Fehlerminimale Navigation lunarer Raumfahrzeuge [article]

Frank Weischede, Klaus Brieß, Technische Universität Berlin, Technische Universität Berlin
The Moon as our next neighbour in the solar system will be utilized first in the framework of future deep space exploration. To scientifically explore and to economically exploit the Moon lunar and cis-lunar spaceflights have to be navigated precisely. Lunar orbit determination, up to now referring to Earth-based tracking methods only, is the central topic of this work. The basis of this work is set up via model building for the implementation of the deep space orbit determination software
more » ... ation software DEEPEST to the first german and european tracking and orbit determination experiment for a real lunar orbiter (Lunar Prospector in 1998/1999). The sequential processing of batch orbit determinations provides information about the influence of observability and dynamic modelling of such satellite orbits. Utilizing this knowledge base and stepping further in the development the software framework has been extended and re-structured such that navigation solutions for tracking networks in lunar and cis-lunar space can be calculated and evaluated. The real data orbit determinations of Lunar Prospector clearly reveal the dominant trajectory errors inherent to present day flights in low lunar orbits and which are caused by the imperfectly determined gravity model for the Moon. Although the Lunar Prospector gravity models of 1998/1999 reveal an unprecedented accuracy for orbit reconstruction a problem inherent to the Earth-Moon system prevents the gravity model from being improved further: the rotation of the Moon around its axis is synchronous with its orbital velocity. This characteristic hides the far side of the Moon from being observed or the spacecraft behind the Moon from being tracked directly. The first mission to resolve this systematic lack of observability shall be the japanese SELENE low lunar orbiter supported by a sub-satellite on a higher elliptical orbit working as a relay node for the Earth-based tracking signal. This work demonstrates exemplarily the improvement of increased navigation capability of such a dual-satel [...]
doi:10.14279/depositonce-1592 fatcat:4tdjdv55cngctjqkgbiwwurthq