Curiosity: Martian Surface Soil Contains Two Percent Water

In five papers published today in the journal Science, scientists using the ChemCam, CheMin instruments, the Alpha Particle X-ray Spectrometer (APXS) and the Sample Analysis at Mars (SAM) suite aboard NASA’s Curiosity Rover team up to describe the Red Planet’s once-volcanic and aquatic history.

The ChemCam instrument showed that the Martian soils consist of two distinct components. In addition to extremely fine-grained particles that seem to be representative of the ubiquitous dust covering the entire planet’s surface like the fine film that collects on the undisturbed surfaces of a long-abandoned home, the ChemCam team discovered coarser-grained particles up to 1 mm in size that reflected the composition of local rocks.

The ChemCam has shown a similar composition to fine-grained dust characterized on other parts of the planet during previous Martian missions. The instrument tested more than 100 targets in a location named Rocknest and found that the dust contained consistent amounts of water regardless of the sampling area.

What’s more, the Curiosity dug into the soils at Rocknest to provide scientists with the opportunity to sample the newly unearthed portion over the course of several Martian days.

The ChemCam instrument measured roughly the same tiny concentration of water – about 2 percent – in the surface soils as it did in the freshly uncovered soil, and the newly excavated area did not dry out over time – as would be expected if moist subsurface material were uncovered.

The water signature may coincide with the tiny amount of ambient humidity in the Red Planet’s arid atmosphere. Multiple observations indicate that the flowing water responsible for shaping and moving the rounded pebbles encountered in the vicinity of the rover landing area has long since been lost to space, though some of it may still exist deep below the surface of the planet at equatorial locations.

Despite the seemingly small measurements of water in the Martian environment, the findings nevertheless are exciting.

More at

Leave a Reply

Your email address will not be published. Required fields are marked *