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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Reusable Reentry Satellite (RRS): Recovery tradeoff study

The main objectives of the Recovery Tradeoff Study were as follows: (1) to determine whether a land or water recovery best suits RRS system requirements; (2) what type of terminal recovery system is best suited for the RRS; and (3) what are the recovery access timelines after system landing. Based on the trade parameters and evaluation criteria used in this study, the land-landing configuration has an advantage over the water-landing configuration. It is recommended that a land-landing configuration be developed assuming WSMR as the landing site. It is also recommended that natural orbits be used for low inclination missions and any orbit adjustments for landing site targeting be performed at the end of the mission. Near-integer orbits should be used for high inclination missions and allow orbital decay to precess the ground track over the landing site range.

Source record↗
NASA NTRS1991

Structural Development of Flight Systems

An overview of the typical process and timeline for the development of structural systems is presented. Structural design and verification requirements, along with the approaches used to implement these requirements, are discussed. Special considerations are given to limit loads estimation, structural qualification by analysis, modal survey and test/analysis correlation, and response limiting during vibration tests. Several controversal issues that cause inconsistencies and difficulties in the current structural development process are identified and an approach for resolving these issues is recommended.

Lou, Michael C.↗
NASA NTRS1991

Autonomous rendezvous targeting techniques for national launch system application

The rendezvous targeting techniques that can be utilized to achieve autonomous guidance for delivering a cargo to Space Station Freedom (SSF) using the National Launch System's (NLS) Heavy Lift Launch Vehicle (HLLV) and the on-orbit Cargo Transfer Vehicle (CTV) are described. This capability is made possible by advancements in autonomous navigation (Global Positioning System - GPS) on-board the CTV and SSF as well as the new generation flight computers. How the HLLV launch window can be decoupled from the CTV phasing window is described. The performance trades that have to be made to determine the length of the launch window and the phasing window between the CTV and SSF are identified and recommendations made that affect mission timelines.

Lomas, James J.↗
NASA NTRS1992

Ulysses operations at Jupiter - Planning for the unknown

The operational preparations for the Ulysses encounter with Jupiter are described with particular attention given to requirements for survival in the Jovian environment, ground-segment planning, a deep-space network, and encounter activities. It is concluded that the successful operation of the Ulysses spacecraft at Jupiter was the culmination of many years of activity, from spacecraft design and mission planning to the coordination of the encounter activities and production of the detailed timeline.

Angold, N.↗
NASA NTRS1992

The NASA CSTI High Capacity Power Project

The elements of the Civilian Space Technology Initiative (CSTI) High Capacity Power Project include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements are presented, along with revised goals and project timelines recently developed.

Winter, J.↗
NASA NTRS1993

An analysis of the history of dust activity on Mars

A comprehensive list of dust storm activity on Mars has been compiled from various published lists and additional data. For uniformity and clarity, each event is classified using a new system that includes a well-defined nomenclature. Maps showing the reported locations of events have been compiled. Detailed commentaries describe the events and/or circumstances of their observation. The seasonal distribution of Martian dust events is diagrammed and discussed together with a seasonal and annual (Mars years) timeline that includes the frequency of photographic coverage. Regional dust storms tend to occur most frequently, and all planet-encircling dust storms have been observed during the southern spring and summer seasons, although there is significant interannual variability.

Martin, Leonard J.↗
NASA NTRS1992

STS-49 - A demonstration of EMU operational capabilities for Space Station Freedom assembly

One of the primary objectives for Space Shuttle mission STS-49 is to perform three EVAs on consecutive days in a manner similar to those planned for Space Station Freedom (SSF) assembly missions. The preparation and completion of this mission will serve as a pathfinder for future EVA intensive SSF assembly flights. Several operational issues pertaining to the EMU have been addressed in preparation for this mission. Provisioning and orbiter stowage of the EMU and associated hardware have been optimized for four EVA crewmembers. EMU preparatory and maintenance activities have been streamlined to help minimize crew overhead and have been carefully integrated into a very demanding mission timeline. The constraints and limitations have been assessed in providing a backup EMU capability for each EVA crewmember. Several EMU concerns have also been addressed in supporting new EVA task requirements, such as large mass handling and performing SSF assembly operations over the crew cabin and nose of the Shuttle orbiter.

Bleisath, Scott A.↗
NASA NTRS1992

Assessment of a SSF servicing facility

A polygonal pseudo-cylindrical hangar that sustains only the Space Transfer Vehicle (STV) has been proposed as an optimal servicing facility at the Space Station Freedom (SSF). The drop tanks would be placed external to the hangar, with final integration occurring outside the sheltered hangar. The potential locations for the hangar are outboard of a lower keel and above the module pattern. A third possibility combines the two cases, extending a support structure/tunnel below the module pattern to the distance of a lower keel. Calculations of servicing timelines indicate that a single STV could be serviced for its next lunar mission in 2 months using a robot similar to the Flight Telerobotic Servicer.

Zaveri, Rohan↗
NASA NTRS1989

LEO/GSO cyclic depot transfer

This paper investigates the development and use of semi-analytic methods for propellant depot orbit selection in cyclic, coplanar, Keplerian GSO missions. The cyclic depot transfer strategy which allows for non-optimum (e.g. non-Hohmann) transfer, is constrained by resonance requirements allowing for descent rendezvous/refueling with fuel depots positioned during the ascent phase of the mission. The mission benefit using this transfer technique allows an improvement in propulsion system efficiency which can lead to approximately 43 percent reduction in initial launch mass when compared to traditional methods, but with the trade-off of longer mission timelines. A family of potential transfers is identified with an 'optimum' selection not based on conventional delta V minimization. The results of this analysis include reduced transfer times and greater potential initial launch mass savings over previous work.

Coffey, Randall E.↗
NASA NTRS1993

Space Station maintenance studies using plaid graphics

The Graphics Analysis Facility (GRAF) has been used frequently to study extravehicular activity (EVA) maintenance scenarios on Space Station Freedom. The ability to use 3-dimensional visualization gives one a more accurate estimate of the Space Station environment. Moreover, human EVA and robotic kinematics can be accurately simulated for columetric reach and collision detection analysis. An animation of this kind was developed for a research group at JSC to study and discover problem areas involved with doing external Space Station maintenance tasks. On the EVA side, it was discovered that items such as handholds and temporary restraint mechanisms should more effectively facilitate EVA movement about the Space Station structure for the suited personnel. Issues concerning CETA cart configuration, PWP storage locations, and locations of EVA storage areas were also identified by use of the animation. In the area of EVA versus robotics, it was found that there is a strong desire to make EVA and robotics interfaces compatible on items such as replacement units and unpressurized logistics carriers. The animation also showed that the use of robotics within an EVA task increases the difficulty and duration of the task setup, leaving less time available for the maintenance task itself. Graphics animation provides a mechanism to simultaneously analyze several mission parameters (i.e., EVA reach, volumetric analysis, and task timelines), and thus, it has proven to be an effective method for mission evaluation.

Helm, Mary E.↗
NASA NTRS1993

STS-55 pad abort: Engine 2011 oxidizer preburner augmented spark igniter check valve leak

The STS-55 initial launch attempt of Columbia (OV102) was terminated on KSC launch pad A March 22, 1993 at 9:51 AM E.S.T. due to violation of an ME-3 (Engine 2011) Launch Commit Criteria (LCC) limit exceedance. The event description and timeline are summarized. Propellant loading was initiated on 22 March, 1993 at 1:15 AM EST. All SSME chill parameters and launch commit criteria (LCC) were nominal. At engine start plus 1.44 seconds, a Failure Identification (FID) was posted against Engine 2011 for exceeding the 50 psia Oxidizer Preburner (OPB) purge pressure redline. The engine was shut down at 1.50 seconds followed by Engines 2034 and 2030. All shut down sequences were nominal and the mission was safely aborted. The OPB purge pressure redline violation and the abort profile/overlay for all three engines are depicted. SSME Avionics hardware and software performed nominally during the incident. A review of vehicle data table (VDT) data and controller software logic revealed no failure indications other than the single FID 013-414, OPB purge pressure redline exceeded. Software logic was executed according to requirements and there was no anomalous controller software operation. Immediately following the abort, a Rocketdyne/NASA failure investigation team was assembled. The team successfully isolated the failure cause to the oxidizer preburner augmented spark igniter purge check valve not being fully closed due to contamination. The source of the contaminant was traced to a cut segment from a rubber O-ring which was used in a fine clean tool during valve production prior to 1992. The valve was apparently contaminated during its fabrication in 1985. The valve had performed acceptably on four previous flights of the engine, and SSME flight history shows 780 combined check valve flights without failure. The failure of an Engine 3 (SSME No. 2011) check valve to close was sensed by onboard engine instruments even though all other engine operations were normal. This resulted in an engine shutdown and safe sequential shutdown of all three engines prior to ignition of the solid boosters.

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NASA NTRS1993

Liquid Oxygen (LO2) propellant conditioning concept testing

Marshall Space Flight Center (MSFC) and industry contractors have undertaken activities to develop a simplified liquid oxygen (LO2) propellant conditioning concept for future expendable launch vehicles. The objective of these activities is to reduce operations costs and timelines and to improve safety of these vehicles. The approach followed has been to identify novel concepts through system level studies and demonstrate the feasibility of these concepts through small-scale and full-scale testing. Testing will also provide data for design guidelines and validation of analytical models. Four different concepts are being investigated: no-bleed, low-bleed, use of a recirculation line, and helium (He) bubbling. This investigation is being done under a Joint Institutional Research and Development (JIRAD) program currently in effect between MSFC and General Dynamics Space Systems (GDSS). A full-scale test article, which is a facsimile of a propellant feed duct with an attached section to simulate heat input from a LO2 turbopump, will be tested at the Cold Flow Facility at MSFC's West Test Area. Liquid nitrogen (LN2), which has similar properties to LO2, will be used in place of LO2 for safety and budget reasons. Work to date includes design and fabrication of the test article, design of the test facility and initial fabrication, development of a test matrix and test procedures, initial predictions of test output, and heat leak calibration and heat exchanger tests on the test article. The tests for all propellant conditioning concepts will be conducted in the summer of 1993, with the final report completed by October, 1993.

Perry, Gretchen L. E.↗
NASA NTRS1992

ROSAT data analysis with EXSAS

For the x-ray observatory ROSAT, data from survey and pointed mission phases taken with different focal plane instruments and according to a complex mission timeline have to be handled. Data analysis therefore puts high demands on appropriate software tools. With EXSAS - the Extended Scientific Analysis System developed with an effort of 20 man years by the German ROSAT Scientific Data Center - a comfortable system for the reduction of data from the ROSAT x-ray and XUV instruments has been made available. EXSAS comprises a large collection of application modules as typically required in analyzing data of this wavelength regime and runs as a specific context in the wide-spread ESO-MIDAS environment. EXSAS, completely written in FORTRAN 77, takes full advantage of all the standards used in MIDAS and therefore, reflects the same portability (different UNIX installations and VMS). If required, the FORTRAN code also enables users to adapt the software in an easy way to their specific needs. To maintain independence from the specifics of different operating systems also on the data input side, all ROSAT data redistributed in the widely accepted FITS format. Although EXSAS has been developed specifically for data analysis of the ROSAT instruments, its structural design is sufficiently general to serve equally well also data from other X-ray and XUV instruments. EXSAS analysis modules are grouped into 4 application packages dealing with Data Preparation and Instrument Correction, Spatial Analysis, Spectral Analysis and Timing Analysis. A special EXSAS header, read and updated by each application, maintains the general information transfer on the origin, the history and the parameter space of the data stored in tables and images. About 100 genuine commands (most of which offer several additional options) allow to interactively explore the functionality of the system. Up to now 40 institutes all over the world have requested the EXSAS software. Maintenance and regular updates of the software and the comprehensive documentation are provided by the ROSAT Scientific Data Center at Garching.

Zimmermann, H. U.↗
NASA NTRS1993

Mission planning for Shuttle Imaging Radar-C (SIR-C) with a real-time interactive planning software

The Shuttle Imaging Radar-C (SIR-C) mission will operate from the payload bay of the space shuttle for 8 days, gathering Synthetic Aperture Radar (SAR) data over specific sites on the Earth. The short duration of the mission and the requirement for realtime planning offer challenges in mission planning and in the design of the Planning and Analysis Subsystem (PAS). The PAS generates shuttle ephemerides and mission planning data and provides an interactive real-time tool for quick mission replanning. It offers a multi-user and multiprocessing environment, and it is able to keep multiple versions of the mission timeline data while maintaining data integrity and security. Its flexible design allows one software to provide different menu options based on the user's operational function, and makes it easy to tailor the software for other Earth orbiting missions.

Potts, Su K.↗
NASA NTRS1993

A packet-based concept for spacecraft command planning

The current generation of spacecraft being developed and operated by the Applied Physics Laboratory provides users with access to a broad spectrum of scientific instruments on maneuverable platforms that can be oriented for observation of both moving and stationary targets of interest. The capability of these increasingly complex spacecraft to perform data collection operations is approaching one observation per orbit. To enable both rapid configuration and generation of complex spacecraft command sequences, as well as reusability of command sequences among data collection operations, a packet-based concept for spacecraft command planning has been developed. The configuration of the spacecraft for any operation is designed using 'packets' where a packet represents a set of commands that is reusable. The packets can be combined in varying levels of functionality, and in varying time relationships, to create an observation timeline. At the lowest packet level are primitives. Primitives relate the details of command generation for a particular spacecraft to a 'message template.' Thus the packet concept itself is reusable from one spacecraft to the next.

Barnes, Valerie B.↗
NASA NTRS1993

The mission events graphic generator software: A small tool with big results

Utilization of graphics has long been a useful methodology for many aspects of spacecraft operations. A personal computer based software tool that implements straight-forward graphics and greatly enhances spacecraft operations is presented. This unique software tool is the Mission Events Graphic Generator (MEGG) software which is used in support of the Hubble Space Telescope (HST) Project. MEGG reads the HST mission schedule and generates a graphical timeline.

Lupisella, Mark↗
NASA NTRS1994

Flight controller alertness and performance during MOD shiftwork operations

Decreased alertness and performance associated with fatigue, sleep loss, and circadian disruption are issues faced by a diverse range of shiftwork operations. During STS operations, MOD personnel provide 24 hr. coverage of critical tasks. A joint JSC and ARC project was undertaken to examine these issues in flight controllers during MOD shiftwork operations. An initial operational test of procedures and measures was conducted during STS-53 in Dec. 1992. The study measures included a background questionnaire, a subjective daily logbook completed on a 24 hr. basis (to report sleep patterns, work periods, etc.), and an 8 minute performance and mood test battery administered at the beginning, middle, and end of each shift period. Seventeen Flight controllers representing the 3 Orbit shifts participated. The initial results clearly support further data collection during other STS missions to document baseline levels of alertness and performance during MOD shiftwork operations. These issues are especially pertinent for the night shift operations and the acute phase advance required for the transition of day shift personnel into the night for shuttle launch. Implementation and evaluation of the countermeasure strategies to maximize alertness and performance is planned. As STS missions extend to further extended duration orbiters, timelines and planning for 24 circadian disruption will remain highly relevant in the MOD environment.

Kelly, Sean M.↗