We’ve got extremely demanding requirements for this mission, says Maria Hernek, head of flight software systems section at ESA.Typically, rebooting the platform such as this takes roughly 40 seconds. Here, we’ve had 50 seconds total to find the issue, have it isolated, have the system operational again, and take recovery action.To reiterate: this operating system, located far away in space, needs to remotely reboot and recover in 50 seconds. Otherwise, the Solar Orbiter is getting fried.
To deal with such unforgiving deadlines, spacecraft like Solar Orbiter are almost always run by real-time operating systems that work in an entirely different way than the ones you and I know from the average laptop. The criteria by which we judge Windows or macOS are fairly simple. They perform a computation, and if the result of this computation is correct, then a task is considered to be done correctly. Operating systems used in space add at least one more central criterion: a computation needs to be done correctly within a strictly specified deadline. When a deadline is not met, the task is considered failed and terminated. And in spaceflight, a missed deadline quite often means your spacecraft has already turned into a fireball or strayed into an incorrect orbit. There’s no point in processing such tasks any further; things must adhere to a very precise clock.
Jacek Krywko
Fascinating article about the software managing robotic missions, from their strict requirements to their conception and history – and a few stories where they inadvertently failed. Their development started, maybe not entirely surprising, with US military programs designing guidance systems for missiles. Over time, just as in the desktop and mobile space, the market largely settled on two competing operating systems, the proprietary VxWorks preferred by NASA and open source RTEMS employed by ESA. And their next iteration may involve… Bitcoin?!
Post a Comment