[IGSTK-Developers] NASA: 'Extreme programming' controls Mars Lander robot

[Luis Ibanez]

http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9094138&pageNumber=1


"NASA: 'Extreme programming' controls Mars Lander robot"

By Sharon Gaudin

"Engineers send code 170 million miles through space daily in search
for life on Mars"


<quote>
June 5, 2008 (Computerworld) Scooping up soil samples and searching for
elements that could support life on Mars isn't just an adventure for the
Mars Lander and the robotic arm doing the scooping.

It's also an adventure for the approximately 30 engineers and
programmers at NASA who 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.

Matthew Robinson, the robotic arm flight software engineer at the Jet
Propulsion Laboratory, 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. One mistake and the Lander sits
idle for a day, wasting precious time that could be used to discover if
the planet can support life.

So far, all the code they've beamed up to Mars in the past week has worked.

"It's a challenge because we have a two- to three-day strategic plan,
and then each day that plan is refined," Robinson told Computerworld.
"They decide on the final plan that day. You have to build 20 to 30
sequences, and each can have 50 lines of code in it. And they have a lot
of interplay between different instruments, so you have to make sure the
sequences are not just working, but working together.

"Building the sequences is an extreme programming challenge every single
day," he added.
</quote>

<quote>
And the developers, who used the C programming language to build their
own software for a Linux operating system, are expected to be dealing
with that challenge for about three months.
</quote>


<quote>
Robinson said a 3-D digital elevation map was used last Sunday to write
code to make the arm reach down and touch the ground. That gave the team
an idea of how accurate the maps are, how easily the soil can be scooped
up, and how well they can control the arm from so far away.
</quote>

<quote>
Then on Monday, they sent the arm instructions to reach down, scoop up
some soil and hold it so onboard cameras could take a picture of it.
After that, the arm dumped the soil back on the ground. On Tuesday, they
did another practice dig.
</quote>


<quote>
On Wednesday, engineers sent up the code to run an actual analysis, but
a satellite orbiting Mars, which transfers the data down to the Lander,
was offline. Robinson explained that the satellite had been hit with
radiation, knocking it into safe mode. "Space is a harsh environment,
and sometimes they just go into safe mode," he noted. "It's a minor
problem. [The satellite] aborts whatever it was doing and waits for
future commanding."

Engineers successfully resent the code on Thursday. As of late Thursday
afternoon, Robinson said they were just waiting for an information feed
to come back to Earth, reporting on how the work went for the day.
</quote>