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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.
http://www.grc.nasa.gov/WWW/K-12/Numbers/Math/Math ematical_Thinking/designing_a_high_altitude.htm
http://www.amsat.org/amsat/balloons/balloon.htm
I'm not fat, just big boned...
I was in the same program last year at a different university (LSU). The stuff is somewhat exciting, but I don't really think it's newsworthy. I feel like it only made the news because it of the famous university name tacked on...
Regardless, what they've done is an outstanding achievement. The year before mine our school tried to take a picture up there (~100,000 feet) but it didn't work because the cold temperature changed the timing of some electronics, causing them to malfunction =/
I was in charge of the thermal stuff, and let me tell you, it's pretty hard to keep it warm but not so warm that the sun toasts it. And keep in mind the payload, as they call it, could only be 500 grams!
This (working to launching rockets from baloons) has been done in the US for quite some time. There are plenty of student baloon payload systems and in fact this week there is a confrence going this week on adressing just this topic. As far as using baloons as a launch platform, there is group from Huntsville AL http://chapters.nss.org/al/HAL5/HALO/that has been launching for quite some time. Good luck to the team from the UK but if any one realy interested in getting things done, perhaps all these individual groups should join forces. Just My 2 Cents
Faith_Healer -- The antethsis to almost everything, and the worlds worst speller.
I'm sure the phones will work at more or less any height - the higher the better. The problem is that at very high altitudes, the phone "sees" hundreds of cell base stations at once, and the system isn't really designed to deal with this. Even if one cell can decide it will take the initial call, cell switching will be occurring every few seconds as the signal strength fluctuates. The problem multiplies if you are crossing those cells at 500mph. Instead the on board mini-station grabs the call and keeps hold of it, allowing a single dedicated downlink to maintain sanity in the system.
At least this is my only partially-informed assumption (a long time ago I was a radio negineer, but I don't know about the actual implementation details of GSM.) But logically, allowing in-flight GSM phone calls is a bad idea because of the reasoning above. The system is designed on the assumption that calls will be made on the ground, therefore range-limited, and thus can only possibly be routed by one or two base stations, not hundreds.
For nearly half a century now we've know how to get into orbit using less energy than the brute force rocket approach. Space tethers are well understood technology that these guys could use to pick up a payload in "space" and swing it into orbit. Tethers that reach into the atmosphere are also possible but the math is just that much harder. Rockets are not the only way to space, they just require the least amount of in-orbit infrastructure. Once you have that infrastructure up there though, they really don't make a lot of sense.
How we know is more important than what we know.
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.
More likely you had too much signal. From altitude you tie up one RF channel on several dozen towers in range instead of running at reduced power on the closest tower. This blanket coverage of dozens of towers tying up a channel without the ability to hand your signal to a single tower and free up the frequency on other towers for use by others is why they don't permit phone use on aircraft. If the system is smart, it may have shut down your phone to clear the frequency as the towers noticed an even signal strength from one phone over dozens of towers. You simply did not get a tower assignment at altitude.
The truth shall set you free!
We did extensive drop tests to make sure that the payload wouldn't hurt anybody if it landed on them even if the parachute failed to open properly.
The casing is made of a type of foam that is very good at absorbing impacts, and the whole thing doesn't weigh very much.
If it landed on you with the parachute open you'd just brush it off. If it landed on you without the parachute you'd get a bruised head but would be okay.
Our launches are insured with £5m public liability cover. Arranging this insurance was quite difficult though.
"Studies have shown that people who eat peanuts live longer than those who do not eat."
We deliberately waited for a day when the jetstream was relatively calm, it was around 40 knots that day which isn't much at all. Also it helped that the low altitude winds were close to opposite the jetstream winds so it went west and then east. And we put quite a bit of excess helium in to get a rapid ascent rate, around 1000 ft/min. So it was up through the relatively shallow band of jetstream (20000~40000 ft) quite quickly. The winds above that are slow indeed. We started following it after it had reached about 28km on the ascent (we predicted that it should burst around 28-29km, the balloon ended up being a bit stronger than spec and it burst at 32km) and found it about 30 minutes after landing. The GPS is nice to have, it would have taken much longer to do it by radio direction finding. Anyway these things usually land in fields because there are lots of fields around, and despite the purple parachute they aren't blindingly obvious unless you're looking for them. So I don't think it's too likely that someone else would find it first. If they did, hopefully they'd be nice and call the phone number printed on it.
"Studies have shown that people who eat peanuts live longer than those who do not eat."