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NASA balloon launch destroys SUV

patchbunny

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patchbunny
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"A huge NASA balloon loaded with a telescope painstakingly built to scan the sky at wavelengths invisible to the human eye crashed in the Australian outback Thursday, destroying the astronomy experiment and just missing nearby onlookers, according to Australian media reports.

In dramatic video released by the Australian Broadcasting Corporation (ABC), the giant 400-foot (121-meter) balloon is seen just beginning to lift its payload, then the telescope gondola appears to unexpectedly come loose from its carriage. The telescope crashes through a fence and overturn a nearby parked sport utility vehicle before finally stopping."

Story and video can be found here.

For those in the know, how do you keep the balloon-mounted telescope from rotating off target?
 
I saw this on the news last night. I think the balloon was released before the balloon was fully inflated. I am suprissed that people and cars were allowed anywhere near the balloon.

NASA could also save heaps of money by using hydrogen instead of helium. The risk of fire is minimal.
 
I don't think under inflation is the primary cause of the problem.

It looks to me that they were launching in excessive wind. The tether from the envelope to the payload looked to be at an angle of at least 30 degrees from vertical. When the balloon is released in that configuration it's going to be have like a simple pendulum. In order to avoid the payload hitting the ground, the envelope would have to rise faster than the former falls. Envelopes do not do that.

One would not launch a passenger carrying hot air balloon if the wind was tilting the balloon at the angle I could see from the video. I've had landings like that, and they are *rough*.
 
I see your point. Then the design should allow for winds. There are a few options.

1. Launch at dawn or dusk when there is little wind.

2. Have a rope from the balloon to the ground, so that the rope that goes to the payload is vertical. At launch the payload is released first, which goes straight up. then the balloon.

3. Have a rope that goes from just above the payload to the ground. When the payload is released this rope is extended so that this accident will not happen. This rope would only be released when the payload is at a good height.

4. Launch from the ground with nothing close by so that even if the payload is dragged along the ground no damage is done.
 
rjh01 said:
I see your point. Then the design should allow for winds. There are a few options.

1. Launch at dawn or dusk when there is little wind.
Click to expand...
Yes, this is the normal approach for launching balloons. I don't know when the NASA launch was, but I presumed it was early morning.

2. Have a rope from the balloon to the ground, so that the rope that goes to the payload is vertical. At launch the payload is released first, which goes straight up. then the balloon.
Click to expand...
interesting idea, but which bit of the envelope? It's a vast object whose density is not very much different to the air in which it is floating. I suppose one could tether the base of the envelope, but I think there would still be some penduluming if that was released. I've never seen a balloon tethered that way -- you always tether the gondola.

3. Have a rope that goes from just above the payload to the ground. When the payload is released this rope is extended so that this accident will not happen. This rope would only be released when the payload is at a good height.
Click to expand...
again, an interesting idea. Not something I've seen.

4. Launch from the ground with nothing close by so that even if the payload is dragged along the ground no damage is done.
Click to expand...

good luck finding such a place :)
 
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did anyone notice the crane when the telescope broke free? It slid in the opposite direction, on it's hydraulic supports. Is that normal?
 
At one point, during my career with NASA, I participated in a balloon borne project out of the Columbia Scientific Balloon Facility (CSBF) in Palestine, Texas. see http://www.csbf.nasa.gov/index.html for some pictures of that operation.

Launching at Palestine, the payload is suspended by a mobile crane that moves downwind to stay under the balloon until lift off. It's not clear to me from the video whether this was what they were attempting at Alice Springs. I think not.

Re telescope pointing, details depend on the nature of the experiment. Ours was extreme. The project was to study the particle physics of high energy radiation from solar flares. We required to point at selected regions on the sun with about an arc minute field of view -- roughly 1/15 solar diameter. Our imaging device had sub arc second resolution, so fine pointing control was crucial.

We used an on board compass to point the instrument approximately toward the sun. A coarse sun sensor, consisting of an ordinary video camera with a wide angle lens, picked up the solar disk, centered it, then passed control to the fine pointing system: an array of three very long lenses, each projecting different parts of the solar limb onto a linear diode.

Adjustments in azimuth were made by a motor driven pivot between the balloon and gondola. Of course, since the whole thing is floating, the balloon and payload both turn, in opposite directions, which doesn't matter at all to the pointing device.
 
OK, had a better look after a3sigma posted. Doesn't look like the supports were lowered. Perhaps the crane was moving prior to the video starting, and we got to see when the wind drag was cancelling out the crane power, and then the crane continuing to move after release.
 
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