Mars Exploration Rover landing site ellipse update
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Mars Exploration Rover mission design landing site↗
Engineering topics
Knocke, P. C.
Publications and source records attributed to Knocke, P. C..
Cometary coma chemical composition (C4) mission
Cometary missions are of enormous fundamental importance for many different space science disciplines, including exobiology. Comets are presumed relics of the earliest, most primitive material in the solar nebula and are related to the planetesimals. They undoubtedly provided a general enrichment of volatiles to the inner solar system (contributing to atmospheres and oceans) and may have been key to the origin of life. A Discovery class, comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, was selected for further study by NASA earlier this year. The C4 Mission is a highly focused and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission, concentrating exclusively on measurements which will lead to an understanding of the chemical composition and make-up of the cometary nucleus. The scientific goals of the Cometary Coma Chemical Composition (C4) Mission are to rendezvous with a short-period comet and (1) to determine the elemental, chemical, and isotopic composition of the nucleus and (2) to characterize the chemical and isotopic nature of its atmosphere. Further, it is a goal to obtain preliminary data on the development of the coma (dust and gas composition) as a function of time and orbital position.
Carle, G. C.↗
Interplanetary mission design for the Comet Rendezvous Asteroid Flyby mission
As part of the CRAF/Cassini Project, the Comet Rendezvous Asteroid Flyby (CRAF) mission will explore primitive solar system bodies. CRAF is unique in that there are a number of scientifically acceptable targets from which to choose. In principle, each may be reached with several types of trajectories. This results in a large number of potential mission opportunities which must be considered. The various mission modes being considered will be discussed along with the criteria by which these missions are evaluated in order to reduce them to a smaller set. Also, the current primary and backup missions will be discussed.
Williams, S. N.↗
Mars global network mission
The status of a program aimed at placing a global network of small surface landers on Mars for direct surface and subsurface measurements is reviewed. A possible baseline mission concept to establish a global network is discussed with particular reference to mission and system requirements, lander entry design considerations, and orbit design. The principal lander subsystems are described, including attitude control, power, command and data handling, telecommunications, and thermal subsystems.
Mostert, R. N.↗
Earth radiation pressure effects on satellites
A diffuse-earth radiation force model is presented, which includes a latitudinally varying representation of the shortwave and longwave radiation of the terrestrial sphere. Applications to various earth satellites indicate that this force, in particular the shortwave component, can materially affect the recovery of estimated parameters. Earth radiation pressure cannot explain the anomalous deceleration of LAGEOS, but can produce significant along track accelerations on satellites with highly eccentric orbits. Analyses of GEOS-1 tracking data confirm this result.
Knocke, P. C.↗