Southampton engineers a Raspberry Pi Supercomputer

Posted Sep 14, 2012 21:36 UTC (Fri) by dlang (guest, #313)
In reply to: Southampton engineers a Raspberry Pi Supercomputer by Cyberax
Parent article: Southampton engineers a Raspberry Pi Supercomputer

the countries that tried the cheap route, how long were their satellites expected to run? how much did they cost to launch?

as I said, if you are spending millions to launch something, spending more on space rated parts makes sense.

for $8k and a few weeks of life, it's far from clear that the space rated parts are worth it.

Assuming that space rated parts only double the cost (and it's probably worse than that), are you better off with two launches of non-rated parts or one launch with rated parts?

if the non rated parts reduce your effective lifetime more than 50% then the rated parts are worth it, if the reduction in effective lifetime is less than 50%, you are better off with two launches of non-rated parts.

remember we're only talking about a couple weeks here, so a non-rated part that will last a month in space is just as good as a rated part that will last 10 years)

also keep in mind that two launches let you learn from the first and alter whatever experiment you have for the second launch.

Southampton engineers a Raspberry Pi Supercomputer

Posted Sep 14, 2012 21:48 UTC (Fri) by Cyberax (✭ supporter ✭, #52523) [Link] (3 responses)

Lots of sats failed just after the launch. And to be useful you need at least a couple of years of service. And then there's a question of reliability - if you ground infrastructure can't trust the satellite to remain available tomorrow then you need to plan for this.

The problem with non-space-rated parts is that probability of failure is cumulative. And it's already non-trivial even for space-rated parts so duplicate and triplicate redundant systems are used.

> remember we're only talking about a couple weeks here, so a non-rated part that will last a month in space is just as good as a rated part that will last 10 years)
A couple of weeks is not useful for anything but publicity stunts and some rare experiments.

Southampton engineers a Raspberry Pi Supercomputer

Posted Sep 14, 2012 21:52 UTC (Fri) by dlang (guest, #313) [Link] (2 responses)

> A couple of weeks is not useful for anything but publicity stunts and some rare experiments.

And this is exactly what we are talking about

the $8K package puts the satellite in a low orbit that will only last a few weeks before re-entry, so you aren't going to get multiple years of service in any case.

nobody planning a multi-year service satellite is going to be planning to use an Android phone to power it, but for an experimenter, this is a reasonable thing since it gives you a lot of stuff in a small, low-power package at a low cost.

Southampton engineers a Raspberry Pi Supercomputer

Posted Sep 16, 2012 4:39 UTC (Sun) by BrucePerens (guest, #2510) [Link] (1 responses)

That $8K doesn't include your ride to space.

It's a sin to send crap into space. At least the LEO orbits don't pollute orbital space for long, they de-orbit fast enough. But given the cost, and the fact that so few people can get their experiments flown, it is the experimenter's responsibility to not be frivolous. Sending up something that can't dissipate its own heat, that outgasses the electrolyte from its capacitors, etc., is just stupid and wasteful.

Southampton engineers a Raspberry Pi Supercomputer

Posted Sep 16, 2012 20:00 UTC (Sun) by BrucePerens (guest, #2510) [Link]

Oops, they say it does include a ride to space. But they are a year late in launching any. It seems a very low cost for such a ride, and the satellite design looks kind of lame too - solar panel area is really small, transceivers very low powered, etc.

And they are also advertising a lunar sample return mission!

File under "too ambitious to be real" for now.