Search NASA⌕ Search

SEARCH · Search NASA

Results for “Options”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Nuclear-electric propulsion - Manned Mars propulsion options

Nuclear-electric propulsion can significantly reduce the launch mass for manned Mars missions. By using high-specific-impulse (lsp) electric propulsion systems with advanced nuclear reactors, the total mass-to-orbit for a series of manned Mars flight is reduced. Propulsion technologies required for the manned Mars mission are described. Multi-megawatt Ion and Magneto-Plasma-Dynamic (MPD) propulsion thrusters, Power-Processing Units and nuclear power source are needed. Xenon (Xe)-Ion and MPD thruster performance are detailed. Mission analyses for several Mars mission options are addressed. Both MPD and Ion propulsion were investigated. A four-megawatt propulsion system power level was assumed. Mass comparisons for all-chemical oxygen/hydrogen propulsion missions and combined chemical and nuclear-electric propulsion Mars fleets are included. With fleets of small nuclear-electric vehicles, short trip times to Mars are also enabled.

Palaszewski, Bryan↗
NASA NTRS1989

Ballistic comet exploration mission options

To attain the fundamental goals of cometary exploration, rendezvous and sample return missions are necessary. This paper investigates various trajectory options and provides a comprehensive set of mission opportunities available for launches in the 1990s. The modes of explorations considered are rendezvous and flybys with atomized-sample-return missions. For each type of exploration, the paper describes various classes and modes of trajectories available, their inherent characteristics, and the techniques of identifying useful trajectories. The energy requirement associated with these missions and the performance possibilities are provided.

Yen, Chen-Wan L.↗
NASA NTRS1990

Multiple main-belt asteroid mission options for a Mariner Mark II spacecraft

This paper presents the trajectory options available for a MMII spacecraft mission to asteroids and introduces systematic methods of uncovering attractive mission opportunities. The analysis presented considers multiple synchronous gravity assists of Mars and introduces a terminal resonant or phasing orbit; a concept useful for both increasing the number of asteroid rendezvous targets attainable during a launch opportunity, and also in increasing the number of potential asteroid flybys. Systematic examinations of the requirements for superior asteroidal alignments are made and a comprehensive set of asteroid rendezvous opportunities for the 1998 to 2010 period are presented. Examples of candidate missions involving one or more rendezvous and several flybys are also presented.

Sauer, Carl G., Jr.↗
NASA NTRS1991

Network interface unit design options performance analysis

An analysis is presented of three design options for the Space Station Freedom (SSF) onboard Data Management System (DMS) Network Interface Unit (NIU). The NIU provides the interface from the Fiber Distributed Data Interface (FDDI) local area network (LAN) to the DMS processing elements. The FDDI LAN provides the primary means for command and control and low and medium rate telemetry data transfers on board the SSF. The results of this analysis provide the basis for the implementation of the NIU.

Miller, Frank W.↗
NASA NTRS1991

Options for Martian propellant production

A quantitative evaluation methodology for utilizing in-situ resources on Mars for the production of useful substances. The emphasis is on the chemical processes. Various options considering different feedstock (mostly, carbon dioxide, water, and iron oxides) are carefully examined for the product mix and the energy needs. Oxygen, carbon monoxide, alcohols, and other chemicals are the end products. The chemical processes involve electrolysis, methanation, and variations. It is shown that maximizing the product utility is more important than the production of oxygen, methane, or alcohols. An important factor is the storage of the chemicals produced. The product utility is dependent, to some extent, upon the mission. A combination of the stability, the enthalpy of formation, and the mass fraction of the products is seen to yield a fairly good quantitative feel for the overall utility and maximum mission impact.

Dowler, Warren↗
NASA NTRS1991

Cryogenic transfer options for exploration missions

The literature of in-space cryogenic transfer is reviewed in order to propose transportation concepts to support the Space Exploration Initiative (SEI). Forty-nine references are listed and key findings are synopsized. An assessment of the current maturity of cryogenic transfer system technology is made. Although the settled transfer technique is the most mature technology, the No-Vent Fill technology is maturing rapidly. Future options for development of cryogenic transfer technology are also discussed.

Chato, David J.↗
NASA NTRS1990

Overview of Mars transportation options and issues

The transportation options for manned Mars missions being considered for the Space Exploration Initiative are discussed. Seven candidate architectures are examined and compared: cryogenic/aerobraking, nuclear-electric propulsion, solar electric propulsion, nuclear rocket propulsion, L-based cryogenic/aerobraking, direct cryogenic/aerobraking, and cycler orbits. The rationales for choosing each one are presented, and cost considerations are addressed.

Adams, Alan↗
NASA NTRS1991

Cryogenic transfer options for exploration missions

The literature of in-space cryogenic transfer is reviewed in order to propose transportation concepts to support the Space Exploration Initiative (SEI). Forty-nine references are listed and key findings are synopsized. An assessment of the current maturity of cryogenic transfer system technology is made. Although the settled transfer techniques is the most mature technology, the No-Vent Fill technology is maturing rapidly. Future options for development of cryogenic transfer technology are also discussed.

Chato, David J.↗
NASA NTRS1991

Space transportation options for the Space Exploration Initiative

The candidate architectures of space transportation vehicles designed for the Space Exploration Initiative are discussed together with the launch systems concepts. Special attention is given to the lunar mission and Mars mission scenarios and the launch- and transfer-vehicle options for Mars and moon missions.

Huber, William G.↗
NASA NTRS1990

Space Station requirements and transportation options for lunar outpost

Preliminary design studies conducted by NASA are summarized which determined the requirements of the Space Station Freedom and transportation options for the establishment of a lunar outpost. Three phases are defined - emplacement, consolidation, and utilization - to describe the gradual development of the outpost. The lunar transportation system is based on the use of an earth-to-orbit and an LEO-lunar surface system for moving vehicles, propellant, crew, and cargo to the outpost. The vehicle-design and size requirements are defined for the reusable lunar-transfer vehicle and the lunar-excursion vehicle. Space Station Freedom is established as the LEO transportation node which transfers the required payloads to the excursion spacecraft following a 300-km low lunar orbit. The proposed lunar excursion vehicle is theorized to be capable of delivering 33 tons of cargo to the surface of the moon in the cargo-expendable mode.

Young, Archie C.↗
NASA NTRS1992

Libration point staging options for SEI lunar missions - Station keeping implications

Libration point staging is one alternative to lunar orbit rendezvous which is being examined for the Space Exploration Initiative lunar missions. The libration point staging strategy being considered would eliminate the lunar mid-latitude accessibility constraint for long duration missions. Staging options for such a strategy are discussed with particular emphasis on the impact of the libration points' stability. The equations of motion for a satellite at the libration points are numerically integrated to investigate the stability and to determine the station-keeping requirements. These requirements are presented, and overall requirements for libration point staging briefly summarized. The results indicate that the slight eccentricity of the Moon's orbit would result in excessive station-keeping requirements for long duration missions.

Haynes, Davy A.↗
NASA NTRS1992

Mars trajectory options for the Space Exploration Initiative

The Mission Definition Office within the Lunar and Mars Exploration Program Office at the NASA/Johnson Space Center has the responsibility for leading the Space Exploration Initiative mission design activities across the Agency. In support of the Synthesis Group architecture analyses, a mission concept that includes fast one-way transits to and from Mars, a powered flyby abort, and an early return option has been developed. This paper will describe this integrated approach to Mars mission planning.

Soldner, John K.↗
NASA NTRS1993

Multi-band gap and new solar cell options workshop

Discussions of the multi-band gap (MBG) and new solar cell options workshop are presented. Topics discussed include: greater than 2 terminal cells; radiation damage preventing development of MBG cells for space; lattice matching; measurement of true performance; future of II-VI materials in MBG devices; and quaternaries.

Hutchby, J.↗
NASA NTRS1993

Options for thrust augmentation for the Beta 2 two-stage-to-orbit launch vehicle

A study to improve the performance of the NASA two-stage-to-orbit vehicle was undertaken. The NASA concept, a horizontal takeoff and landing, fully reusable, two-stage to orbit vehicle, will be capable of launching and returning a 10,000 pound payload to a 100 nmi polar orbit. The vehicle, Beta 2, is a derivative of the USAF/Boeing Beta vehicle which was designed to deliver a 50,000 pound payload to a similar orbit. Beta 2 stages at Mach 6.5 and about 100,000 feet altitude. The propulsion system for the booster is an over/under turbine engine/ramjet configuration. In this paper a study was performed for one of the candidate engines, the variable cycle engine, to assess its potential to meet the required performance needs of the Beta 2 vehicle. Several options for thrust augmentation were studied in order to improve the performance of the engine where there was a critical need. The methodology, constraints, propulsion performance, and mission study results are presented.

Jules, Kenol↗
NASA NTRS1994

Power generation technology options for a Mars mission

The power requirements and resultant power system performances of an aggressive Mars mission are characterized. The power system technologies discussed will support both cargo and piloted space transport vehicles as well as a six-person crew on the Martian surface for 600 days. The mission uses materials transported by cargo vehicles and materials produced using in-situ planetary feed stock to establish a life-support cache and infrastructure for the follow-on piloted lander. Numerous power system technical options are sized to meet the mission power requirements using conventional and solar, nuclear, and wireless power transmission technologies for stationary, mobile surface, and space applications. Technology selections will depend on key criteria such as mass, volume, area, maturity, and application flexibility.

Bozek, John M.↗
NASA NTRS1992

Lunar Transportation Facilities and Operations Study, option 2

During the Option 2 period of the Lunar Transportation Facilities and Operations Study (LTFOS), a joint McDonnell Douglas Space Systems Company Kennedy Space Center (MDSSC-KSC) and National Aeronautics and Space Administration Kennedy Space Center (NASA-KSC) Study team conducted a comparison of the functional testing of the RL-10 and Space Shuttle Main Engine, a quick-look impact assessment of the Synthesis Group Report, and a detailed assessment of the Synthesis Group Report. The results of these KSC LTFOS team efforts are included. The most recent study task effort was a detailed assessment of the Synthesis Group Report. The assessment was conducted to determine the impact on planetary launch and landing facilities and operations. The result of that effort is a report entitled 'Analysis of the Synthesis Group Report, its Architectures and their Impacts on PSS Launch and Landing Operations' and is contained in Appendix A. The report is structured in a briefing format with facing pages as opposed to a narrative style. A quick-look assessment of the Synthesis Group Report was conducted to determine the impact of implementing the recommendations of the Synthesis Group on KSC launch facilities and operations. The data was documented in a presentation format as requested by Kennedy Space Center Technology and Advanced Projects Office and is included in Appendix B. Appendix C is a white paper on the comparison of the functional testing of the RL-10 and Space Shuttle Main Engine. The comparison was undertaken to provide insight regarding common test requirements that would be applicable to Lunar and Mars Excursion Vehicles (LEV and MEV).

Source record↗
NASA NTRS1995

Direct drive options for electric propulsion systems

Power processing units (PPU's) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally greater than 0.9, heat loads are often substantial. This heat must be rejected by thermal control systems which generally have specific masses of 15-30 kg/kW. PPU's also represent a large fraction of the electric propulsion system dry mass. Simplification or elimination of power processing in a propulsion system would reduce the electric propulsion system specific mass and improve the overall reliability and performance. A direct drive system would eliminate all or some of the power supplies required to operate a thruster by directly connecting the various thruster loads to the solar array. The development of concentrator solar arrays has enabled power bus voltages in excess of 300 V which is high enough for direct drive applications for Hall thrusters such as the Stationary Plasma Thruster (SPT). The option of solar array direct drive for SPT's is explored to provide a comparison between conventional and direct drive system mass.

Hamley, John A.↗
NASA NTRS1995

A conceptual framework for evaluating variable speed generator options for wind energy applications

Interest in variable speed generating technology has accelerated as greater emphasis on overall efficiency and superior dynamic and control properties in wind-electric generating systems are sought. This paper reviews variable speed technology options providing advantages and disadvantages of each. Furthermore, the dynamic properties of variable speed systems are contrasted with synchronous operation. Finally, control properties of variable speed systems are examined.

Reddoch, T. W.↗