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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 NTRS1995

NASA technology flight experiments program

In addition to its scientific and life sciences experimental programs, NASA conducts flight experiments directed at development of space systems technologies. The experiments are conducted to obtain research data, to evaluate the performance or operation of experimental hardware in the space environment, or to validate components, subsystems, or systems prior to application in future spacecraft or missions. The requirements for specific technology experiments, and the priority assigned to them, vary significantly depending on the maturity of the technology. Some of the flight experiments address technologies still in the early research stage, while others are conducted to validate technology at relatively advanced levels of maturity. This paper discusses the overall technology flight experiments program and reports in some detail on four current or recently flown experiments ranging from research to technology validation at the system prototype level.

Pruscha, Stephen L.↗
NASA NTRS1998

Suppression of Transient Events by Levitation (STABLE): Results From the USML-2 Mission

Microgravity science payloads can be extremely sensitive to vibrations from machinery, acoustics, ventilation, and crew activity. Suppression of Transient Acceleration by Levitation (STABLE) is an active vibration isolation system designed to protect payloads from these disturbances. This paper gives an account of results from the flight demonstration of the STABLE microgravity isolation system, which was developed and successfully flight tested in orbit during USML-2, with the participation of Astronaut Fred Leslie. Following a very brief description of the operational principles, the hardware and software design, and performance criteria, results of the analysis of measured flight data are presented to provide an evaluation of system performance parameters, including acceleration attenuation, assessment of sway space, system power consumption, and other factors critical to the performance of an isolation system. Lessons learned and potential design improvements and evolutions are discussed. Data reduction by Robert Boucher of McDonnell Douglas Aerospace (MDA) was substantially assisted by Kenneth Hrovat of Tal-Cut, Inc., under support from National Aeronautics and Space Administration/Lewis Research Center (LeRC), Cleveland, OH.

Nurre, Gerald S.↗
NASA NTRS2000

Pointing and Tracking Concepts for Deep Space Missions

This paper summarizes part of a FY1998 effort on the design and development of an optical communications (Opcomm) subsystem for the Advanced Deep Space System Development (ADSSD) Project. This study was funded by the JPL X2000 program to develop an optical communications (Opcomm) subsystem for use in future planetary missions. The goal of this development effort was aimed at providing prototype hardware with the capability of performing uplink, downlink, and ranging functions from deep space distances. Such a system was envisioned to support future deep space missions in the Outer Planets/Solar Probe (OPSP) mission set such as the Pluto express and Europa orbiter by providing a significant enhancement of data return capability. A study effort was initiated to develop a flyable engineering model optical terminal to support the proposed Europa Orbiter mission - as either the prime telecom subsystem or for mission augmentation. The design concept was to extend the prototype lasercom terminal development effort currently conducted by JPL's Optical Communications Group. The subsystem would track the sun illuminated Earth at Europa and farther distances for pointing reference. During the course of the study, a number of challenging issues were found. These included thermo-mechanical distortion, straylight control, and pointing. This paper focuses on the pointing aspects required to locate and direct a laser beam from a spacecraft (S/C) near Jupiter to a receiving station on Earth.

Alexander, J. W.↗
NASA NTRS2000

Simulation of a Flywheel Electrical System for Aerospace Applications

A Flywheel Energy Storage Demonstration Project was initiated at the NASA Glenn Research Center as a possible replacement for the battery energy storage system on the International Space Station (ISS). While the hardware fabrication work was being performed at a university and contractor's facility, the related simulation activity was begun at Glenn. At the top level, Glenn researchers simulated the operation of the ISS primary electrical system (as described in another paper) with the Flywheel Energy Storage Unit (FESU) replacing one Battery Charge and Discharge Unit (BCDU). The FESU consists of a Permanent Magnet Synchronous Motor/Generator (PMSM), which is connected to the flywheel; the power electronics that connects the PMSM to the ISS direct-current bus; and the associated controller. The PMSM model is still under development, but this paper describes the rest of the FESU model-the simulation of the converter and the associated control system that regulates energy transfer to and from the flywheel.

Truong, Long V.↗
NASA NTRS2000

NASA's Student Glovebox: An Inquiry-Based Technology Educator's Guide

A glovebox is a sealed container with built-in gloves. Astronauts perform small experiments and test hardware inside of them. Gloveboxes have flown on NASA's space shuttles and on the Russian space station Mir. The International Space Station (ISS) will have a permanent glovebox on the U.S. laboratory, Destiny. This document contains cursory technical information on gloveboxes and glovebox experiments and is intended for use by middle school educators and students. Information is provided on constructing a model glovebox as well as realistic cut-outs to be pasted on the model.

Rosenberg, Carla B.↗
NASA NTRS1997

Cooperative Data Sharing: Simple Support for Clusters of SMP Nodes

Libraries like PVM and MPI send typed messages to allow for heterogeneous cluster computing. Lower-level libraries, such as GAM, provide more efficient access to communication by removing the need to copy messages between the interface and user space in some cases. still lower-level interfaces, such as UNET, get right down to the hardware level to provide maximum performance. However, these are all still interfaces for passing messages from one process to another, and have limited utility in a shared-memory environment, due primarily to the fact that message passing is just another term for copying. This drawback is made more pertinent by today's hybrid architectures (e.g. clusters of SMPs), where it is difficult to know beforehand whether two communicating processes will share memory. As a result, even portable language tools (like HPF compilers) must either map all interprocess communication, into message passing with the accompanying performance degradation in shared memory environments, or they must check each communication at run-time and implement the shared-memory case separately for efficiency. Cooperative Data Sharing (CDS) is a single user-level API which abstracts all communication between processes into the sharing and access coordination of memory regions, in a model which might be described as "distributed shared messages" or "large-grain distributed shared memory". As a result, the user programs to a simple latency-tolerant abstract communication specification which can be mapped efficiently to either a shared-memory or message-passing based run-time system, depending upon the available architecture. Unlike some distributed shared memory interfaces, the user still has complete control over the assignment of data to processors, the forwarding of data to its next likely destination, and the queuing of data until it is needed, so even the relatively high latency present in clusters can be accomodated. CDS does not require special use of an MMU, which can add overhead to some DSM systems, and does not require an SPMD programming model. unlike some message-passing interfaces, CDS allows the user to implement efficient demand-driven applications where processes must "fight" over data, and does not perform copying if processes share memory and do not attempt concurrent writes. CDS also supports heterogeneous computing, dynamic process creation, handlers, and a very simple thread-arbitration mechanism. Additional support for array subsections is currently being considered. The CDS1 API, which forms the kernel of CDS, is built primarily upon only 2 communication primitives, one process initiation primitive, and some data translation (and marshalling) routines, memory allocation routines, and priority control routines. The entire current collection of 28 routines provides enough functionality to implement most (or all) of MPI 1 and 2, which has a much larger interface consisting of hundreds of routines. still, the API is small enough to consider integrating into standard os interfaces for handling inter-process communication in a network-independent way. This approach would also help to solve many of the problems plaguing other higher-level standards such as MPI and PVM which must, in some cases, "play OS" to adequately address progress and process control issues. The CDS2 API, a higher level of interface roughly equivalent in functionality to MPI and to be built entirely upon CDS1, is still being designed. It is intended to add support for the equivalent of communicators, reduction and other collective operations, process topologies, additional support for process creation, and some automatic memory management. CDS2 will not exactly match MPI, because the copy-free semantics of communication from CDS1 will be supported. CDS2 application programs will be free to carefully also use CDS1. CDS1 has been implemented on networks of workstations running unmodified Unix-based operating systems, using UDP/IP and vendor-supplied high- performance locks. Although its inter-node performance is currently unimpressive due to rudimentary implementation technique, it even now outperforms highly-optimized MPI implementation on intra-node communication due to its support for non-copy communication. The similarity of the CDS1 architecture to that of other projects such as UNET and TRAP suggests that the inter-node performance can be increased significantly to surpass MPI or PVM, and it may be possible to migrate some of its functionality to communication controllers.

DiNucci, David C.↗
NASA NTRS2001

Stellar and Binary Evolution in Star Clusters

This paper presents a final report on research activities covered on Stellar and Binary Evolution in Star Clusters. Substantial progress was made in the development and dissemination of the "Starlab" software environment. Significant improvements were made to "kira," an N-body simulation program tailored to the study of dense stellar systems such as star clusters and galactic nuclei. Key advances include (1) the inclusion of stellar and binary evolution in a self-consistent manner, (2) proper treatment of the anisotropic Galactic tidal field, (3) numerous technical enhancements in the treatment of binary dynamics and interactions, and (4) full support for the special-purpose GRAPE-4 hardware, boosting the program's performance by a factor of 10-100 over the accelerated version. The data-reduction and analysis tools in Starlab were also substantially expanded. A Starlab Web site (http://www.sns.ias.edu/-starlab) was created and developed. The site contains detailed information on the structure and function of the various tools that comprise the package, as well as download information, "how to" tips and examples of common operations, demonstration programs, animations, etc. All versions of the software are freely distributed to all interested users, along with detailed installation instructions.

McMillan, Stephen L. W.↗
NASA NTRS1994

Conditions and constraints of food processing in space

Requirements and constraints of food processing in space include a balanced diet, food variety, stability for storage, hardware weight and volume, plant performance, build-up of microorganisms, and waste processing. Lunar, Martian, and space station environmental conditions include variations in atmosphere, day length, temperature, gravity, magnetic field, and radiation environment. Weightlessness affects fluid behavior, heat transfer, and mass transfer. Concerns about microbial behavior include survival on Martian and lunar surfaces and in enclosed environments. Many present technologies can be adapted to meet space conditions.

NASA Discipline Life Support Systems↗
NASA NTRS2004

Prototype Test Results for the Single Photon Detection SLR2000 Satellite Laser Ranging System

NASA's aging Satellite Laser Ranging (SLR) network is scheduled to be replaced over the next few years with a fully automated single photon detection system. A prototype of this new system, called SLR2000, is currently undergoing field trials at the Goddard Space Flight Center in Greenbelt, Maryland to evaluate photon counting techniques and determine system hardware, software, and control algorithm performance levels and limitations. Newly developed diode pumped microchip lasers and quadrant microchannel plate-based photomultiplier tubes have enabled the development of this high repetition rate single photon detection SLR system. The SLR2000 receiver threshold is set at the single photoelectron (pe) level but tracks satellites with an average signal level typically much less than 1 pe. The 2 kHz laser fire rate aids in satellite acquisition and tracking and will enable closed loop tracking by accumulating single photon count statistics in a quadrant detector and using this information to correct for pointing errors. Laser transmitter beamwidths of 10 arcseconds (FWHM) or less are currently being used to maintain an adequate signal level for tracking while the receiver field of view (FOV) has been opened to 40 arcseconds to accommodate point ahead/look behind angular offsets. In the near future, the laser transmitter point ahead will be controlled by a pair of Risley prisms. This will allow the telescope to point behind and enable closure of the receiver FOV to roughly match the transmitter beam divergence. Bandpass filters (BPF) are removed for night tracking operations while 0.2 nm or 1 nm filters are used during daylight operation. Both day and night laser tracking of Low Earth Orbit (LEO) satellites has been achieved with a laser transmitter energy of only 65 microjoules per pulse. Satellite tracking is presently limited to LEO satellites until the brassboard laser transmitter can be upgraded or replaced. Simultaneous tracks have also been observed with NASA s SLR standard, MOBLAS 7, for the purposes of data comparison and identification of biases. Work continues to optimize the receive optics; upgrade or replace the laser transmitter; calibrate the quadrant detector, the point ahead Risley prisms, and event timer verniers; and test normal point generation with SLR2000 data. This paper will report on the satellite tracking results to date, issues yet to be resolved, and future plans for the SLR2000 system.

Zagwodzki, Thomas W.↗
NASA NTRS2004

The Fluids and Combustion Facility

Microgravity is an environment with very weak gravitational effects. The Fluids and Combustion Facility (FCF) on the International Space Station (ISS) will support the study of fluid physics and combustion science in a long-duration microgravity environment. The Fluid Combustion Facility's design will permit both independent and remote control operations from the Telescience Support Center. The crew of the International Space Station will continue to insert and remove the experiment module, store and reload removable data storage and media data tapes, and reconfigure diagnostics on either side of the optics benches. Upon completion of the Fluids Combustion Facility, about ten experiments will be conducted within a ten-year period. Several different areas of fluid physics will be studied in the Fluids Combustion Facility. These areas include complex fluids, interfacial phenomena, dynamics and instabilities, and multiphase flows and phase change. Recently, emphasis has been placed in areas that relate directly to NASA missions including life support, power, propulsion, and thermal control systems. By 2006 or 2007, a Fluids Integrated Rack (FIR) and a Combustion Integrated Rack (CIR) will be installed inside the International Space Station. The Fluids Integrated Rack will contain all the hardware and software necessary to perform experiments in fluid physics. A wide range of experiments that meet the requirements of the international space station, including research from other specialties, will be considered. Experiments will be contained in subsystems such as the international standard payload rack, the active rack isolation system, the optics bench, environmental subsystem, electrical power control unit, the gas interface subsystem, and the command and data management subsystem. In conclusion, the Fluids and Combustion Facility will allow researchers to study fluid physics and combustion science in a long-duration microgravity environment. Additional information is included in the original extended abstract.

Kundu, Sampa↗
NASA NTRS1995

Small Spacecraft Technology

Aerospace designers are aggressively pursuing new ideas in advanced technology for smaller spacecraft. NASA's 'faster, better, cheaper' philosophy is the driving force to accomplish higher level scientific exploration more efficiently. More memory and higher performance is packed into computer hardware that takes up a fraction of the space of earlier generation spacecraft. Current technology is described.

small spacecraft technology NASA philosophy scienc↗
NASA NTRS2002

Spacewire on Earth orbiting scatterometers

The need for a high speed, reliable and easy to implement communication link has led to the development of a space flight oriented version of IEEE 1355 called SpaceWire. SpaceWire is based on high-speed (200 Mbps) serial point-to-point links using Low Voltage Differential Signaling (LVDS). SpaceWIre has provisions for routing messages between a large network of processors, using wormhole routing for low overhead and latency. {additionally, there are available space qualified hybrids, which provide the Link layer to the user's bus}. A test bed of multiple digital signal processor breadboards, demonstrating the ability to meet signal processing requirements for an orbiting scatterometer has been implemented using three Astrium MCM-DSPs, each breadboard consists of a Multi Chip Module (MCM) that combines a space qualified Digital Signal Processor and peripherals, including IEEE-1355 links. With the addition of appropriate physical layer interfaces and software on the DSP, the SpaceWire link is used to communicate between processors on the test bed, e.g. sending timing references, commands, status, and science data among the processors. Results are presented on development issues surrounding the use of SpaceWire in this environment, from physical layer implementation (cables, connectors, LVDS drivers) to diagnostic tools, driver firmware, and development methodology. The tools, methods, and hardware, software challenges and preliminary performance are investigated and discussed.

serial↗
NASA NTRS2006

Tapered Roller Bearing Damage Detection Using Decision Fusion Analysis

A diagnostic tool was developed for detecting fatigue damage of tapered roller bearings. Tapered roller bearings are used in helicopter transmissions and have potential for use in high bypass advanced gas turbine aircraft engines. A diagnostic tool was developed and evaluated experimentally by collecting oil debris data from failure progression tests conducted using health monitoring hardware. Failure progression tests were performed with tapered roller bearings under simulated engine load conditions. Tests were performed on one healthy bearing and three pre-damaged bearings. During each test, data from an on-line, in-line, inductance type oil debris sensor and three accelerometers were monitored and recorded for the occurrence of bearing failure. The bearing was removed and inspected periodically for damage progression throughout testing. Using data fusion techniques, two different monitoring technologies, oil debris analysis and vibration, were integrated into a health monitoring system for detecting bearing surface fatigue pitting damage. The data fusion diagnostic tool was evaluated during bearing failure progression tests under simulated engine load conditions. This integrated system showed improved detection of fatigue damage and health assessment of the tapered roller bearings as compared to using individual health monitoring technologies.

Dempsey, Paula J.↗
NASA NTRS2008

The First Development of Human Factors Engineering Requirements for Application to Ground Task Design for a NASA Flight Program

The National Aeronautics and Space Administration has long applied standards-derived human engineering requirements to the development of hardware and software for use by astronauts while in flight. The most important source of these requirements has been NASA-STD-3000. While there have been several ground systems human engineering requirements documents, none has been applicable to the flight system as handled at NASA's launch facility at Kennedy Space Center. At the time of the development of previous human launch systems, there were other considerations that were deemed more important than developing worksites for ground crews; e.g., hardware development schedule and vehicle performance. However, experience with these systems has shown that failure to design for ground tasks has resulted in launch schedule delays, ground operations that are more costly than they might be, and threats to flight safety. As the Agency begins the development of new systems to return humans to the moon, the new Constellation Program is addressing this issue with a new set of human engineering requirements. Among these requirements is a subset that will apply to the design of the flight components and that is intended to assure ground crew success in vehicle assembly and maintenance tasks. These requirements address worksite design for usability and for ground crew safety.

Dischinger, H. Charles, Jr.↗
NASA NTRS2010

Orion Touchdown Heading Control

At touchdown Orion must be aligned so that the crew person's feet are forward in the direction of the horizontal velocity. To ensure that this requirement is met active heading control is being implemented on the Orion crew module. This technique reduces probability of roll-over during splashdown, assures axial loads on the crew at touchdown, and alleviates structural requirements on impact allowing for a light-weight structural design. On-board sensors are used to measure current vehicle orientation and horizontal velocity used in generation of the heading error signal. Linear velocity measured by the IMU drifts while under parachutes due to wind gusts and has to be corrected by GPS; this makes GPS critical for successful landing. Jet fire logic is achieved by use of a phase-plane and commands are realized by using roll jets from the reaction control system (RCS); using pre existing hardware eliminates additional hardware and structural requirements. Touchdown performance is measured by an orientation envelope that was co-developed with structures so that the performance requirements overlap adding system redundancy. Heading control also introduces new difficulties to be addressed such as parachute line twist torque as well as increasing vehicle sensitivity to wind shifts and sea states. Solving these difficulties requires added complexity to flight software as well as increasing the propellant required to achieve successful touchdown. while offering promising results, the criticality of GPS along with a significant propellant cost raises questions on the effectiveness of using touchdown heading control.

Kane, Mark A.↗
NASA NTRS2004

Earth to Moon Transfer: Direct vs Via Libration Points (L1, L2)

For some three decades, the Apollo-style mission has served as a proven baseline technique for transporting flight crews to the Moon and back with expendable hardware. This approach provides an optimal design for expeditionary missions, emphasizing operational flexibility in terms of safely returning the crew in the event of a hardware failure. However, its application is limited essentially to low-latitude lunar sites, and it leaves much to be desired as a model for exploratory and evolutionary programs that employ reusable space-based hardware. This study compares the performance requirements for a lunar orbit rendezvous mission type with one using the cislunar libration point (L1) as a stopover and staging point for access to arbitrary sites on the lunar surface. For selected constraints and mission objectives, it contrasts the relative uniformity of performance cost when the L1 staging point is used with the wide variation of cost for the Apollo-style lunar orbit rendezvous.

Condon, Gerald L.↗
NASA NTRS2002

On Using Commercial Off-the-Shelf (COTS) Electronic Products in Space

NASA's Johnson Space Center (JSC) has utilized COTS products in its programs since the early 1990's. Recently it has become evident that, of all failure modes possible, radiation will probably dominate; sometimes to the point of driving system architecture. It is now imperative that radiation susceptibility be addressed when writing the system requirements. Susceptibility assessment, e.g. testing, must begin early in the design phase to establish performance and continue through the hardware qualification program to prove satisfaction of the original requirements(s). Examples of requirements, testing, and architecture versus failure rate will be given.

Culpepper, William X.↗