Stress-Testing Software For Deep Space 87
kenekaplan writes "NASA has used VxWorks for several deep space missions, including Sojourner, Spirit, Opportunity and the Mars Reconnaissance Orbiter. When the space agency's Jet Propulsion Laboratory (JPL) needs to run stress tests or simulations for upgrades and fixes to the OS, Wind River's Mike Deliman gets the call. In a recent interview, Deliman, a senior member of the technical staff at Wind River, which is owned by Intel, gave a peek at the legacy technology under Curiosity's hood and recalled the emergency call he got when an earlier Mars mission hit a software snag after liftoff."
Re:Seems like a rationalization (Score:2, Insightful)
Remember, too, that Curiosity has been in the works for almost a decade. They had to commit to a spec for the computers a long time ago, so it's no wonder by today's standards things seem out of date.
Re:Seems like a rationalization (Score:5, Insightful)
My understanding is that the thinking goes like this.
Sure, there are newer processors that claim to fit the bill. But space hasn't changed so much since the Apollo days that we need all new processors; by and large anything that needs "heavy lifting" CPU wise can be transmitted back to Earth. For unmanned probes, there's very little demand for high speed CPU tasks that can't be offloaded to Earth. And even if there was, when your latency back to your operator is about 14 minutes (with an extra 14 to receive further instructions, plus the time it takes to interpret the previous data set, determine new instructions, then program those instructions), that's a lot of down time to work on various tasks.
The Mars rover CPUs, I imagine, spend the vast majority of their time idling.
However... the old stuff works. It has its faults and flaws, sure, but they're extremely well known and documented. You can work around them. You have the old grognards that have been kicking around since Apollo who know every damn thing about them. They're risky, sure, but it's a managed, controlled, limited and understood risk. But new processors are *new*. You lose that element of certainty, and the CPU is the heart of a probe. You lose it, you're fucked.
You're trusting the mission, a mission that costs billions of bucks, to a new, untested device that hasn't been field tested, hasn't got that certainty, and *you just don't need*.
Re:Seems like a rationalization (Score:4, Insightful)
It demonstrate how inefficient desktop software is (Score:4, Insightful)
An old Power PC can fly a spaceship to mars, execute a difficult landing and now semi autonomously drive a robot across the surface of a planet 30 million miles away , yet its not up to the job of writing documents using the latest word processors. Whats wrong with this picture?