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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

An Inter Planetary Network Enabled by SmallSats

This paper describes the implementation of an unparalleled large sensor and communications platform along the solar system that we call the inter planetary network (IPN). The proposed IPN consists of thousands of small spacecraft (e.g. CubeSats) strategically deployed around planetary bodies in the solar system where each spacecraft is furnished with fast communications and sensor systems. The IPN concept is being proposed as an avant-garde science and communications platform that could allow for continuous fast communications and remarkable science returns. The IPN spacecraft, furnished with suitable miniaturized sensors, could form an amazing deep space platform for unique observation of the solar system, stars, galaxies and universe. A key feature of the IPN architecture is the use of swarms of spacecraft as network units. Super-high-speed intra-swarm communications could be achieved via omnidirectional optical links. The swarms act as autonomous network nodes and are capable of forming large synthetic apertures that enable high data rate communications among the IPN nodes. Depending on the sensors they carry, these swarms may also be capable of forming large synthetic sensors by rapidly combining data among the spacecraft. We envision distances between spacecraft forming a swarm to be in the range of 102-104 kilometers, whereas distances of 106-108 kilometers among swarms (IPN nodes) are expected. We provide an example of an initial IPN implementation in the inner solar system where swarms of spacecraft are deployed around the Earth, Moon, Mars, Venus and Mercury. Placing swarms around 3 Lagrange points per planet yield a total of 12 possible IPN network nodes. We present communications link calculations among IPN nodes that allow high data rate communications between Earth and Mars while Mars is in solar conjunction (behind the Sun). A second example of an IPN platforms includes a giant spaceborne radio telescope behind the moon.

Velazco, Jose E↗
NASA NTRS1996

The Army's Use of the Advanced Communications Technology Satellite

Tactical operations require military commanders to be mobile and have a high level of independence in their actions. Communications capabilities providing intelligence and command orders in these tactical situations have been limited to simple voice communications or low-rate narrow bandwidth communications because of the need for immediate reliable connectivity. The Advanced Communications Technology Satellite (ACTS) has brought an improved communications tool to the tactical commander giving the ability to gain access to a global communications system using high data rates and wide bandwidths. The Army has successfully tested this new capability of bandwidth-on-demand and high data rates for commanders in real-world conditions during Operation UPHOLD DEMOCRACY in Haiti during the fall and winter of 1994. This paper examines ACTS use by field commanders and details the success of the ACTS system in support of a wide variety of field condition command functions.

Ilse, Kenneth↗
NASA NTRS1993

EOS ground data systems: A description and interface overview

The Earth Observing System (EOS) is planned as a space-based measurement system, earth-science research program, and data and information system (EOSDIS). It will consist of several high data rate spacecraft with multiple earth sensing instruments which provide investigators with a thorough, longterm view of the earth's environment. Up to seven spacecraft may be supported at once, either in operational, checkout, or testing phases; and the average data rate from the EOS satellites in orbit at any one time is expected to be from 18 to 60 Mbps. Providing the data processing and flight operations support for EOS will be the EOSDIS Core System (ECS). The ECS will command and control the spacecraft; process and store the EOS data; provide access to the data for years; and support researchers. The data processing aspects of the ECS consist of a collection of Distributed Active Archive Centers (DAAC's) which perform the product generation, data archive and distribution, and information management services. Flight operations aspects will be provided by the EOS Operations Center, by instrument control centers, and by widely distributed instrument support terminals. The communications and system management aspects will be provided by the EOSDIS Science Network and the System Management Center. In addition to the EOS satellite data, other data sets from earlier earth science missions are also to be added to designated DAAC's. Other ground data systems which will provide support to EOS for acquiring, transporting, processing, and distributing the transformed spacecraft data are currently being defined or are being upgraded for the EOS era. These systems include the Space Network consisting of the Tracking and Data Relay Satellite System (TDRSS), the TDRSS Ground Terminals, and the Network Control Center as well as the night Dynamics Facility, the EOS Data and Operations System, and EOS Communications. This paper briefly describes data handling by the ECS, the support data systems, their interfaces, and their roles.

Smith, Gene↗
NASA NTRS1998

Remote Observing with the Keck Telescope Using the ACTS Satellite

As a technical demonstration project for the NASA Advanced Communications Technology Satellite (ACTS), we have implemented remote observing on the 10-meter Keck II telescope on Mauna Kea in Hawaii from the California Institute of Technology campus in Pasadena. The data connection consists of optical fiber networks in Hawaii and California, connecting the end-points to high data rate (HDR) ACTS satellite antennae at JPL in Pasadena and at the Tripler Army Medical Center in Honolulu. The terrestrial fiber networks run the asynchronous transfer mode (ATM) protocol at DS-3 (45 Mbit/sec) speeds, providing ample bandwidth to enable remote observing with a software environment identical to that used for on-site observing in Hawaii. This experiment has explored the data requirements of remote observing with a modern research telescope and large-format detector arrays. While the maximum burst data rates are lower than those required for many other applications (e.g., HDTV), the network reliability and data integrity requirements are critical. As we show in this report, the former issue particularly may be the greatest challenge for satellite networks for this class of application. We have also experimented with the portability of standard TCP/IP applications to satellite networks, demonstrating the need for alternative TCP congestion algorithms and minimization of bit error rates (BER). Reliability issues aside, we have demonstrated that true remote observing over high-speed networks provides several important advantages over standard observing paradigms. Technical advantages of the high-speed network access include more rapid download of data to a user's home institution and the opportunity for alternative communication facilities between members of an observing team, such as audio- and videoconferencing.

SATELLITE COMMUNICATIONS↗
NASA NTRS1991

A bandwidth efficient coding scheme for the Hubble Space Telescope

As a demonstration of the performance capabilities of trellis codes using multidimensional signal sets, a Viterbi decoder was designed. The choice of code was based on two factors. The first factor was its application as a possible replacement for the coding scheme currently used on the Hubble Space Telescope (HST). The HST at present uses the rate 1/3 nu = 6 (with 2 (exp nu) = 64 states) convolutional code with Binary Phase Shift Keying (BPSK) modulation. With the modulator restricted to a 3 Msym/s, this implies a data rate of only 1 Mbit/s, since the bandwidth efficiency K = 1/3 bit/sym. This is a very bandwidth inefficient scheme, although the system has the advantage of simplicity and large coding gain. The basic requirement from NASA was for a scheme that has as large a K as possible. Since a satellite channel was being used, 8PSK modulation was selected. This allows a K of between 2 and 3 bit/sym. The next influencing factor was INTELSAT's intention of transmitting the SONET 155.52 Mbit/s standard data rate over the 72 MHz transponders on its satellites. This requires a bandwidth efficiency of around 2.5 bit/sym. A Reed-Solomon block code is used as an outer code to give very low bit error rates (BER). A 16 state rate 5/6, 2.5 bit/sym, 4D-8PSK trellis code was selected. This code has reasonable complexity and has a coding gain of 4.8 dB compared to uncoded 8PSK (2). This trellis code also has the advantage that it is 45 deg rotationally invariant. This means that the decoder needs only to synchronize to one of the two naturally mapped 8PSK signals in the signal set.

Pietrobon, Steven S.↗
NASA NTRS1972

Tracking and data relay satellite system configuration and tradeoff study. Volume 2: System engineering, part 1, final report

All elements of the TDRS system were studied with emphasis on the design of a 3-axis stabilized satellite, and a telecommunication system optimized for support of low and medium data rate user spacecraft constrained to be launched on a Delta 2914. The research is reported to upgrade the spacecraft design to provide telecommunications support low, medium and high data rate users, considering launches with the Atlas/Centaur and the space shuttle. For Vols. 4, 5, 7, and 8, see N74-10809 through N74-10812.

Source record↗
NASA NTRS2002

On-Orbit Performance Verification and End-to-End Characterization of the TDRS-H Ka-Band Communications Payload

In June 2000, NASA launched the first of three next generation Tracking and Data Relay Satellites (TDRS-H) equipped with a Ka-band forward and return service capability. This Ka-band service supports forward data rates up to 25 Mb/sec using the 22.55 - 23.55 GHz space-to-space allocation. Return services are supported via channel bandwidths of 225 and 650 MHz for data rates up to 800 Mb/sec (QPSK) using the 25.25 - 27.5 GHz space-to-space allocation. As part of NASA's acceptance of the TDRS-H spacecraft, an extensive on-orbit calibration, verification and characterization effort was performed to ensure that on-orbit spacecraft performance is within specified limits. This process verified the compliance of the Ka-band communications payload with all performance specifications and demonstrated an end-to-end Ka-band service capability. This paper summarizes the results of the TDRS-H Ka-band communications payload on-orbit performance verification and end-to-end service characterization. Performance parameters addressed include Effective Isotropically Radiated Power (EIRP), antenna Gain-to-System Noise Temperature (G/T), antenna gain pattern, frequency tunability and accuracy, channel magnitude response, and Ka-band service Bit-Error-Rate (BER) performance.

Toral, Marco↗
NASA NTRS2002

On-Orbit Performance Verification and End-To-End Characterization of the TDRS-H Ka-band Communications Payload

In June 2000, NASA launched the first of three next generation Tracking and Data Relay Satellites (TDRS-H) equipped with a Ka-band forward and return service capability. This Ka-band service supports forward data rates of up to 25 Mb/sec using the 22.55-23.55 GHz space-to-space allocation. Return services are supported via channel bandwidths of 225 and 650 MHz for data rates up to at least 800 Mb/sec using the 25.25 - 27.5 GHz space-to-space allocation. As part of NASA's acceptance of the TDRS-H spacecraft, an extensive on-orbit calibration, verification and characterization effort was performed to ensure that on-orbit spacecraft performance is within specified limits. This process verified the compliance of the Ka-band communications payload with all performance specifications, and demonstrated an end-to-end Ka-band service capability. This paper summarizes the results of the TDRS-H Ka-band communications payload on-orbit performance verification and end-to-end service characterization. Performance parameters addressed include antenna gain pattern, antenna Gain-to-System Noise Temperature (G/T), Effective Isotropically Radiated Power (EIRP), antenna pointing accuracy, frequency tunability, channel magnitude response, and Ka-band service Bit-Error-Rate (BER) performance.

Toral, Marco↗
DOE OSTI2024

Region of Interest Filter in DUNE DAQ

The Deep Underground Neutrino Experiment (DUNE) is the next generation neutrino experiment currently under construction. It consists of a broadband neutrino beam at Fermilab, a high precision near detector, and the largest liquid argon time projection chamber far detector ever designed at the Sanford Underground Research Facility (SURF). The Region of Interest (ROI) filter is designed for DUNE’s online Data Acquisition (DAQ) system to address data rate constraints and enable low energy physics in the <10 MeV range. The filter employs zero suppression on the detector signal, and by tuning the readout window and threshold the data rates can be reduced by >90%. Performance of the ROI is analyzed in LArsoft on MARLEY generated low energy MC events propagated through the detector simulation. Notably, the optimized ROI filter enables a lower trigger threshold for readout at ~5-10 MeV, allowing DUNE to explore low-energy physics, specifically focusing on solar boron 8 neutrinos which are relevant in this energy range. This advancement enhances DUNE's scientific capabilities, opening avenues for detailed analyses of previously inaccessible low-energy neutrino interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1978

Electronically scanned pressure sensor module with in SITU calibration capability

This high data rate pressure sensor module helps reduce energy consumption in wind tunnel facilities without loss of measurement accuracy. The sensor module allows for nearly a two order of magnitude increase in data rates over conventional electromechanically scanned pressure sampling techniques. The module consists of 16 solid state pressure sensor chips and signal multiplexing electronics integrally mounted to a four position pressure selector switch. One of the four positions of the pressure selector switch allows the in situ calibration of the 16 pressure sensors; the three other positions allow 48 channels (three sets of 16) pressure inputs to be measured by the sensors. The small size of the sensor module will allow mounting within many wind tunnel models, thus eliminating long tube lengths and their corresponding slow pressure response.

Gross, C.↗
NASA NTRS2018

Recommendations Emerging from an Analysis of NASA's Deep Space Communications Capacity

During 2016-2017, NASA’s Space Communications and Navigation (SCaN) Office chartered a study of Deep Space Network (DSN) communications capacity relative to projected future-mission demand over the next 30 years. In this paper, we briefly describe the methodology used to analyze capacity vs. demand over such a broad timeframe, summarize key findings emerging from the analysis, and discuss the associated recommendations. Performing the analysis entailed: identifying key factors shaping the anticipated future mission set, identifying several alternative future mission set scenarios consistent with these factors, and then analyzing each mission set scenario in terms of required antenna capacity, downlink and uplink capabilities, and spectrum as a function of time. On the basis of these aggregate requirements, DSN loading simulations were then conducted that examined how well each of the postulated mission sets could load up onto the the DSN’s “in-plan” architecture. To the extent that capacity shortfalls emerged during these baseline simulations, architectural solutions to the shortfalls were then postulated and tested via additional simulations. In general, the trend analyses and baseline loading simulations indicated a significant progression in challenges over the next three decades. In the current decade, the DSN appeared to be operating very close to capacity. The first human exploration mission and its secondary payload launch opportunities for cubesats traveling beyond GEO contributed to this loading. As a consequence, the main challenge appeared to be managing peak assetcontention periods. In the next decade, the DSN continued to operate close to capacity but also began transitioning to more frequent human mission support. Upgrading for, and operating, a human-rated system while continuing to meet robotic mission customer requirements emerged as the key challenge. In the 2030’s and beyond, simulations suggested a need for fundamentally new capability and capacity. The high data rates and long link distances characteristic of human Mars exploration drove requirements far beyond what is currently “in plan.” The key challenge then became determining the most cost-effective combination of RF and optical assets for communicating with the postulated human Mars assets while still providing for the needs of all the other missions across the solar system. Various link budget, visibility, and loading analyses ultimately suggested that the human Mars exploration demands of the 2030’s could best be addressed with two cross-linked RF-optical areostationary relays (or an areostationary relay and deep space habitat) providing a dual “trunk link” to an array of 2-to-3 additional 34m beam waveguide antennas and an ~8.5m optical antenna at each DSN Complex. The dual “trunk link” would enable the same amount of total data return to Earth as a single trunk link at twice the data rate, but with only half the required array size on the ground, assuming use of Multiple Spacecraft Per Antenna (MSPA) techniques. MSPA techniques, including a Multiple Uplink Per Antenna (MUPA) technique currently under investigation, also showed promise for reducing asset contention in the decades prior to human Mars exploration.

Lee, Carlyn-Ann↗
NASA NTRS1990

A burst compression and expansion technique for variable-rate users in satellite-switched TDMA networks

A burst compression and expansion technique is described for asynchronously interconnecting variable-data-rate users with cost-efficient ground terminals in a satellite-switched, time-division-multiple-access (SS/TDMA) network. Compression and expansion buffers in each ground terminal convert between lower rate, asynchronous, continuous-user data streams and higher-rate TDMA bursts synchronized with the satellite-switched timing. The technique described uses a first-in, first-out (FIFO) memory approach which enables the use of inexpensive clock sources by both the users and the ground terminals and obviates the need for elaborate user clock synchronization processes. A continous range of data rates from kilobits per second to that approaching the modulator burst rate (hundreds of megabits per second) can be accommodated. The technique was developed for use in the NASA Lewis Research Center System Integration, Test, and Evaluation (SITE) facility. Some key features of the technique have also been implemented in the gound terminals developed at NASA Lewis for use in on-orbit evaluation of the Advanced Communications Technology Satellite (ACTS) high burst rate (HBR) system.

Budinger, James M.↗
NASA NTRS1990

A burst compression and expansion technique for variable-rate users in satellite-switched TDMA networks

A burst compression and expansion technique is described for asynchronously interconnecting variable-data-rate users with cost-efficient ground terminals in a satellite-switched, time-division-multiple-access (SS/TDMA) network. Compression and expansion buffers in each ground terminal convert between lower rate, asynchronous, continuous-user data streams and higher-rate TDMA bursts synchronized with the satellite-switched timing. The technique described uses a first-in, first-out (FIFO) memory approach which enables the use of inexpensive clock sources by both the users and the ground terminals and obviates the need for elaborate user clock synchronization processes. A continuous range of data rates from kilobits per second to that approaching the modulator burst rate (hundreds of megabits per second) can be accommodated. The technique was developed for use in the NASA Lewis Research Center System Integration, Test, and Evaluation (SITE) facility. Some key features of the technique have also been implemented in the ground terminals developed at NASA Lewis for use in on-orbit evaluation of the Advanced Communications Technology Satellite (ACTS) high burst rate (HBR) system.

Budinger, James M.↗
DOE OSTI2022

Peak Prediction Using Multi Layer Perceptron (MLP) for Edge Computing ASICs Targeting Scientific Applications

High data rate detectors play an integral part in scientific research and their development is actively pursued at High Energy Physics (HEP) facilities around the world. Edge Machine Learning (ML) offers the ability to reduce data rates by integrating ML algorithms into Application Specific Integrated Circuits (ASICs) on the front end electronics. In this work, we explore a set of neural network architectures for predicting the peak amplitudes in the detector's sensor response. We have designed and synthesized several MLP based neural networks comparing their inference accuracy, power consumption, and area targeting for minimal latency. The neural networks are synthesized in a commercial 65nm process. The effect of quantizing the network's weights and biases on hardware performance and area is reported. We also conduct design space exploration to compare between design alternatives

47 OTHER INSTRUMENTATION↗
NASA NTRS2001

Ocean-Science Mission Needs: Real-Time AUV Data for Command, Control, and Model Inputs

Predictive models for tides, hydrodynamics, and bio-optical properties affecting the visibility and buoyancy of coastal waters are needed to evaluate the safety of personnel and equipment engaged in maritime operations under potentially hazardous conditions. Predicted currents can be markedly different for two-layer systems affected by terrestrial runoff than for well-mixed conditions because the layering decouples the surface and bottom Ekman layers and rectifies the current response to oscillatory upwelling-and downwelling-favorable winds. Standard ocean models (e.g. Princeton Ocean Model) require initial-and boundary data on the physical and optical properties of the multilayered water column to provide accurate simulations of heat budgets and circulation. Two observational systems are designed to measure vertically structured conditions on the West Florida Shelf (WFS): a tethered buoy network and an autonomous underwater vehicle (AUV) observational system. The AUV system is described with a focus on the observational systems that challenge or limit the communications command and control network for various types of measurement programs. These include vertical oscillatory missions on shelf transects to observe the optical and hydrographic properties of the water column, and bottom-following missions for measuring the bottom albedo. Models of light propagation, absorption, and conversion to heat as well as determination of the buoyancy terms for physical models require these measurements. High data rates associated with video bottom imagery are the most challenging for the real-time, command and control communications system, but they are met through a combination of loss-less and lossy data-compression methods, depending upon the data-rate of the radio links.

Carder, Kendall L.↗
NASA NTRS2016

Exploring Cognition Using Software Defined Radios for NASA Missions

NASA missions typically operate using a communication infrastructure that requires significant schedule planning with limited flexibility when the needs of the mission change. Parameters such as modulation, coding scheme, frequency, and data rate are fixed for the life of the mission. This is due to antiquated hardware and software for both the space and ground assets and a very complex set of mission profiles. Automated techniques in place by commercial telecommunication companies are being explored by NASA to determine their usability by NASA to reduce cost and increase science return. Adding cognition the ability to learn from past decisions and adjust behavior is also being investigated. Software Defined Radios are an ideal way to implement cognitive concepts. Cognition can be considered in many different aspects of the communication system. Radio functions, such as frequency, modulation, data rate, coding and filters can be adjusted based on measurements of signal degradation. Data delivery mechanisms and route changes based on past successes and failures can be made to more efficiently deliver the data to the end user. Automated antenna pointing can be added to improve gain, coverage, or adjust the target. Scheduling improvements and automation to reduce the dependence on humans provide more flexible capabilities. The Cognitive Communications project, funded by the Space Communication and Navigation Program, is exploring these concepts and using the SCaN Testbed on board the International Space Station to implement them as they evolve. The SCaN Testbed contains three Software Defined Radios and a flight computer. These four computing platforms, along with a tracking antenna system and the supporting ground infrastructure, will be used to implement various concepts in a system similar to those used by missions. Multiple universities and SBIR companies are supporting this investigation. This paper will describe the cognitive system ideas under consideration and the plan for implementing them on platforms, including the SCaN Testbed. Discussions in the paper will include how these concepts might be used to reduce cost and improve the science return for NASA missions.

transmitters receivers↗
NASA NTRS2020

Q4 – A CubeSat Mission to Demonstrate Omnidirectional Optical Communications

We are proposing a technology demonstration mission for JPL’s Inter-Satellite Optical Communicator (ISOC). The ISOC has the potential to enable up to 1 Gbps data rates over a distance up to 200 km in free space. Key features of the ISOC include full sky coverage and the ability to maintain multiple links simultaneously. The Q4 mission consists of (4) 6U CubeSats furnished with ISOCs to demonstrate high data rate communications among the spacecraft. More specifically, we seek to demonstrate the omnidirectionality of the ISOC by providing simultaneous optical links between one spacecraft and the other three. Q4 will be a demonstrator for small spacecraft swarm capabilities. Following a proposed deployment from the ISS, the CubeSats will utilize their onboard thrusters to enter their desired orbit. The orbit consists of one “leader” spacecraft in a circular orbit with a 400 km LEO altitude and three “follower” spacecraft in slightly elliptical orbits rotating azimuthally about the leader. The main mission will consist of three consecutive phases: First, the spacecraft will demonstrate pointing, acquisition, and tracking using newly developed protocols. Next, link establishment and different channel access methods (CDMA and TDMA) will be tested. Finally, Delay Tolerant Network protocols will be implemented to allow fast data sharing among the spacecraft. The distance between the communicating spacecraft will be increased as the mission progresses to characterize the link quality as a function of distance. All communications over the course of the mission will be recorded and analyzed on the ground using bit error rate as a metric for success. The current design for each the four Q4 CubeSats contains an XACT advanced ADCS system for precision beam pointing. Other components currently under consideration include MiPS cold gas thrusters for orbital maneuvering and gimbaled eHaWK 84W solar arrays. In this paper we present design considerations for the Q4 CubeSats, link budget calculations, results from preliminary mission analysis, and expected results.

Velazco, Jose E↗
NASA NTRS1992

Communications support for lunar missions using the TDRS II system

For several years NASA has been performing systems engineering analysis for lunar exploration scenarios with studies focused mainly on lunar communications, data systems and operations. Two basic earth-region communications architectures have been seriously considered, ground terminal architectures such as the deep space network (DSN) and geosynchronous relay satellites such as the tracking and data relay satellite II (TDRS II). An overview of TDRS II is given and lunar coverage, data rate capability, impacts to ground based elements, availability and operational scenarios are discussed. Development of the system is scheduled to begin soon and TDRS II can provide substantial support to early lunar missions without modification. Coverage and data rates are adequate and FLO missions can be supported. With enhancement nearly continuous coverage can be provided. TDRS II is a viable architecture and low cost option and should be considered as an alternative to the currently baselined DSN for precursor and possibly FLO missions.

Todd, Jacqueline↗