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NASA to use consumer Android smartphones in new satellites

nasa.gov

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Re: NASA to use consumer Android smartphones in new satellites

#31

Post by ars »

sliverstorm wrote: post #14
est wrote: post #3

Earlier quoted context omitted.

Use a shield.

Of lead? At $10,000/lb launch cost?

Lead wouldn't work anyway - it would make things worse actually.

Lead is good for gamma (and X) rays, but very very terrible for cosmic radiation which is protons and neutrons (nucleons).

For those you want water.

It works like this: For photons you want them absorbed, so heavy metals are great.

But it's not possible to absorb nucleons. Instead you want to steal their energy. If you use lead they simply bounce loosing hardly any energy.

Instead you want very light elements - hydrogen especially. Then when they bounce all the energy gets transfered to the hydrogen.

Lead can make things worse because the nucleon can actually fission the lead atom emitting secondary radiation that is even worse than the original.

If you are shielding from electrons you can get Bremsstrahlung radiation if you use lead see: http://en.wikipedia.org/wiki/Bremsstrahlung#Radiation_safety

In summary: Lead for photons, water (or other light materials like wax or plastic) for everything else.

Re: NASA to use consumer Android smartphones in new satellites

#32

Post by seclorum »

shinratdr wrote: post #22
fchollet wrote: post #21

Earlier quoted context omitted.

Surely the phone is going to be radiation-shielded inside the satellite. I see no critical contraction here...

Right but if we can just simply "radiation-sheild" off the shelf devices, why didn't we do that instead of custom building a robot made of specifically radiation hardened parts that are also much more expensive? Why was the most important consideration by far for the processor in the previous NASA project was designed from the ground up to be radiation-hardned, but yet we can launch this no problem? I just don't get…

The answer is that modern consumer memory packages have come a long way from core memory. Standard ECC tech is extremely resilient to bit-rot and can recover in cases where older memory technologies would have failed catastrophically.

And in the case of real memory corruption, i.e. where cosmic radiation overwhelms the ECC controllers ability to correct the bit rot, well .. "reboot and retry" has been a standard for years, and will continue to work as a strategy as long as it is considered by the software architects of the system.

Re: NASA to use consumer Android smartphones in new satellites

#33

Post by veemjeem »

joenathan wrote: post #23
mrj wrote: post #9

I bet they'll be stuck on 2.1 forever .

I know this is sort of a joke, but the Nexus S shipped with Android 2.3 Gingerbread, and it's been updated to Android 4.1 Jellybean as of July 20th.

Is the update for the Nexus S OTA? I haven't gotten mine yet. In fact, I haven't gotten the 4.0 (ICS) OTA yet. I heard they released a version but pulled it... I have yet to see anything beyond 2.3 for my Nexus S.

Re: NASA to use consumer Android smartphones in new satellites

#37

Post by robryan »

shinratdr wrote: post #22
fchollet wrote: post #21

Earlier quoted context omitted.

Surely the phone is going to be radiation-shielded inside the satellite. I see no critical contraction here...

Right but if we can just simply "radiation-sheild" off the shelf devices, why didn't we do that instead of custom building a robot made of specifically radiation hardened parts that are also much more expensive? Why was the most important consideration by far for the processor in the previous NASA project was designed from the ground up to be radiation-hardned, but yet we can launch this no problem? I just don't get…

I think it has a bit to do with how mission critical something is. With the Mars rover, if it fails that is a lot more money and time down the drain than if a small phone satellite does.

As I commented on a Curiosity article, I hope they eventually tend more towards using lots of commodity hardware running instructions in parallel and working off probability rather than any one processor having to be perfectly deterministic.

Re: NASA to use consumer Android smartphones in new satellites

#38

Post by Tichy »

veemjeem wrote: post #33
joenathan wrote: post #23

Earlier quoted context omitted.

I know this is sort of a joke, but the Nexus S shipped with Android 2.3 Gingerbread, and it's been updated to Android 4.1 Jellybean as of July 20th.

Is the update for the Nexus S OTA? I haven't gotten mine yet. In fact, I haven't gotten the 4.0 (ICS) OTA yet. I heard they released a version but pulled it... I have yet to see anything beyond 2.3 for my Nexus S.

We got it OTA.

Re: NASA to use consumer Android smartphones in new satellites

#40

Post by natep »

shinratdr wrote: post #18

...This raises questions about that other article that claimed everything had to be specially hardened to withstand radiation, no? I had always assumed that was the case and the article text was obvious, but if we can launch off the shelf Android devices into space with no problems then why are the other NASA projects utilizing such out of date hardware?

I'm guessing that these spacecraft have none of the mission requirements that most others have. They're not doing a flyby mission where they have to work during the flyby, or doing anything actually critical (such as provide comms/science, or use propulsion). The system is designed to reboot in the case of problems, which

The closest to a mission goal I can find in the post is "This approach allows engineers to see what capabilities commercial technologies can provide, rather than trying to custom-design technology solutions to meet set requirements." So the only goal is to see _if_ they work.

Trust me, if other missions could get away with less shielding, they would. That's one reason why RBSP[1] is being launched, so we can better understand the radiation environment in Earth's orbit, so future missions aren't undershielded or sent up with unneccessary shielding. But I doubt that most big-budget missions could get away with no shielding.

[1] Shameless plug/full disclosure: I have been working on this project for the last 2+ years, and am now one of its flight controllers. For updates, you can check rbsp.jhuapl.edu or http://spaceflightnow.com/atlas/av032/status.html

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