Space On a Shoestring

An anonymous reader writes, "Three engineering students from Cambridge University plan to send an unmanned craft into space for £1,000 ($1,880) and have just sent a test mission up 32 km for a lot less. Their snaps from the upper atmosphere are impressive, and were taken by a balloon equipped with off-the-shelf technology including GSM text messaging, radio communications, and an ordinary 5-megapixel camera. They now plan to use a similar craft as a launching stage to get a cheap rocket into space." There's also a video of the balloon launch.

Comments

GSM text messaging

[ubersonic]

So GSM phones do work at that height?

Why do we need inflight GSM mini stations then?

Re: GSM text messaging

[another_henry]

In experiments with light aircraft and with the balloon we found that ordinary GSM mobile phones / cellphones stop working at about 2km, 6000ft altitude. There are a few ideas as to why but my best bet is that it's caused by the phone being able to see several towers operating on the same frequency, which you can rarely/never do from the ground. We had telemetry from the two 434MHz radios during the flight and the GSM phone was a backup to send the landing site location if it landed in an area of poor radio reception (which was not unlikely - when the balloon is in the air it should be possible to receive transmissions from the 10mW transmitter at a distance of at least 400km but when it's on the ground, especially with the antenna facing down, you're lucky to hear it within 1km)

Re:Yes, but orbital?

[Martigan80]

I'm sure this is also understood. The key point here I see is that these people where able to pull of such an event at the cost they did. To me this also seems as a spirited event to prove that you don't need the government or big corps to do such things. I mean for fun this is great but it just might be the trigger to get other people/groups thinking on how to proceed with the next step.

Re: GSM text messaging while flying

[cloricus]

Having made several flights lately in light aircraft I've been rather bored and have happily sat watching the bars on my mobile phone...Now I didn't realise there was a full on tin foil hat issue here though my results are as follows:

Outbound from where I live on a Nokia 6230 I had signal for a decent phone call up to ~5,000 feet and could send SMS to around ~6,000 feet, soon after this I lost signal. Leaving on the way back to here I had phone signal for a call up to ~7,000 feet and lost phone and SMS at about the same time.

The Blackberry 7230 I had with me made it another 500-1000 feet over my Nokia in regards to signal though GPRS didn't fare so well. Luckily Brick doesn't require phone signal. :)

We tended to fly at around 12,000 feet most times and those observations from one trip seem about right for the rest plus I can confirm from having to drive several of the distances that there is full phone coverage a long the routes.

Re:Very cool hobby...

[gkhan1]

What kind of permissions from the local flight authority does it require? Aren't they hard enough to get to prohibit hobbyist involvement?

Re:Moo

[another_henry]

If the parachute fails (unlikely but not impossible) it will "plummet" at a stately 15 mph. We decided to have a launch criterion that it must not visibly damage a melon when dropped on it at a velocity matching the terminal velocity for a no-parachute descent. The testing for that was a lot of fun and we did get through a couple of melons before reaching the right combination of foam material, thickness and shape but now we are confident that it wouldn't hurt someone if it hit them even with a parachute failure. The chances of hitting anyone are very slim anyway, these things always land in fields. Plus we have software running on the balloon that predicts the landing location based on recorded and predicted wind speeds, and aerodynamic characteristics, and will operate the cutdown to release the payload early if it threatens to land in the sea or a heavily built-up area.