Libration Point Missions, Vehicles and Lunar Exploration
- Paper number
IAC-07-D3.3.01
- Author
Mr. Florian Renk, University of Stuttgart, Germany
- Coauthor
Mr. Ernst W. Messerschmid, University of Stuttgart, Germany
- Coauthor
Mrs. Britta Ganzer, University of Stuttgart, Germany
- Coauthor
Mr. Juergen Schlutz, University of Stuttgart, Germany
- Year
2007
- Abstract
The IAA Cosmic Study "The Next Steps in Exploring Deep Space" envisions an exploration scenario with different stepping stones to reach the ultimate goal of a manned Mars mission. The first step should be the development of a vehicle capable of leaving the Low Earth Orbit (LEO) for e.g. missions to the Sun-Earth libration points (SEL). The lunar surface is seen as an alternative destination. With a methodology and software tools for human space missions design called the "Space Station Design Workshop" (SSDW) a scenario combining both destinations by utilizing the Earth-Moon Libration Points (EML) as a staging location was investigated. Those are energetically close to the SEL points and thus low cost trajectories connecting both areas are possible. The deltaV requirements for e.g. a satellite servicing mission at the SEL are already available from the lunar exploration missions that require a high deltaV for the descent and ascent stage. The important question for the EML staging to be utilized as an alternative to the current approach is its performance of lunar missions compared to the Low Lunar Orbit (LLO) staging currently employed by NASA, which is based on the ESAS study report. EML staging was ruled out as an option based on prior ESMD reports. However, these reports mainly focused on the cislunar libration point. As proposed by Farquhar, the translunar libration point can be reached by a powered lunar fly-by manoeuvre and hence the deltaV required for both, inbound and outbound leg, can be reduced. While the geometrical properties of the trajectories stay almost constant for the libration point staging and thus providing for infinite transfer window periods this is not the case for LLO rendezvous. The global access and anytime abort requirements can only be met with expensive plane changes or in-orbit loitering, especially with increasing mission duration as required by future plans to establish a lunar outpost, exceeding the currently seven day surface stay time proposed by ESAS. Comparing vehicles for LLO staging with staging at the translunar libration point shows that the initial mass in LEO (IMLEO) depends highly on the ratio of the mass required for the habitation module on the lunar lander and the re-entry- and its support module waiting at the staging location. EML staging can provide similar IMLEO mass with greater mission flexibility to the lunar surface and additional missions to the SEL. However, the drawback of long travel times has to be accepted.
- Abstract document