Engineering topics

Young, Archie C.

Publications and source records attributed to Young, Archie C..

7 records

NASA NTRS1992

Nuclear propulsion system options for Mars missions

This paper focuses on the use of a nuclear thermal rocket to accomplish a variety of space missions with emphasis on the manned Mars mission. The particle-bed-reactor type nuclear engine was chosen as the baseline engine because of its perceived versatility over other nuclear propulsion systems in conducting a wide variety of tasks. This study indicates that the particle-bed-reactor engine with its high engine thrust-to-weight ratio (about 20) and high specific impulse (about 950 to 1050 sec) offers distinct advantages over the larger and heavier NERVA-type nuclear engines.

Emrich, William J., Jr.↗

NASA NTRS1992

Mars transportation system synthesis

Performance and requirements synthesized to support the manned Mars mission of the Space Exploration Initiative (SEI) are presented. Emphasis is placed on the Mars transportation system (MTS), which uses nuclear thermal rocket (NTR) propulsion technology associated with accomplishing the manned Mars mission. Data are also presented for a propulsion system options comparison of chemical/aerobrake and nuclear electric propulsion systems. Vehicle- and weight-scaling are used to determine the MTS mass, size, and performance range required for different Mars mission durations. The split sprint, opposition, and conjunction class mission modes are employed to determine the MTS requirements envelope. MTS sensitivity to Mars surface payload, crew size, Mars orbit payload, NTR engine thrust level, engine specific impulse, and NTR engine thrust-to-weight ratio are synthesized. A suggested NTR technology level to accomplish both cargo and piloted Mars missions is discussed.

Young, Archie C.↗

NASA NTRS1990

Ballistic trajectory options for manned Mars Missions

Mars Mission profile options and mission requirements data are presented for earth-Mars opposition and conjunction class round-trip flyby and stopover mission opportunities. The opposition-class flyby and sprint mission uses direct transfer trajectories to and on return from Mars. The opposition-class stopover mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg in order to reduce the propulsion requirement associated with the opposition-class mission. The conjunction-class mission minimizes propulsion requirements by optimizing the stopover time at Mars. Representative interplanetary space vehicle systems are sized to compare and show sensitivity of the initial mass required in low earth orbit to one mission profile option and mission opportunity to another.

Young, Archie C.↗

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 NTRS1989

Mars Mission profile options and opportunities

Mars Mission profile options and mission requirements data are presented for earth-Mars opposition and conjuction class round-trip flyby and stopover mission opportunities. The opposition class flyby and sprint mission uses direct transfer trajectories to and on return from Mars. The opposition-class stopover mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg in order to reduce the propulsion requirement associated with the opposition-class mission. The conjuction-class mission minimizes propulsion requirements by optimizing the stopover time at Mars. Representative interplanetary space vehicle systems are sized to compare and show sensitivity of the initial mass required in low earth orbit to one mission profile option and mission opportunity to another.

Young, Archie C.↗

NASA NTRS1988

Mars Mission profile options and opportunities

Mars Mission profile options and mission requirements data are presented for Earth-Mars opposition and conjunction class round-trip flyby and stopover mission opportunities. The opposition class flyby and sprint mission uses direct transfer trajectories to and on return from Mars. The opposition class stopover mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg in order to reduce the propulsion requirement associated with the opposition class mission. The conjunction class mission minimizes propulsion requirements by optimizing the stopover time at Mars. Representative interplanetary space vehicle systems are sized to compare and show sensitivity of the initial mass required in low Earth orbit to one mission profile option and mission opportunity to another.

Young, Archie C.↗

NASA NTRS1986

Use of the Orbital Maneuvering Vehicle (OMV) for placement and retrieval of spacecraft and platforms

This paper describes the Orbital Maneuvering Vehicle (OMV) and its intended role as a key element of NASA's space infrastructure. Status, plans, and operational modes are summarized. Typical mission scenarios supporting the servicing of spacecraft and platforms from both the Shuttle and the Space Station are described. Particular emphasis is placed on the orbital mechanics associated with the placement and retrieval of spacecraft and platforms. For example, the optimum placement of a Space Station co-orbiting spacecraft in order to maximize the time interval during which it can be retrieved by a Space Station based OMV is shown as a function of the ballistic coefficient of the spacecraft.

Snoddy, William C.↗