NASA plans a robotic mission to search for life on Europa | io9
It looks like it’s finally going to happen, an actual mission to Jupiter’s icy moon Europa — one of the the solar system’s best candidates for hosting alien life.
Yesterday, NASA announced an injection of $17.5 billion from the federal government (down by $1.2 billion from its 2010 peak). Of this, $15 million will be allocated for “pre-formulation” work on a mission to Europa, with plans to make detailed observations from orbit and possibly sample its interior oceans with a robotic probe. Mission details are sparse, but if all goes well, it could be launched by 2025 and arriving in the early 2030s.
This is incredibly exciting. Recent evidence points to a reasonable chance of habitability. Its massive subsurface ocean contains almost twice as much water as found on Earth. The water is kept in liquid state owing to the gravitational forces exerted by Jupiter and the moon’s turbulent global ocean currents. The good news is that a probe may not have to dig very deep to conduct its search for life; the moon’s massive plumes are ejecting water directly onto the surface.
THIS MAKES ME REALLY EXCITED!
Rhea, the second largest moon of Saturn, is a dirty snowball of rock and ice. The only moon with an oxygen atmosphere, thin though it may be, Rhea is one of the most heavily cratered satellites in the solar system.
A very faint oxygen atmosphere exists around Rhea, the first direct evidence of an oxygen atmosphere on a body other than Earth. The atmosphere is thin, with oxygen measuring about 5 trillion times less dense than that found on Earth. Oxygen could be released as the surface is irradiated by ions from Saturn’s magnetosphere. The source of the carbon dioxide is less clear, but could be the result of similar irradiation, or from dry ice much like comets.
On March 6, 2008, NASA announced that Rhea may have a tenuous ring system. This would mark the first discovery of rings about a moon. The rings’ existence was inferred by observed changes in the flow of electrons trapped by Saturn’s magnetic field as Cassini passed by Rhea. Dust and debris could extend out to Rhea’s Hill sphere, but were thought to be denser nearer the moon, with three narrow rings of higher density. The case for a ring was strengthened by the subsequent finding of the presence of a set of small ultraviolet-bright spots distributed along Rhea’s equator (interpreted as the impact points of deorbiting ring material).However, when Cassini made targeted observations of the putative ring plane from several angles, no evidence of ring material was found, but there’s still something around Rhea that is causing a strange, symmetrical structure in the charged-particle environment around Saturn’s second-largest moon.
Image credit: NASA/JPL-Caltech/SSI,Gordan Ugarkovic