KeywordsAsteroid Carbonaceous chondrite In situ Mars Mars Express Phobos Satellite
Phobos-Grunt is a mission to Phobos, one of the two small satellites of Mars; it was developed by the Russian agency Roskosmos, with the participation of other countries to the science payload. Launch occured in Baikonur, on November 8, 2011, for an arrival end-2012, and a landing on Phobos mid-2013; the payload consisted in Phobos-Grunt and YingHuo-1, a Chinese satellite, intended to study Mars and Phobos. One of the goals of Phobos-Grunt was to proceed to in situ soil analyses, to help understand the composition of Phobos (structure, mineralogy, organic matter), hence its origin. About 200 g of soil samples should have been sent from Phobos to Earth, for a; landing in 2014. Unfortunately, due to some concerns in the cruise stage, the probe was unable to leave its elliptical orbit around the Earth, and to begin its cruise to Mars and Phobos. After orbiting for 2 months, it desintegrated while entering Earth dense layers of the atmosphere, and the debris felt in Pacific Ocean. The idea of a return to Phobos exists, this reflight should mainly utilize spare models of the experiments that were on the previous probe.
The in situ science payload of the P-G lander (Zelenyi et al. 2010) resembles those of MSL and Exomars. Its 40 kg includes, among others, cameras, radar, and seismometer to understand Phobos structure, and classical in situ instruments searching for elementary and mineralogical composition (Mossbauer, APX, IR, γ and n spectrometers, laser ablation mass spectrometer). The Gas Analytical Package will proceed to analyze soil samples, delivered by the P-G manipulator arm, possibly using a drill. Heating and pyrolysis of these samples, followed by analysis of evolved gases (GC-Ms and IR laser spectroscopy), will detect the presence of any water ice (Christensen et al. 1977) and the structural gases of the minerals (H2O, CO2, etc.). Using the same techniques, this instrument will be able to search for noble gases, organic molecules (nature, isotopic ratios) present in the ground, to be compared to the ones present in meteorites (Rivkin et al. 2002), to give clues on the origin and history of Phobos. Once landed, P-G will also sample the ground and bring to Earth (arrival July 2014; Galimov 2010) about 200 g of material, in a devoted container (see Fig. 3: small brown sphere on top of P-G) for further analyses.
The experiment Living Interplanetary Fight Experiment (LIFE) proposed by a US nonprofit association (the Planetary Society) will sit in the Phobos sample return capsule. Two titanium containers specially designed by the Russian Institute for Medico-Biological Problems will house terrestrial organisms (like seeds) and microorganisms. Pure culture of known resistant microorganisms strains from the three domains of life (Archaea, Bacteria, and Eukarya) will sit along a sample of a terrestrial natural soil. All this samples will be tested for survival upon their recovery with the Phobos samples and subsequently analyzed. The containers will mimic rock and this will be an attempt to evaluate the possibility of panspermia while those organisms will experience a 34-month round trip to Mars.
References and Further Reading
- Christensen EJ, Born GH, Hildebrand CE, Williams BG (1977) The mass of Phobos from Viking flybys. Icarus 4:555–557Google Scholar