Engineering topics

Priest, C. C.

Publications and source records attributed to Priest, C. C..

8 records

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 NTRS1990

Space transportation systems supporting a lunar base

Results are presented on preliminary design studies conducted by NASA and its contractors to define the transportation vehicle for the support of a human return to the moon mission. Attention is given to the transportation needs and requirements, the design solutions to meet these requirements, the rationale for the selection of the designs, and the ground/orbital support facilities for placing these systems into routine earth-moon transportation service. The reference system includes a partially reusable lunar transfer vehicle that operates between the earth and lunar orbits and a fully reusable lunar excursion vehicle that operates between the lunar orbit and the lunar surface. The system can deliver 27 metric tons of cargo to the lunar surface in an automated flight mode, and can transport a crew of four and deliver 15 tons of cargo in a piloted mode.

Priest, C. C.↗

NASA NTRS1987

Space Station overview

This paper presents an overview of the Space Station, including program guidelines, international involvement, current baseline configuration, and utilization for science and application missions. Space Station configuration and capabilities, plus methods of utilizing the Space Station for scientific and engineering investigations, are described. The Space Station is being designed as a multipurpose facility to support a number of functions, such as a laboratory in space, a transportation node, an assembly facility, a staging base, etc. The description includes the baseline configuration, location of the pressurized modules, servicing and assembly facilities, and the work package structure for Space Station management. The Space Station will accommodate a wide variety of user requirements in laboratory modules and as attached payloads. To show the utility of the Space Station, a variety of science and application missions currently being studied for NASA at the Marshall Space Flight Center are discussed.

De Sanctis, Carmine E.↗

NASA NTRS1982

Preliminary risk benefit assessment for nuclear waste disposal in space

This paper describes the recent work of the authors on the evaluation of health risk benefits of space disposal of nuclear waste. The paper describes a risk model approach that has been developed to estimate the non-recoverable, cumulative, expected radionuclide release to the earth's biosphere for different options of nuclear waste disposal in space. Risk estimates for the disposal of nuclear waste in a mined geologic repository and the short- and long-term risk estimates for space disposal were developed. The results showed that the preliminary estimates of space disposal risks are low, even with the estimated uncertainty bounds. If calculated release risks for mined geologic repositories remain as low as given by the U.S. DOE, and U.S. EPA requirements continue to be met, then no additional space disposal study effort in the U.S. is warranted at this time. If risks perceived by the public are significant in the acceptance of mined geologic repositories, then consideration of space disposal as a complement to the mined geologic repository is warranted.

Rice, E. E.↗

NASA NTRS1981

Space platforms/stations

Platforms in low-earth orbit are examined as simple and cost-effective solutions to the problem of long-duration space flight, providing stability, utilities and access for a variety of Shuttle-tended replaceable payloads over extended periods of time. The requirements for space platforms, which will encompass the advantages of both the free-flying and Shuttle-Spacelab operational modes, are discussed, with consideration given to payloads, operations and platform systems, and the status of the space platform concept, which is expected to begin development in early 1983 following definition studies and design selection, is noted. Possible paths in the evolution of space platform facilities to more advanced concepts are then outlined. Finally, the concept of the Science and Applications Manned Space Platform is examined as the first step toward a permanent manned United States presence in space.

Priest, C. C.↗

NASA NTRS1980

U.S. program assessing nuclear waste disposal in space - A status report

Various concepts for the space disposal of nuclear waste are discussed, with attention given to the destinations now being considered (high earth orbit, lunar orbit, lunar surface, solar orbit, solar system escape, sun). Waste mixes are considered in the context of the 'Purex' (Plutonium and Uranium extraction) process and the potential forms for nuclear waste disposal (ORNL cermet, Boro-silicate glass, Metal matrix, Hot-pressed supercalcine) are described. Preliminary estimates of the energy required and the cost surcharge needed to support the space disposal of nuclear waste are presented (8 metric tons/year, requiring three Shuttle launches). When Purex is employed, the generated electrical energy needed to support the Shuttle launches is shown to be less than 1%, and the projected surcharge to electrical users is shown to be slightly more than two mills/kW-hour.

Rice, E. E.↗

NASA NTRS1980

Space disposal of nuclear wastes

The DOE has been studying several options for nuclear waste disposal, among them space disposal, which NASA has been assessing. Attention is given to space disposal destinations noting that a circular heliocentric orbit about halfway between Earth and Venus is the reference option in space disposal studies. Discussion also covers the waste form, showing that parameters to be considered include high waste loading, high thermal conductivity, thermochemical stability, resistance to leaching, fabrication, resistance to oxidation and to thermal shock. Finally, the Space Shuttle nuclear waste disposal mission profile is presented.

Priest, C. C.↗

NASA NTRS1972

Dual mode nuclear rocket system applications.

Mission areas where the dual-mode nuclear rocket system is superior to nondual-mode systems are demonstrated. It is shown that the dual-mode system is competitive with the nondual-mode system even for those specific missions and particular payload configurations where it does not have a clear-cut advantage.

Boretz, J. E.↗