5 ms·

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 hundr

by sktrdie 14y ago

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.

jgrahamc 14y ago
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).
- papalalu 14y ago
  presumably the 8 year old design would use already-proven tech too..
  - ballooney 14y ago
    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.
- robryan 14y ago
  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.
- harrywincup 14y ago
  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.
  - mturmon 14y ago
    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.
- facorreia 14y ago
  Maybe there's a lesson for us right there.
- angstrom 14y ago
  Now tack on the fact that it has an initial 2 year mission powered by an RTG. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen... ...but not just any RTG, a MMRTG: http://en.wikipedia.org/wiki/Multi-Mission_Radioisotope_Thermoelectric_Generator http://en.wikipedia.org/wiki/Multi-Mission_Radioisotope_Ther... 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.
  - felipemnoa 14y ago
    >> the rover could turn power off to non critical components after 14 years and continue to run on 100W That constant source is charging a battery. As long as the battery is still working it would just take longer to charge the battery.
  - sp332 14y ago
    How does the radiation from the power supply not screw with the electronics?
akent 14y ago
The CPU is a radiation hardened PowerPC 750 known as a RAD750 made by BAE. Some more info at http://news.cnet.com/8301-11386_3-57491281-76/slow-but-rugged-curiositys-computer-was-built-for-mars http://news.cnet.com/8301-11386_3-57491281-76/slow-but-rugge...
rwmj 14y ago
Raises the interesting question: Are there radiation-hardened hard drives (not SSDs)?
- Someone 14y ago
  Hard drives will not work in a vacuum. http://www.dansdata.com/spacecomp.htm http://www.dansdata.com/spacecomp.htm: "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.
  - rwmj 14y ago
    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.
    - Raphael 14y ago
      Apparently he could make the text look fine, but some of the graphics weren't scaling along.
- jlgreco 14y ago
  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.
Dylan16807 14y ago
The main storage is 2GB. Each camera has 8GB of storage. There is no way in hell this was solely because of space constraints.

by sktrdie 14y ago

jgrahamc 14y ago

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).

papalalu 14y ago
presumably the 8 year old design would use already-proven tech too..
- ballooney 14y ago
  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.
robryan 14y ago
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.
harrywincup 14y ago
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.
- mturmon 14y ago
  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.
facorreia 14y ago
Maybe there's a lesson for us right there.
angstrom 14y ago
Now tack on the fact that it has an initial 2 year mission powered by an RTG. http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen... ...but not just any RTG, a MMRTG: http://en.wikipedia.org/wiki/Multi-Mission_Radioisotope_Thermoelectric_Generator http://en.wikipedia.org/wiki/Multi-Mission_Radioisotope_Ther... 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.
- felipemnoa 14y ago
  >> the rover could turn power off to non critical components after 14 years and continue to run on 100W That constant source is charging a battery. As long as the battery is still working it would just take longer to charge the battery.
- sp332 14y ago
  How does the radiation from the power supply not screw with the electronics?

akent 14y ago

The CPU is a radiation hardened PowerPC 750 known as a RAD750 made by BAE. Some more info at http://news.cnet.com/8301-11386_3-57491281-76/slow-but-rugged-curiositys-computer-was-built-for-mars http://news.cnet.com/8301-11386_3-57491281-76/slow-but-rugge...

rwmj 14y ago

Raises the interesting question: Are there radiation-hardened hard drives (not SSDs)?

Someone 14y ago
Hard drives will not work in a vacuum. http://www.dansdata.com/spacecomp.htm http://www.dansdata.com/spacecomp.htm: "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.
- rwmj 14y ago
  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.
  - Raphael 14y ago
    Apparently he could make the text look fine, but some of the graphics weren't scaling along.
jlgreco 14y ago
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.

Dylan16807 14y ago

The main storage is 2GB. Each camera has 8GB of storage. There is no way in hell this was solely because of space constraints.