BLAST High Altitude Telescope Launched

Xandu writes "BLAST, the Balloon-borne Large Aperture Sub-millimeter Telescope, was launched on the 11th at 11:09 UTC from Esrange in northern Sweden, and is currently floating over Greenland. BLAST is a 2700kg telescope with a 2 meter primary mirror that hangs from a 1.1 million m^3 balloon floating at an altitude of 38km that will study the star formation history of the universe. It will float west at nearly constant latitude for about 5 days before the flight is terminated over northwest Canada or northern Alaska. Real time position and flight track is available from the NSBF. Two of the graduate students working on the project have photo blogs of the entire (8 week) prep period, including several launch photos. The press has more traditional coverage as well. And if that isn't geeky enough to make it on Slashdot, the flight computers run Slack."

in other news, NASA will lose all gov't funding...

[avi33]

...for their controversial and unproven theory about the star formation history of the universe.

They should just look this up in the Bible.

Duration - Why Not Longer?

[justanyone]

The BLAST mission is touted as being for a set duration, lasting 5 to 7 days. I'm a little confused why this time length was chosen. Why not let the thing just float there forever?

* Are all failure modes catastrophic?
* What is the primary failure mode? Loss of lifting gas?
* Is use of Hydrogen instead of helium an option? In carefully controlled operations, the additional risk might be worth the extra lifting capacity...
* Does H2 leak faster than helium (due to molecular size)?
* Is it difficult to create a parachute and floatation system to sheild the payload in various failure modes?
* What is the problem with just letting this thing float around until it doesn't ?
* Is battery power an issue and is the payload powered by thinfilm solar cells? Is power a limitation?
* What kind device or systems keep the orientation correct? Gyroscopes?
* If there are gyroscopes, are they a major percent of payload weight?
* What kind of ambient buffetting ocurrs at float altitude? Is there any percieved motion?
* Is the limitation of a baloon the internal-to-external pressure differential?
* What percent of the cost of the mission is the balloon, and what is the payload? Flight operations costs?

It would be cool if there was more data available on the BLAST website, but it's pretty scarce. Can someone contact them? Does anyone else know about this stuff?

Re:Sometimes Balloons are good enough

[Fyz]

Which reminds me of a cartoon in NYTimes at some point about NASA, outlining an idea of a major overhaul in their manned mission plan to replace the shuttle, consisting of hot air balloon missions that fly up to a certain altitude and throw out huge bags of hundred-dollar bills "to see if they swoop around in pretty patterns", because it:

1. is safer.
2. is cheaper.
3. has greater scientific payback.