Curiosity Mars rover eyes rock drill site
19 January BBC
The US space agency (Nasa) says it is now ready for its Curiosity
rover to start drilling on Mars.
A target patch of ground has been chosen in an area that contains a
diverse range of rocks, many of which were clearly deposited in water.
Richard Cook, the rover project manager, said the team still needed to
identify the exact spot for drilling.
This would become apparent after an assessment was made using the
robot's survey instruments, he explained. Probably within two weeks is
when we'll start our first drill holes," he told the BBC.
And he cautioned that it would be a slow process, not least because
the drill mechanism needs to be cleaned of any contaminants that might
have journeyed to Mars from Earth.
This means taking and dumping several cores before finally delivering
a smaller than aspirin-sized pinch of powdered rock to Curiosity's two
big onboard analysis labs. The mission team has named the prospective
drill site after a former rover engineer, John Klein, who died in 2011.
Curiosity, which has now spent five months on the Red Planet, is
trying to determine whether past environments in the deep crater where
it landed might have allowed microbial life to flourish.Already it has
identified rock deposits that were laid down in a streambed billions of
years ago.
These sediments, which were seen just weeks after the 6 August
touch-down, contained pebbles that had been rounded in the erosive
process of being carried in water.Curiosity has also identified some
sharply inclined layers of finer-grained material that again hint at
deposition in a stream.
Both of these rock forms were on higher ground to where Curiosity
finds itself today. Currently, the rover is sitting in a small
depression known as Yellowknife Bay. This region of lower ground
contains older sediments, but ones that still reflect conditions where a
lot of water must have been present at some point.Among these rocks is
the candidate drill site, John Klein.
This outcrop contains yet finer grains but it is cut through with
veins that the rover's ChemCam laser spectrometer indicates hold
precipitated minerals most likely hydrated calcium sulphate, possibly
bassinite or gypsum.
"On Earth, usually, these veins are formed by water circulation in
fractures, and this usually occurs in low to moderate temperatures,"
said ChemCam team member Nicolas Mangold of the Laboratoire de
Planetologie et Geodynamique de Nantes, France.Apparent, also, are lots
of small spherules, or concretions, which again are strongly indicative
of mineral precipitation in water.Curiosity project scientist John
Grotzinger told reporters that the rover had hit the "jackpot".He said
the drilling operations would attempt in the coming weeks to acquire
samples from the veins and the concretions for study in the robot's
CheMin and Sam labs.
The main goal is to try to assess this material in a very general way
that will give us an appraisal of the habitability of this environment,"
he explained.
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