Southampton engineers a Raspberry Pi Supercomputer
Southampton engineers a Raspberry Pi Supercomputer
Posted Sep 13, 2012 23:58 UTC (Thu) by dlang (guest, #313)In reply to: Southampton engineers a Raspberry Pi Supercomputer by BrucePerens
Parent article: Southampton engineers a Raspberry Pi Supercomputer
the question is if it's going to survive the radiation.
Posted Sep 14, 2012 17:45 UTC (Fri)
by BrucePerens (guest, #2510)
[Link] (7 responses)
But the components don't have the thermal, mechanical thermal cycling, and vacuum qualification they need to operate in space.
Posted Sep 14, 2012 18:01 UTC (Fri)
by dlang (guest, #313)
[Link] (6 responses)
I agree that these won't have the _qualifications_ to operate in space.
the point of disagreement is how badly you _need_ qualifications.
just because something hasn't been certified doesn't mean it won't work.
If you are spending millions of dollars launching something, it makes sense to spend a few thousand dollars to test everything first.
If you are only spending a few thousand dollars to start with, it's probably not worth the extra cost.
I actually expect that a modern phone will work reasonably well. If the solar cells can provide enough power to keep it going, it will probably hold together for the short time that these systems will be in orbit.
you don't think that sputnic-1 had all it's electronics 'qualified' before it was launched do you? that didn't stop it from working.
we're talking about roughly the same orbit (but with 1% the mass, and significantly more capabilities)
Posted Sep 14, 2012 21:02 UTC (Fri)
by Cyberax (✭ supporter ✭, #52523)
[Link] (5 responses)
Also, all of the first Soviet satellites were _pressurized_ exactly because regular electronics don't really work that well in space. In particular, thermal hot spots, that happen easily without convection (never mind the actual lack of air), can quickly wreck silicon.
Many countries tried the 'cheap disposable satellite with non-space-rated parts' route later. It hasn't worked out well enough to justify the costs.
Also, there's nothing magic in space-rated parts. They are just produced in low volumes so the economics of scale doesn't have a chance to kick-in.
Posted Sep 14, 2012 21:36 UTC (Fri)
by dlang (guest, #313)
[Link] (4 responses)
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.
Posted Sep 14, 2012 21:48 UTC (Fri)
by Cyberax (✭ supporter ✭, #52523)
[Link] (3 responses)
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)
Posted Sep 14, 2012 21:52 UTC (Fri)
by dlang (guest, #313)
[Link] (2 responses)
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.
Posted Sep 16, 2012 4:39 UTC (Sun)
by BrucePerens (guest, #2510)
[Link] (1 responses)
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.
Posted Sep 16, 2012 20:00 UTC (Sun)
by BrucePerens (guest, #2510)
[Link]
And they are also advertising a lunar sample return mission!
File under "too ambitious to be real" for now.
Oh, sure. And if radiation is the only problem, it would survive in low earth orbit because the radiation is higher up. And they aren't getting a ride anywhere else but low earth orbit.Southampton engineers a Raspberry Pi Supercomputer
Southampton engineers a Raspberry Pi Supercomputer
Southampton engineers a Raspberry Pi Supercomputer
Actually, they were. Sputnik-1 had been tested before the flight.
Southampton engineers a Raspberry Pi Supercomputer
Southampton engineers a Raspberry Pi Supercomputer
A couple of weeks is not useful for anything but publicity stunts and some rare experiments.
Southampton engineers a Raspberry Pi Supercomputer
That $8K doesn't include your ride to space.Southampton engineers a Raspberry Pi Supercomputer
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.Southampton engineers a Raspberry Pi Supercomputer