The Phoenix lander's 2008 Mars observations of droplets on its legs and evidence of atmospheric exchange with liquid water: Difference between revisions

[[File:Phoenix landing2.jpg|thumb|Artist's impression of the Phoenix Lander settling down on Mars.<br><br>Its measurements of isotope ratios of carbon and oxygen gave evidence for liquid water on the surface now or in the recent geological past.<ref name=phoenixisotope>[http://uanews.org/story/phoenix-mars-lander-finds-surprises-about-planet%E2%80%99s-watery-past Phoenix Mars Lander Finds Surprises About Planet’s Watery Past] University of Arizona news, By Daniel Stolte, University Communications, and NASA's Jet Propulsion Laboratory | September 9, 2010</ref>.<br><br>Its observations of possible droplets on its legs suggested new ways that water could be stable temporarily on Mars.<ref name=phoenix_droplets_2009>[https://www.newscientist.com/article/dn16620-first-liquid-water-may-have-been-spotted-on-mars.html?full=true#.VRReJ_msV8E First liquid water may have been spotted on Mars], New Scientist, February 2009 by David Shiga</ref> These observations lead many scientists to reassess the present habitability of Mars]]

The [[Phoenix (spacecraft) | Phoenix lander]] spacecraft landed in what is thought to be an ancient ocean bed near the north pole of [[Mars]]. It is the first, and so far the only spacecraft to land successfully in the Martian polar regions. The [[Mars Polar Lander]] was the only other attempt but it crashed. Until 2008, most scientists thought that there was no possibility of liquid water on Mars for any length of time in the current conditions there. However, Phoenix observed droplet like features on its legs and also made observations of isotope ratios in the Martian atmosphere, both of which suggested presence of liquid brines on Mars right now or in the geologically recent past.

==Droplets on its landing legs==

 

{{quote|Introduction: We have developed the Michigan Mars Environmental Chamber (MMEC) to simulate the entire range of Martian surface and shallow subsurface conditions with respect to temperature, pressure, relative humidity, solar radiation and soil wetness. Our goal is to simulate the Martian diurnal cycle for equatorial as well as polar Martian conditions and test the hypothesis that salts known to exist in the Martian regolith can deliquesce and form brine pockets or layers by freeze-thaw cycles. Motivation: Liquid water is one of the necessary ingredients for the development of life as we know it. ... It has been shown that liquid brines are ubiquitous in the Martian polar regions and microbial communities have been seen to survive under similar conditions in Antarctica's Dry Valleys.|sign=|source=}}

 

 

[[File:Phoenix Deck after Sample Deliveries.jpg|thumb|400 px|The deck of the Phoenix lander, photographed on Mars. The mass spectrometer used to make the atmosphere isotope measurements is at bottom right. Its observations showed that liquid water on the surface of Mars has exchanged oxygen atoms chemically with the carbon dioxide in the atmosphere in the recent geological past. Though it wasn't able to distinguish between water that is present on the surface intermittently (e.g. after a meteorite impact or volcanic eruption) or continuously (e.g. as deliquescing subsurface brines).]]