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Wallace, R. A.

Publications and source records attributed to Wallace, R. A..

27 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Preliminary Mariner Jupiter-Saturn 1977 launch/encounter strategy

An overview of mission strategy is presented for Mariner Jupiter-Saturn 1977. A launch/encounter strategy is required which will ensure high value science return for all possible launch combinations. The paper consists of three major sections. Section one is concerned with a statement of mission definition, engineering constraints, and scientific objectives. Section two is concerned with the definition of constraint regions within the MJS77 available trajectory space. The last section derives an example launch/encounter strategy which satisfies a set of engineering and science groundrules.

Wallace, R. A.↗
NASA NTRS1973

Computation and analysis of satellite opportunities for the Mariner Jupiter/Saturn 1977 mission

The MJS77 mission provides the United States with the first opportunity to study the large satellites of Jupiter and Saturn at close range. Techniques are presented which allow the mission analyst to generate single and multiple satellite encounters at Jupiter and Saturn, and to incorporate satellite gravity assist into the targeting problem. These methods are applied to the MJS77 mission to generate, parametrically, the single and multiple satellite opportunities and characteristics at both flyby planets. An interesting consequence of this study is that a close encounter with a Galilean satellite increases the flexibility of a trajectory design which would otherwise require sizable post-Jupiter trajectory correction maneuvers to achieve the desired Saturn arrival date timing. In addition the Saturn studies revealed that as many as four satellites can be encountered on a single trajectory.

Beerer, J. G.↗
NASA NTRS1973

Saturn satellite encounter opportunities for Mariner Jupiter-Saturn 1977

The opportunities for close satellite encounters which meet the planetary constraints at Saturn that are imposed by science value return and environmental conditions are investigated. Since the satellites travel at various speeds in their orbits, Saturn arrival time is critical and was chosen as the design parameter. Arrival times are recommended which afford close satellite encounters and also meet important mission constraints. A design chart illustrates the satellite opportunities as a function of Saturn arrival date. Through the use of such a design chart, the Saturn encounter design process, which will take place according to recommendations by the selected science investigators over the next several years, will be considerably streamlined. Potential applications are given to illustrate the use of the Saturn satellite opportunity chart in encounter design.

Wallace, R. A.↗
NASA NTRS1972

Mercury in the environment

Problems in assessing mercury concentrations in environmental materials are discussed. Data for situations involving air, water, rocks, soils, sediments, sludges, fossil fuels, plants, animals, foods, and man are drawn together and briefly evaluated. Details are provided regarding the toxicity of mercury along with tentative standards and guidelines for mercury in air, drinking water, and food.

Fulkerson, W.↗
NASA NTRS1972

Mariner Jupiter/Saturn 1977 - The mission frame.

Following the cancellation of the Outer Planet Grand Tour Project, NASA and JPL examined less ambitious, alternative missions for exploring the outer planets. The mission that proved most attractive scientifically and fits within the projected NASA budget constraints embraces dual flights to Jupiter and Saturn, with launch in 1977. NASA has implemented it as the Mariner Jupiter/Saturn 1977 (MJS77) Project. The MJS77 mission covers exploratory investigations of the Jupiter and Saturn planetary systems and the interplanetary medium out to Saturn. Items of special interest include Jupiter's great red spot, the question of Io's anomalous brightening and phenomena associated with its EM behavior. After Saturn encounter, the spacecraft will escape the solar system in the general direction of the solar apex.

Bourke, R. D.↗
NASA NTRS1972

Mariner Jupiter/Saturn 1977 preliminary mission design.

Current plans of NASA are to take advantage of the 1977 launch opportunity by sending a Mariner class spacecraft on a gravity assisted flyby of Jupiter which will then continue on to Saturn. The background of this Mariner Jupiter-Saturn 77 Project is reviewed and science objectives for this mission as currently adapted are given. This paper illustrates properties of the Jupiter-Saturn opportunities between 1976 and 1980 to give context to the 1977 opportunity. Details of the possibilities for the 1977 launch are shown along with constraints and example candidate trajectories. Options include close flybys and/or occultations of the satellites at Jupiter and Saturn, penetration of Saturn's rings, and various occultations of the planets. A short discussion of other factors, such as navigation and planetary quarantine (documented elsewhere) are included.

Bourke, R. D.↗