article image

Curiosity gets set to drill as more clues to water flood in

Paul Sutherland, Feature writer
Jan 17, 2013, 8:00 UTC

Sen—NASA's Curiosity rover on Mars has uncovered more powerful evidence that Gale Crater was once under water as it prepares to drill for the first time for a sample of rock.

The robotic runabout is currently trundling towards a flat, pale-veined rock that mission scientists believe could hold yet more vital clues to the Red Planet's wet past.

If it still looks attractive to engineers when Curiosity gets close up, it will finally use its drill to collect a piece of the rock for further detailed analysis.

As the rover - formally named Mars Science Laboratory (MSL) - makes its way there, it has already provided fascinating data for a team of US and French researchers. They have used observations made by its ChemCam instrument to follow a trail of minerals that point to the presence once of water.

Veins of gypsum have been seen running through a zone known as Yellowknife Bay which lies around 700 meters from the spot where Curiosity was lowered to the ground in Gale Crater by a sky crane in August.

Gypsum and related minerals are known to form on Earth when water reacts with other rocks and minerals. Its presence, along with its close relative bassinite, supports other evidence of alluvial flow patterns that MSL has observed.

These may be telling scientists that the area once held ponds of water either collected by runoff or which had bubbled up from below the surface. The area differs from the landing site which may once have had a stream flowing through it.

ChemCam team member Nicolas Mangold, of the Laboratoire de Planétologie et Géodynamique de Nantes, in France, said: "These veins are composed mainly of hydrated calcium sulphate, such as bassinite or gypsum. On Earth, forming veins like these requires water circulating in fractures."

The first indications of gypsum's presence came when ChemCam fired its powerful laser to vaporise rock and then analysed the gas given off. Increasing amounts of calcium were detected when the camera viewed pale mineral veins in the rock's surface.

As Curiosity advanced into Yellowknife Bay, a growing number of light-colored veins of minerals were seen to indicate that Mars may once have been a wet planet - an exciting finding because water is essential for life as we know it.

Light veined rocksAn outcrop imaged by Curiosity's Mast Camera (Mastcam) shows well-defined veins filled with whitish minerals. Credit: NASA/JPL-Caltech/MSSS

ChemCam team leader Roger Wiens, of Los Alamos National Laboratory in the US, said: "Since the Mars Science Laboratory mission is focused on whether Mars is or was habitable, this new evidence of water on or below the planet's surface is very exciting.

"We should be able to learn more about what we're seeing once mission scientists can use Curiosity's drill to sample some of these larger portions of material and analyse them using the CheMin instrument."

The rock that is likely to be the first to be drilled is in an area where Curiosity's Mast Camera (Mastcam) and other cameras have found a mix of unexpected features, including veins, nodules, cross-bedded layering, an exotic pebble within sandstone, and maybe some holes in the ground.

The rock, which lies on some flat-lying bedrock, has been dubbed "John Klein" in tribute to former Mars Science Laboratory deputy project manager John W. Klein, who died in 2011.

MSL project manager Richard Cook, of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said: "Drilling into a rock to collect a sample will be this mission's most challenging activity since the landing. It has never been done on Mars."