Spirit readies for long drive after rock cleaning, grinding

Posted: February 6, 2004

Whipping half-inch stainless steel bristles against a pyramid-shaped rock, the Spirit rover has performed "the greatest interplanetary brushing of all time," a scientist joked Friday with the unveiling the latest images from Mars.

The brush on Spirit's instrument arm is shown in this image with Adirondack as backdrop. Credit: NASA/JPL/Cornell
The rock, nicknamed Adirondack, is the first rock that Spirit has examined since landing on Mars a month ago. Sidelined by computer memory trouble that is now fully resolved, the rover has resumed its science activities.

"I think I can say this morning, with as much certainty as we can say anything here, that our patient is healed. We are very excited about that!" mission manager Jennifer Trosper told reporters at Friday's rover status briefing.

On Wednesday, controllers spent about three hours erasing the flash memory and an hour reformatting and resetting the vehicle.

"All indications were that worked extremely well. Of course it was nerve-racking...In the end, the spacecraft did what we wanted it to do and it performed perfectly. It's in great health right now," Trosper said.

This image taken by the panoramic camera shows the post-brushing view of Adirondack. The cleaned patch is clearly visible. Credit: NASA/JPL/Cornell
Download a larger image here

The brush in the rover's Rock Abrasion Tool, or RAT, was used for five minutes Thursday to remove dust from the outer surface of Adirondack.

Scientists weren't expecting to see much change in the rock's appearance since it seemed clean. Instead, the brushing created a dark blotch on Adirondack.

"I didn't expect much of a difference. This is a big surprise," said Stephen Gorevan of Honeybee Robotics, lead scientist for the RATs. "Ladies and gentlemen, I present you the greatest interplanetary brushing of all time."

"To our surprise, there was quite a bit of dust on the surface," said Ken Herkenhoff, lead scientist for the rovers' Microscopic Imagers. "Remember, we selected this rock target because it looked relatively dust-free."

"The material on the surface posed literally no resistance," Gorevan said. "We saw almost no effort in the motor telemetry that said this material offered any resistance whatsoever."

The close-up images show "a bunch of details in here we are just beginning to understand," Herkenhoff said.

"We are seeing...mineral crystals on the rock surface. Of course as we continue to abrade the surface with the RAT, we are very excited to see what that will show us."

This microscopic image shows a cleaned off portion of the rock dubbed Adirondack. The observed area is 3 centimeters (1.2 inches) across. Credit: NASA/JPL/Cornell/USGS
Download a larger image here

Late Friday, Spirit was expected to use the RAT to grind into Adirondack, which is a hard, volcanic rock. The device's diamond teeth will carve out a hole so the rover's science instruments can examine the minerals and elemental composition of the rock's interior.

Once finished with Adirondack, Spirit could begin driving Saturday, bound for a large crater in the distance.

"We are kind of on the west-southwest side of the lander. We are going to drive around the lander and head northeast for Bonneville Crater. We do believe we will be able to get there," Trosper said.

"We're having strategy discussions now on how we would use the capabilities of the vehicle in terms of traversing and auto-navigation in order to get us there.

"Our initial thinking is we will start with being able to just designate traverses from the imaging. So we will tell the rover exactly were to drive, but at the end of that traverse we will turn on our auto-navigation software and allow the rover, for a meter or so just to check out the auto-navigation software, to determine how to get to the next way point."

As Spirit continues to journey across Gusev Crater, controllers expect to expand the distance it can travel in each increment.

"We will start in those baby steps and each sol (day) that we are driving, we will probably expand the numbers," Trosper said. "There is going to be a lot of driving on Spirit."

Over the course of the long trip, the rover will make a few extended stops to perform science investigations along the route.

"We have worked with the science team and we've talked about four or five different places that we might stop and do some specific science with the (arm) as we go. That's our plan, long-term."

Imagery indicates that there will be a path for the rover to actually reach the crater rim.

"Of course we will know that better as we move closer," Trosper said.

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