Engineering topics

Stetson, D. S.

Publications and source records attributed to Stetson, D. S..

6 records

NASA NTRS1998

Mission to the Solar System: Exploration and Discovery. A Mission and Technology Roadmap

Solar System exploration addresses some of humanity's most fundamental questions: How and when did life form on Earth? Does life exist elsewhere in the Solar System or in the Universe? - How did the Solar System form and evolve in time? - What can the other planets teach us about the Earth? This document describes a Mission and Technology Roadmap for addressing these and other fundamental Solar System Questions. A Roadmap Development Team of scientists, engineers, educators, and technologists worked to define the next evolutionary steps in in situ exploration, sample return, and completion of the overall Solar System survey. Guidelines were to "develop aa visionary, but affordable, mission and technology development Roadmap for the exploration of the Solar System in the 2000 to 2012 timeframe." The Roadmap provides a catalog of potential flight missions. (Supporting research and technology, ground-based observations, and laboratory research, which are no less important than flight missions, are not included in this Roadmap.)

Gulkis, S.↗

NASA NTRS1990

Saturn orbit insertion options for the Cassini mission

The main objectives of the Cassini mission are to deliver a spacecraft into orbit about Saturn and a Probe into the atmosphere of Titan. Two fundamental constraints drive the design of the initial Saturn orbit and thus affect the mission performance. The first requirement is safe passage through the ring system upon Saturn arrival; the second is delivery of the Probe to Titan with an acceptable relative approach velocity. These constraints lead to the selection of a dual-burn insertion strategy, with maneuvers at periapsis and apoapsis of the initial orbit. Additional science goals constrain the Saturn arrival date and may affect the timing of the orbit insertion burn.

Weinstein, S. S.↗

NASA NTRS1987

Trajectory options for the Comet Rendezvous Asteroid Flyby mission

The Comet Rendezvous Asteroid Flyby mission is strongly supported by the scientific community. Two major events during the past year have forced a re-analysis of the mission options, with the goal of selecting a baseline mission for launch in 1993. Venus and earth gravity assists can be used to allow rendezvous with comet Tempel 2 in 1996; the scientific potential of the resulting mission is excellent. Although backup mission opportunities have been identified, the significantly longer flight times weaken the scientific appeal of these missions.

Miller, S. L.↗

NASA NTRS1986

Trajectory options for the Mariner Mark II Tempel 2 rendezvous mission

Recent schedule changes have motivated a reassessment of the mission options for the Mariner Mark II Comet Rendezvous Asteroid Flyby. A new baseline mission has been selected, which will launch in September 1992 and arrive at comet Tempel 2 in December 1996. The geometry of the comet's orbit imposes on the mission total delta-V requirements that can best be met by selection of a delta-V-EGA trajectory, during which an earth gravity assist is used to improve mission performance. There is considerable freedom in the choice of comet arrival date and asteroid flyby targets; associated with each potential asteroid flyby is a different penalty in terms of delta-V and comet arrival data. Analysis of the trajectory and the asteroid flyby options will continue throughout the early phases of the Project.

Stetson, D. S.↗

NASA NTRS1986

Interplanetary trajectory design for the Mariner Mark II Comet Rendezvous/Asteroid Flyby mission

The primary purpose of the first mission utilizing a Mariner Mark II spacecraft will be to rendezvous with the short-period comet Wild 2 and conduct a proximal examination during the comet's quiescent and active phases. The purpose of the present study is to elucidate, using an accurate dynamic model, some of the characteristics of the interplanetary trajectory that are relevant to the mission design. Optimal transfer trajectories are generated, constrained by the Shuttle/Centaur launch vehicle capability and the total spacecraft mass and performance. Asteroid flyby opportunities are examined, and the effects of selected asteroid encounters on mission performance are discussed.

Myers, M. R.↗

NASA NTRS1984

The Mariner Mark II Comet Rendezvous/Asteroid Flyby Mission

The Comet Rendezvous/Asteroid Flyby will be the first mission in the Mariner Mark II program. The July 1990 launch will result in a fast flyby of the asteroid Tanete in May 1991 and a rendezvous with comet Kopff in February 1994, 879 days before comet perihelion. The spacecraft will return detailed data on the comet nucleus and its environment for nearly 1000 days. Several important comet characteristics will not be precisely known until the spacecraft performs its first measurements, which means that operations strategies must be adaptable to a range of conditions. In addition, the operation of a spacecraft in a dusty environment near a low-mass body imposes unique constraints on trajectory and orbit design.

Stetson, D. S.↗