NASA readies for Martian soil test, first microscopic images

On its seventh try, Mars Lander successfully shakes soil sample into analyzer

After struggling for five days, the Phoenix Mars Lander has successfully shaken Martian soil into its oven so it can begin testing it for elements that could support life.

NASA technicians didn't just have one big event this week, though. Engineers and programmers today beamed up code that will instruct the Mars Lander's robotic arm to deposit a different soil sample onto a microscope that is slated to send back pictures Thursday morning, according to Bill Boynton, a co-investigator on the Mars mission.

"It's about challenges in general," said Matthew Robinson, the robotic arm flight software engineer at the Jet Propulsion Laboratory. "We're going to a place we've never been before, so you're faced with challenges. You don't know quite what challenges Mars will throw at you, and that makes it exciting."

The mission hit a snag last Friday when the robotic arm unsuccessfully tried to deliver a scoop of Martian soil and ice to one of the Lander's eight analysis ovens, which will heat the soil so the gases that are emitted from it can be analyzed.

A hopper leads down to the oven, which only holds 50 milligrams of soil -- about the equivalent of the ink in a new ballpoint pen cartridge. A thin-meshed screen covers the entrance to the hopper.

Robinson explained that when the robotic arm deposited the soil onto the screen, none of it would fall through to sift down into the oven. Basically, the soil was too clumpy. A rasp attached to the arm vibrated the screen to try to shake some soil down through, but it didn't work.

Boynton said it didn't work during six different tries this week. Only a few particles got through when the screen on the oven was vibrated on June 6, 8 and 9. Then yesterday, it finally worked.

It's possible, according to Boynton, that the soil had warmed and dried out while it sat on the screen in the sun for several days.

The earliest that the oven can run what will be the Lander's first analysis test will be tomorrow.

"Part of the reason to go there is that we don't know what the material is or how it will behave," said Robinson. "That's part of going there -- learning about the material properties in the Martian north pole."

And while scientists were trying to solve the problem of getting a sufficient soil sample into the oven, other NASA scientists were writing the code needed to tell the robotic arm to gather another soil sample and deliver it to the Lander's microscopic imager. The instruction sequence was beamed up to the robotic arm on Wednesday, and Boynton said he expects images showing a microscopic look at the soil to be sent back to Earth tomorrow morning.

The mission is focused on collecting ice and soil samples that can be analyzed in the eight different ovens, four wet-chemistry cells and the microscopic imager on the Lander. Robinson explained that scientists are not looking for life; they're looking for the elements that support life.

The robotic arm, which weighs between 20 and 30 pounds on Earth, is the key to the effort. The arm has a scoop attached to its end that is designed to dig up ice and soil and then deliver it to the analysis tools. No soil, no analysis.

Thirty engineers and programmers at NASA are tasked with writing and testing 1,000 to 1,500 lines of software code and then beaming it about 170 million miles away -- every day. Robinson said the team has to write the code sequences to run different parts of the Phoenix spacecraft, including the robotic arm, the cameras and analysis equipment.

Copyright © 2008 IDG Communications, Inc.

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