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...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launch off the shelf Android devices into space with no problems then why are the other NASA projects utilizing such out of date hardware?
...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launch off the shelf Android devices into space with no problems then why are the other NASA projects utilizing such out of date hardware?
Surely the phone is going to be radiation-shielded inside the satellite. I see no critical contraction here...
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 it. I also don't appreciate the downvotes. I'm not trolling or looking to start an argument. I don't have dog in this race, I'm genuinely confused.
I bet they'll be stuck on 2.1 forever .
Earlier quoted context omitted.
Radiation, such as cosmic rays, would tend to cause transient bit errors in memory that would cause the phone to crash or otherwise stop working. The article mentions that they have a circuit that automatically re-boots the phone when it stops transmitting a signal, so it can recover from these problems.
Wow. That's surprisingly un-NASA. I wonder if they have qualified the MTBF? For this kind of solution to work, it'd have to be at least a couple hours.
Because at the end of the day, "Radiation hardening" just means, "Less likely to experience one of these errors but oh hey a solar flare is inc..." Satellites just sort of float until their orbit decays, they are de-orbited, or they are lost.
You wouldn't do this for a spy satellite you need to send you images of the sky in realtime for end-of-the-world missile guidance, but for something that's doing science missions it's probably way more important to make something light and cheap that a russian mission can drop out the back of its launch.
...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?
Surely the phone is going to be radiation-shielded inside the satellite. I see no critical contraction here...
Earlier quoted context omitted.
Radiation, such as cosmic rays, would tend to cause transient bit errors in memory that would cause the phone to crash or otherwise stop working. The article mentions that they have a circuit that automatically re-boots the phone when it stops transmitting a signal, so it can recover from these problems.
Wow. That's surprisingly un-NASA. I wonder if they have qualified the MTBF? For this kind of solution to work, it'd have to be at least a couple hours.
Why is it important to make satellites which are cheap to build? Isn't the total cost dominated by the cost of bringing it to orbit anyway?
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…
However, I'm guessing there are probably people who have simulated this and it probably hasn't worked out to be very economical for past missions. I think part of the problem is that the level of shielding required would really limit your payload to orbit. It's probably going to take a huge amount of material seeing as even the Space Shuttle couldn't act as a perfect buffer between computers and radiation.
From a NASA article[1]:
"Designers also found out that laptops would crash when the shuttle passes through the "South Atlantic Anomaly," which is an area where the magnetic field draws in to Earth, again offering less radiation filtering for spacecraft flying through it."
Completely speculating here, but I would imagine that part of this experiment is to get operational experience with using standard grade electronics in space.
From the OP's article, the satellite has:
"...a watchdog circuit that monitors the systems and reboots the phone if it stops sending radio signals."
Anything with a human or with a high price tag attached to outages can't work with that caveat. If DirectTV's satellites did that, people wouldn't stay signed up for long. Imagine a Mars rover having to reboot every half hour... not very convenient.
But perhaps NASA might want to know if they can cheaply build "disposable" orbital experiments... i.e. ones that can complete their missions in a few hours. The sort of reliability where you just have to deal with the odd 30 seconds of rebooting every so often could be alright, especially if the payload can be stowed on a cargo ship and simply shoved out an air lock like the SuitSat[2].
Again spitballing, maybe they will find that things work out more or less OK if they send up five moderately shielded Raspberry Pis and they "vote" a la the Space Shuttle's flight computers[3]. If so, maybe that opens up space experimentation to universities with smaller budgets to squeeze onto resupply/manned launches that happen to have a spare square foot of space.
[1] http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_...
[2] http://science.nasa.gov/science-news/science-at-nasa/2006/26...
[3] http://history.nasa.gov/computers/Ch4-4.html (search for "vote" to get to the specific spot detailing how this works)
From reading the article, there is no reason why Android was chosen specifically. So this experiment could have been done with any modern smartphone out there, they just happen to choose a couple of android phones. Is that right?
For instance, most other major options (elephant in the room being Apple), have onerous terms for their accessory development kits which would preclude that. Last I checked, Apple even keep the Dock port pinout "confidential" from people not in their accessory dev program, which would be a show-stopper since presumably this uses the dock/USB port for control.
Why is it important to make satellites which are cheap to build? Isn't the total cost dominated by the cost of bringing it to orbit anyway?
The other advantage in having NASA lead the way in the cheap satellite area, it will be easier for others to take advantage of cheap launches when they are eventually available. And possibly help create demand.