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NASA NTRS2006

Fission Surface Power for the Exploration and Colonization of Mars

The colonization of Mars will require abundant energy. One potential energy source is nuclear fission. Terrestrial fission systems are highly developed and have the demonstrated ability to safely produce tremendous amounts of energy. In space, fission systems not only have the potential to safely generate tremendous amounts of energy, but could also potentially be used on missions where alternatives are not practical. Programmatic risks such as cost and schedule are potential concerns with fission surface power (FSP) systems. To be mission enabling, FSP systems must be affordable and programmatic risk must be kept acceptably low to avoid jeopardizing exploration efforts that may rely on FSP. Initial FSP systems on Mars could be "workhorse" units sized to enable the establishment of a Mars base and the early growth of a colony. These systems could be nearly identical to FSP systems used on the moon. The systems could be designed to be safe, reliable, and have low development and recurring costs. Systems could also be designed to fit on relatively small landers. One potential option for an early Mars FSP system would be a 100 kWt class, NaK cooled system analogous to space reactors developed and flown under the U.S. "SNAP" program or those developed and flown by the former Soviet Union ("BUK" reactor). The systems could use highly developed fuel and materials. Water and Martian soil could be used to provide shielding. A modern, high-efficiency power conversion subsystem could be used to reduce required reactor thermal power. This, in turn, would reduce fuel burnup and radiation damage .effects by reducing "nuclear" fuels and materials development costs. A realistic, non-nuclear heated and fully integrated technology demonstration unit (TDU) could be used to reduce cost and programmatic uncertainties prior to initiating a flight program.

Houts, Mike↗

NASA NTRS2018

Next-Generation Radioisotope Thermoelectric Generator Study

Radioisotope Thermoelectric Generators (RTGs) have been used to power NASA missions of various types throughout the past five decades. The most recent RTG iteration, used for NASA’s Mars Science Laboratory, is the Multi-Mission RTG (MMRTG), which is currently the only spaceflight-qualified system available. The U.S. planetary science community has expressed a desire for more power system options to be available to accommodate a range of ambitious future mission concepts across the solar system. Recent advancements in thermoelectric (TE) materials technology have raised a potential for significantly increased efficiency in future RTGs, which helped spur a recent in-depth NASA study of options for future systems. A “next-generation” RTG study was conducted to develop new RTG concepts that could meet the needs of planetary science missions through the 2030s and beyond. A Next-Generation RTG would aim to extend the types of potential NASA missions able to be supported, while fulfilling requirements related to technical risk and schedule. In this study, 21 potential thermoelectric couple configurations were analyzed by considering various high-performance, high-temperature TE materials and segmentation techniques that maximize convertor efficiency and power density. System modularity was explored, and found to be a promising means to offer improved flexibility for NASA mission concepts with varying scope and power requirements. This paper presents the results of the study, demonstrating the viability of developing an updated RTG system design, and defining conceptual system approaches for a new, potentially revolutionary RTG.

Matthes, Christopher S. R.↗

NASA NTRS1987

Maintaining consistency between planning hierarchies: Techniques and applications

In many planning and scheduling environments, it is desirable to be able to view and manipulate plans at different levels of abstraction, allowing the users the option of viewing and manipulating either a very detailed representation of the plan or a high-level more abstract version of the plan. Generating a detailed plan from a more abstract plan requires domain-specific planning/scheduling knowledge; the reverse process of generating a high-level plan from a detailed plan Reverse Plan Maintenance, or RPM) requires having the system remember the actions it took based on its domain-specific knowledge and its reasons for taking those actions. This reverse plan maintenance process is described as implemented in a specific planning and scheduling tool, The Mission Operations Planning Assistant (MOPA), as well as the applications of RPM to other planning and scheduling problems; emphasizing the knowledge that is needed to maintain the correspondence between the different hierarchical planning levels.

Zoch, David R.↗

NASA NTRS2012

Woven TPS - A New Approach to TPS Design and Manufacturing

NASA's Office of the Chief Technologist (OCT) Game Changing Division recently funded an effort to advance a Woven TPS (WTPS) concept. WTPS is a new approach to producing TPS materials that uses precisely engineered 3D weaving techniques to customize material characteristics needed to meet specific missions requirements for protecting space vehicles from the intense heating generated during atmospheric entry. Using WTPS, sustainable, scalable, mission-optimized TPS solutions can be achieved with relatively low life cycle costs compared with the high costs and long development schedules currently associated with material development and certification. WTPS leverages the mature state-of-the-art weaving technology that has evolved from the textile industry to design TPS materials with tailorable performance by varying material composition and properties via the controlled placement of fibers within a woven structure. The resulting material can be designed to perform optimally for a wide range of entry conditions encompassing NASAs current and future mission needs. WTPS enables these optimized TPS designs to be translated precisely into mission-specific, manufactured materials that can substantially increase the efficiency, utility, and robustness of heat shield materials compared to the current state-of-the-art material options. By delivering improved heat shield performance and affordability, this technology will impact all future exploration missions, from the robotic in-situ science missions to Mars, Venus and Saturn to the next generation of human missions. WTPS can change the way NASA develops, certifies, and integrates TPS into mission life cycles - instead of being a mission constraint, TPS will become a mission enabler. It is anticipated that WTPS will have direct impact on SMD, HEOMD and OCT and will be of interest for DoD and COTS applications. This presentation will overview the WTPS concept and present some results from initial testing completed.

Feldman, Jay↗

NASA NTRS2006

Multi-Agent System for Managing Human Activities in Space Operations

In manned space operations today, the astronauts' activity schedules are preplanned and adjusted daily on Earth. We have developed the Distributed Collaboration and Interaction (DCI) multi-agent system to investigate automating aspects of human activity management. The DCI System assists (1) plan generation, (2) human activity tracking, (3) plan revision, and (4) mixed initiative interaction with the plan. We have deployed and evaluated the DCI system at JSC to assist control engineers in managing anomaly handling activities for automated life support systems. DCI operated round the clock for 20 months in the Water Research Facility at JSC. Using this software, we reduced anomaly response time by engineers from up to 10 hours in previous tests to under an hour. Based on this evaluation, we conclude that agent assistance for schedule management has potential to improve astronaut activity awareness and reduce response time in situations where crew are interrupted to handle anomalies.

Schrenkenghost, Debra↗

NASA NTRS1979

Multivariable control altitude demonstration on the F100 turbofan engine

The control system designed under the Multivariable Control Synthesis (MVCS) program for the F100 turbofan engine is described. The MVCS program, applied the linear quadratic regulator (LQR) synthesis methods in the design of a multivariable engine control system to obtain enhanced performance from cross-coupled controls, maximum use of engine variable geometry, and a systematic design procedure that can be applied efficiently to new engine systems. Basic components of the control system, a reference value generator for deriving a desired equilibrium state and an approximate control vector, a transition model to produce compatible reference point trajectories during gross transients, gain schedules for producing feedback terms appropriate to the flight condition, and integral switching logic to produce acceptable steady-state performance without engine operating limit exceedance are described and the details of the F100 implementation presented. The engine altitude test phase of the MVCS program, and engine responses in a variety of test operating points and power transitions are presented.

Lehtinen, B.↗

NASA NTRS1980

Orbit transfer vehicle engine study. Volume 2: Technical report

The orbit transfer vehicle (OTV) engine study provided parametric performance, engine programmatic, and cost data on the complete propulsive spectrum that is available for a variety of high energy, space maneuvering missions. Candidate OTV engines from the near term RL 10 (and its derivatives) to advanced high performance expander and staged combustion cycle engines were examined. The RL 10/RL 10 derivative performance, cost and schedule data were updated and provisions defined which would be necessary to accommodate extended low thrust operation. Parametric performance, weight, envelope, and cost data were generated for advanced expander and staged combustion OTV engine concepts. A prepoint design study was conducted to optimize thrust chamber geometry and cooling, engine cycle variations, and controls for an advanced expander engine. Operation at low thrust was defined for the advanced expander engine and the feasibility and design impact of kitting was investigated. An analysis of crew safety and mission reliability was conducted for both the staged combustion and advanced expander OTV engine candidates.

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NASA NTRS1982

Beta experiment

A focused laser doppler velocimeter (LDV) system was developed for the measurement of atmospheric backscatter (beta) from aerosols at infrared wavelengths. A Doppler signal generator was used in mapping the coherent sensitive focal volume of a focused LDV system. System calibration data was analyzed during the flight test activity scheduled for the Beta system. These analyses were performed to determine the acceptability of the Beta measurement system's performance.

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NASA NTRS1985

Seeing Comet IRAS with a radar eye

IRAS data in April 1983 held evidence for the approach of a comet which would pass close enough to earth to bounce radar signals off the cometary nucleus. The closest pass was calculated to be 450,000 km. Ephemerides were prepared for the object while radio observatory tracking schedules were arranged. S-band observations were selected for the JPL 64 m antenna to obtain 2.7 arcmin resolution. A 400 kW signal was generated. Two 4 hr observational periods were achieved, revealing a rough, faceted surface by using S-band in the first run and the X-band in the second. The comet was concluded irregularly shaped and roughly elliptical, with a 2 d period.

Jurgens, R. F.↗

NASA NTRS1986

Automating the U.S. Space Station's electrical power system

NASA's Lewis Research Center is developing a highly automated system for the generation, storage and distribution of electrical power aboard the projected Space Station. This autonomous power system will employ conventional algorithms, enhanced by expert systems, to schedule power, allocate energy, diagnose causes of failure, propose goals, prepare plans for their implementation, evaluate their consequences, and select optimum plans for their execution. While crew-interactive expert systems will be ready for the initial Space Station, total system autonomy is expected to require additional development time.

Dolce, James L.↗

NASA NTRS1991

Human factors issues in the design of user interfaces for planning and scheduling

The purpose is to provide and overview of human factors issues that impact the effectiveness of user interfaces to automated scheduling tools. The following methods are employed: (1) a survey of planning and scheduling tools; (2) the identification and analysis of human factors issues; (3) the development of design guidelines based on human factors literature; and (4) the generation of display concepts to illustrate guidelines.

Murphy, Elizabeth D.↗

NASA NTRS1993

Satellite laser station Helwan status 1992

The Satellite Laser Station Helwan has been operated jointly by the National Research Institute of Astronomy and Geophysics in Helwan, Egypt and the Czech Technical University in Prague, Czechslovakia. The station components have been carefully tuned to increase the systems overall stability and reliability critical for the remote location. The mount correction model based on the Gaussian smoothing has been implemented to simplify the blind satellite acquisition and tracking. The on-site normal points generation algorithm has been implemented, the station has been connected to the international information network. The ERS-1 satellite has been included into the tracking schedule. The station range capability has been verified by experimental Etalon 1 ranging by April 1992. The ranging precision of 2-3 centimeters is obtained when ranging to ERS-1, Starlette, and Lageos satellites.

Cech, M.↗

NASA NTRS1993

Advanced transportation system studies technical area 3: Alternate propulsion subsystem concepts, volume 3

The objective of this contract was to provide definition of alternate propulsion systems for both earth-to-orbit (ETO) and in-space vehicles (upper stages and space transfer vehicles). For such propulsion systems, technical data to describe performance, weight, dimensions, etc. was provided along with programmatic information such as cost, schedule, needed facilities, etc. Advanced technology and advanced development needs were determined and provided. This volume separately presents the various program cost estimates that were generated under three tasks: the F-1A Restart Task, the J-2S Restart Task, and the SSME Upper Stage Use Task. The conclusions, technical results, and the program cost estimates are described in more detail in Volume 1 - Executive Summary and in individual Final Task Reports.

Levak, Daniel↗

NASA NTRS1994

Analysis of EDP performance

The objective of this contract was the investigation of the potential performance gains that would result from an upgrade of the Space Station Freedom (SSF) Data Management System (DMS) Embedded Data Processor (EDP) '386' design with the Intel Pentium (registered trade-mark of Intel Corp.) '586' microprocessor. The Pentium ('586') is the latest member of the industry standard Intel X86 family of CISC (Complex Instruction Set Computer) microprocessors. This contract was scheduled to run in parallel with an internal IBM Federal Systems Company (FSC) Internal Research and Development (IR&D) task that had the goal to generate a baseline flight design for an upgraded EDP using the Pentium. This final report summarizes the activities performed in support of Contract NAS2-13758. Our plan was to baseline performance analyses and measurements on the latest state-of-the-art commercially available Pentium processor, representative of the proposed space station design, and then phase to an IBM capital funded breadboard version of the flight design (if available from IR&D and Space Station work) for additional evaluation of results. Unfortunately, the phase-over to the flight design breadboard did not take place, since the IBM Data Management System (DMS) for the Space Station Freedom was terminated by NASA before the referenced capital funded EDP breadboard could be completed. The baseline performance analyses and measurements, however, were successfully completed, as planned, on the commercial Pentium hardware. The results of those analyses, evaluations, and measurements are presented in this final report.

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NASA NTRS2000

Advanced Transportation System Studies. Technical Area 3: Alternate Propulsion Subsystems Concepts: Program Cost Estimates - Volume 3

The objective of this contract was to provide definition of alternate propulsion systems for both earth-to-orbit (ETO) and in-space vehicles (upper stages and space transfer vehicles). For such propulsion systems, technical data to describe performance, weight, dimensions, etc. was provided along with programmatic information such as cost, schedule, needed facilities, etc. Advanced technology and advanced development needs were determined and provided. This volume separately presents the various program cost estimates that were generated under three tasks: the F- IA Restart Task, the J-2S Restart Task, and the SSME Upper Stage Use Task. The conclusions, technical results , and the program cost estimates are described in more detail in Volume I - Executive Summary and in individual Final Task Reports.

Levack, Daniel J. H.↗

NASA NTRS2006

The Design of a High-Q, MACH-5 Nozzle for the Langley 8-Foot HTT

A new nozzle has ben designed for the NASA Langley Research Center 8-Foot High Temperature Tunnel. The new nozzle was designed with a Mach-5 exit flow at a Mach-5 flight-enthalpy test condition and has a smaller throat area than the existing Mach-5 nozzle which significantly increases the range of dynamic pressures that can be achieved in the facility. The nozzle was designed using the NASA Langley IMOCND computer program which solves the potential equation using the classical method of characteristics. Several axisymmetric nozzle contours were generated and evaluated using viscous computational fluid dynamics. A number of items were considered in the evaluation, including flow uniformity, thermal and structural design, manufacturing schedule and cost. Once the final contour was selected, studies were done to determine the effects of manufacturing irregularities (steps and cavities at joints). These studies were done to develop manufacturing specifications and assembly tolerances.

Gaffey, Richard L., Jr.↗

NASA NTRS2016

The Geoscience Spaceborne Imaging Spectroscopy Technical Committees Calibration and Validation Workshop

Calibration is the process of quantitatively defining a system's responses to known, controlled signal inputs, and validation is the process of assessing, by independent means, the quality of the data products derived from those system outputs [1]. Similar to other Earth observation (EO) sensors, the calibration and validation of spaceborne imaging spectroscopy sensors is a fundamental underpinning activity. Calibration and validation determine the quality and integrity of the data provided by spaceborne imaging spectroscopy sensors and have enormous downstream impacts on the accuracy and reliability of products generated from these sensors. At least five imaging spectroscopy satellites are planned to be launched within the next five years, with the two most advanced scheduled to be launched in the next two years [2]. The launch of these sensors requires the establishment of suitable, standardized, and harmonized calibration and validation strategies to ensure that high-quality data are acquired and comparable between these sensor systems. Such activities are extremely important for the community of imaging spectroscopy users. Recognizing the need to focus on this underpinning topic, the Geoscience Spaceborne Imaging Spectroscopy (previously, the International Spaceborne Imaging Spectroscopy) Technical Committee launched a calibration and validation initiative at the 2013 International Geoscience and Remote Sensing Symposium (IGARSS) in Melbourne, Australia, and a post-conference activity of a vicarious calibration field trip at Lake Lefroy in Western Australia.

Ong, Cindy↗

NASA NTRSDate not supplied

Overview of the Research Aircraft for eVTOL Enabling techNologies (RAVEN) Activity

The Research Aircraft for eVTOL Enabling techNologies (RAVEN) activity is a collaboration between Georgia Tech and NASA to design and develop a 1,000 lb gross weight class eVTOL research aircraft. The vision for RAVEN is that the aircraft will serve as a “flying laboratory” for enduring research and technology development applications across the realm of eVTOL technologies. A major goal of RAVEN is to disseminate the aircraft design geometry and data from flight tests for the benefit of the broader aeronautics community. Initial research applications will include flight dynamics, controls, acoustics, and automation/autonomy. The aircraft is based on the airframe of a fixed-wing experimental homebuilt airplane that will be modified to incorporate a distributed propulsion system, battery system, fly-by-wire flight control system, and avionics to enable remotely piloted operation. The aircraft is being designed to use commercial off-the-shelf components to the maximum extent practicable to save costs and to accelerate the development schedule without compromising the goal of publishing design geometry and test data. The RAVEN activity is also focused on workforce development by training the next generation of aerospace engineers in eVTOL technologies.

eVTOL↗