During testing of Mars rover Curiosity’s mast-mounted Navcams on the second day of operations (Sol 2), small pieces of debris could be seen littering the deck of the rover. Where did it come from? But most importantly, could it be a hazard to Curiosity’s instrumentation?
Fortunately, Discovery News was able to pose these questions to Mike Watkins, JPL mission manager for the Mars Science Laboratory, during Thursday’s NASA press briefing.
The upshot is that during the descent and landing of the one-ton rover, the mission’s Sky Crane rockets winched the rover the final few meters to the Martian surface. The main reason for keeping the rocket-powered platform high was to avoid excessive dust being kicked up from the surface by the rocket thrust, potentially covering the rover.
Still, dust was inevitable, as was apparent from the first dusty images to be beamed back to Earth. Fortunately, the dust issue was mitigated by covering the 17 different cameras with transparent dust covers.
Although the Sky Crane was high above the rover when it lowered Curiosity and then throttled up, flying away to a safe distance before ditching, craters were excavated in the Mars topsoil. Dust and small rocks were blown out, exposing the bedrock below. Some of those small rocks — no bigger than a dime — ended up atop Curiosity’s deck.
During the briefing, Watkins confirmed that the debris was “unexpected” and that the entry, descent and landing (EDL) team hadn’t anticipated anything larger than dust grains to end up on the deck. He theorized that either the material surrounding the rover — a region called Aeolis Palus — was composed of lighter material than the EDL team believed, or that there was a greater degree of thrust on the ground than their simulations predicted.
Although the excavated debris (or “Mars gravel” as it’s being referred to) was unexpected, Watkins is confident that it doesn’t pose a problem. At first glance, instruments like the Radiation Assessment Detector (RAD) — the coaster-sized “window” shown in the upper left of both panels in the top image — appear free from any debris that could cause an obstruction.
“Some of the instruments (could be vulnerable to debris), but all check out OK,” Watkins said.
So, will the rover be carrying these little pieces of gravel for the whole of it’s mission duration? We’ll have to see, says Watkins. As the rover moves and tilts (especially as it makes its way to Mt. Sharp), they will likely fall off.
Curiosity is designed to carry out a 2-year primary mission on the Martian surface, exploring the plain inside Gale Crater, making its way to Mt. Sharp (Aeolis Mons), a 3-mile high mountain with layered rock deposits, exposing a wealth of geologic and (potentially) organic history of the red planet. We’ve only just begun this captivating mission and already the nuclear-powered rover is returning a slew of images and data from a planet mankind will possibly explore first hand in the not-so-distant future.
Image: Top: Curiosity’s deck as seen by the mast-mounted left (A) and right (A) Navcams. Bottom: A mosaic of Navcam images showing the whole deck of the rover. Credit: NASA/JPL-Caltech