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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 379 records · Page 21
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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)↗
NASA NTRS1983

Progress in the application of VLBI to interplanetary navigation

In comparison with conventional range and Doppler, VLBI data from a spacecraft and an angularly nearby extragalactic radio source have the potential of providing significant improvements in deep space navigation performance. Observations of the Voyager spacecraft at Saturn, the Pioneer orbiter at Venus, and clusters of natural radio sources are being used to validate these new navigation data types. This paper briefly describes a few of the navigation applications of VLBI, and gives estimates of the measurement accuracies that can be achieved. Recent results are presented which show current VLBI system accuracy at or near the expected level.

Hildebrand, C. E.↗
NASA NTRS1988

Gravitational wave searches using the DSN (Deep Space Network)

The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed.

Nelson, S. J.↗
NASA NTRS2005

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

One of the advantages of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used to maintain electronic components within a controlled temperature range, to warm propulsion tanks and mobility actuators, and to gasify liquid propellants. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated a very large quantity of waste heat due to the relatively low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-watt Stirling Radioisotope Generator (SRG110) will have much higher conversion efficiencies than their predecessors and therefore may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of approx. 6 to 7% and 200 C housing surface temperatures, would need to use large and heavy radiator heat exchangers to transfer the waste heat to the internal spacecraft components. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation by using the heat exchangers or additional shields. The SRG110, with an efficiency around 22% and 50 C nominal housing surface temperature, can use the available waste heat more efficiently by more direct heat transfer methods such as heat pipes, thermal straps, or fluid loops. The lower temperatures allow the SRG110 much more flexibility to the spacecraft designers in configuring the generator without concern of overheating nearby scientific instruments, thereby eliminating the need for thermal shields. This paper will investigate using a high efficiency SRG110 for spacecraft thermal management and outline potential methods in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander) to illustrate the advantages with regard to ease of assembly, less complex interfaces, and overall mass savings.

Pantano, David R.↗
NASA NTRS2012

Dual-Band Optical Bench for Terahertz Radiometer for Outer Planet Atmospheres (TROPA)

We have developed a wide-band dual frequency spectrometer for use in deep space planetary atmospheric spectroscopy. The instrument uses a dual-band architecture, both to be able to observe spectral lines from a wide range of atmospheric species, and to allow a higher precision retrieval of temperature/pressure/partial pressure and wind profiles. This dual-band approach requires a new design for the optical bench to couple both frequencies into their respective receivers.

submillitmeter↗
NASA NTRS2017

Space Technology: Game Changing Development Deep Space Engine (DSE) 100 lbf and 5 lbf Thruster Development and Qualification

Science mission studies require spacecraft propulsion systems that are high-performance, lightweight, and compact. Highly matured technology and low-cost, short development time of the propulsion system are also very desirable. The Deep Space Engine (DSE) 100-lbf thruster is being developed to meet these needs. The overall goal of this game changing technology project is to qualify the DSE thrusters along with 5-lbf attitude control thrusters for space flight and for inclusion in science and exploration missions. The aim is to perform qualification tests representative of mission duty cycles. Most exploration missions are constrained by mass, power and cost. As major propulsion components, thrusters are identified as high-risk, long-lead development items. NASA spacecraft primarily rely on 1960s' heritage in-space thruster designs and opportunities exist for reducing size, weight, power, and cost through the utilization of modern materials and advanced manufacturing techniques. Advancements in MON-25/MMH hypergolic bipropellant thrusters represent a promising avenue for addressing these deficiencies with tremendous mission enhancing benefits. DSE is much lighter and costs less than currently available thrusters in comparable thrust classes. Because MON-25 propellants operate at lower temperatures, less power is needed for propellant conditioning for in-space propulsion applications, especially long duration and/or deep-space missions. Reduced power results in reduced mass for batteries and solar panels. DSE is capable of operating at a wide propellant temperature range (between -22 F and 122 F) while a similar existing thruster operates between 45 F and 70 F. Such a capability offers robust propulsion operation as well as flexibility in design. NASA's Marshall Space Flight Center evaluated available operational Missile Defense Agency heritage thrusters suitable for the science and lunar lander propulsion systems.

Barnett, Gregory↗
NASA NTRS2006

Mars Reconnaissance Orbiter Ka-band (32 GHz) Demonstration: Cruise Phase Operations

The X-band (8.41 GHz) frequency currently used for deep space telecommunications is too narrow (50 MHz) to support future high rate missions. Because of this NASA has decided to transition to Ka-band (32 GHz) frequencies. As weather effects cause much larger fluctuations on Ka-band than on X-band, the traditional method of using a few dBs of margin to cover these fluctuations is wasteful of power for Ka-band; therefore, a different operations concept is needed for Ka-band links. As part of the development of the operations concept for Ka-band, NASA has implemented a fully functioning Ka-band communications suite on its Mars Reconnaissance Orbiter (MRO). This suite will be used during the primary science phase to develop and refine the Ka-band operations concept for deep space missions. In order to test the functional readiness of the spacecraft and the Deep Space Network's (DSN) readiness to support the demonstration activities a series of passes over DSN 34-m Beam Waveguide (BWG) antennas were scheduled during the cruise phase of the mission. MRO was launched on August 12, 2005 from Kennedy Space Center, Cape Canaveral, Florida, USA and went into Mars Orbit on March 10, 2006. A total of ten telemetry demonstration and one high gain antenna (HGA) calibration passes were allocated to the Ka-band demonstration. Furthermore, a number of "shadow" passes were also scheduled where, during a regular MRO track over a Ka-band capable antenna, Ka-band was identically configured as the X-band and tracked by the station. In addition, nine Ka-band delta differential one way ranging ((delta)DOR) passes were scheduled. During these passes, the spacecraft and the ground system were put through their respective paces. Among the highlights of these was setting a single day record for data return from a deep space spacecraft (133 Gbits) achieved during one 10-hour pass; achieving the highest data rate ever from a planetary mission (6 Mbps) and successfully demonstrating Ka-band DDOR. In addition, DSN performed well. However, there are concerns with the active pointing of the Ka-band antennas as well as delivery of the monitor data from the stations. The spacecraft also presented challenges not normally associated with planetary missions mostly because of its very high equivalent isotropic radiated power (EIRP). This caused problems in accurately evaluating the in-flight EIRP of the spacecraft which led to difficulties evaluating the quality of the HGA calibration data. These led to the development of additional measurement techniques that could be used for future high-power deep space missions.

Mars Reconnaissance Orbiter (MRO)↗
NASA NTRS2010

Thermal Performance Expectations of the Advanced Stirling Convertor Over a Range of Operating Scenarios

The Advanced Stirling Radioisotope Generator (ASRG) will enable various missions such as small body sample return, atmospheric missions around Venus, as well as long - duration deep space missions. Analysis of the temperature distributions are performed on an Advanced Stirling Convertor, and the results are compared with available experimental measurements. This analysis includes applied environmental conditions that are similar to those that will be experienced while the convertor is in operation. The applied conditions represent a potential mission profile including pre-takeoff sterilization, launch, transit, and return. The results focus on the anticipated peak temperatures of the magnets in the linear alternator. These results confirm that the ASC can support future missions to deep space targets, extreme environment landers, as well as more conventional goals.

Reid, Terry V.↗
NASA NTRS1995

Differenced Range Versus Integrated Doppler (DRVID) ionospheric analysis of metric tracking in the Tracking and Data Relay Satellite System (TDRSS)

The Differenced Range (DR) Versus Integrated Doppler (ID) (DRVID) method exploits the opposition of high-frequency signal versus phase retardation by plasma media to obtain information about the plasma's corruption of simultaneous range and Doppler spacecraft tracking measurements. Thus, DR Plus ID (DRPID) is an observable independent of plasma refraction, while actual DRVID (DR minus ID) measures the time variation of the path electron content independently of spacecraft motion. The DRVID principle has been known since 1961. It has been used to observe interplanetary plasmas, is implemented in Deep Space Network tracking hardware, and has recently been applied to single-frequency Global Positioning System user navigation This paper discusses exploration at the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) of DRVID synthesized from simultaneous two-way range and Doppler tracking for low Earth-orbiting missions supported by the Tracking and Data Relay Satellite System (TDRSS) The paper presents comparisons of actual DR and ID residuals and relates those comparisons to predictions of the Bent model. The complications due to the pilot tone influence on relayed Doppler measurements are considered. Further use of DRVID to evaluate ionospheric models is discussed, as is use of DRPID in reducing dependence on ionospheric modeling in orbit determination.

Radomski, M. S.↗
NASA NTRS1993

A Deep Space Optical Communications Demonstration with the Galileo Spacecraft on its Way to Jupiter (abstract)

The GOPEX (Galileo Optical communications from an Earth-based transmitter) demonstration was performed from transmitter sites at Table Mountain Observatory, CA and Starfire Optical Range, NM. The experiment was done over an eight day period, December 9 through December 16 as Galileo receded from Earth on its way to Jupiter. At a range of 6 million kilometers (15 times the Earth-Moon distance), the transmission from Table Mountain Observatory eight days after Earth-flyby represents the longest range for laser transmission and detection.

laser space communications experiment optical comm↗
NASA NTRS2006

Navigation and EDL for the Mars Exploration Rovers

A viewgraph presentation on Deep Space Navigation, and Entry, Decent, and Landing (EDL) for Mars Exploration Rovers is shown. The contents include: 1) JPL Spacecraft Operating across the Solar System; 2) 2003 - 2004: The Busiest Period in JPL's History; 3) Deep Space Navigation Will Enable Many of the New NASA Missions; 4) What Exactly is Navigation vs. GNC for Deep Space?; 5) Cruise and Approach: Why is Deep Space Navigation So Difficult?; 6) Project Importance of GNC: Landing Site Selection; 7) Planetary Communications and Tracking; 8) Tracking Data Types; 9) Delta Differential One-Way Range (deltaDOR); 10) All Solutions Leading up to TCM-4 Design; 11) Entry Flight Path Sensitivities; 12) MER Navigation Results; 13) Atmospheric Entry Targeting and Delivery; 14) Landing Ellipse Orientation; 15) MER Landing Site Trade Example; 16) Entry, Descent and Landing: Entry Guidance or What Things Do We NOT do for MER Landings (but we will later...); 17) Entering Martian Space 8:29 p.m. PST (ERT); 18) Entry, Descent and Landing; 19) Entry, Descent and Landing: Terminal Guidance; 20) The Challenge Going from 12,000 mph to Zero in Less Than Six Minutes; 21) Spirit Landing Location; 22) Entry, Descent and Landing: The Future; 23) Powered Descent Time-Line; and 24) Updated Sky Crane Maneuver Description. A short summary is also given on planetary guidance, navigation and control as it pertains to EDL systems

Mars Exploration Rover (MER)↗
NASA NTRS2016

Deep HST/STIS Visible-Light Imaging of Debris Systems Around Solar Analog Hosts

We present new Hubble Space Telescope observations of three a priori known starlight-scattering circumstellar debris systems (CDSs) viewed at intermediate inclinations around nearby close-solar analog stars: HD 207129, HD202628, and HD 202917. Each of these CDSs possesses ring-like components that are more massive analogs of our solar systems Edgeworth Kuiper Belt. These systems were chosen for follow-up observations to provide imaging with higher fidelity and better sensitivity for the sparse sample of solar-analog CDSs that range over two decades in systemic ages, with HD 202628 and HD 207129 (both approx. 2.3 Gyr) currently the oldest CDSs imaged in visible or near-IR light. These deep (10-14 ks) observations, made with six-roll point-spread-function template visible-light coronagraphy using the Space Telescope Imaging Spectrograph, were designed to better reveal their angularly large debris rings of diffuse low surface brightness, and for all targets probe their exo-ring environments for starlight-scattering materials that present observational challenges for current ground-based facilities and instruments. Contemporaneously also observing with a narrower occulter position, these observations additionally probe the CDS endo-ring environments that are seen to be relatively devoid of scatterers. We discuss the morphological, geometrical, and photometric properties of these CDSs also in the context of other CDSs hosted by FGK stars that we have previously imaged as a homogeneously observed ensemble. From this combined sample we report a general decay in quiescent-disk F disk /F star optical brightness approx. t( exp.-0.8), similar to what is seen at thermal IR wavelengths, and CDSs with a significant diversity in scattering phase asymmetries, and spatial distributions of their starlight-scattering grains.

starlight-scattering circumstellar debris systems ↗
NASA NTRS1982

Field interface module for antenna control assembly

The hardware aspects and capabilities of the field interface module (FIM) developed for monitor and control functions in the antenna mechanical subsystems of the deep space network and in the technical facilities controllers for the various complexes are described. The FIM is capable of monitoring and responding to a range of anaog and digital inputs and controlling external elements. The flexibility of the design makes it applicable to other control needs, using software developed for those specific applications.

Baher, F.↗
NASA NTRS2004

Future capabilities for the Deep Space Network

This paper will look at three new capabilities that are in different stages of development. First, turbo decoding, which provides improved telemetry performance for data rates up to about 1 Mbps, will be discussed. Next, pseudo-noise ranging will be presented. Pseudo-noise ranging has several advantages over the current sequential ranging, anmely easier operations, improved performance, and the capability to be used in a regenerative implementation on a spacecraft. Finally, Low Density Parity Check decoding will be discussed. LDPC codes can provide performance that matches or slightly exceed turbo codes, but are designed for use in the 10 Mbps range.

turbo code↗
NASA NTRS2007

Future Opportunities for Dynamic Power Systems for NASA Missions

Dynamic power systems have the potential to be used in Radioisotope Power Systems (RPS) and Fission Surface Power Systems (FSPS) to provide high efficiency, reliable and long life power generation for future NASA applications and missions. Dynamic power systems have been developed by NASA over the decades, but none have ever operated in space. Advanced Stirling convertors are currently being developed at the NASA Glenn Research Center. These systems have demonstrated high efficiencies to enable high system specific power (>8 W(sub e)/kg) for 100 W(sub e) class Advanced Stirling Radioisotope Generators (ASRG). The ASRG could enable significant extended and expanded operation on the Mars surface and on long-life deep space missions. In addition, advanced high power Stirling convertors (>150 W(sub e)/kg), for use with surface fission power systems, could provide power ranging from 30 to 50 kWe, and would be enabling for both lunar and Mars exploration. This paper will discuss the status of various energy conversion options currently under development by NASA Glenn for the Radioisotope Power System Program for NASA s Science Mission Directorate (SMD) and the Prometheus Program for the Exploration Systems Mission Directorate (ESMD).

Shaltens, Richard K.↗
NASA NTRS2008

Ka-Band Transponder for Deep-Space Radio Science

A one-page document describes a Ka-band transponder being developed for use in deep-space radio science. The transponder receives in the Deep Space Network (DSN) uplink frequency band of 34.2 to 34.7 GHz, transmits in the 31.8- to 32.3 GHz DSN downlink band, and performs regenerative ranging on a DSN standard 4-MHz ranging tone subcarrier phase-modulated onto the uplink carrier signal. A primary consideration in this development is reduction in size, relative to other such transponders. The transponder design is all-analog, chosen to minimize not only the size but also the number of parts and the design time and, thus, the cost. The receiver features two stages of frequency down-conversion. The receiver locks onto the uplink carrier signal. The exciter signal for the transmitter is derived from the same source as that used to generate the first-stage local-oscillator signal. The ranging-tone subcarrier is down-converted along with the carrier to the second intermediate frequency, where the 4-MHz tone is demodulated from the composite signal and fed into a ranging-tone-tracking loop, which regenerates the tone. The regenerated tone is linearly phase-modulated onto the downlink carrier.

Dennis, Matthew S.↗
NASA NTRS2015

Orbit Determination for the Lunar Reconnaissance Orbiter Using an Extended Kalman Filter

Since launch, the FDF has performed daily OD for LRO using the Goddard Trajectory Determination System (GTDS). GTDS is a batch least-squares (BLS) estimator. The tracking data arc for OD is 36 hours. Current operational OD uses 200 x 200 lunar gravity, solid lunar tides, solar radiation pressure (SRP) using a spherical spacecraft area model, and point mass gravity for the Earth, Sun, and Jupiter. LRO tracking data consists of range and range-rate measurements from: Universal Space Network (USN) stations in Sweden, Germany, Australia, and Hawaii. A NASA antenna at White Sands, New Mexico (WS1S). NASA Deep Space Network (DSN) stations. DSN data was sparse and not included in this study. Tracking is predominantly (50) from WS1S. The OD accuracy requirements are: Definitive ephemeris accuracy of 500 meters total position root-mean-squared (RMS) and18 meters radial RMS. Predicted orbit accuracy less than 800 meters root sum squared (RSS) over an 84-hour prediction span.

LRO↗
NASA NTRS2021

DSN Radio Astronomy Spectrometer

The Deep Space Network (DSN) enables NASA to communicate with its deep space spacecraft. By virtue of its large antennas, the DSN can be used as a powerful instrument for radio astronomy. In particular, Deep Space Station (DSS) 43, the 70 m antenna at the Canberra Deep Space Communications Complex (CDSCC) has a K-band radio astronomy system covering a 10 GHz bandwidth at 17 to 27 GHz. This spectral range covers a number of atomic and molecular lines, produced in a rich variety of interstellar gas conditions. A new high-resolution spectrometer was deployed at CDSCC in November 2019 and connected to the K-band downconverter. The system has two different firmware modes: 1) Using a 65k-pt FFT to provide 32,768 spectral channels at ~30.5 kHz (0.45 km/s velocity resolution) and 2) Using a 16k-pt polyphase filterbank (PFB) to provide 8,192 spectral channels with ~122 kHz resolution (1.8 km/s velocity resolution). Previous work extensively described the spectrometer system. In this paper we present added functionality and updates to the commissioned spectrometer. The changes include developments in system timing, metadata, firmware and data products.

Bradford, Brian↗