Scenario 4: Asteroid/Phobos mission
SC1: Konrad Willner
SC2: Jürgen Oberst
Results of the Hands-on Sessions.
Relevance for planned missions
Ever since its discovery, the two Martian moons – Phobos and Deimos, have raised great interest among the scientific community. The excitement is initiated by their irregular shapes, unknown origin, varying surface spectra, the proximity of Phobos to Mars, and many more unanswered questions. For instance, how the Phobos groove system formed that was only discovered after space missions like the Viking Orbiters observed this natural satellite during close flybys.
Other space missions with the primary goal to explore Mars also observed its moons from far the distance or occasionally during close approaches. With ESA's Mars Express mission, regular close encounters of Phobos were and are currently made that have extended our knowledge significantly. However, current data does unfortunately not have the potential to answer all the questions but raises in some perspectives new ones.
Hence, Phobos had been identified as potential mission target in the past (Aladdin) and is currently again in favor as potential space mission target by many mission planers (PRIME, M-PADS, HALL, Phobos-Grunt, GETEMME). While the proposals are driven by a variety of objectives, most mission scenarios include a lander of one kind. Also, Phobos is considered to be a stepping stone for the human exploration of Mars (Lee et. al,2005; West, 2005). The latter is envisaged by NASA's Mars Exploration Program. Likewise ESA's exploration program Aurora aims to further robotic and human exploration of solar system bodies holding promise for traces of life that a mission to Phobos could deliver.
Style of mission
For this workshop it is proposed to identify and characterize a landing site for a science mission to Phobos. The target Phobos has the benefit that it is economically accessible from a low-Earth orbit, thus a mission could fit into an ESA Cosmic Vision M-Class mission budget. The mission shall carry a lander with a sampling device to take probes of the moon's regolith to a) determine what the surface of Phobos consists of: in order to derive further constraints on the origin of Phobos; b) determine if water or water ice is present and Phobos could be used as resource on the way to the human exploration of Mars (Lee et. al,2005). Analysis of the sample could be performed in-situ or a return of the sample (similar to Phobos-Grunt) could be planned (to be discussed in this forum). To explore the surroundings of the lander it could also carry a rover. Other scientific instruments to analyze the surface or upper parts of the regolith are yet to be defined by the scenario team.
Technical aspects
The mission layout should initially envisage a mission duration of approximately 1 Martian year or less, depending on the technical constraints such as power supply at the landing location, thermal issues etc.
Preliminary criteria for the landing site
Many scientists have expressed their interest to sample both of the previously observed blue and red material of Phobos. Another interesting feature to investigate could be the large rocks/monoliths on Phobos that were first imaged by the Mars Orbiter Camera on the Mars Global Surveyor mission. Even more boulders are recognizable in images recently obtained by HiRISE on the Mars Reconnaissance Orbiter. Such objectives would confine the preliminary landing site to Mars facing site of Phobos as the mentioned features are currently only observed in this area. This in turn could conflict with engineering requirements for the landing site such as smoothness of the landing site area, sun elevation, radio communication opportunities etc.
References
Lee, P.; Braham, S.; Gladman, B.; Mungas, G.; Silver, M.; Thomas, P. & West, M. (2005), Mars Indirect: Phobos as a Critical Step in Human Mars Exploration, in 'Int. Space Dev. Conf.'.
- West, M. D. (2005), Stepping Stones to Mars: Reconsidering Human Exploration of Phobos, in 'Proceedings of the 5th Australian Mars Exploration Conference: 'Roving the Red Planet'.