Engineering topics

Stetson, Douglas

Publications and source records attributed to Stetson, Douglas.

4 records

NASA NTRS1994

Solar System Exploration Technology Requirements and Planning Process

The NASA Office of Space Science, in alliance with the Office of Advanced Concepts and Technology, has developed an Integrated Technology Strategy to guide its investment in technology for space science missions. This strategy establishes goals and strategic objectives that ensure that NASA and the nation derive the greatest possible scientific and economic benefits from investments in space science missions and technologies. Within the Office of Space Science, the Solar System Exploration Division in collaboration with the Office of Space Access and Technology, is developing a Technology Plan to implement these goals and to identify specific goals and to identify specific technology needs for solar system missions. This paper describes the philosophy, processes, and preliminary results of the systematic process being established for the identification and prioritization of solar system exploration technology needs.

space↗

NASA NTRS1993

Solar System Exploration Division: Requirements for space nuclear propulsion

The rationale and requirements for space nuclear propulsion (SNP) are outlined. Some specific nuclear electric propulsion requirements for planned planetary missions and low-power missions are given.

Stetson, Douglas↗

NASA NTRS1988

Near-nucleus trajectory design for Comet Penetrator-Lander data relay

A Comet Penetrator-Lander is included in the payload of the Comet Rendezvous Asteroid Flyby spacecraft; it will be deployed from an orbit about the comet nucleus and will implant itself in the nucleus at a pre-selected site. Throughout the following 9 days, the orbiting spacecraft must be in position to receive transmissions from the Penetrator-Lander at specified intervals. Using conic orbits and a simplified model of the nucleus, several types of trajectories have been identified which will allow the data relay requirements to be met. These are sensitive to the mass and rotational properties of the comet nucleus and to the latitude of the Penetrator-Lander impact site; no single orbital strategy can cover the entire range of possibilities. Frequent spacecraft maneuvers would provide more flexibility, but would result in a much more complicated mission scenario. More accurate modeling of the comet nucleus and the orbiter trajectories will refine the relay orbit options presented here.

Stetson, Douglas↗

NASA NTRS1988

Low launch-energy trajectories to the outer solar system via Venus and earth gravity-assist flybys

Recent cancellation of the program to develop a Centaur upper stage for use in the Space Transportation System (STS) has motivated considerable interest in trajectory modes with low launch-energy requirements to the outer solar system. Flyby encounters of the inner planets, especially Venus and earth, may be used to enable missions to Jupiter, Saturn, and a restricted class of comets. An examination of mission opportunities to these targets is presented through the end of this century using gravity-assist trajectories.

Diehl, Roger↗