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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 NTRS1992

Current trajectory options for a comet nucleus sample return mission

A summary of the current trajectory options available for the ESA comet nucleus sample return mission, Rosetta, is presented. These options include direct trajectories, delta-V-EGA trajectories using a Titan IV/Centaur launch vehicle with upgraded solid rocket motors, a trajectory involving a gravity assist of the earth (VEGA) prior to comet rendezvous, and one involving an additional gravity assist of the earth (VEEGA). Other propulsion options proposed and discussed are solar electric propulsion/ballistic trajectory modes and nuclear electric propulsion trajectory modes. Tables of performance data for each of these trajectory options are given.

Sauer, Carl G., Jr.↗

NASA NTRS1993

Space Station redesign option A: Modular buildup concept

In early 1993, President Clinton mandated that NASA look at lower cost alternatives to Space Station Freedom. He also established an independent advisory committee - the Blue Ribbon Panel - to review the redesign work and evaluate alternatives. Daniel Goldin, NASA Administrator, established a Station Redesign Team that began operating in late March from Crystal City, Virginia. NASA intercenter teams - one each at Marshall Space Flight Center, Johnson Space Center, and Langley Research Center provided engineering and other support. The results of the Option A study done at Marshall Space Flight Center are summarized. Two configurations (A-1 and A-2) are covered. Additional data is provided in the briefing package MSFC SRT-001, Final System Review to SRT-002, Space Station Option A Modular Buildup Concept, Volumes 1-5, Revision B, June 10, 1993. In June 1993, President Clinton decided to proceed with a modular concept consistent with Option A, and asked NASA to provide an Implementation Plan by September. All data from the Option A redesign activity was provided to NASA's Transition Team for use in developing the Implementation Plan.

Source record↗

NASA NTRS1995

Fuel cell systems for First Lunar Outpost-reactant storage option

The office of Space, DOE, appointed a Lunar Surface Power Working Group to review candidate systems for the First Lunar Outpost habitat. The working group met for a total of five days in the fall of 1992 and concluded that the candidate involving a photovoltaic unit, a fuel cell, a regenerator to recycle the reactants, and storage of oxygen and hydrogen gases was the most attractive for this application. Most of the volume (97 percent) and weight (63 percent) are taken up by the reactants and their storage tanks. Therefore, in my work for the Group, and in this report, I have concentrated on finding ways to reduce these volumes and weights. Three options were considered: (1) the baseline case considered in the preliminary system design, that of separate high pressure (200 bar) storage tanks; (2) the use of two of the descent storage propellant tanks wrapped with graphite fibers to increase the pressure capability; and (3) the use of cryogenic storage of reactants in the propellant tanks. The first option results in high storage tank mass and volume. The second option saves 90 percent of the volume by making use of the propellant tanks, but it has little if any weight advantages; the weight saved by not providing extra tanks for reactant storage is nearly entirely added back by the weight of the additional material (graphite fibers) to strengthen the propellant tanks. Use of the descent storage propellant tanks for storage of the fuel cell reactants as cryogenic liquids requires a gas liquefaction system. The weight of this system is expected to be less than that of the storage tanks but it would require development and testing to prove its reliability. The solar array would have to be 40 percent larger and the heat projection range would be 170 percent larger than for storage of reactants as high pressure gases. For a high power system (greater than 20 kW) the larger energy storage requirement would probably favor the cryogenic storage option.

Nelson, P. A.↗

NASA NTRS1996

Options for flight testing rocket-based combined-cycle (RBCC) engines

While NASA's current next-generation launch vehicle research has largely focused on advanced all-rocket single-stage-to-orbit vehicles (i.e. the X-33 and it's RLV operational follow-on), some attention is being given to advanced propulsion concepts suitable for 'next-generation-and-a-half' vehicles. Rocket-based combined-cycle (RBCC) engines combining rocket and airbreathing elements are one candidate concept. Preliminary RBCC engine development was undertaken by the United States in the 1960's. However, additional ground and flight research is required to bring the engine to technological maturity. This paper presents two options for flight testing early versions of the RBCC ejector scramjet engine. The first option mounts a single RBCC engine module to the X-34 air-launched technology testbed for test flights up to about Mach 6.4. The second option links RBCC engine testing to the simultaneous development of a small-payload (220 lb.) two-stage-to-orbit operational vehicle in the Bantam payload class. This launcher/testbed concept has been dubbed the W vehicle. The W vehicle can also serve as an early ejector ramjet RBCC launcher (albeit at a lower payload). To complement current RBCC ground testing efforts, both flight test engines will use earth-storable propellants for their RBCC rocket primaries and hydrocarbon fuel for their airbreathing modes. Performance and vehicle sizing results are presented for both options.

Olds, John↗

NASA NTRS2006

A Comparison of Fission Power System Options for Lunar and Mars Surface Applications

This paper presents a comparison of reactor and power conversion design options for 50 kWe class lunar and Mars surface power applications with scaling from 25 to 200 kWe. Design concepts and integration approaches are provided for three reactor-converter combinations: gas-cooled Brayton, liquid-metal Stirling, and liquid-metal thermoelectric. The study examines the mass and performance of low temperature, stainless steel based reactors and higher temperature refractory reactors. The preferred system implementation approach uses crew-assisted assembly and in-situ radiation shielding via installation of the reactor in an excavated hole. As an alternative, self-deployable system concepts that use earth-delivered, on-board radiation shielding are evaluated. The analyses indicate that among the 50 kWe stainless steel reactor options, the liquid-metal Stirling system provides the lowest mass at about 5300 kg followed by the gas-cooled Brayton at 5700 kg and the liquid-metal thermoelectric at 8400 kg. The use of a higher temperature, refractory reactor favors the gas-cooled Brayton option with a system mass of about 4200 kg as compared to the Stirling and thermoelectric options at 4700 and 5600 kg, respectively. The self-deployed concepts with on-board shielding result in a factor of two system mass increase as compared to the in-situ shielded concepts.

Mason, Lee S.↗

NASA NTRS2005

Tool for Ranking Research Options

Tool for Research Enhancement Decision Support (TREDS) is a computer program developed to assist managers in ranking options for research aboard the International Space Station (ISS). It could likely also be adapted to perform similar decision-support functions in industrial and academic settings. TREDS provides a ranking of the options, based on a quantifiable assessment of all the relevant programmatic decision factors of benefit, cost, and risk. The computation of the benefit for each option is based on a figure of merit (FOM) for ISS research capacity that incorporates both quantitative and qualitative inputs. Qualitative inputs are gathered and partly quantified by use of the time-tested analytical hierarchical process and used to set weighting factors in the FOM corresponding to priorities determined by the cognizant decision maker(s). Then by use of algorithms developed specifically for this application, TREDS adjusts the projected benefit for each option on the basis of levels of technical implementation, cost, and schedule risk. Based partly on Excel spreadsheets, TREDS provides screens for entering cost, benefit, and risk information. Drop-down boxes are provided for entry of qualitative information. TREDS produces graphical output in multiple formats that can be tailored by users.

Ortiz, James N.↗

NASA NTRS2011

Ground Vibration Testing Options for Space Launch Vehicles

New NASA launch vehicles will require development of robust systems in a fiscally-constrained environment. NASA, Department of Defense (DoD), and commercial space companies routinely conduct ground vibration tests as an essential part of math model validation and launch vehicle certification. Although ground vibration testing must be a part of the integrated test planning process, more affordable approaches must also be considered. A study evaluated several ground vibration test options for the NASA Constellation Program flight test vehicles, Orion-1 and Orion-2, which concluded that more affordable ground vibration test options are available. The motivation for ground vibration testing is supported by historical examples from NASA and DoD. The approach used in the present study employed surveys of ground vibration test subject-matter experts that provided data to qualitatively rank six test options. Twenty-five experts from NASA, DoD, and industry provided scoring and comments for this study. The current study determined that both element-level modal tests and integrated vehicle modal tests have technical merits. Both have been successful in validating structural dynamic math models of launch vehicles. However, element-level testing has less overall cost and schedule risk as compared to integrated vehicle testing. Future NASA launch vehicle development programs should anticipate that some structural dynamics testing will be necessary. Analysis alone will be inadequate to certify a crew-capable launch vehicle. At a minimum, component and element structural dynamic tests are recommended for new vehicle elements. Three viable structural dynamic test options were identified. Modal testing of the new vehicle elements and an integrated vehicle test on the mobile launcher provided the optimal trade between technical, cost, and schedule.

Patterson, Alan↗

NASA NTRS2014

International Space Station (ISS) External Thermal Control System (ETCS) Loop A Pump Module (PM) Jettison Options Assessment

On December 11, 2013, the International Space Station (ISS) experienced a failure of the External Thermal Control System (ETCS) Loop A Pump Module (PM). To minimize the number of extravehicular activities (EVA) required to replace the PM, jettisoning the faulty pump was evaluated. The objective of this study was to independently evaluate the jettison options considered by the ISS Trajectory Operations Officer (TOPO) and to provide recommendations for safe jettison of the ETCS Loop A PM. The simulation selected to evaluate the TOPO options was the NASA Engineering and Safety Center's (NESC) version of Program to Optimize Simulated Trajectories II (POST2) developed to support another NESC assessment. The objective of the jettison analysis was twofold: (1) to independently verify TOPO posigrade and retrograde jettison results, and (2) to determine jettison guidelines based on additional sensitivity, trade study, and Monte Carlo (MC) analysis that would prevent PM recontact. Recontact in this study designates a propagated PM trajectory that comes within 500 m of the ISS propagated trajectory. An additional simulation using Systems Tool Kit (STK) was run for independent verification of the POST2 simulation results. Ultimately, the ISS Program removed the PM jettison option from consideration. However, prior to the Program decision, the retrograde jettison option remained part of the EVA contingency plan. The jettison analysis presented showed that, in addition to separation velocity/direction and the atmosphere conditions, the key variables in determining the time to recontact the ISS is highly dependent on the ballistic number (BN) difference between the object being jettisoned and the ISS.

Murri, Daniel G.↗

NASA NTRSDate not supplied

Demonstrating Early-Adopter Benefits of Submitting Multiple Trajectory Options for Airlines

A workshop at NASA Ames Research Center was held with airline industry stakeholders to demonstrate the impact of using Trajectory Options Sets (TOSs) during a Collaborative Trajectory Options Program (CTOP) for severe weather operations. The demonstration was conducted using apart-task Human-in-the-Loop (HITL) simulation of the Integrated Demand Management (IDM) concept, which is an air traffic management method that uses CTOP to deliver preconditioned traffic to the Time-Based Flow Management (TBFM) region. The demonstration addressed the following research objectives: first, determine who receives a greater benefit, TOS-participating or TOS-excluded airlines? Second, determine which method of trajectory selection yields a better solution, human/manual selection or automation? Finally, obtain feedback from stakeholders on their impression of the concept and recommendations for future work. The results showed that TOS-participating airlines received greater benefit in terms of total ground delay, ground delay savings, number of reroute options, and additional flight time, compared to TOS-excluded airlines. However, this result was dependent on the situational context, such as the number and location of flights. We found that all airlines benefitted when just a subset of airlines submitted TOS, but the greatest benefit went to the TOS-participating airlines. These benefits to the TOS-participating airlines were diminished as the number of TOS-participants in the system increased. Therefore, there was an “early-adopter” effect that suggested airlines could benefit by becoming the first to equip TOS without causing unfair disadvantages to those who do not equip TOS. In addition, we found that manual selection of trajectory options performed similarly to CTOP, but the CTOP solution was more efficient in terms of number of reroutes, additional flight time, and average ground delay for rerouted flights. Feedback from the stakeholders was solicited, and their overall impressions of the demonstrations were positive. They remarked that CTOP could do a better job than current day solutions, and they thought airlines could benefit from continuing to develop TOS capabilities.

Integrated Demand Management↗

NASA NTRS2022

Using the Decision Tree (DT) to Help Scientists Navigate the Access to Space (ATS) Options

Abstract – The Decision Tree (DT) is a tool that uses a tree-like model of decisions and their possible consequences, including outcomes, costs, schedule, risks, and performance. The paper applies the decision tree tool to the Access To Space (ATS) options to help scientists and small sat teams select the best approach that meets their ATS requirements. The ATS DT has three primary branches: rideshare, hosted payloads, and dedicated launch vehicles. Each of these branches has multiple sub-branches of ATS options. This paper describes the ATS options and provides industry contacts for each ATS option.

Rideshare↗

NASA NTRSDate not supplied

Design and Comparison of Lunar Sample Return Options

Returning lunar samples to earth is a high priority for NASA in order to better understand Lunar Geology, Lunar formation, and potential resource utilization. Core samples of frozen volatiles from permanently shadowed regions are sought after, but require intensive cryogenic cooling to preserve. Returning samples to Earth using the Orion capsule is restrictive for moderate amounts of mass/volume and thus alternate means of transport are investigated in this paper. The trade-space of potential options includes varying: sample mass amount, sample containment conditions, transfer path from Lunar surface to Earth surface, and various vehicle system trades. An integrated solver is applied with parametric estimators and known system heuristics to effectively estimate size, mass, and power of various subsystems. Modeled subsystems include sample containment, EDL technologies(heat shield, parachute, recovery), power, thermal, avionics, structures, and propulsive systems. Transfer path options include various trajectory options, transfer methods, staging points, and vehicle staging options. A Design of Experiments was conducted to explore the tradespace, to identify sensitivities, and to identify promising designs. Results are detailed for various stakeholder objectives including total mass, sample mass, science return, architecture impacts, and operational flexibility.

Lunar outpost↗

NASA NTRS1976

SEATSAT programs option analysis

A preliminary analysis of the costs of SEASAT follow-on options is presented. All the options assume the existence of SEASAT-A as currently defined in the SEASAT Economic Assessment. It is assumed that each option will continue through the year 2000 and approach operational system status in the 1983-1986 period, depending upon the sensor package selected. The launch vehicle assumed through 1983 is the Atlas Agena. After 1983, it is assumed SEASAT-A will switch to the use of the Space Shuttle. All cost estimates are 1976 dollars for fiscal year cost accounting, with no inflation rate included.

Luckl, L.↗

NASA NTRS1976

Effects of selected R&D options on fuel usage in the commercial air system

The study on which this paper is based, known as RECAT (Study of Cost Benefit Tradeoffs for Reducing the Energy Consumption of the Commercial Air Transportation System), was sponsored by NASA to establish a basis for assigning priorities in its aircraft fuel-conservation R&D program. The study involved coordinated efforts by four independent contractors to conceive and quantify fuel-conserving technology alternatives, transform these alternatives into viable R&D options, and simulate each option in a general model of the U.S. domestic air transportation system. This paper deals primarily with the latter phase and concentrates on the results of the study, as revealed not only by estimated fuel usage but also by other impacts of the technology options, such as demand growth, operator economics, and fleet composition. However, while the paper focuses on results, the basic assumptions and technology inputs are documented, and a general description of the modeling approach is provided to demonstrate the level of detail considered in the analysis.

Gobetz, F. W.↗

NASA NTRS1979

Multirole cargo aircraft options and configurations

The paper discusses multirole cargo aircraft options and configurations. It was shown that derivatives of current wide-body aircraft would be economically attractive through 2008, but new dedicated airfreighters incorporating 1990 technology would offer little or no economic incentive. Option studies indicate that Mach 0.7 propfans would be economically attractive in trip cost, aircraft price, and airline ROI; spanloaders would be lower priced with higher ROI, but would have a relatively higher trip cost because of aerodynamic inefficiencies. Finally, air cushion landing gear configurations are identified as an option for avoiding runway constraints on airport accommodation of very large airfreighters.

Conner, D. W.↗

NASA NTRS1980

A survey of Saturn orbiter transfer options

This paper is a description of recent work to categorize and enumerate the various options available for transfer from earth to Saturn orbit. The fundamental period of investigation is the 20-year synodic period of Jupiter and Saturn which permits a scenario of Jupiter gravity assist trajectories for various trip times. Against the background of the Jupiter swingby trajectories are compared a number of other options including Delta V-EGA and VEGA trajectories, direct earth-Saturn transfers, and solar and nuclear electric propulsion options. All are compared and contrasted in the context of expected launch vehicle capabilities and realistic transfer times.

Uphoff, C.↗

NASA NTRS1982

TOPEX satellite concept. TOPEX option study report

Candidate bus equipment from the Viking, Applications Explorer Mission, and Small Scientific Satellite programs for application to the TOPEX mission options is assessed. Propulsion module equipment and subsystem candidates from the Applications Explorer Mission satellites and the Small Scientific Satellite spacecraft are evaluated for those TOPEX options. Several subsystem concepts appropriate to the TOPEX options are described. These descriptions consider performance characteristics of the subsystems. Cost and availability information on the candidate equipment and subsystems are also provided.

Meyer, D. P.↗

NASA NTRS1983

Architectural options and development issues

The design options for the space station are discussed in general terms, reflecting the approach taken by the NASA Concept Development Group. Primary aims are flexibility and transparency, to fulfill as many scientific and commercial user requirements as possible and to open the station to as many new users as possible; utilities, facilities, and functional support must be designed to meet these aims. General architecture options considered include the present STS, an extended STS, a limited-duration manned transportation node with unmanned platforms, and a manned station with unmanned platforms and transportation-node capability (OTV, TMS). The latter option is found most promising and developed further, with consideration of the technical challenges involved.

Powell, L. E.↗

NASA NTRS1986

The optimal number of menu options per panel

An evaluation is made of the effects of the 'funneling' phenomenon, in an analysis of hierarchical menu structures' optimal search times which builds on the work of Lee and MacGregor (1985). Funneling is a reduction in the total number of options processed through the design of a system of greater choice 'depth' and correspondingly restricted choice 'breadth'. Both random and ordered menus are treated. The available evidence is found to support the general conclusion that randomly ordered menu panels should have only a few (4-8) options, while organized menus should contain as many options as 64.

Paap, Kenneth R.↗