiltelefoner har lett till en minskning av storlek och kostnader för andra autonoma komplexa inbyggda system som t.ex. satelliter. Så kallade småsatelliter kan numera byggas snabbare och för endast en bråkdel av tidigare kostnader med hjälp av Commercial Off The Shelf (COTS) komponenter. Det finns dock vissa hinder som måste övervinnas om man vill designa en pålitligt fungerande småsatellit. Till dessa kan räknas strålningsmiljön, väl fungerande värmeledning, det totala systemets komplexitet samt snäva tidtabeller. Detta examensarbete behandlar dessa frågor och föreslår en övergripande strategi för att designa elektronik för småsatelliter. Detta tillvägagångssätt kan sammanfattas i 6 rekommendationer: Håll det enkelt Implementera snabba hårdvaruiterationer Använd inte rymdklassade komponenter Använd ingen redundans på systemnivå Designa med en begränsad tilltro på mjukvaran Dokumentera på ett enkelt, tillgängligt och lätt uppdateringsbart sätt Dessa rekommendationer har använts till att utveckla ett databehandlingssystem, kallat "Processing Board", till småsatelliten ICEYE-1. ICEYE-1 är en kommersiell Synthetic Aperture Radar (SAR) satellit som kommer att skjutas i omloppsbana i december 2017. Databehandlingssystemet i fråga har utvecklats och verifierats i samband med flygplansburna testkampanjer.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2012.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 47-50).
Sleepiness impacts performance in all aspects of life. This thesis addresses the impact of sleepiness on astronauts and adolescents in their everyday tasks. The first part describes the results of an experiment assessing the effect of sleepiness and workload on performance in simulated space telerobotics tasks. The second part describes the results of a forum discussion with high school students about school start time based on information about adolescent sleep biology and various stakeholder perspectives. Astronauts must maintain a high level of performance during space robotics operations, despite sleep schedules that hinder their cognitive function, response time, and attention. This study aimed to determine the usefulness of secondary tasks to assess sleepiness and workload during simulated space robotics performance. 13 naive subjects were trained to perform two types of robotics tasks and two types of secondary tasks measuring response time. Subjects completed two 2-hour robotics sessions, one at midday after approximately 4 hours awake, and one at night after 18 hours awake. Comparing 18 hours awake versus 4, Karolinska Sleepiness Scale scores increased by at least 2 points. Subjects maintained primary robotics task performance at the night session, but secondary task measures such as inverse response time showed significant changes, with moderate Hedges' g (0.35 to 0.74) effect sizes. For a passive monitoring of arm movement primary task, a simple response secondary task metric proved more sensitive to time awake than a two choice response secondary task, but the converse was found when the primary task involved track and capture manual control. Our visual secondary task was sensitive to changes in primary task workload and sleepiness. Secondary task workload measures are a potentially useful adjunct to primary task drowsiness metrics like PVT and deserve further investigation. In Part II, we hypothesized that informed high school students can make strong recommendations about school start time after learning about the biology of their sleep needs and participating in a discussion forum to consider various stakeholder perspectives. 26 high school students from Fenway High School participated in a forum at the Museum of Science. Before the forum, they completed a survey about their sleep habits. During the forum, they participated in a role play exercise, taking on the roles of parent, sleep researcher, administrator, student, and teacher and negotiating tradeoffs about school start time. In the post-forum survey, students showed learning about sleep and made good recommendations to share with their peers. They value sleep and think that getting enough sleep is important, yet by their self-reported actions they seem to value other activities more.
"Part I of this research was supported by the NSBRI through NASA Contract NCC 9-58"--PDF p. 3
by Caroline Lowenthal.
S.M.in Technology and Policy
S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 155-161).
Extravehicular Activity (EVA) spacesuits are a key enabling technology which allow astronauts to survive and work in the harsh environment of space. Of the entire spacesuit, the gloves may perhaps be considered the most difficult engineering design issue. A significant number of astronauts sustain hand and shoulder injuries during extravehicular activity (EVA) training and operations. In extreme cases these injuries lead to fingernail delamination (onycholysis) or rotator cuff tears and require medical or surgical intervention. In an effort to better understand the causal mechanisms of injury, a study consisting of modeling, statistical and experimental analyses was performed in section I of this thesis. A cursory musculoskeletal modeling tool was developed for use in comparing various spacesuit hard upper torso designs. The modeling effort focuses on optimizing comfort and range of motion of the shoulder joint within the suit. The statistical analysis investigated correlations between the anthropometrics of the hand and susceptibility to injury. A database of 192 male crewmembers' injury records and anthropometrics was sourced from NASA's Johnson Space Center. Hand circumference and width of the metacarpophalangeal (MCP) joint were found to be significantly associated with injuries by the Kruskal-Wallis test. Experimental testing was conducted to characterize skin blood flow and contact pressure inside the glove. This was done as part of NASA's effort to evaluate a hypothesis that fingernail delamination is caused by decreasing blood flow in the finger tips due to compression of the skin inside the extravehicular mobility unit (EMU) glove. The initial investigation consisted of a series of skin blood flow and contact pressure tests of the bare finger, and showed that blood flow decreased to approximately 60% of baseline value with increasing force, however, this occurred more rapidly for finger pads (4N) than for finger tips (ION). A gripping test of a pressure bulb using the bare hand was also performed at a moderate pressure of 13.33kPa (100mmHg) and at a high pressure of 26.66kPa (200mmHg), and showed that blood flow decreased 50% and 45%, respectively. Excessive hyperperfusion was observed for all tests following contact force or pressure, which may also contribute to the onset of delamination. Preliminary data from gripping tests inside the EMU glove in a hypobaric chamber at NASA's Johnson Space Center show that skin blood flow decreased by 45% and 40% when gripping at 3 moderate and high pressures, respectively. These tests show that finger skin blood flow is significantly altered by contact force/pressure, and that occlusion is more sensitive when it is applied to the finger pad than the finger tip. Our results indicate that the pressure on the finger pads required to articulate stiff gloves is more likely to impact blood flow than the pressure on the fingertips associated with tight or ill-fitting gloves. Improving the flexibility of the gloves will therefore not only benefit operational performance, but may also be an effective approach in reducing the incidence of finger injury. Space Policy Abstract EVA injury is only one of many dangers astronauts face in the extreme environment of space. Orbital debris presents a significant threat to astronaut safety and is a growing cause of concern. Since the dawn of satellites in the early 1950's, space debris from intentionally exploded spacecraft, dead satellites, and on-orbit collisions has significantly increased and currently outnumbers operational space hardware. Adding to this phenomenon, the advent of commercial spaceflight and the recent space activities in China and India to establish themselves as spacefairing nations are bound to accelerate the rate of space debris accumulating in low Earth orbit, thus, exacerbating the problem. The policies regulating orbital debris were drafted in the 1960s and 1970s and fail to effectively address the dynamic nature of the debris problem. These policies are not legally enforced under international law and implementation is entirely voluntary. Space debris is a relevant issue in international space cooperation. Unless regulated, some projections indicate space debris will reach a point of critical density, after which the debris will grow exponentially, as more fragments are generated by collisions than are removed by atmospheric drag. Space debris proliferation negatively impacts human spaceflight safety, presents a hazard to orbiting space assets, and may lead to portions of near-Earth orbit becoming inaccessible, thus limiting mission operations. The aim of this research effort was to review current international space policy, legislation and mitigation strategies in light of two recent orbital collision episodes. The first is the February 2009 collision between a defunct Russian Cosmos spacecraft and a commercial Iridium satellite. The second is China's display of technological prowess during the January 2007 intentional demolition of its inactive Fengyun-IC weather satellite using a SC-19 antisatellite (ASAT) missile. In each case the stakeholders, politics, policies, and consequences of the collision are analyzed. The results of this analysis as well as recommendations for alternative mitigation and regulatory strategies are presented.
by Roedolph A. Opperman.
S.M.in Technology and Policy
S.M.

Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, Institute for Data, Systems, and Society, Technology and Policy Program, 2016.
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 212-225).
Human spaceflight programs are facing new challenges rising from the evolution of the exploration agenda, as well as the changing international panel of actors. Planetary exploration missions will require intensive extravehicular activities (EVA). Simultaneously, the design of such missions will increasingly rely on cooperation between several types of actors: international and public/private. Adapting this paradigm shift requires astronauts, both symbols and key elements of human space exploration, to be fully equipped to explore and share their experiences. Consequently, astronaut mobility during the exploration mission, characterized by spacesuit kinematics, as well as astronaut mobility for space public outreach, characterized by the ability to inspire multiple types of people, are critical for the future of human spaceflight. This thesis focuses on these two elements of astronaut mobility: spacesuit motion and public inspiration for human spaceflight. All of the spacesuits currently in use are gas-pressurized and enable a wide range of astronaut performance. However, the pressurization causes an inherent stiffness, leading to astronauts' fatigue, unnecessary energy expenditure and limited mobility in the spacesuit. Better understanding of spacesuit kinematics is crucial to enable future human space exploration during extreme mobility tasks such as climbing, loping and excavating. Different methods are currently used to assess spacesuit mobility, but they are restricted to laboratory settings and do not measure the interactions between the suit and the person inside the suit. The first objective of this research is to develop a novel method to assess spacesuit kinematics and visualize human-spacesuit interactions. Upper body mobility of different suits was assessed by placing inertial measurement units (IMUs) on the person's body and on the outside of the spacesuit. IMUs incorporate accelerometers and gyroscopes to estimate relative rotation. They are mobile and low power, offering an economical and efficient kinematic tracking capability. A comparison of joint angle amplitude between different pressurization conditions and different motions was performed, and a 3D kinematic visualization tool was developed. While space-based technologies for Earth applications are flourishing, space exploration activities suffer from a lack of public awareness as well as decreasing budgets. Recent robotic exploration missions have positively influenced public perception by utilizing video and social media communication. How can these new communication technologies be used to better serve human spaceflight? How can space agencies and astronauts inspire tax-paying citizens, and thus politicians, to commit to an ambitious, global human spaceflight program based on international collaboration? The second part of the research analyzes how astronauts' use of interactive platforms can increase international public interest in human space exploration. An analysis of the Twitter network related to human spaceflight was performed, measuring how influence and relationships are linked, to better capture the best practices.
by Pierre J. Bertrand.
S.M. in Technology and Policy
S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 73-76).
Engineering, management, and social science methodologies have been employed to analyze a new asset tracking and management system for human spaceflight applications. The Massachusetts Institute of Technology and Aurora Flight Sciences developed Rule-based analytic Asset Management for Space Exploration System (RAMSES) via NASA Small- Business Technology Transfer (STTR) Phase I and Phase II contracts. RAMSES leverages Generation II passive Radio Frequency Identification (RFID) technology to automate the tracking the tens of thousands of small, portable cargo assets that are currently stored onboard the International Space Station (ISS). A Monte Carlo Net Present Value analysis found that RAMSES is likely to have significant positive value for NASA when ISS inventory transactions are concentrated in a subset of the total cargo transfer bag (CTB) population, and/or if ISS Operations are continued into 2018/2020. The volume, mass, and accuracy of the RAMSES system have a significant impact upon the estimated NPV. Testing of the prototype hardware in reduced-gravity conditions reaffirmed the viability of the system. Metals cargo objects were detected with up to 100% accuracy, paper with 96%, and water with roughly 93%. Finally, a comparative analysis of RAMSES and five other NASA Small-Business Innovation Research (SBIR) / Small-Business Technology Transfer (STTR) projects identified three non-technical characteristics and/or informal processes that might be unique to SBIR/STTR technologies that are successfully infused into the mainstream NASA innovation system. These included pre-proposal knowledge exchanges between companies and NASA, strong matching of a project with a relevant NASA COTR, and the availability of an infusion opportunity
by Abraham T. Grindle.
S.M.in Technology and Policy
S.M.

The past decades have seen the state of the art in aerospace system design progress from a scope of simple optimization to one including robustness, with the objective of permitting a single system to perform well even in off-nominal future environments. Integrating flexibility, or the capability to easily modify a system after it has been fielded in response to changing environments, into system design represents a further step forward. One challenge in accomplishing this rests in that the decision-maker must consider not only the present system design decision, but also sequential future design and operation decisions. Despite extensive interest in the topic, the state of the art in designing flexibility into aerospace systems, and particularly space systems, tends to be limited to analyses that are qualitative, deterministic, single-objective, and/or limited to consider a single future time period. To address these gaps, this thesis develops a stochastic, multi-objective, and multi-period framework for integrating flexibility into space system design decisions. Central to the framework are five steps. First, system configuration options are identified and costs of switching from one configuration to another are compiled into a cost transition matrix. Second, probabilities that demand on the system will transition from one mission to another are compiled into a mission demand Markov chain. Third, one performance matrix for each design objective is populated to describe how well the identified system configurations perform in each of the identified mission demand environments. The fourth step employs multi-period decision analysis techniques, including Markov decision processes (MDPs) from the field of operations research, to find efficient paths and policies a decision-maker may follow. The final step examines the implications of these paths and policies for the primary goal of informing initial system selection. Overall, this thesis unifies state-centric concepts of flexibility from economics and engineering literature with sequential decision-making techniques from operations research. The end objective of this thesis' framework and its supporting analytic and computational tools is to enable selection of the next-generation space systems today, tailored to decision-maker budget and performance preferences, that will be best able to adapt and perform in a future of changing environments and requirements. Following extensive theoretical development, the framework and its steps are applied to space system planning problems of (1) DARPA-motivated multiple- or distributed-payload satellite selection and (2) NASA human space exploration architecture selection.

Aufgrund des Mißerfolges der Mars Observer Mission 1992 und allgemeiner sinkender Raumfahrtetats, entwickelte NASA 1995 die „Faster Better Cheaper“ (FBC) Philosophie. Diese sah vor, daß planetare Missionen innerhalb eines kurzen Zeitraumes und mit begrenzten Budgets geplant, gebaut, getestet und gestartet werden sollten. Dabei sollten neue Technologien und neue Betriebsmethoden zum Einsatz kommen. Mögliche Fehlschläge durch unerprobte Instrumente oder Prozesse wurden dabei nicht ausgeschlossen. Der Mißerfolg der Mars-Missionen im Jahr 1999 und weiterer Projekte zwangen jedoch zu einem Umdenken der „Faster Better Cheaper“ Philosophie. Eine Vielzahl von Abhandlungen und Untersuchungen wurden daraufhin veröffentlicht, die Fehler der FBC Philosophie aufzeigten, ohne dabei jedoch auf mögliche Verbesserungen einzugehen. Das Ziel dieser Arbeit besteht in der Ermittlung effektiver Maßnahmen, so daß Ressourcen während des Lebenszyklus eines Projektes optimal eingesetzt werden können. Aus der Analyse der fehlgeschlagenen Missionen und einer Erläuterung der Funktionen verschiedener planetarer Missionskonzepte, werden mögliche Maßnahmen zur Verringerung der Kosten ermittelt. Die Effektivität dieser Maßnahmen wird anhand eines Bewertungskataloges im Rahmen einer Simulation zu verschiedenen Zeitpunkten einer Mission bestimmt. Es wird dabei eine Handlungshilfe erstellt, mit der ein Projektmanager die Verteilung von Ressourcen optimieren kann. Die Systemtechnik bietet hierzu eine Vielzahl von Analyse- und Simulationsmethoden, mit der die hier gemachten Angaben bewertet und überprüft werden können.
Due to the failure of the Mars Observer Mission in 1992 and decreasing budgets, NASA developed a new philosophy for the development, design and operations called „Faster Better Cheaper“ (FBC). New technologies and new management methods were deployed to reduce lift cycle costs. Possible mission failures were expected. After the losses of the Mars Missions in 1999 and other missions, NASA was forced to rethink its FBC approach. Numerous papers have been published in the meantime which identified the mistakes of the missions and of FBC, but none have identified potential improvements. The objective of this paper is the development of potential measurements for the design of the operations of unmanned space missions that should be applied during its life cycles. A new tool in form of an EXCEL spreadsheet will be developed based on historical missions, which can be used a program manager who can allocate resources in optimal way. Systems Engineering Techniques will be used in various ways to identify problems and to measure potential improvements.

Electrical Engineering
M.S.E.E.
The space-based solar power system is an alternative to the ground-based solar power system because of its round-the-clock availability. For the space-based solar power transmission, the accurate pointing of a laser from space to ground poses a challenging control task. A gimbaled laser target system, which is used for pointing laser to a target, is a test bench for such a transmission system. The objective of this research is to determine the optimal controller for the gimbaled laser target system in terms of pointing error and error variation. In order to achieve the objective, we modeled the gimbaled laser target system, simulated the model with the controllers, and tested them on the test bench. In this thesis, we developed a mathematical model of a two-axis gimbaled laser target system. The model consists of a pitch-yaw gimbal for the dynamic laser motion, brushless dc motors for actuating the gimbal, and an image-based position sensor. We used a Proportional-Integral-Derivative (PID) controller as the basis for the performance comparison since it is the most commonly used control method in the industry. Then we compared the PID controller with two statistical control methods - Linear Quadratic Gaussian (LQG), and Minimal Cost Variance (MCV) optimal controllers. We evaluated the pointing performance of the controllers by measuring the mean and the standard deviation of the pointing error. The simulation results indicated that the statistical controllers perform better than the PID controller under Gaussian disturbances. Between the statistical controllers, the LQG method had the smaller pointing error, while the MCV method had the smaller standard deviation of the pointing error. We then implemented the PID, LQG, and MCV controllers in an off-the-shelf dSPACE digital signal processing controller board, and tested the controllers on the test bench in a real time environment. The experimental results showed that the LQG method decreased the mean pointing error by 46.28% compared to the PID method. The LQG method reduced the standard deviation of pointing error by 47.85% compared to the PID method. The MCV method reduced the standard deviation of the pointing error by 53.09% compared to the LQG method. Both the simulation and experimental results showed that the MCV controller improved the pointing error variation performance over the LQG controller significantly, while slightly degrading the pointing error performance of the gimbaled laser target system. Experimental results indicate that the statistical controllers will provide a design parameter either to improve the mean pointing error or the standard deviation of the pointing error for the gimbaled laser target system. Subsequently, we believe that the statistical controllers will improve the space-based solar power transmission efficiency.
Temple University--Theses

This report is the result of a conducted Minor Field Study (MFS), to the greatestextent funded by the Swedish International Development Cooperation Agency(SIDA), in an attempt to design a system for evaluating smaller solar power systems indeveloping countries. The study was to the greater part conducted in Nairobi, Kenyain close collaboration with the University of Nairobi. The aim was to develop asystem that would use easily available components and keep the costs to a minimum,yet deliver adequate performance. The system would measure certain parameters of asolar power system and also relevant environmental data in order to evaluate theperformance of the system. Due to the specific competence of the collaboratinggroup at the University of Nairobi, a Kinetis Freescale K64-microcontroller with anARM-Cortex processor was selected as the core of the design. Components wereselected, schematics were drawn, a circuit board was designed and manufactured andsoftware was written. After 12 weeks a somewhat satisfying proof-of-concept wasreached at the end of the field study in Kenya. The project however proved howdifficult it is to go from first idea to a functional proof-of-concept during a limitedtimeframe, and also in an East-African country. The final proof-of-concept was testedat Mpala Research Centre in Kenya and despite containing some flaws proved that itwould indeed be possible to design a working system on the principles discussed inthis report. The system is open-source, so anyone may use and modify it.

The complexity and amount of medical hardware needed by National Aeronautics and Space Administration (NASA) constantly shifts with mission requirements. Early missions such as Mercury, Gemini, and Apollo required minimal, relatively non-complex medical hardware, but as mission lengths have increased from hours to multiple months and mission crew sizes have increased from one to seven, so has the amount and complexity of medical hardware. As such, a need has arisen to develop a methodology by which medical hardware is certified for the space environment in a safe, consistent, and economically viable manner. This record of study documents my experiences certifying medical hardware for the space environment by providing two specific certification examples, a defibrillator, and automated external defibrillator and provides a brief history of the medical hardware used by NASA for its manned space programs.

The evolution of General Circulation Models (GCM) for climate study has led to more accurate predictions for atmospheric transport, yet precision in predictions remains in need of improvement. The National Aeronautics and Space Administration Goddard Earth Observation System model, Version 5 (GEOS-5) represents a state of the art climate model capable of simulating a wide variety of atmospheric processes informed continuously by satellite observations. This thesis examines some of the physical parameterizations employed by GEOS-5 and their effect on the transport of two greenhouse gasses: ozone and carbon dioxide.