Exploration Missions in the Sun-Earth-Moon System: A Detailed View on Selected Transfer Problems

Paper number

IAC-08.A5.3.5

Author

Mr. Florian Renk, Institute of Space Systems, Universität Stuttgart, Germany

Coauthor

Mr. Martin Hechler, European Space Agency (ESA), Germany

Coauthor

Prof. Ernst Messerschmid, University of Stuttgart, Germany

Year

2008

Abstract

The Astronautics and Space Station Department of the Universitaet Stuttgart has developed a design environment for the conceptual design of manned space missions. While this design environment was so far focused on orbital missions, international exploration scenarios required a major extension toward missions leaving the Low Earth Orbit. Suitable destinations for a next step can be the lunar surface or the Sun-Earth Libration points (SEL), where satellite servicing could take place.
Going to the lunar surface via a Low Lunar Orbit (LLO) has the disadvantage that expensive plane changes might be required at arrival, departure and in case of a contingency. By utilizing orbits about the Earth-Moon Libration Points (EML) as first proposed by Farquhar, the disadvantages of the LLO staging can be avoided, because the geometry of the trajectories with respect to the lunar surface is almost unchanged. This is due to the synchronous rotation of the moon.
To allow for a reliable mission design, the transfer times, the ΔV and variations in the ΔV between the different locations in the Sun-Earth-Moon system must be known, especially taking the rendezvous constraints for human spaceflight missions into account. Since the variations in ΔV should be kept as small as possible, the information about ΔV variations is essential for selecting a specific orbit as a staging location.
This paper focuses on selected mission analysis tools that have been developed in cooperation with the European Space Operations Center in Darmstadt. The results cover transfer trajectories from Earth to different orbits about the collinear EML 1 & 2 and further on to the lunar surface. For the Earth – EML transfer direct, fly-by and trajectories via the Weak Stability Boundary (WSB) region of the Sun-Earth system as discovered by E. Belbruno are treated. Transfer time trades and ΔV variations due to the rendezvous constraints on these orbits are presented. Additionally to the advantages for lunar exploration, missions to the SEL region become possible via low-cost transfer trajectories almost without any ΔV as shown by Lo, Canalias and Howell. These transfers make repair and servicing of expensive observatories parked in orbits about the SEL regions possible by making use of the natural dynamics of the libration point orbits.

Abstract document

IAC-08.A5.3.5.pdf

Manuscript document

IAC-08.A5.3.5.pdf (🔒 authorized access only).

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