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Comment by leeoniya | Hacker News Reader

couple thoughts.

1. isnt this small enough to look like space debris, and maybe dangerous?

2. "The mobile phones are designed to be thrown around the room and for people to drop them in water. They're really robust bits of technology," -- i'm not sure how this physical durability has any bearing on its performance in near absolute-zero temps and in the radiation of space without being using radiation hardened silicon...not to mention that it would never be subjected to any of the things described.

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"isnt this small enough to look like space debris, and maybe dangerous?"

The fact that they said this burns up when it runs out of "juice" implies that it is in very low Earth orbit, where the atmosphere still exists and imparts drag. These will reenter the atmosphere on a moderately predictable time scale and burn up. Space junk is only a problem at higher orbits which can be stable for very long periods of time without propellant.

As for 2... they put on up and it worked. What's the point of theorizing about how it might not work, when they've already done it? It might stand up to a good solar blast, but that's hardly a surprise, and if it's disposably cheap, who cares?

"It might stand up to a good solar blast, but that's hardly a surprise, and if it's disposably cheap, who cares?"

the phone itself might be cheap, but putting it up there is most certainly not (yet)...which is why most things that are designed to go into orbit are expensive :(

would you care to spend 150k+ to put a $300 cell phone into space for 2 weeks?

If the data it could collect in those 2 weeks was worth $200k, hell yes. Sign me up for 2 launches/month.

heh, i was gonna add the clause *unless you're the NSA or have some deep pockets

i think as long as launches are limited, the asking price will be kept artificially high anyways to render the cost of the actual satellite minimal compared to the launch expenses, regardless if it's $300 or $300,000 going up.

Cubesats are always secondary payloads, usually jettisoned after the first main stage burn. Their mass is insignificant compared to the main payload, so they usually ride for free.

http://en.wikipedia.org/wiki/CubeSat

So I can't speak for all conditions, but cubesats do not usually ride for free. The prices I've seen are usually in the 50k / unit range. So if you've got a 1U cubesat, expect to spend at least 50k on launch. Part of the reason for this is that there are integration costs for attaching a cubesat deployer to an existing launch vehicle, as well as liability risks, control and thrust timing modifications etc.

> near absolute-zero temps

Although space is cold, due to the vacuum the biggest issue is getting heat away from the devices. That's why the main part of EVA suits is liquid cooling.

> radiation of space without being using radiation hardened silicon

They are only in low earth orbit, so the magnetic field of the earth would provide pretty good protection.

Phonesats have low enough mass that magnetorquers can provide all the attitude control, too.

Well, the fact that it's working means that it's working. Your questions may be valid, but either they've been answered by the scientists or they're non-issues.

1. Space debris certainly doesn't have to be small to be dangerous. Objects about 1cm in cross section can be tracked from the ground, and these are in a known orbit, so are probably okay.

2. I heard somewhere that the batteries needed to be replaced but not much else did, don't have a reliable source for that though

The only part that's really being used in the CPU, memory, and sensors. New batteries are installed and new radios and antennas are used bypassing all the on-phone radio equipment. This really is nothing more than a way to hype up a not so useful project. There are dozen of short to medium life cubesats that are launched every year with off the shelf components.

You have a point about the phone being kind of a red herring. Here's a link to the larger CubeSat program:

http://www.nasa.gov/directorates/heo/home/CubeSats_initiativ...

There is significant interest in these small units (10cm on a side, but combinable up to 6 units) on the part of universities. Here's a list of the upcoming launches:

http://www.jpl.nasa.gov/news/news.php?release=2013-073

I think that within NASA CubeSats are regarded with limited interest. The conventional route for a new satellite measurement from the lab to space is via airborne, or in some cases balloon-borne, experiments. That's how, say, new radar, lidar, hyperspectral imaging, etc., technologies are proven. Lab bench, field experiments, airplane, space.

The CubeSat program is awesome for universities. There are also lots of launch opportunities from the Chinese, Indians, and Russians. Just yesterday there were a couple university sponsored CubeSats that where launched on a Chinese rocket.

http://amsat-uk.org/2013/04/26/ham-radio-cubesats-successful...

I neglected the international angle. Thanks for that.

The camera is also being used (OK that's technically a sensor...)

regarding 2: The robustness to physical shock isn't particularly relevant once deployed, but during launch the hardware is subjected to huge vibration and g forces. If the hardware is not well assembled, parts will come off. This poses a risk to the cubesat as well as the launch vehicle. Also, radiation hardening is statistically a long-term concern for missions. Most large satellites are designed for a minimum 5 year mission, some for 20-25 year missions (many geostationary birds). On those timescales, radiation is a significant issue. These satellites are in a low earth orbit and will be burned up in the atmosphere within a year - probably less. The chances of a single event upset are really small, and there are 3 phonesats. It takes a long time for radiation to degrade the silicon in a chip, much longer than the lifespan of these particular satellites.

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