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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 343 records · Page 19

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NASA NTRS2004

Precision Formation Keeping at L2 Using the Autonomous Formation Flying Sensor

Recent advances in formation keeping for large numbers of spacecraft using the Autonomous Formation Flying are presented. This sensor, currently under development at JPL, has been identified as a key component in future formation flying spacecraft missions. The sensor provides accurate range and bearing measurements between pairs of spacecraft using GPS technology. Previous theoretical work by the authors has focused on developing a decentralized scheduling algorithm to control the tasking of such a sensor between the relative range and bearing measurements to each node in the formation. The resulting algorithm has been modified to include switching constraints in the sensor. This paper also presents a testbed for real time validation of a sixteen-node formation based on the Stellar Imager mission. Key aspects of the simulation include minimum fuel maneuvers based on free-body dynamics and a three body propagator for simulating the formation at L2.

McLoughlin, Terence H.↗

NASA NTRS1998

SSRPT (SSR Pointer Trackeer) for Cassini Mission Operations - A Ground Data Analysis Tool

Tracking the resources of the two redundant Solid State Recorders (SSR) is a necessary routine for Cassini spacecraft mission operations. Instead of relying on a full-fledged spacecraft hardware/software simulator to track and predict the SSR recording and playback pointer positions, a stand-alone SSR Pointer Tracker tool was developed as part of JPL's Multimission Spacecraft Analysis system.

spacecraft ground analysis software↗

NASA NTRS2003

Evaluation of a Drag-Free Control Concept for Missions in Low Earth Orbit

Atmospheric drag causes the greatest uncertainty in the equations of motion for spacecraft in Low Earth Orbit (LEO). If atmospheric drag eflects can be continuously and autonomously counteracted through the use of a drag-fee control system, drag may essentially be eliminated from the equations of motion for the spacecraft. The main perturbations on the spacecraft will then be those due to the gravitational field, which are much more easily predicted Through dynamical analysis and numerical simulation, this paper presents some potential costs and benefits associated with the fuel used during continuous drag compensation. In light of this cost-benefit analysis, simulation results are used to validate the concept of drag-free control for LEO spacecraft missions having certain characteristics.

Fleck, Melissa E.↗

NASA NTRS1973

Study of application of adaptive systems to the exploration of the solar system. Volume 2: Survey of solar system missions

Ways in which human intelligence might be simulated onboard an unmanned mission to achieve some of the decision making capability or adaptability of the manned mission are examined. The relative cost and simplicity advantages of the unmanned spacecraft missions are emphasized. Reliable techniques for making onboard decisions and for modifying mission science operations in response to the findings are analyzed.

Source record↗

NASA NTRS1993

Spacecraft signal sources portable test system

There is a frequent need to measure the frequency stability and phase noise levels of very high performance signal sources that are required for certain spacecraft missions. These measurements need to be done at different locations as the spacecraft subsystems progress through the various stages of development, assembly, test, and integration. Allan Deviation and Phase Noise of high performance sources are generally measured by comparing the unit under test to a reference standard. Five basic requirements are associated with making these kind of measurements: (1) the reference standard performance needs to be equal or better than the unit under test; (2) the measurement system needs to accommodate odd, nonstandard measurement frequencies that can range from 4 MHz to 35 GHz; (3) warm-up frequency drift and aging can corrupt a measurement and must be dealt with; (4) test equipment generated noise must be understood and prevented from limiting the measurements; (5) test equipment noise performance must be verifiable in the field as needed. A portable measurement system that was built by JPL and used in the field is described. The methods of addressing the above requirements are outlined and some measurement noise floor values are given. This test set was recently used to measure state of the art crystal oscillator frequency standards on the TOPEX and MARS OBSERVER spacecraft during several stages of acceptance tests.

Kirk, Albert↗

NASA NTRS2005

The Living With a Star (LWS) Sentinels Mission

The Sentinels Mission, the heliospheric element of the NASA Living With a Star (LWS) program, is still rapidly evolving, especially as the Sentinels Science and Technology Definition Team is progressing with its work. With the Solar Dynamics Observatory, the solar component, and the Geospace elements taking a more finalized form, it becomes clearer what scientific and measurement objectives will be necessary to establish the solar-geospace connection in order to achieve the goals of the LWS program. Possible, early formulation designs of the Sentinels mission will be presented that includes the Inner Heliospheric Mappers, a four spacecraft mission to observe the inner heliosphere between 0.25 and 1.0 AUs along with a Far Side Sentinel that will perform remote solar observations from nearly the opposite side of the Sun. Moreover, the complementarity of the various planned international missions (e.g., ESA Solar Orbiter, and Beppi Colombo) along with NASA planetary projects (e.g., Mars program and MESSENGER) will be discussed and how they can form a coherent system. Finally, the importance of already available heliospheric data will be emphasized.

Szabo, A.↗

NASA NTRSDate not supplied

Small Spacecraft Sample Return Mission Concept to Support Gateway and Lunar Science

The Lunar Gateway is a planned orbital outpost to support Lunar surface, Cislunar, and deep space exploration activities. NASA, together with international and commercial partners, are providing various capabilities, infrastructure, and services to build the Lunar economy. As Gateway capabilities and transportation logistics evolve, utilization is expected to increase, providing ample science, technology demonstration, and commercial development opportunities. Elements of the transportation network supporting Lunar activities are primarily focused on the outbound segment, which include Commercial Lunar Payload Services (CLPS), Human Landing System (HLS), Deep Space Logistics (DSL), and the SLS/Orion crew transportation system. Initially, the only Earth return segment will be provided via Orion. However, infrequent mission cadence (once every 12 months), limited payload return mass (100 kg), and operational constraints suggest that additional sample return logistics capability will be needed. Sustaining long-term presence at the Moon will likely require innovative approaches for frequent and affordable payload return. NASA Ames Research Center and the DSL team at Kennedy Space Center (which provides the Gateway Logistics Services missions) have investigated the development of a small spacecraft-based sample return capability to complement Orion. The goal of the first mission is to demonstrate the capability as a part of an early DSL mission, and provide up to 10 kg of scientific sample return from the Gateway. The mission concept envisions the progressive addition of sample return capabilities, including returning temperature- and acceleration-sensitive payloads, and evolution into a commercially provided service, similar to existing ISS payload return logistics. An overview of payload science and technology use cases and small spacecraft mission concepts will be presented to engage scientists, payload developers and mission planners who are considering Lunar exploration activities that will require the return of high-value samples from the Gateway and/or the lunar surface.

Small Spacecraft↗

NASA NTRS2021

Case Studies in Verifying Spacecraft Autonomy

Spacecraft, operating with a time-to-effect faster than human command response, or with absent or delayed communication, have depended on autonomy. It is likely that this reliance will continue, and increase further in future missions. Spacecraft autonomy is used when operator intervention is not available or feasible, or when dynamic aspects of a spacecraft situation cannot be predicted in advance. This paper provides case studies of several successfully verified autonomous software systems across multiple spacecraft, flight phases (launch, transit, entry and landing, science utilization), and software classifications, and can serve as examples to future missions in methods of successfully assuring spacecraft autonomy.

Johnson, Stephen B.↗

NASA NTRSDate not supplied

Small Spacecraft Sample Return Mission Concept to Support Gateway and Lunar Science

Alan Cassell↗

NASA NTRS2003

On the Utilization of In-flight Radiation-induced Performance Data and Anomaly Resolution of Commercial Off the Shelf (COTS) Electronics

This viewgraph presentation presents an overview of the use of in-flight science data to review the radiation effects on commercial off the shelf (COTS) electronics used in recent spacecraft missions. The authors review the hazards that the space radiation environment pose for spacecraft electronics. They specifically discuss long term effects such as total ionizing dose (TID) and short term effects like single particle events (SEE). The advantages of using COTS electronics despite not being radiation hardened are mentioned. The reasons cite for tracking in-flight performance of COTS electronics include: anomaly resolution, validate ground tests and environmental predictions and provide lessons for future designers. Sample radiation impacts of science data from the following missions are analyzed: SOHO/LASCO 3 Coronograph, Microwave Anisotrophy Probe, Hubble Space Telescope and Chandra X-Ray Observatory.

Kenneth A. LeBel↗

NASA NTRS2014

An Architecture to Enable Autonomous Control of Spacecraft

Autonomy is required for manned spacecraft missions distant enough that light-time communication delays make ground-based mission control infeasible. Presently, ground controllers develop a complete schedule of power modes for all spacecraft components based on a large number of factors. The proposed architecture is an early attempt to formalize and automate this process using on-vehicle computation resources. In order to demonstrate this architecture, an autonomous electrical power system controller and vehicle Mission Manager are constructed. These two components are designed to work together in order to plan upcoming load use as well as respond to unanticipated deviations from the plan. The communication protocol was developed using "paper" simulations prior to formally encoding the messages and developing software to implement the required functionality. These software routines exchange data via TCP/IP sockets with the Mission Manager operating at NASA Ames Research Center and the autonomous power controller running at NASA Glenn Research Center. The interconnected systems are tested and shown to be effective at planning the operation of a simulated quasi-steady state spacecraft power system and responding to unexpected disturbances.

space power systems↗

NASA NTRS2016

Cupid's Arrow: An Innovative Nanosat to Sample Venus' Upper Atmosphere

In NASA's Discovery 2014 AO, the opportunity to propose a Technology Demonstration Opportunity (TDO) to enhance the primary mission was specified. For the Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy (VERITAS) mission, we elected to include the Cupid's Arrow nanosat TDO to sample and measure the abundances of noble gases and their isotopic ratios in Venus's upper atmosphere below the homopause. This paper will provide a basic overview of the VERITAS mission, with a focus on the Cupid's Arrow concept including a description of the mission, spacecraft design, and JPL's quadrupole ion trap mass spectrometer (QITMS) instrument specifications and design. In previous planetary entry probe mission designs, particularly at Venus, engineers w ere focused on entry and descent. A landed probe was also proposed for the New Frontiers SAGE mission. For Cupid's Arrow, the nanosat is designed to skim through the upper atmosphere, just below the homopause, in order to sample the atmosphere, perform the analysis, and then exit the atmosphere to transmit its data to the orbiting VERITAS spacecraft. Cupid's Arrow is a compelling addition to the VERITAS geology mission. A key missing link in our understanding of Venus' evolution is the noble gas abundances and their isotopic ratios. Not since Pioneer Venus have these measurements been made in the Venus atmosphere and never in the upper atmosphere, just below the homopause, to the degree of accuracy that will be accomplished by VERITAS' Cupid's Arrow nanosat.Such measurements were ranked as the number 1 investigation of the number 1 objective of the goal "Atmospheric Formation, Evolution, and Climate History ".

Discovery↗

NASA NTRS1973

The Jet Propulsion Laboratory 7.62-m space simulator modification

The JPL 7.62-m space simulator was modified to simulate the solar intensities at the planet Mercury. The capability of the simulator was increased to support testing of both the Mariner spacecraft mission to Venus and Mercury (to be launched in 1973) and the Helios spacecraft. The design of the off-axis reflecting system of the JPL simulators allowed attaining increased solar intensity, at the expense of test area, by placing a smaller collimating mirror at a lower elevation in the space simulator. In addition to requiring a new collimating mirror 4.57-m in diameter, the optical integrating system required a new design and there were several other efforts necessary to support these primary alterations.

Morgan, N. R.↗

NASA NTRS2017

Status of NASA’s Deep Space Optical Communication Technology Demonstration

With NASA funding, the Deep Space Optical Communication (DSOC) Project at JPL is planning a system level technology demonstration of optical communications from deep space. A 22 cm diameter flight laser transceiver (FLT) is being developed for space flight. The FLT will be designed to transmit an average laser power of 4W at 1550 nm and receive a weak 1064 nm laser signal (> 100 femtowatts). Use of the Hale telescope at Palomar Mountain, CA, retrofitted with a photoncounting receiver to detect the downlink from space, is planned. The Optical Communication Telescope Laboratory (OCTL) at Table Mountain, CA will transmit a 1064 nm laser beacon to serve as a pointing reference for the FLT and support low-rate uplink data-rates. The DSOC FLT is part of the baseline payload for the Psyche mission spacecraft recently selected for flight by NASA, providing link demonstration opportunities during the mission cruise phase. Link demonstration opportunities at distances of approximately 0.1 to 2 astronomical units (AU) are expected. The DSOC system is being designed to support downlink data-rates of 0.2 to > 200 Mb/s and uplink data rates of approximately 1.6 kb/s. A status update of DSOC Project activities on flight and ground development will be summarized in this paper.

Biswas, Abhijit↗

NASA NTRS2019

An Exploration of Mission Concepts That Could Utilize Small RPS

The NASA Radioisotope Power Systems (RPS) Program Mission Analysis Team at the Jet Propulsion Laboratory (JPL) requested a JPL Innovation Foundry Architecture Team (A-Team) study to assess mission pull for small RPS (1 mWe - 40 We) in order to inform the RPS Program Office on what future power system developments should be focused on. The A-Team is JPL’s concurrent engineering design team for science definition and early mission concept development, targeting concept maturation levels of 1 through 3. The requested small RPS study was tasked to identify the architecture space of potential small RPS missions, and suggest power levels that could enable or enhance potential future small spacecraft missions. This paper describes the collaborative engineering processes that the A-Team and Mission Analysis Team used to reach results quickly and the findings to inform the RPS Program about mission concept power requirements on RPS for small missions.

Bairstow, Brian K.↗

NASA NTRS1989

Advanced solar-propelled cargo spacecraft for Mars missions

At the University of Washington, three concepts for an unmanned, solar powered, cargo spacecraft for Mars-support missions have been investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: a solar radiation absorption (SRA) system, a solar-pumped laser (SPL) system, and a solar powered mangetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process developed at the University of Washington. A solar concentrator focuses sunlight into an absorption chamber. A mixture of hydrogen and potassium vapor absorbs the incident radiation and is heated to approximately 3700 K. The hot propellant gas exhausts through a nozzle to produce thrust. The SRA has an I(sub sp) of approximately 1000 sec and produces a thrust of 2940 N using two thrust chambers. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sun-synchronous Earth orbit converts solar energy to laser energy. The laser beams are transmitted to the spacecraft via laser relay satellites. The laser energy heats the hydrogen propellant through a plasma breakdown process in the center of an absorption chamber. Propellant flowing through the chamber, heated by the plasma core, expands through a nozzle to produce thrust. The SPL has an I(sub sp) of 1285 sec and produces a thrust of 1200 N using two thrust chambers. The MPD system uses indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. In this system, the argon propellant is ionized and electromagnetically accelerated by a magnetoplasmadynamic arc to produce thrust. The MPD spacecraft has an I(sub sp) of 2490 sec and produces a thrust of 100 N. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary propulsion system boosts the payload into a Hohmann transfer to Mars. The SPL spacecraft releases the payload as the spacecraft passes by Mars. Both the SRA-powered spacecraft and the SPL-powered spacecraft return to Earth for subsequent missions. The MPD-propelled spacecraft, however, remains at Mars as an orbiting space station. A patched conic approximation was used to determine a heliocentric interplanetary transfer orbit for the MPD propelled spacecraft. All three solar-powered spacecraft use an aerobrake procedure to place the payload into a low Mars parking orbit. The payload delivery times range from 160 days to 873 days (2.39 years).

Auziasdeturenne, J.↗

NASA NTRS1993

Magellan spacecraft and memory state tracking: Lessons learned, future thoughts

Numerous studies have been dedicated to improving the two main elements of Spacecraft Mission Operations: Command and Telemetry. As a result, not much attention has been given to other tasks that can become tedious, repetitive, and error prone. One such task is Spacecraft and Memory State Tracking, the process by which the status of critical spacecraft components, parameters, and the contents of on-board memory are managed on the ground to maintain knowledge of spacecraft and memory states for future testing, anomaly investigation, and on-board memory reconstruction. The task of Spacecraft and Memory State Tracking has traditionally been a manual task allocated to Mission Operations Procedures. During nominal Mission Operations this job is tedious and error prone. Because the task is not complex and can be accomplished manually, the worth of a sophisticated software tool is often questioned. However, in the event of an anomaly which alters spacecraft components autonomously or a memory anomaly such as a corrupt memory or flight software error, an accurate ground image that can be reconstructed quickly is a priceless commodity. This study explores the process of Spacecraft and Memory State Tracking used by the Magellan Spacecraft Team highlighting its strengths as well as identifying lessons learned during the primary and extended missions, two memory anomalies, and other hardships encountered due to incomplete knowledge of spacecraft states. Ideas for future state tracking tools that require minimal user interaction and are integrated into the Ground Data System will also be discussed.

Bucher, Allen W.↗

NASA NTRS1998

Overview of CPL and LHP Applications on NASA MIssions

Capillary Pumped Loops (CPL's) and Loop Heat Pipes (LHP's) are finding increased acceptance on upcoming NASA spacecraft missions, as well as military and commercial applications, The transition from a research and development tool to an "off the shelf' system is underway. The state of the art of two phase systems (TPS) is reviewed and applications on various NASA missions are discussed, with particular emphasis on new technology developments. Upcoming research areas and flight experiments are also addressed, along with recommendations for future activities.

Butler, C. Dan↗