The Software Behind the Mars Phoenix Lander

chromatic writes "Imagine managing a million lines of code to send over seven hundred pounds of equipment millions of miles through space to land safely on Mars and perform dozens of experiments. You have C, 128 MB of RAM, and very few opportunities to retry if you get it wrong. O'Reilly News interviewed Peter Gluck, project software engineer for NASA's Mars Phoenix Lander, about the process of writing software and managing these constraints — and why you're unlikely to see the source code to the project any time soon."

Comments

wow, long article, here's the answer to the teaser

[deft]

basically, its because the code is part of a space vehicle regulated by international arms and trafficking laws. That means Joe Blow doesnt get it.

Sorry dude, you're Joe Blow. Unless you're reading this from a JPL/NASA'ish sort of place. Then you're just smirking.

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FTA:
Sort of on a different topic, I have a quote here. One of our editors talked to Frank Hecker from the Mozilla Foundation the other day.

Okay.

In that talk, he suggested that all software developed by the Federal Government should be released to the public domain or a very, very liberal open-source license. That's not even a copyleft license. Does the American public have any access to the source code currently on the Phoenix? Are there plans to make some of the source code available?

Well, no. There are no plans to make that available. And one of the issues that we have is that our spacecraft are designated as subject to international trafficking and arms regulations. So even --

Crypto regulations in exporting and such?

Yeah. Yeah. I mean even though these are not military spacecraft, the technology used in them is space technology. And so the State Department does not allow us to release anything that we've done in terms of technical details to foreign scrutiny. Now, in fact as I said, we have a team of Canadians. The Canadians delivered our meteorology instruments, and we had to be very careful about our relationship with them and how much we could disclose to them.

Really?

Yeah. Yeah.

I can see that in applying control software, but how about the payload software?

Even the payload software -- in this particular case, remember that the payload software operates within the confines of the RAD 6000 that contains the spacecraft software. And although the newer versions of real-time operating systems allow you to compartmentalize better, the older ones are just global name space. So there really wasn't any way to allow them to provide software for the MET instruments. So we had to define an interface and build the software at JPL, and then do our integration testing. And we worked closely with the Canadians in terms of the integration testing and making sure that the software was going to do what they needed it to do.

Right.

But we could not actually release the source code to them.