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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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NASA NTRS1985

Navigation systems

The elements of the measurement and communications network comprising the global deep space navigation system (DSN) for NASA missions are described. Among the measurement systems discussed are: VLBI, two-way Doppler and range measurements, and optical measurements carried out on board the spacecraft. Processing of navigation measurement is carried out using two modules: an N-body numerical integration of the trajectory (and state transition partial derivatives) based on pre-guessed initial conditions; and partial derivatives of simulated observables corresponding to each actual observation. Calculations of velocity correction parameters is performed by precise modelling of all physical phenomena influencing the observational measurements, including: planetary motions; tracking station locations, gravity field structure, and transmission media effects. Some of the contributions to earth-relative orbit estimate errors for the Doppler/range system on board Voyager are discussed in detail. A line drawing of the DSN navigation system is provided.

Jordan, J. F.↗
NASA NTRS1991

Low power DIPS design for NASA missions

Conceptual designs of low power dynamic isotope power systems (DIPS) for NASA's future deep space missions are being developed to characterize the power system's unique features in the 0.5-1.0 kilowatt-electric (kWe) range. The August 1990 Mariner Mark II spacecraft design was used for the spacecraft integration study. One basic design with slight mission specific variations was developed for the Cassini, Comet Nucleus Sample Return, and Outer Planet Orbiter Probe missions. A low power DIPS flight unit offers comparable specific power values to the MOD-RTG unit with a factor-of-three improvement in radioisotope fuel requirements. This was accomplished by fully exploiting the dynamic power conversion technology available in the DIPS program.

Johnson, Richard A.↗
NASA NTRS2005

Space Exploration: Where We Have Been, Where We Are and Where We Are Going: A Human Perspective

NASA is moving forward towards the agency's new vision for space exploration in the 21st Century encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. Exposure from the hazards of severe space radiation in deep space long duration missions is the show stopper. Langley has developed state-of-the-art radiation protection and shielding technology for space missions. The payload penalty demands a very stringent requirement on the design of the spacecrafts for human deep space missions. The exploration beyond low Earth orbit (LEO) to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of space radiation, Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE), and minimizing the production of secondary radiation is a great advantage. The better understanding of radiation environment (GCR & SPE) and their interaction is a key to the success of the program due to the vital role and importance of cosmic rays for space missions.

Tripathi, R. K.↗
NASA NTRS2005

Exploring the Feasibility of Electrostatic Shielding for Spacecrafts

NASA is moving forward towards the agency's new vision for space exploration in the 21st Century encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. Exposure from the hazards of severe space radiation in deep space long duration missions is the show stopper. Langley has developed state-of-the-art radiation protection and shielding technology for space missions. The payload penalty demands a very stringent requirement on the design of the spacecrafts for human deep space missions. The exploration beyond low Earth orbit (LEO) to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of space radiation, Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE), and minimizing the production of secondary radiation is a great advantage. There is a need to look to new horizons for newer technologies. The present investigation explores the feasibility of using electrostatic shielding in concert with innovative materials shielding and protection technologies. The asymmetries of the radiation shielding problem would be exploited in the electrostatics shielding process. The goal is to repel enough positive charge ions so that they miss the spacecraft without attracting thermal electrons. Conclusions are drawn about the advantages the electrostatic shielding, should it be successful, would bring to the radiation protection design process.

Tripathi, R. K.↗
NASA NTRS2008

Combined GMSK Communications and PN Ranging

A document discusses a method by which GMSK (Gaussian minimum shift keying) modulation and a pseudonoise (PN) ranging signal may be combined. By isolating the in-phase and quadrature components after carrier lock, and extracting their low-pass and band-pass filtered components, there is enough information available to both demodulate data and track the PN signal. The proposed combined GMSK communications and PN ranging is one potential approach to address emerging requirements for simultaneous high data rate communications from and tracking of vehicles in deep space or at the Moon.

Orr, Richard↗
NASA NTRS2007

Triple and Quadruple Junctions Thermophotovoltaic Devices Lattice Matched to InP

Thermophotovoltaic (TPV) conversion of IR radiation emanating from a radioisotope heat source is under consideration for deep space exploration. Ideally, for radiator temperatures of interest, the TPV cell must convert efficiently photons in the 0.4-0.7 eV spectral range. Best experimental data for single junction cells are obtained for lattice-mismatched 0.55 eV InGaAs based devices. It was suggested, that a tandem InGaAs based TPV cell made by monolithically combining two or more lattice mismatched InGaAs subcells on InP would result in a sizeable efficiency improvement. However, from a practical standpoint the implementation of more than two subcells with lattice mismatch systems will require extremely thick graded layers (defect filtering systems) to accommodate the lattice mismatch between the sub-cells and could detrimentally affect the recycling of the unused IR energy to the emitter. A buffer structure, consisting of various InPAs layers, is incorporated to accommodate the lattice mismatch between the high and low bandgap subcells. There are evidences that the presence of the buffer structure may generate defects, which could extend down to the underlying InGaAs layer. The unusual large band gap lowering observed in GaAs(1-x)N(x) with low nitrogen fraction [1] has sparked a new interest in the development of dilute nitrogen containing III-V semiconductors for long-wavelength optoelectronic devices (e.g. IR lasers, detector, solar cells) [2-7]. Lattice matched Ga1-yInyNxAs1-x on InP has recently been investigated for the potential use in the mid-infrared device applications [8], and it could be a strong candidate for the applications in TPV devices. This novel quaternary alloy allows the tuning of the band gap from 1.42 eV to below 1 eV on GaAs and band gap as low as 0.6eV when strained to InP, but it has its own limitations. To achieve such a low band gap using the quaternary Ga1-yInyNxAs1-x, either it needs to be strained on InP, which creates further complications due to the creation of defects and short life of the device or to introduce high content of indium, which again is found problematic due to the difficulties in diluting nitrogen in the presence of high indium [9]. An availability of material of proper band gap and lattice matching on InP are important issues for the development of TPV devices to perform better. To address those issues, recently we have shown that by adjusting the thickness of individual sublayers and the nitrogen composition, strain balanced GaAs(1-x)N(x)/InAs(1-y)N(y) superlattice can be designed to be both lattice matched to InP and have an effective bandgap in the desirable 0.4- 0.7eV range [10,11]. Theoretically the already reduced band gap of GaAs(1-x)N(x), due to the nitrogen effects, can be further reduced by subjecting it to a biaxial tensile strain, for example, by fabricating pseudomorphically strained layers on commonly available InP substrates. While such an approach in principle could allow access to smaller band gap (longer wavelength), only a few atomic monolayers of the material can be grown due to the large lattice mismatch between GaAs(1-x)N(x) and InP (approx.3.8-4.8 % for x<0.05, 300K). This limitation can be avoided using the principle of strain balancing [12], by introducing the alternating layers of InAs(1-y)N(y) with opposite strain (approx.2.4-3.1% for x<0.05, 300K) in combination with GaAs(1-x)N(x). Therefore, even an infinite pseudomorphically strained superlattice thickness can be realized from a sequence of GaAs(1-x)N(x) and InAs(1-y)N(y) layers if the thickness of each layer is kept below the threshold for its lattice relaxation

Bhusal, L.↗
NASA NTRSDate not supplied

Solar Sail Propulsion for Planetary Missions

Solar sails have the potential to provide high ΔV for many types of missions. Solar sails are large, mirror-like structures made of a lightweight material that reflects sunlight to propel the spacecraft. The continuous solar photon pressure provides thrust with no need for the heavy, expendable propellants used by conventional chemical and electric propulsion systems. NASA, with industry partners, are developing and flying solar sails applicable to a wide range of space science missions, including those of interest for planetary science. Currently funded technology development activities support two classes of missions: Deep space interplanetary CubeSats (12 – 24 kg) and smallsats (up to ~125 kg).

Solar Sail↗
NASA NTRS2014

System-Level Testing of the Advanced Stirling Radioisotope Generator Engineering Hardware

To support future NASA deep space missions, a radioisotope power system utilizing Stirling power conversion technology was under development. This development effort was performed under the joint sponsorship of the Department of Energy and NASA, until its termination at the end of 2013 due to budget constraints. The higher conversion efficiency of the Stirling cycle compared with that of the Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, Pluto New Horizons and Mars Science Laboratory) offers the advantage of a four-fold reduction in Pu-238 fuel, thereby extending its limited domestic supply. As part of closeout activities, system-level testing of flight-like Advanced Stirling Convertors (ASCs) with a flight-like ASC Controller Unit (ACU) was performed in February 2014. This hardware is the most representative of the flight design tested to date. The test fully demonstrates the following ACU and system functionality: system startup; ASC control and operation at nominal and worst-case operating conditions; power rectification; DC output power management throughout nominal and out-of-range host voltage levels; ACU fault management, and system command / telemetry via MIL-STD 1553 bus. This testing shows the viability of such a system for future deep space missions and bolsters confidence in the maturity of the flight design.

Deep space↗
NASA NTRS1976

An observational program to search for radio signals from extraterrestrial intelligence through the use of existing facilities

It is argued that a substantial portion of the capability for detecting microwave signals from extraterrestrial civilizations lies not in the application of ever larger antenna collecting areas but rather in the application of millions or billions of simultaneous frequency-channel observations combined with rapid and powerful data processing techniques. The application of these methods to existing facilities is discussed in terms of a program of modest expense and duration which will seek to discover certain classes of extraterrestrial signals of intelligent origin while defining boundaries to the search problem throughout the range of interest. This program will investigate radio-astronomical phenomena of interest and simultaneously define the background of environmental radiation in order to determine physical limitations on both the search strategies and the potential for deep-space communications. Signal parameters that must be determined are examined along with the potential of existing radio-astronomical facilities for detecting narrow-band signals. A seven-year program is described which will carry out a search for extraterrestrial intelligence over 80% of the sky and over the entire frequency range from 1 to 25 GHz with a sensitivity limit varying from 10 to the -21st power W/sq cm at the lowest frequencies to 10 to the -19th power W/sq cm at the higher frequencies.

Edelson, R. E.↗
NASA NTRS2008

NASA Propulsion Investments for Exploration and Science

The National Aeronautics and Space Administration (NASA) invests in chemical and electric propulsion systems to achieve future mission objectives for both human exploration and robotic science. Propulsion system requirements for human missions are derived from the exploration architecture being implemented in the Constellation Program. The Constellation Program first develops a system consisting of the Ares I launch vehicle and Orion spacecraft to access the Space Station, then builds on this initial system with the heavy-lift Ares V launch vehicle, Earth departure stage, and lunar module to enable missions to the lunar surface. A variety of chemical engines for all mission phases including primary propulsion, reaction control, abort, lunar ascent, and lunar descent are under development or are in early risk reduction to meet the specific requirements of the Ares I and V launch vehicles, Orion crew and service modules, and Altair lunar module. Exploration propulsion systems draw from Apollo, space shuttle, and commercial heritage and are applied across the Constellation architecture vehicles. Selection of these launch systems and engines is driven by numerous factors including development cost, existing infrastructure, operations cost, and reliability. Incorporation of green systems for sustained operations and extensibility into future systems is an additional consideration for system design. Science missions will directly benefit from the development of Constellation launch systems, and are making advancements in electric and chemical propulsion systems for challenging deep space, rendezvous, and sample return missions. Both Hall effect and ion electric propulsion systems are in development or qualification to address the range of NASA s Heliophysics, Planetary Science, and Astrophysics mission requirements. These address the spectrum of potential requirements from cost-capped missions to enabling challenging high delta-v, long-life missions. Additionally, a high specific impulse chemical engine is in development that will add additional capability to performance-demanding space science missions. In summary, the paper provides a survey of current NASA development and risk reduction propulsion investments for exploration and science.

Smith, Bryan K.↗
NASA NTRS2017

In-Situ Navigation and Timing Services for the Human Mars Landing Site Part 1: System Concept

In [1] and [2], we introduce a new geometric trilateration method that simultaneously performs absolute positioning and relative positioning. The relative position is derived from a “differencing” function of two raw-range measurements between a known reference point and of the target from a navigation satellite, thereby eliminating most of the common errors like atmospheric delays, ephemeris errors, and instrument delays in real-time. In the Mars environment this “error-cancellation” function greatly reduces the need to perform extensive orbit determination (OD) of the navigation satellites like the Earth’s GPS, and only requires occasional tracks from the Earth’s large-aperture deep space antennas to perform OD’s. Leveraging on this scheme, we propose a low-cost, low-maintenance regional navigation satellite system architecture that provides in-situ navigation and timing services for robotic and human missions in the vicinity of a Mars landing site. This architecture is built upon the proposed Mars relay network infrastructure, and a number of notional Mars orbiting and surface missions in the human exploration era of Mars. We assume two areostationary Mars relay orbiters that have continuous line-of-sight visibility with the Mars landing site, a Deep Space Habitat (DSH) in an inclined 48-hour circular orbit, and a surface communication lander that could serve as the reference point. These orbiting and surface infrastructure elements broadcast GPS-like ranging signals and other ephemeris information to the mission users. With one or more additional orbiters in areosynchronous orbits that trace around a figure-8 path, a regional navigation satellite system can be realized that provides in-situ course absolute localization and precision relative localization and timing services to the users in the vicinity of a Mars landing site. This paper describes the system concept of the proposed Mars regional navigation satellite system.

Lee, Charles↗
NASA NTRSDate not supplied

Sub-kW Class Hall-Effect Thruster Power Processing Unit for Wide Output Range Applications

The National Aeronautics and Space Administration (NASA) Small Spacecraft Electric Propulsion (SSEP) project is maturing high-propellant throughput sub-kilowatt Hall-effect thruster technologies to enable small spacecraft deep space science and exploration missions with high delta-v requirements. In support of this effort, development of a power processing unit (PPU) capable of providing discharge power of up to 1 kW continues to be pursued at the NASA Glenn Research Center (GRC). Previous reported work included a successful integrated test of a scalable, modular breadboard discharge power supply with the NASA-H64M laboratory model Hall-effect thruster and presentation of notional designs for the various auxiliary power supplies needed for thruster operation. Since that time, auxiliary power supply designs have been completed and fabricated, with the cathode heater and keeper power supplies being successfully tested with a hollow cathode assembly (HCA) in the NASA GRC Vacuum Facility 56 (VF-56). The desire for a lower mass, higher efficiency, and more versatile PPU to maximize performance of power and mass-limited small spacecraft has led to the exploration of a discharge power supply based on a series-parallel (LCC) resonant topology. This topology has enabled the discharge power supply to operate over a wider output range at switching frequencies 4-5 times higher than previous design iterations. Simulation models of the topology have been developed and a breadboard of the topology has been fabricated and evaluated on both resistive loads and an integrated Hall thruster test. This paper will present collected performance and integrated test data from both the fabricated auxiliary and resonant discharge power supplies. Advantages of the resonant converter architecture over more traditional pulse-width modulated (PWM) techniques in Hall-effect thruster discharge power supply applications will also be described.

electric propulsion↗
NASA NTRSDate not supplied

Sub-kW Class Hall-Effect Thruster Power Processing Unit for Wide Output Range Applications

The National Aeronautics and Space Administration (NASA) Small Spacecraft Electric Propulsion (SSEP) project is maturing high-propellant throughput sub-kilowatt Hall-effect thruster technologies to enable small spacecraft deep space science and exploration missions with high delta-v requirements. In support of this effort, development of a power processing unit (PPU) capable of providing discharge power of up to 1 kW continues to be pursued at the NASA Glenn Research Center (GRC). Previous reported work included a successful integrated test of a scalable, modular breadboard discharge power supply with the NASA-H64M laboratory model Hall-effect thruster and presentation of notional designs for the various auxiliary power supplies needed for thruster operation. Since that time, auxiliary power supply designs have been completed and fabricated, with the cathode heater and keeper power supplies being successfully tested with a hollow cathode assembly (HCA) in the NASA GRC Vacuum Facility 56 (VF-56). The desire for a lower mass, higher efficiency, and more versatile PPU to maximize performance of power and mass-limited small spacecraft has led to the exploration of a discharge power supply based on a series-parallel (LCC) resonant topology. This topology has enabled the discharge power supply to operate over a wider output range at switching frequencies 4-5 times higher than previous design iterations. Simulation models of the topology have been developed and a breadboard of the topology has been fabricated and evaluated on both resistive loads and an integrated Hall thruster test. This paper will present collected performance and integrated test data from both the fabricated auxiliary and resonant discharge power supplies. Advantages of the resonant converter architecture over more traditional pulse-width modulated (PWM) techniques in Hall-effect thruster discharge power supply applications will also be described.

electric propulsion↗
NASA NTRSDate not supplied

A Heritage BioSensor for Lunar Biology Experiments

Introduction: Automated biological experiments on small spacecraft missions have gained prominence over the past decade due to their simplicity, accessibility, and small mass, volume, and power needs. Most recently, the BioSensor microfluidic CubeSat payload aboard BioSentinel used an automated microfluidic cell culture system to study the effects of environmental stressors like deep space radiation and microgravity on yeast growth and metabolism. BioSentinel’s successor, the Lunar Explorer Instrument for space biology Applications (LEIA), will study the effects of lunar gravity and radiation using an improved version of the BioSensor microfluidic platform. The BioSensor payload has great adaptability to host a diverse range of biological experiments with single- and multi-celled organisms in both crewed and uncrewed missions, making it a compelling candidate for future space biology studies in a lunar surface environment. BioSensor Instrumentation on BioSentinel: The first spaceflight mission with the BioSensor, BioSentinel’s biology experiments occurred at three locations -- deep space, ISS and ground. The payload contained 18 microfluidic cards, each featuring 16 growth wells (a total of 288 growth wells). Each well was loaded before launch with desiccated yeast. In space, liquid culture medium (nutrients) was automatically introduced to batches of wells at a time to initiate a series of biology experiments. Temperature was maintained by thin film heaters on both sides of each card. Each well was equipped with three LEDs emitting at 570 nm, 630 nm, and 850 nm, paired with photodetectors to measure cell concentration and the alamarBlue (metabolic indicator dye) color transition from blue to pink. Phenotypic parameters like cell viability, metabolic rate, and generation time can be derived from these measurements. The sequence and timing of fluid fills, optical measurements, and thermal control were stored onboard, but could be updated asynchronously via ground communication. LEIA: LEIA is slated for launch no earlier than 2026 on a CLPS lander. BioSentinel’s BioSensor has been modified for use in LEIA. These improvements include: (a) storage for multiple culture medium types, (b) additional LED color (465 nm) for a new biological assay for antioxidant (carotenoid) production, (c) housing modifications for later biology load before launch, (d) improved isolation between electronic and fluidic components, and (e) improved humidity control for prolonged organism viability in case of post-load launch delay. Future Prospects: The consistent and successful demonstration of complex fluidics platforms alongside reliable instrument operations in a space environment is poised to create strong momentum for BioSensor-based biological experiment payloads. Planned future developments with the BioSensor include extending compatibility to a broader range of organisms and assays. Preliminary work has already demonstrated successful growth of Arabidopsis seedlings in fluidic cards. With a few modifications to the optical assembly, the setup could easily measure photosynthetic traits in plants and cyanobacteria. The addition of fluorescence measurements and generation of novel luminescent assays will elevate BioSensor’s functionality further. Beyond the BioSensor’s potential uses on free-flyer missions, ISS and Gateway, and CLPS landers, deploying the BioSensor to the lunar surface or in an artificial habitat on crewed missions could enable pioneering research on both how life responds to lunar conditions and future bioproduction capabilities making the BioSensor an indispensable tool for future space biology research.

Chinmayee Govinda Raj↗
NASA NTRS2007

DSN Antenna Array Architectures Based on Future NASA Mission Needs

A flexible method of parametric, full life-cycle cost analysis has been combined with data on NASA's future communication needs to estimate the required number and operational dates of new antennas for the Deep Space Network (DSN). The requirements were derived from a subset of missions in the Integrated Mission Set database of NASA's Space Communications Architecture Working Group. Assuming that no new antennas are 'constructed', the simulation shows that the DSN is unlikely to meet more than 20% of mission requirements by 2030. Minimum full life-cycle costs result when antennas in the diameter range, 18m-34m, are constructed. Architectures using a mixture of antenna diameters produce a slightly lower full life-cycle cost.

array↗
NASA NTRS2004

Design and Fabrication of a Stirling Thermal Vacuum Test

A Stirling Radioisotope Generator (SRG110) is being developed for potential use on future NASA space science missions. The development effort is being conducted by Lockheed Martin under contract to the Department of Energy (DOE). The Stirling Technology Company supplies the free-piston Stirling power convertors, and NASA Glenn Research Center (GRC) provides support to the effort in a range of technologies. This generator features higher efficiency and specific power compared to the currently used alternatives. One potential application for the generator would entail significant cruise time in the vacuum of deep space. A test has been conceived at GRC to demonstrate functionality of the Stirling convertors in a thermal vacuum environment. The test article resembles the configuration of the SRG, however the requirement for low mass was not considered. This test will demonstrate the operation of the Stirling convertors in the thermal vacuum environment, simulating deep space, over an extended period of operation. The analysis, design, and fabrication of the test article will be described in this paper.

Oriti, Salvatore M.↗
NASA NTRS2004

Design and Fabrication of a Stirling Thermal Vacuum Test

A Stirling Radioisotope Generator (SRG110) is being developed for potential use on future NASA space science missions. The development effort is being conducted by Lockheed Martin under contract to the Department of Energy (DOE). The Stirling Technology Company supplies the free-piston Stirling power convertors, and NASA Glenn Research Center (GRC) provides support to the effort in a range of technologies. This generator features higher efficiency and specific power compared to the currently used alternatives. One potential application for the generator would entail significant cruise time in the vacuum of deep space. A test has been conceived at GRC to demonstrate functionality of the Stirling convertors in a thermal vacuum environment. The test article resembles the configuration of the SRG, however the requirement for low mass was not considered. This test will demonstrate the operation of the Stirling convertors in the thermal vacuum environment, simulating deep space, over an extended period of operation. The analysis, design, and fabrication of the test article will be described in this paper.

Oriti, Salvatore M.↗
NASA NTRS2004

Mars Express Interplanetary Navigation from Launch to Mars Orbit Insertion: The JPL Experience

The National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) played a significant role in supporting the safe arrival of the European Space Agency (ESA) Mars Express (MEX) orbiter to Mars on 25 December 2003. MEX mission is an international collaboration between member nations of the ESA and NASA, where NASA is supporting partner. JPL's involvement included providing commanding and tracking service with JPL's Deep Space Network (DSN), in addition to navigation assurance. The collaborative navigation effort between European Space Operations Centre (ESOC) and JPL is the first since ESA's last deep space mission, Giotto, and began many years before the MEX launch. This paper discusses the navigational experience during the cruise and final approach phase of the mission from JPL's perspective. Topics include technical challenges such as orbit determination using non-DSN tracking data and media calibrations, and modeling of spacecraft physical properties for accurate representation of non-gravitational dynamics. Also mentioned in this paper is preparation and usage of DSN Delta Differential Oneway Range ((Delta)DOR) measurements, a key element to the accuracy of the orbit determination.

Deep Space Network (DSN)↗