The astrobiological case for renewed robotic and human exploration of the Moon

Abstract

An ambitious programme of lunar exploration will reveal much of astrobiological interest. Examples include: (i) better characterization of the impact cratering rate in the Earth–Moon system, with implications for understanding the possible ‘impact frustration’ of the origin of life; (ii) preservation of ancient meteorites blasted off Earth, Mars and Venus, which may preserve evidence of the early surface environments of these planets, as well as constraining models of lithopanspermia; (iii) preservation of samples of the Earth's early atmosphere not otherwise available; (iv) preservation of cometary volatiles and organics in permanently shadowed polar craters, which would help elucidate the importance of these sources in ‘seeding’ the terrestrial planets with pre-biotic materials; and (v) possible preservation of extraterrestrial artefacts on the lunar surface, which may permit limits to be placed on the prevalence of technological civilizations in the Galaxy. Much of this valuable information is likely to be buried below the present surface (e.g. in palaeoregolith deposits) and will require a considerable amount of geological fieldwork to retrieve. This would be greatly facilitated by a renewed human presence on the Moon, and may be wholly impractical otherwise. In the longer term, such lunar operations would pave the way for the human exploration of Mars, which may also be expected to yield astrobiological discoveries not otherwise obtainable.

On the Survivability and Detectability of Terrestrial Meteorites on the Moon

“…Following this argument, Armstrong et al (2002) estimated that at present the average concentration of terrestrial materials exposed at the lunar surface will be of the order of 7 ppm. However, the extent to which biomarkers within buried terrestrial material will survive the impact excavation, gardening, and comminution of the regolith is yet to be assessed, and it may be that the deliberate excavation of terrestrial meteorites preserved at depth [e.g., in buried palaeoregolith deposits (Crawford, 2006;Crawford et al, 2007)] will be required to obtain scientifically useful samples.…”

“…It would thus be of great value to try to push the record of life further back and to test the indications from phylogenetic analyses that life arose before 4.1 Gyr (Battistuzzi et al, 2004). For these reasons, identifying ancient terrestrial materials on the Moon constitutes a strong astrobiological argument for a vigorous robotic and human lunar exploration program (Crawford, 2006). Armstrong et al (2002) estimated that between 10 7 and several times 10 8 kg/km 2 of terrestrial materials may have landed on the Moon during the Late Heavy Bombardment (corresponding to an equivalent layer several mm to several cm thick; or between roughly 0.05% and 0.5% by mass for a 10 m thick regolith).…”

Lunar Net—a proposal in response to an ESA M3 call in 2010 for a medium sized mission

“…[9,30,45,59]). Some of these objectives are astrobiological in nature, in that they will enhance our understanding of the cosmic conditions under which life first arose on Earth [10].…”

LunarEX—a proposal to cosmic vision

“…[3,26,34]]. Some of these objectives are astrobiological in nature, in that they will enhance our understanding of the cosmic conditions under which life first arose on Earth [4]. However, although the Clementine and Lunar Prospector missions have in recent years greatly added to our knowledge of the geochemical and mineralogical makeup of the lunar surface (see, e.g.…”