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At least 1,477 records · Page 82

Space station thermal control surfaces. Volume 1: Interim report

The U.S. space program goals for long-duration manned missions place particular demands on thermal-control systems. The objective of this program is to develop plans which are based on the present thermal-control technology, and which will keep pace with the other space program elements. The program tasks are as follows: (1) requirements analysis, with the objectives to define the thermal-control-surface requirements for both space station and 25 kW power module, to analyze the missions, and to determine the thermal-control-surface technology needed to satisfy both sets of requirements; (2) technology assessment, with the objectives to perform a literature/industry survey on thermal-control surfaces, to compare current technology with the requirements developed in the first task, and to determine what technology advancements are required for both the space station and the 25 kW power module; and (3) program planning that defines new initiative and/or program augmentation for development and testing areas required to provide the proper environment control for the space station and the 25 kW power module.

Maag, C. R.↗

Contamination Control and Assessment Strategy for Martian Moons Exploration (MMX)

Martian Moons eXploration (MMX) is a sample return mission from the Martian moon Phobos. The MMX spacecraft is scheduled for launch in 2026 and return to Earth in 2031. The primary science objective of MMX is to reveal the origin of the Martian moons, thereby advancing the understanding of planetary system formation and material transport in the solar system, as well as to observe processes affecting the circumplanetary and surface environments of Mars. The returned sample will be transported to the curation facility at ISAS/JAXA, and the subsequent curation and sample analysis activity will be conducted. As a sample return mission, MMX requires strict contamination control to prevent the intrusion of terrestrial materials.

H Sugahara↗

Deep space network radio science system for Voyager Uranus and Galileo missions

An overview is presented of major new requirements, challenges and conceptual designs for the DSN Radio Science System in the 1985 to 1988 period. The Voyager Uranus encounter is being supported with larger combined aperture, higher sample rate, and a centrally controlled network. The Galileo mission will be provided with a high resolution S-Band Faraday rotation detection capability and a high-stability Doppler system with X-Band uplink for gravitational wave search.

Peng, T. K.↗

Radio astronomy Explorer-B postlaunch attitude operations analysis

The attitude support activities of the Radio Astronomy Explorer-B are reported. The performance of the spacecraft hardware and software are discussed along with details of the mission events, from launch through main boom deployment. Reproductions of displays are presented which were used during support activities. The interactive graphics proved the support function by providing the quality control necessary to ensure mission success in an environment where flight simulated ground testing of spacecraft hardware cannot be performed.

Werking, R. D.↗

Astrodynamics 1975; Conference, Nassau, Bahamas, July 28-30, 1975, Technical Papers

Articles are grouped under four headings: (1) dynamics and control of satellites; (2) satellite mission analysis; (3) Aeros-B and Symphonie satellite engineering problems; (4) optimization and control techniques applied to solar space heating and cooling of buildings. Topics covered include: communications and earth survey satellite systems, a system of two counter-orbiting satellites measuring GRT-predicted nodal drag, statistical mechanics studies of the spatial density function of orbiting space junk, attitude control of satellites, nutation dampers, low thrust inertial guidance and ascent inertial guidance, a shuttle-launched multi-comet intercept mission, preflight and in-flight analysis of the Atmosphere Explorer (AE-C) satellite, and launch-encounter strategy for the Mariner 1977 Jupiter-Saturn mission. Individual items are announced in this issue.

Powers, W. F.↗

Attitude control subsystem study for the Land Mobile Satellite System Spacecraft

This Attitude Control Subsystem study applies the generic antenna control technology to the specific requirements of the Land Mobile Satellite System mission and defines suitable attitude control subsystem designs for both the wrap/rib and hoop/column antenna configurations. The technology developments required to establish technology readiness by 1987 are also identified.

Tolivar, A. F.↗

Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions Workshop Booklet - 2015

Although NASA's preparations for the Apollo lunar missions had only a limited time to consider issues associated with the protection of the Moon from biological contamination and the quarantine of the astronauts returning to Earth, they learned many valuable lessons (both positive and negative) in the process. As such, those efforts represent the baseline of planetary protection preparations for sending humans to Mars. Neither the post-Apollo experience or the Shuttle and other follow-on missions of either the US or Russian human spaceflight programs could add many additional insights to that baseline. Current mission designers have had the intervening four decades for their consideration, and in that time there has been much learned about human-associated microbes, about Mars, and about humans in space that has helped prepare us for a broad spectrum of considerations regarding potential biological contamination in human Mars missions and how to control it. This paper will review the approaches used in getting this far, and highlight some implications of this history for the future development of planetary protection provisions for human missions to Mars. The role of NASA and ESA's planetary protection offices, and the aegis of COSPAR have been particularly important in the ongoing process.

Fonda, Mark L.↗

The Pascal Mars Scout Mission

Except for Earth, Mars is the planet most amenable to surface-based climate studies. Its surface is accessible, and the kind of observations that are needed, such as meteorological measurements from a long-lived global network, are readily achievable. Weather controls the movement of dust, the exchange of water between the surface and atmosphere, and the cycling of CO2 between the poles. We know there is a weather signal, we know how to measure it, and we know how to interpret it. Pascal seeks to understand the long-term global behavior of near-surface weather systems on Mars, how they interact with its surface, and, therefore, how they control its climate system. To achieve this, Pascal delivers 18 Science Stations to the surface of the planet that operate for three Mars years (5.6 Earth years). The network has stations operating in the tropics, midlatitudes, and polar regions of both hemispheres. During entry, descent, and landing, each Pascal probe acquires deceleration measurements to determine thermal structure, and descent images to characterize local terrain. On the surface, each Science Station takes daily measurements of pressure, opacity, temperature, wind speed, and water vapor concentration and monthly panoramic images of the landing environment. These data will characterize the planet's climate system and how atmosphere-surface interactions control it. The Pascal mission is named after 17th century French Scientist, Blaise Pascal, who pioneered measurements of atmospheric pressure. Pressure is the most critical measurement because it records the "heartbeat" of the planet's general circulation and climate system.

Haberle, R. M.↗

Advanced Curation Activities at NASA: Preparation for Upcoming Missions

The responsibility for curating NASA's astromaterials collections falls to the NASA Curation Office at Johnson Space Center. Under the governing document, NASA Policy Directive (NPD) 7100.10F and derivative requirements documents, JSC is charged with curation of all extraterrestrial material under NASA control, including future NASA missions to include material returned in Mars Sample Return (MSR) efforts, OSIRIS-REx, NASA's subset of Hayabusa-2 samples, and any other sample return missions. The Directive defines Curation as activities including documentation, preservation, sample preparation, distribution, and tracking of samples for research, education, and public outreach. In this abstract we will describe Curation's research and development efforts to improve the care of existing collections and prepare for future NASA sample return missions. These efforts are collectively referred to as Advanced Curation, a term first coined in 2002.

Fries, M. D.↗

Dawn's Mission at Ceres

Dawn is NASA's ninth Discovery class mission. The Dawn spacecraft was designed to orbit both the giant asteroid Vesta and the dwarf planet Ceres in succession, a mission only made possible by the high efficiency of ion propulsion. While the same spacecraft visited both bodies, the mission planning and maneuver execution at the two bodies were necessarily very different. The mission at Vesta benefited from at least three functioningreaction control wheels. At Ceres, all maneuvering and coasting during transfers was done without reaction wheel control due to the loss of the second of four wheels while departing Vesta. Loss of the second wheel made conserving attitude control propellant (hydrazine) critical to achieving mission success at Ceres. To save hydrazine, avoiding unnecessary coasting and attitude turns became essential during the interplanetary cruise to Ceres and for all transfers once at Ceres. In contrast, operations at Vesta did not need to avoid coasting. Operating at Ceres requires being farther from the Sun. Greaterheliocentric distances (approaching 3 AU (Astronomical Units) make Dawn's attitude control constraints while maneuvering more restrictive as a result of reduced control authority.

Whiffen, Gregory J.↗

Inflatable Re-entry Vehicle Experiment (IRVE-4) Overview

The suite of Inflatable Re-Entry Vehicle Experiments (IRVE) is designed to further our knowledge and understanding of Hypersonic Inflatable Aerodynamic Decelerators (HIADs). Before infusion into a future mission, three challenges need to be addressed: surviving the heat pulse during re-entry, demonstrating system performance at relevant scales, and demonstrating controllability in the atmosphere. IRVE-4 will contribute to a better understanding of controllability by characterizing how a HIAD responds to a set of controlled inputs. The ability to control a HIAD is vital for missions that are g-limited, require precision targeting and guidance for aerocapture or entry, descent, and landing. The IRVE-4 flight test will focus on taking a first look into controlling a HIAD. This paper will give an overview of the IRVE-4 mission including the control response portion of the flight test sequence, and will provide a review of the mission s development.

Litton, Daniel K.↗

Precision slew/settle technologies for flexible spacecraft

Many spacecraft missions in the next decade will require both a high degree of agility and precision pointing. Agility includes both rotational maneuvering for retargeting and translational motion for orbit adjustment and threat avoidance. The major challenge associated with such missions is the need for control over a wide range of amplitudes and frequencies, ranging from tens of degrees at less than 1 Hz to a few micron radians at hundreds of Hz. TRW's internally funded Precision Control of Agile Spacecraft (PCAS) project is concerned with developing and validating in hardware the tools necessary to successfully complete the combined agile maneuvering/precision pointing missions. Development has been undertaken on a number of fronts for quietly slewing flexible structures. Various methods for designing slew torque profiles have been investigated. Prime candidates for slew/settle scenarios include Inverse Dynamics and Parameterized Function Space. Joint work with Processor Bayo at the University of California, Santa Barbara and Professor Flashner at the University of Southern California has led to promising torque profile design methods. Active and passive vibration suppression techniques also play a key role for rapid slew/settle mission scenarios. Active members with local control loops and passive members with high loss factor viscoelastic material have been selected for hardware verification. Progress in each of these areas produces large gains in the quiet slewing of flexible spacecraft. The main thrust of the effort to date has been the development of a modular testbed for hardware validation of the precision control concepts. The testbed is a slewing eighteen foot long flexible truss. Active and passive members can be interchanged with the baseline aluminum members to augment the inherent damping in the system. For precision control the active members utilize control laws running on a high speed digital structural control processor. Tip and midspan motions of the truss are determined using optical sensors while accelerometers can be used to monitor the motions of other points of interest. Preliminary results indicate that a mix of technologies produces the greatest benefit. For example, shaping the torque profile produces large improvements in slew/settle performance, but without added damping settling times may still be excessive. With the introduction of moderate amounts of damping, slew/settle performance is vastly improved. On the other hand, introducing damping without shaping the torque profile may not yield the desired level of performance.

Manning, R. A.↗

Real-time computer simulation/emulation for verification of multi-fault-tolerant control of Centaur-in-Shuttle

NASA has contracted with General Dynamics to design and develop an advanced Centaur liquid upper stage for support of the Galileo and Solar Polar interplanetary missions in 1985-86. The control of the Centaur while it resides in the Shuttle cargo bay must meet the STS safety requirements to be dual failure tolerant in all mission critical functions. The demonstration of the integrity of this control system in the event of multiple component failures and worst-case time-phase asynchroniety among the system's computers is performed by a real-time computer simulation. The simulation emulates the control hardware, subsystem interfaces, and imbedded software processes, wire-by-wire, to provide accessibility for fault insertion. Observability is provided via graphics and diagnostic software. Verification is the product of Monte Carlo simulation analysis.

Szatkowski, G. P.↗

Silver Foam as Long-Term Passive Biocide for Potable Water Systems

A spacecraft water disinfection system, suitable for extended length space exploration missions, should prevent or control the growth of microbes, prevent or limit biofilm formation, and prevent microbiologically-influenced corrosion. In addition, the system should have minimal maintenance requirements, the effluent should be chemically compatible with all materials in contact with the water, be safe for human consumption, and suitable to be shared across international spacecraft platforms and mission architectures. Silver ions are a proven broad spectrum biocide. Silver is also the potable water biocide of choice for future exploration missions. Currently, the proposed method for implementing silver biocide in spacecraft systems relies on silver electrode technology to produce a controlled amount of silver ions. Unfortunately, electrolytic-based silver dosing presents multiple inherent challenges that affect performance and increase maintenance requirements over time. To decrease the risk of failure, an alternative silver biocide delivery method is needed. Control-release technology is an attractive option for developing a passive high-reliability silver dosing device. The concept of a nanoparticle/polyurethane (PU) composite foam for the controlled release of silver was prompted by the controlled release technology developed by NASA for the delivery of corrosion inhibitors and indicators. This paper presents the technical background and results from the synthesis and properties testing of the silver nanoparticles (AgNPs)/PU composite foam that is being developed for use in spacecraft potable water systems.

Irwin, Tesia D.↗

Centaur zero gravity coast and engine restart demonstration on the Titan/Centaur (TC-2) extended mission

The Centaur propellant management and thermal control techniques required for zero gravity coasting were successfully demonstrated during an extended mission following spacecraft separation on the TC-2 flight. As part of the demonstration, two successful engine starts were accomplished. The first engine start followed a one-hour zero gravity coast, and the second engine start followed a three-hour zero gravity coast. All of the Centaur systems performed satisfactorily, the design parameters for zero gravity coasting were verified, and no significant problems were encountered. The flight results showed that the propellant location and behavior, propellant heating, and tank pressure rise rates observed during the zero-gravity coasts were less severe than expected. Consequently, the majority of the propellants remained at the tank bottom, the propellant collection times were very short, and more than 7 hours of coast could have been achieved before a tank venting was required. The tank pressurization prior to the engine starts provided boost pump Net Positive Suction Head values well in excess of the values required. The LO2 tank pressurization was accomplished by a new bubbler method that greatly reduced the helium usage.

Lacovic, R. F.↗

Human Centered Autonomous and Assistant Systems Testbed for Exploration Operations

The Engineering and Mission Operations Directorates at NASA Johnson Space Center are combining laboratories and expertise to establish the Human Centered Autonomous and Assistant Systems Testbed for Exploration Operations. This is a testbed for human centered design, development and evaluation of intelligent autonomous and assistant systems that will be needed for human exploration and development of space. This project will improve human-centered analysis, design and evaluation methods for developing intelligent software. This software will support human-machine cognitive and collaborative activities in future interplanetary work environments where distributed computer and human agents cooperate. We are developing and evaluating prototype intelligent systems for distributed multi-agent mixed-initiative operations. The primary target domain is control of life support systems in a planetary base. Technical approaches will be evaluated for use during extended manned tests in the target domain, the Bioregenerative Advanced Life Support Systems Test Complex (BIO-Plex). A spinoff target domain is the International Space Station (ISS) Mission Control Center (MCC). Prodl}cts of this project include human-centered intelligent software technology, innovative human interface designs, and human-centered software development processes, methods and products. The testbed uses adjustable autonomy software and life support systems simulation models from the Adjustable Autonomy Testbed, to represent operations on the remote planet. Ground operations prototypes and concepts will be evaluated in the Exploration Planning and Operations Center (ExPOC) and Jupiter Facility.

Malin, Jane T.↗

An Approach to Magnetic Cleanliness for the Psyche Mission

In this paper we describe the derivation of these requirements, test and analyses methods, and more generally the processes and procedures that govern the magnetics program for Psyche. The paper concludes with a discussion of the challenges and work to go and a comparison with the magnetic control processes of other missions with similar magnetic cleanliness constraints.

de Soria-Santacruz Pich, Maria↗