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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13

Transient vibration test criteria for spacecraft hardware

Transient vibration test criteria, developed for spacecraft hardware, provide a test rationale to verify the capability of the hardware to withstand the low and mid frequency transient vibration environments induced by launch vehicle events. A test method, consisting of a series of discrete frequency, limited cycle, modulated sine wave pulses, was developed to avoid the slow swept sine drawbacks, yet provide a repeatable test that would excite all frequencies. The shape of the waveform is that of the classic response of the mass of a one degree of freedom system when it is base-excited by an exponentially decayed sine wave transient. Criteria were developed to define pulse amplitudes, shapes, and center frequencies from spacecraft loads analyses. Test tolerance criteria were also developed and specified. The transient vibration test criteria were implemented on spacecraft flight hardware and provided a more realistic test simulation (i.e., less conservative) for qualification of spacecraft hardware without risk of undertest.

Kern, D. L.↗

Autonomous Coordination of Science Observations Using Multiple Spacecraft

This software provides capabilities for autonomous cross-cueing and coordinated observations between multiple orbital and landed assets. Previous work has been done in re-tasking a single Earth orbiter or a Mars rover in response to that craft detecting a science event. This work enables multiple spacecraft to communicate (over a network designed for deep-space communications) and autonomously coordinate the characterization of such a science event. This work investigates a new paradigm of space science campaigns where opportunistic science observations are autonomously coordinated among multiple spacecraft. In this paradigm, opportunistic science detections can be cued by multiple assets where a second asset is requested to take additional observations characterizing the identified surface feature or event. To support this new paradigm, an autonomous science system for multiple spacecraft assets was integrated with the Interplanetary Network DTN (Delay Tolerant Network) to provide communication between spacecraft assets. This technology enables new mission concepts that are not feasible with current technology. The ability to rapidly coordinate activities across spacecraft without requiring ground in the loop enables rapid reaction to dynamic events across platforms, such as a survey instrument followed by a targeted high resolution instrument, as well as regular simultaneous observations.

Estlin, Tara A.↗

Flight Results and Lessons Learned from the Starling Propulsion System

NASA’s Starling mission is a swarm of four 6U Cubesats flying in formation in Low Earth Orbit to demonstrate scalable swarm technologies, particularly related to crosslink networking. In order to maintain and modify their formation, the Starling spacecraft use a cold gas propulsion system called Hamlet, which provides each spacecraft with 30 m/s of delta-V, as well as attitude control during maneuvers. Hamlet is a fully self-contained system, incorporating propellant tanks, valves, nozzles, and control electronics. Most of the structure of Hamlet is a single piece of stereolithography-printed composite, which simplifies assembly and allows for unusual tank geometry that maximizes propellant volume in the allocated space. An extensive qualification campaign was conducted for Hamlet, including performance characterization that has been largely validated by in-flight measurements. Since the start of nominal mission operations in late summer 2023, Hamlet has conducted weekly or bi-weekly maneuvers of up to 0.29 m/s to assemble the swarm, maintain formation, and change swarm configurations as required by the experiments. Operations have not been without challenges, including a propellant leak on one unit and thrust variability issues on all four. This paper describes the design and implementation of Hamlet, as well as in-flight performance data, anomaly investigation and resolution, and lessons learned.

Starling↗

NASA Proof-of-Concept 1-W Stirling Convertor Development for Small RPS

Low power Stirling convertors are being developed at NASA Glenn Research Center (GRC) to provide future small spacecraft with electrical power by converting heat from one or more Light Weight Radioisotope Heater Units (LWRHU). An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. A variety of mission concepts have been studied by NASA and the U.S. Department of Energy (DOE) that would utilize low power Radioisotope Power Systems (RPS) for probes, landers, rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data such as, radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies propose using fractional versions of the General Purpose Heat Source (GPHS) or multiple LWRHUs to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Efforts to develop the concept have focused on maturation of a 1-We (1-watt electrical) convertor and controller design and performance evaluation of an evacuated metal foil insulation. A proof-of-concept 1-We convertor, controller, and evacuated metal foil insulation package have been fabricated and are undergoing characterization testing. The current status, findings, and path forward for the effort are explained in this paper.

Stirling↗

NASA Proof-of-Concept 1-W(sub e) Stirling Convertor Development for Small Radioisotope Power Systems

Low power Stirling convertors are being developed at NASA Glenn Research Center to provide future small spacecraft with electrical power by converting heat from one or more Light Weight Radioisotope Heater Units (LWRHU). An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. A variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize low power Radioisotope Power Systems (RPS) for probes, landers, rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data such as, radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies propose using fractional versions of the General Purpose Heat Source or multiple LWRHUs to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Efforts to develop the concept have focused on maturation of a 1-We convertor and controller design and performance evaluation of an evacuated metal foil insulation. A proof-of-concept 1-We convertor, controller, and evacuated metal foil insulation package have been fabricated and are undergoing characterization testing. The current status, findings, and path forward for the effort are explained in this paper.

Schifer, Nicholas A.↗

NASA Proof-of-Concept 1-W Stirling Convertor Development for Small RPS

Low power Stirling convertors are being developed at NASA Glenn Research Center (GRC) to provide future small spacecraft with electrical power by converting heat from one or more Light Weight Radioisotope Heater Units (LWRHU). An initial design converts multiple watts of heat to one watt of electrical power output using a Stirling convertor. A variety of mission concepts have been studied by NASA and the U. S. Department of Energy (DOE) that would utilize low power Radioisotope Power Systems (RPS) for probes, landers, rovers, and repeaters. These missions would contain science instruments distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Landers could be used to provide data such as, radiation, temperature, pressure, seismic activity, and other surface measurements for planetary science and to inform future mission planners. The studies propose using fractional versions of the General Purpose Heat Source (GPHS) or multiple LWRHUs to heat power conversion technologies for science instruments and communication. Dynamic power systems are capable of higher conversion efficiencies, which could enable equal power using less fuel or more power using equal fuel, when compared to less efficient static power conversion technologies. Providing spacecraft with more power would decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. Efforts to develop the concept have focused on maturation of a 1-We convertor and controller design and performance evaluation of an evacuated metal foil insulation. A proof-of-concept 1-We convertor, controller, and evacuated metal foil insulation package have been fabricated and are undergoing characterization testing. The current status, findings, and path forward for the effort are explained in this paper.

Schifer, Nicholas A.↗

Propulsive Small Expendable Deployer System (ProSEDS) Space Demonstration

The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system. The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes-all using electrodynamic thrust. ProSEDS which is planned to fly in 2000, will use the flight proven Small Expendable C, Deployer System (SEDS) to deploy a tether (5 km bare wire plus 15 km spectra) from a Delta II upper stage to achieve approximately 0.4N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of endmass collector and insulated tether approach used on previous missions. ProSEDS will utilize tether-generated current to provide limited spacecraft power. In addition to the use of this technology to provide orbit transfer of payloads and upper stages from LEO to higher orbits it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere.

Johnson, Les↗

Propulsive Small Expendable Deployer System (ProSEDS) Space Experiment

The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system. The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes-all using electrodynamic thrust. ProSEDS which is planned to fly in 2000, will use the flight proven Small Expendable Deployer System (SEDS) to deploy a tether (5km bare wire plus 15 km spectra) from a Delta II upper stage to achieve approximately 0.4N drag thrust, thus demonstrating deorbit thrust. The experiment will use a predominantly 'bare' tether for current collection in lieu of endmass collector and insulated tether approach used on previous missions. ProSEDS will utilize tether-generated current to provide limited spacecraft power. In addition to the use of this technology to provide orbit transfer of payloads and upper stages from LEO to higher orbits it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere.

Johnson, Les↗

Operational considerations of using GPS for spacecraft navigation

The Flight Dynamics Facility (FDF) at the NASA Goddard Space Flight Center (GSFC) has provided operational spacecraft orbit support for many years, currently generating orbit products for about 20 satellites. To date, operational orbit determination in the FDF has been performed on the ground using data from ground-based or space-based tracking systems. Current development of spaceborne Global Positioning System (GPS) receivers is projected to have a significant effect on the support needed for operational satellite navigation. This paper identifies the functions performed in spacecraft navigation and examines and quantifies how the functions and support levels will be affected as onboard GPS receivers are implemented on spacecraft. Cases are considered spacecraft using or not using NASA ground and space networks resources.

Hart, Roger C.↗

A review of nuclear electric propulsion spacecraft system concepts

The last 25-30 years of system concepts and design philosophies for spacecraft employing nuclear-electric propulsion (NEP) are reviewed. NEP spacecraft-system design constraints and criteria are identified, including radiation exposure of humans and electronics, thermal control requirements, effluent contamination of spacecraft surfaces, surface erosion, launch-vehicle integration, operations and safety requirements, attitude control, EM interference, and power control and distribution. The impact on spacecraft design philosophy of these constraints and criteria is explored. Several NEP spacecraft are characterized and discussed with respect to the propulsion system used. The electric propulsion system catagories are electrothermal (arcjet), EM (magnetoplasmadynamic and pulsed-inductive thruster) and electrostatic (ion engine). A brief summary of the mission, nuclear power source, electric propulsion system, and spacecraft configuration are provided for each NEP spacecraft concept.

Deininger, W. D.↗

The Laser Communications Relay Demonstration Experiment Program

This paper elaborates on the Laser Communications Relay Demonstration (LCRD) Experiment Program, which will engage in a number of pre-determined experiments and also call upon a wide variety of experimenters to test new laser communications technology and techniques, and to gather valuable data. LCRD is a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). LCRD will test the functionality in various settings and scenarios of optical communications links from a GEO (Geosynchronous Earth Orbit) payload to ground stations in Southern California and Hawaii over a two-year period following launch in 2019. The LCRD investigator team will execute numerous experiments to test critical aspects of laser communications activities over real links and systems, collecting data on the effects of atmospheric turbulence and weather on performance and communications availability. LCRD will also incorporate emulations of target scenarios, including direct-to-Earth (DTE) links from user spacecraft and optical relay providers supporting user spacecraft. To supplement and expand upon the results of these experiments, the project also includes a Guest Experimenters Program, which encourages individuals and groups from government agencies, academia and industry to propose diverse experiment ideas.

Optical↗

The Laser Communications Relay Demonstration Experiment Program

This paper elaborates on the Laser Communications Relay Demonstration (LCRD) Experiment Program, which will engage in a number of pre-determined experiments and also call upon a wide variety of experimenters to test new laser communications technology and techniques, and to gather valuable data. LCRD is a joint project between NASAs Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). LCRD will test the functionality in various settings and scenarios of optical communications links from a GEO payload to ground stations in Southern California and Hawaii over a two-year period following launch in 2019. The LCRD investigator team will execute numerous experiments to test critical aspects of laser communications activities over real links and systems, collecting data on the effects of atmospheric turbulence and weather on performance and communications availability. LCRD will also incorporate emulations of target scenarios, including direct-to-Earth (DTE) links from user spacecraft and optical relay providers supporting user spacecraft. To supplement and expand upon the results of these experiments, the project also includes a Guest Experimenters Program, which encourages individuals and groups from government agencies, academia and industry to propose diverse experiment ideas.

Optical Communicatio↗

Video guidance, landing, and imaging systems

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions.

Schappell, R. T.↗

Dynamic Modeling of Ascent Abort Scenarios for Crewed Launches

For the last 30 years, the United States's human space program has been focused on low Earth orbit exploration and operations with the Space Shuttle and International Space Station programs. After nearly 50 years, the U.S. is again working to return humans beyond Earth orbit. To do so, NASA is developing a new launch vehicle and spacecraft to provide this capability. The launch vehicle is referred to as the Space Launch System (SLS) and the spacecraft is called Orion. The new launch system is being developed with an abort system that will enable the crew to escape launch failures that would otherwise be catastrophic as well as probabilistic design requirements set for probability of loss of crew (LOC) and loss of mission (LOM). In order to optimize the risk associated with designing this new launch system, as well as verifying the associated requirements, NASA has developed a comprehensive Probabilistic Risk Assessment (PRA) of the integrated ascent phase of the mission that includes the launch vehicle, spacecraft and ground launch facilities. Given the dynamic nature of rocket launches and the potential for things to go wrong, developing a PRA to assess the risk can be a very challenging effort. Prior to launch and after the crew has boarded the spacecraft, the risk exposure time can be on the order of three hours. During this time, events may initiate from either of the spacecraft, the launch vehicle, or the ground systems, thus requiring an emergency egress from the spacecraft to a safe ground location or a pad abort via the spacecraft's launch abort system. Following launch, again either the spacecraft or the launch vehicle can initiate the need for the crew to abort the mission and return to the home. Obviously, there are thousands of scenarios whose outcome depends on when the abort is initiated during ascent as to how the abort is performed. This includes modeling the risk associated with explosions and benign system failures that require aborting a spacecraft under very dynamic conditions, particularly in the lower atmosphere, and returning the crew home safely. This paper will provide an overview of the PRA model that has been developed of this new launch system, including some of the challenges that are associated with this effort. Key Words: PRA, space launches, human space program, ascent abort, spacecraft, launch vehicles

Bigler, Mark↗

Lightweight Innovative Solar Array (LISA): Providing Higher Power to Small Spacecraft

Affordable and convenient access to electrical power is essential for all spacecraft and is a critical design driver for the next generation of smallsats, including cubesats, which are currently extremely power limited. The Lightweight Innovative Solar Array (LISA), a concept designed, prototyped, and tested at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama provides an affordable, lightweight, scalable, and easily manufactured approach for power generation in space. This flexible technology has many wide‐ranging applications from serving small satellites to providing abundant power to large spacecraft in GEO and beyond. By using very thin, ultra‐flexible solar arrays adhered to an inflatable structure, a large area (and thus large amount of power) can be folded and packaged into a relatively small volume. The LISA array comprises a launch‐stowed, orbit‐deployed structure on which lightweight photovoltaic devices and, potentially, transceiver elements are embedded. The system will provide a 2.5 to 5 fold increase in specific power generation (Watts/kilogram) coupled with a >2x enhancement of stowed volume (Watts/cubic‐meter) and a decrease in cost (dollars/Watt) when compared to state‐of‐the‐art solar arrays.

Johnson, Les↗

Analysis of Opportunities for Intercalibration Between Two Spacecraft

There is currently a strong interest in obtaining highly accurate measurements of solar radiation reflected by Earth. For example, the Traceable Radiometry Underpinning Terrestrial- and Helio- Studies (TRUTHS) satellite mission has been under consideration in Europe for several years, and planning is now under way for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) spacecraft in the United States. Such spacecraft will provide measurements whose high accuracy is traceable to SI standards; these measurements will be useful as a reference for calibrating similar instruments on board other spacecraft. Hence, analysis of opportunities for intercalibration between two spacecraft plays an important role in the planning of future missions. In order for intercalibration to take place, the measurements obtained from two spacecraft must have similar viewing geometry and be taken within a few minutes of one another. Viewing geometry is characterized in terms of viewing zenith angle, solar zenith angle, and relative azimuth angle. Opportunities for intercalibration are greater in number and longer in duration if the sensor with high accuracy can be aimed at points on the surface of the Earth other than the nadir or sub-satellite point. Analysis of intercalibration over long periods is rendered tractable by making several simplifying assumptions regarding orbital motions of the two spacecraft about Earth, as well as Earth s orbit about the Sun. The shape of the Earth is also considered. A geometric construction called a tent is introduced to facilitate analysis. It is helpful to think of an intercalibration opportunity as the passage of one spacecraft through a tent that has a fixed shape and moves with the spacecraft whose measurements are to be calibrated. Selection of points on Earth s surface as targets for measurement is discussed, as is aiming the boresight of a steerable instrument. Analysis results for a pair of spacecraft in typical low Earth orbits are provided.

Roithmayr, Carlos M.↗

Lightweight Integrated Solar Array (LISA): Providing Higher Power to Small Spacecraft

Affordable and convenient access to electrical power is essential for all spacecraft and is a critical design driver for the next generation of smallsats, including CubeSats, which are currently extremely power limited. The Lightweight Integrated Solar Array (LISA), a concept designed, prototyped, and tested at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama provides an affordable, lightweight, scalable, and easily manufactured approach for power generation in space. This flexible technology has many wide-ranging applications from serving small satellites to providing abundant power to large spacecraft in GEO and beyond. By using very thin, ultraflexible solar arrays adhered to an inflatable or deployable structure, a large area (and thus large amount of power) can be folded and packaged into a relatively small volume.

Johnson, Les↗

PTD: Enabling New Space Technologies

Significant advances in the capabilities of small spacecraft over the past 20 years, coupled with improved access to space from a variety of launch platforms have created new opportunities for scientific exploration and commercial application using these high-value (and yet low cost) platforms. Continued development and demonstration of key technologies are improving the performance of the 3U and 6U class CubeSats while expanding the small spacecraft reach into larger platforms, such as 12U and ESPA class missions. The availability and relatively low cost of CubeSat spacecraft allows key technologies to be flight qualified, bridging the TRL 6/7 gap and making truly novel and enabling technologies available to much larger missions in the planning stages at NASA. The key is connecting the technologists with the flight opportunity in a time and cost efficient manner. NASA’s Small Satellite Technology (SST) program is using existing commercial spacecraft to provide a common bus for technology demonstration, taking advantage of their proven platforms and system with proven flight heritage and extensive infrastructure. In this paper we discuss the Pathfinder Technology Demonstrator (PTD) series of four spacecraft and the CubeSat Laser Infrared CrosslinK (CLICK) series of three spacecraft, the approach SST took in facilitating the missions, the successes of those missions as well as lessons learned in the process. NASA’s PTD spacecraft series is demonstrating a variety of new technologies on-orbit, providing proof of the maturity of these significant new technologies, and enhancing the performance of future CubeSats. Each of the four PTD mission consists of one 6-unit (6U) CubeSat weighing approximately 12 kilograms and measuring approximately 30 centimeters x 25 centimeters x 10 centimeters, characterizing its payload within 90 days of orbit insertion. The spacecraft bus, integration and test, and mission operations services are being provided by Terran Orbital. The PTD missions have demonstrated a novel nano-spacecraft compatible propulsion systems (enabling deep space and maneuverable Cubeat missions) and an optical communications system (enabling high data rate collection and communications) already. The CLICK missions are demonstrating compact space-to-space optical communications first with the CLICK A technology demonstrator (already flown) and finally with the CLICK BC dual spacecraft mission. Both projects are part of the SST program within the NASA Space Technology Mission Directorate. SST is chartered to develop and demonstrate technologies to enhance and expand the capabilities of small spacecraft with a particular focus on enabling new mission architectures through the use of small spacecraft, expanding the reach of small spacecraft to new destinations, and augmenting future missions with supporting small spacecraft.

J. Hanson↗