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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.
Consumers don't NEED them at all. They're there so the airlines can make a buck.
Anyone familiar with the story of flight 93 knows that cell phones work at the cruising altitude of commericial jet aircraft.
Lee
Muslim community leaders warn of backlash from tomorrow morning's terrorist attack.
Sending rockets out into space is pretty easy, but the real trick is orbit. Cheap shots to the upper atmosphere don't do a lot of good in terms of launching satellites and other objects into orbit, although I'm sure they can provide experience with the technology. Achieving orbit requires a lot more energy. There's a reason missiles and rockets are the size they are.
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.
On the flip side, the phone can't deal with dozens of control signals from dozens of towers on the same channel. Normal operation a phone sees a control channel from several towers nearby on several frequencies. These control channels get geographly re-used. At altitude it's the ability to see many towers on the same frequency at the same time scramples the signal to the phone and breaks the phone ability to lock on to a control signal. This is the sudden loss of signal bars seen on an airbone phone. Too many towers in view at close to the same signal strength and on the same channels as each other.
The truth shall set you free!
For this balloon thing though, could put the GSM unit into a downward facing pringles tube, increasing the signal strength, narrowing the transmitted area, and sticking to their "cheap, very very cheap" idea :-)
The revolution will not be televised... but it will have a page on Wikipedia
I actually worked in the same lab as these guys, so here's my input: The reason that this was an important launch was not the photos, although those are cool, but to test the electronics of the tracker devices they'dd designed and built. If you read their website at http://www.cuspaceflight.co.uk/ you'll see the other projects - the rocket to space, but also a controllable parachute that can descend to within 100m of a given location. All fairly impressive stuff, given that they've only jsut finished their 1st year of study. As for costs - only a couple of hundred pounds...
Acceleration through gravity has nothing to do with terminal velocity. It describes how fast the falling body reaches its terminal velocity. The speed at which it will fall is where the forces from gravity meet the countering forces from air resistance. The payload will accelerate to a very fast speed at altitude, but slow down gradually as the density of air increases and therefore the air resistance increases. This is not a situation when you can do simple calculus with 9.81 m/s^2 and ignore air resistance.