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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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Highly efficient laser sources are required for deep space optical telecommunication. This paper investigates the efficiency components for pulsed diode pumped solid state laser transmittersand determines the overall wall-plug efficiency applicable to a spaceborne system.
Maxar has completed development activity for its deep-space electric propulsion system in support of NASA’s Psyche mission. Psyche’s electric propulsion system relies heavily on Maxar’s heritage EP-140 subsystem centered on the SPT-140. The evolution to the EP-140DS demonstrates an expanded thruster discharge capability from 0.9kW through 4.5kW and includes the addition of a constant keeper current function. This system, with development support from industry experts at JPL, will serve as the primary propulsion on board the Psyche spacecraft through the 3.6 year cruise to the Psyche asteroid. Subsystem level testing to validate the first EP-140DS design is complete. Major findings from system testing including xenon flow control loop timing, noise hardening, and constant keeper current and test activities are now being implemented in hardware and the status and plans are discussed.
NASA's New Millennium Deep Space One (DS1) is the first interplanetary spacecraft operated on solar electric propulsion.
This paper describes the activities at JPL to evaluate optical communication systems for use on deep space exploration spacecraft.
Lunar Ice Cube (LIC) is one of 13 6U cubesats that will be deployed by EM1 in cislunar space. LIC along with Lunar Flashlight and LunaH-Map, all focused on the search for volatiles but with very different payloads, will be the first deep space cubesats designed to address goals for both demonstrating new technologies and collecting scientific data. Effectively, as their developments are occurring in parallel, they are acting as prototypes for future deep space cubesats missions. One useful outcome of this experiment is to evolve a working paradigm for the development and operation of compact, cost-capped, standardized (supporting subsystems) spacecraft to serve the needs of diverse user communities.
The atmospheric noise temperature at 31.4GHz was measured at NASA's Deep Space Communications Complex at Madrid from September 1990 to December 1996 excluding February 1991 and May 1992 using a Water Vapor Radiometer.
Virtually all previously-suggested rate 1/2 binary convolutional codes with KE = 24 are compared. Their distance properties are given; and their performance, both in computation and in error probability, with sequential decoding on the deep-space channel is determined by simulation. Recommendations are made both for the choice of a specific KE = 24 code as well as for codes to be included in future coding standards for the deep-space channel. A new result given in this report is a method for determining the statistical significance of error probability data when the error probability is so small that it is not feasible to perform enough decoding simulations to obtain more than a very small number of decoding errors.
The DSTB Facility provides a new capability for the National Aeronautics and Space Administration s (NASA s) Space Radiation Shielding Project (SRSP). The objective of the DSTB is to provide a platform to conduct radiation shielding investigations in an environment more similar to deep space than most Low Earth orbits or is achievable at a particle accelerator. The DSTB provides a means to experimentally test radiation shielding effectiveness of various materials and to test the accuracy of radiation transport code predictions in the deep space cosmic ray environment more frequently and at a lower cost compared to space flight missions. New spectrometers, dosimeters and other techniques may be exercised and verified using the DSTB before space flight. The DSTB will be implemented through NASA s National Scientific Balloon Facility (NSBF) which provides polar balloon flights that lift science payloads to high altitude (120,000 A. (36.58km)) to escape much of the shielding effects of the Earth s atmosphere and magnetosphere. Polar flights are conducted through NSBF in coordination with the United States Polar Program. The DSTB will be launched on a Long Duration Balloon (LDB) from McMurdo, Antarctica (77.86 degrees south latitude) for circumpolar flights, nominally 20 days, traveling to the west and typically bounded between 73 to 82 degrees south latitude. Float altitudes for these balloons with payload are 115,000 to 130,000 feet (35.05 to 39.62km). The DSTB will be able to accommodate up to 20 investigations per flight. Annual flight opportunities are planned starting in December 2005. Balloon campaigns in Antarctica occur in December and January during the Austral summer. Since a key goal of the DSTB facility is to efficiently serve the varied needs of the radiation shielding community; it must be designed with a flexible architecture. By implementing the DSTB facility with NASA s balloon program, which operates under reduced formalities compared to space flight, the DSTB facility can adjust for different investigation priorities on successive flights. This flexibility in the DSTB will be applied at several levels; in the distribution of the shared resources for each flight; addressing the payload configuration on a system level for each flight; and utilizing a selection process for investigations that considers yearly flight opportunities as well as the possibility for repeated flights. This approach for operating the DSTB facility will allow it to handle a wide range of investigations.
Characteristics and format of tracking data to be obtained by Deep Space Instrumentation Facility /DSIF/ for lunar orbiter
In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, more deep space missions now being planned have baselined photovoltaic solar arrays due to the low power requirements (usually significantly less than 100 W) needed for engineering and science payloads. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. This paper will discuss representative requirements for a range of planetary and deep space science missions now in the planning stages. We have divided the requirements into three categories: Inner planets and the sun; outer planets (greater than 3 AU); and Mars, cometary, and asteroid landers and probes. Requirements for Mercury and Ganymede landers will be covered in the Inner and Outer Planets sections with their respective orbiters. We will also discuss special requirements associated with solar electric propulsion (SEP). New technology developments will be needed to meet the demanding environments presented by these future applications as many of the technologies envisioned have not yet been demonstrated. In addition, new technologies that will be needed reside not only in the photovoltaic solar array, but also in other spacecraft systems that are key to operating the spacecraft reliably with the photovoltaics.
This paper presents a proposed approach for Ka-band link management for deep space applications using daily weather forecasts and discusses the tools that will be employed for operations. Performance metrics are also presented. The proposed approach will be tested in a two-year experiment campaign.
Understanding solar energetic particle (SEP) event characteristics is critical to the proper design of human and robotic space missions. This report details a study of operational response time for monitoring space weather for crewed flights, specifically targeting lunar and Mars missions. The NESC assessment team evaluated the required minimum latency for data streams and forecasts that will directly affect mission operations using a 41-year database (i.e., European Space Agency (ESA) Solar Energetic Particle Environment Modeling (SEPEM) RSDv2.0) of SEP events. The database contained 192 SEP events that resulted in a dose increase above background levels. Of those, 10% were “multiple events,” or events that occurred in quick succession. The analysis provides probabilistic values for time to peak flux and dose rate for the duration of each event. This NESC assessment also evaluated the SEP threshold levels for exploration missions to determine the relevant energy range of required proton measurements.
A mission plan for an integrated radio and optical communications payload, based on the Mars Reconnaissance Orbiter, is presented with emphasis on the derivation of precision pointing requirements. The Canfield joint, a parallel robotic linkage capable of hemispherical pointing, is discussed as a platform for optical communication and other deep space instrumentation. The capabilities of a prototype are compared to those of currently available gimbals qualified for deep space, and the advantages of the Canfield joint, including size, weight and power (SWaP) savings, cable handling, and mechanical redundancy, are discussed. Validation procedures and results for the space hardware prototype are presented. This work was undertaken through the Integrated Radio and Optical Communication (iROC) project at NASA Glenn Research Center.
Understanding how the Sun, Earth, and other objects in the solar system interact with the space radiation environment is crucial for improving activities of humans on Earth and in space. Low-power, low-noise, multidirectional robust detectors for detecting ions with a wide range of mass and energies will provide a more complete understanding of space environment physics. To meet these challenges, new ion detectors based on wide band gap (WBG) semiconductors are being developed for integration on a variety of deep space platforms. NASA Glenn Research Center (GRC) is applying its expertise and facilities in harsh environment instrumentation to develop supporting technologies to enable improved instruments for space science missions. New detector technologies being developed at GRC include SiC solid-state devices as practical robust, thermally stable large area detectors for LET measurements in compact, stacked charged particle telescope. The low-noise, thermally stable nature of the WBG detectors allows a small multidirectional array of charged particle telescopes to be packed in a 6U CubeSat without active cooling for operation in lunar orbit or deep space. Using a full variety of different WBG detectors, an extremely compact instrument to provide multi-directional, comprehensive (composition, velocity, and direction) in-situ measurements of heavy ions in space plasma environments can be realized.
The NASA Psyche mission is set to explore an asteroid located between Mars and Jupiter with a launch date in 2022. On-board the Psyche spacecraft is experimental demonstrator technology that will allow scientists to explore the capabilities of optical communications – a program called Deep Space Optical Communication (DSOC) led by Jet Propulsion Laboratory (JPL). DSOC seeks to improve communications performance by developing a space-based Flight Laser Transceiver (FLT) and a ground-based transceiver to enable photon-efficient communications with equipment in deep space. An integral part to this FLT system is a high-efficiency photon-counting camera (PCC) that is able to detect both the 1064nm uplink/beacon laser photons and 1550nm downlink laser photons with low background noise, and is capable of withstanding the rigors of space-travel. The paper details the characterization of several asynchronous Geiger-Mode Avalanche Photodiode (GmAPD) arrays developed by MIT Lincoln Laboratory for use in the PCC- specifically evaluating the temperature dependence of background noise, photon detection efficiency at 1064nm and 1550nm wavelengths, pixel lifetime testing, and angle of acceptance measurements. The results of this characterization are used to determine the nominal conditions for the device to operate in while in flight to maintain an efficient link with the ground-based transceiver.
Launched on October 24, 1998, Deep Space 1 (DS1) was the first mission of NASA's New Millennium Program, chartered to validate in space high-risk, new technologies important for future space science programs. The advanced technology payload that was tested on DS1 comprises solar electric propulsion, solar concentrator arrays, autonomous on-board navigation and other autonomous systems, several telecommunications and microelectronics devices, and two low-mass integrated science instrument packages. The mission met or exceeded all of its success criteria. The 12 technologies were rigorously exercised so that subsequent flight projects would not have to incur the cost and risk of being the fist users of these new capabilities. Examples of the benefits to future small body missions from DS1's technologies will be described.
Insertion loss and reflection coefficient measurements and changes on waveguide system of Venus deep space station cone
Modifications to an existing radiofrequency telescope are described which would enable it to operate as an R&D optical receiver terminal for deep-space communications. The low overall cost of the telescope is due to the unique process of fabricating the 10.4 meter primary mirror and its support structure, the lightweight of the primary (10-11 kg/m 2 ), and the requirement that the telescope act only as a photon bucket, which lowers the cost of optically figuring and polishing the mirror. The entrie optical ground terminal facility is estimated to cost approximately $10M to construct.