I find it weird that the rover wouldn't have enough storage to hold both the logics of the landing and the surface mission. I mean, SSDs nowadays can hold hundreds of gigs and are very small.
Does anybody have more details on that? A complete software update just sounds like a really risky thing, for something that you have no physical access to.
My opinion is that they probably have really strict protocols from legacy missions, and since they just work, they're not going to change them.
Every time there's a report about Curiosity doing something that overlaps with software or hardware that we at HN are familiar with comments like this appear.
The bottom line is: (a) Curiosity was designed 8 years ago so the tech. on board is old (b) everything that's on board has to be radiation hardened and (c) NASA are conservative about 'new stuff' because they need it to work (e.g. the thrusters on the skycrane were derived from the Viking landers).
It's able to supply a steady 125 W of power for 14 years, before dropping to 100W. The technology has been used reliably on multiple projects. Based on the longevity of the previous rovers that have safely made it to Mars it's worth considering that barring mechanical malfunctions and hardware failures (it has two main computers) the rover could turn power off to non critical components after 14 years and continue to run on 100W. It might not be far fetched to think that this rover could still be running if/when humans arrive in the 2030s.
That's far cooler than what you would get running on the latest and greatest for convenience.
I wonder whether it will get to the point where they just send processors was a large amount of redundancy, multicore/ multiprocessor, and just not trust any one result but probabilistically across operations in parallel.
It must be unbearably frustrating building this stuff to work around the limitations of 10+ year-old technologies when the superior tech inside even the phone in your pocket could achieve so much more.
Almost all of the radiation effects appear to be single event upsets (SEUs). So in principle, it should be possible to design robust software to detect and recover from faults (SEUs do no permanent damage to hardware).
There have been efforts within NASA to design robust OS extensions -- redundancy, watchdogs, heartbeats, checkpoints, etc. -- so that fast/cheap COTS hardware could be used, at least for some functions like image processing. This has never reached critical mass and been carried to completion, however.
So yes, as you guessed, there is significant pain and heartburn that computational capabilities are so far behind. Engineers have to spend a lot of time and cleverness squeezing, say, stereo vision processing, or image compression, into the hardware available.
Indeed, their shopping list 8 years ago was not from Newegg with whatever Intel had at the time, it was whatever BAE had spent many years rad hardening and qualifying by that point, which would itself have been based on an already proven CPU (read: older) when BAE first started looking. All of a sudden it's 1993.
"Many people think hard drives are hermetically sealed, but they're not - they just have no through-flow ventilation. In vacuum, a hard drive will instantly eat itself when turned on.
[…] Even if you run at full atmospheric pressure, you don't want all your computers to die if you lose some air.
Very good point. I guess the other thing I hadn't thought about is temperature (variability in particular) which must affect hard drives with all their moving/expanding metal parts a lot more than it does SSDs.
It probably wouldn't be too hard to do. I think the problem with that for an application like this would be standard physical harddrive reliability issues. More moving parts, no matter how reliable we normally think of them, probably wouldn't be something that would thrill the people who build these rovers.
Does anybody have more details on that? A complete software update just sounds like a really risky thing, for something that you have no physical access to.
My opinion is that they probably have really strict protocols from legacy missions, and since they just work, they're not going to change them.