WET MARS: Plentiful, Readily-Available Martian Water and its Implications
Water and its major constituent, oxygen, in large specific quantities are essential for maintenance of human life. Providing them in adequate quantities is widely believed to be a major challenge for human exploration and settlement of Mars. The Martian regolith isn't known to bear either water or hydrogen, the ice-rich Martian polar regions are thermally inhospitable, and the measured water content of Mars' thin atmosphere represents a layer of liquid water of average thickness only {approx}1% that available on the Moon, or {approx}0.001 cm. Crucially, however, the atmospheric Martian water inventory is advected meteorologically to everyplace on Mars, so that the few cubic kilometers of liquid water-equivalent in the atmosphere are available anywhere when, merely for the effort of condensing it. Well-engineered apparatus deployed essentially anywhere on Mars can condense water from the atmosphere in daily quantities not much smaller than its own mass, rejecting into space from radiators deployed over the local terrain the water's heat-of-condensation and the heat from non-ideality of the equipment's operation. Thus, an optimized, photovoltaically-powered water-condensing system of {approx}0.3 tons mass could strip 40 tons of water each year from {approx} 10{sup 4} times this mass of thin, dry Martian air. Given a 490 set I{sup sp} of H{sub 2}-O{sub 2} propulsion systems exhausting into the 6 millibar Mars-surface atmosphere and the 5.0 km/s Martian gravity well, {approx}40 tons of water two-thirds converted into 5:1 O{sub 2}/H{sub 2} cryogenic fuel could support exploration and loft a crew-of-four and their 8-ton ascent vehicle into Earth-return trajectory. The remaining H{sub 2}O and excess O{sub 2} would suffice for half-open-cycle life support for a year's exploration-intensive stay on Mars. A Mars Expedition thus needs to land only explorers, dehydrated food, habitation gear and unfueled exploration/Earth-return equipment--and a water/oxygen/fuel plant exploiting Martian atmospheric water. All of the oxygen, water and propellants necessary for life-support, extensive exploration and Earth-return can be provided readily by the host planet. Crewed exploration of Mars launched from LEO with on1.V 2 Shuttle-loads of equipment and consumables--a commercial total cost-equivalent of {approx}$650 M--thereby becomes feasible. The most challenging current problem with respect to human expeditions to Mars is escape from Earth's deep, 11.2 km/s gravity well, and is largely an economic issue. Living on Mars, exploring it extensively and returning to Earth, each hitherto major technical issues, are actually much less difficult, thanks in no small part to the effective ''wetness'' of Mars. Similar considerations apply to other water-rich locations in the Solar system, e.g. Europa.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Defense Programs (DP) (US)
- DOE Contract Number:
- W-7405-Eng-48
- OSTI ID:
- 791693
- Report Number(s):
- UCRL-JC-135329-REV-1; TRN: US200303%%65
- Resource Relation:
- Conference: 2nd Annual International Conference of the Mars Society, Boulder, CO (US), 08/12/1999--08/15/1999; Other Information: PBD: 14 Sep 1999
- Country of Publication:
- United States
- Language:
- English
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