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Recycled Satellite Yields Scientific Treasure
Rob (not Malda) sent us this story about how UC Berkeley astronomer Derek Buzasi found that a satellite with a malfunctioning main telescope had a perfectly functional "spotting" scope that could still be used to gather valuable data. Now, because of Buzasi's inspiration, the Wide Field Infrared Explorer (WIRE) satellite NASA had written off as a $73 million piece of space trash is a useful astronomical tool that makes approximately 750,000 observations per day.
The problem is not with the material large enough for this to work with. The problem is with the material that is too small to even track, such as paint chips and naturally-occuring micrometeorites.
Christopher A. Bohn
cb
Oooh! What does this button do!?
The problem is it's not that simple. Add in orbital inclinations and eccentricities, and we no longer have a collection of bodies that pose no possible threat to each other.
Granted, in most conceivable scenarios, there won't be a "head-on" collision (the only conceivable scenario would be two bodies in near-polar orbit), but you don't need to have a "head-on" collision to cause damage.
Christopher A. Bohn
cb
Oooh! What does this button do!?
Plans for shuttle operations out of Vandenberg were canned when the DoD decided it wasn't going to rely on the shuttle for its launches. SLC-6 has since been turned into a commercial launch facility.
Christopher A. Bohn
cb
Oooh! What does this button do!?
... reducing astronomical data often can't be sped up by throwing more processors at the job. The Seti system is a case where the data reduction is straight forward, so it can be distributed easily. However, an astronomer often has to make adjustments to the data analysis process by hand, for each target or each set of targets, depending on the observing conditions and what you'd like to know about the target.
:) I'm sure scientists will start to ask for your help more and more over the next few years... and maybe, depending on the methods involved, this will be one of next distributed projects.
Perhaps the sort of data their getting from all their targets is similar, and can be reduced using the same method. Perhaps, though, their looking for different things from different targets, so a general enough distributed method that is convenient for the astronomer is difficult to design.
I'm glad people would like to participate in distributed data reduction and scientific computing. I think it's a heck of a lot more useful to society that cracking one of an infinite set of code keys.
Hope this sheds some light on things!
John
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The telescope itself is working perfectly, but it isn't cold enough.
There's two things that I can think of, and I'm not sure which applies here. Maybe both of these reasons apply.
The first is keeping the photon detectors cold enough so that electronic noise doesn't wipe out the image. If you've read about sidewinder missles that track heat from airplanes, then you would have read that they carry a store of a cryogenic fluid (liquid nitrogen??) to cool the detector. That's because at room temperatures there's enough energy to cause atoms in the detector to jump back and forth between high and low energy states. Looking at that on a display would be like looking at a snowy picture. Cooling the detector down stops that random jumping around, and atoms only move to the higher energy state when a photon hits them. The picture would be cleared up.
The second reason is that the telescope itself emits infrared radiation, and that emission from the telescope itself would cause the image to be washed out completely. If you can cool the telescope down with liquid hydrogen then the very very faint infrared sources won't be washed out by the heat from the telescope. As an analogy, imagine how bad the image would be if you mounted flashlights inside an optical telescope and tried to look at stars. You wouldn't see anything.
If tits were wings it'd be flying around.
This is an obvious plug. We're a small company and don't have our named mentioned all that often. The star tracker (as it is really called) was built by Ball Aerospace. It is the Ball CT-601 model tracker with a 7.5in shell and 92mm lens, so I'm told.
Our trackers are used all over the place, so perhaps other spacecraft can be used similarly.
Needless to say, our star tracker folks are excited.
~afniv
"Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
~afniv
"Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
Richard von Weizs
It's undoubtably super news that there is an aspect of the satellite that may prove useful. Having any telescope in space, even one as small as this spotting scope is astonishly great for calibrating ground-based telescope observations which need to be made through miles of crud in our atmosphere.
But while this is a small improvement on what would have been a total loss, it is certainly not going to be free. For every active satellite (or even any active ground-based telescope to a lesser extent), there is a substantial expenditure in maintainance and data processing. For a satellite a large part of the price comes from ground operations, including issuing commands and maintaining a downlink station to receive the data as it comes in.
More information for the confused: Why is a tiny telescope (2 inch diameter) in space such a big deal? After all, anyone could pay about $200 and buy a telescope from a department store with equivalent light collection power. The key is that any telescope in orbit is above terrestrial weather. Measuring stellar brightness and color (which in turn yield info about a star's age, mass, distance, etc) is difficult from the ground because the atmosphere is not transparent. Weather makes the transparency change on short timescales, so a star's brightness appears to change rapidly. This is especially difficult for an astronomer who wants to study stars which have intrinsically variable brightness.
In short, a little satellite-borne telescope is a stable instrument for consistent work, like all those 386's running Linux and serving web pages out there.
It's amazing how bad the space trash problem is getting up there. And every little speck of debris is a serious problem.
Every time the Space Shuttle goes up, they have to replace the glass, and many of the panels, due to collisions with tiny particles. Even something the size of a grain of sand can cause a visible pit. A 1" screw in a head-on collision could possibly cause a hull breach.
Remember that everything in orbit is going about 16,000 mph. A head-on collision means that screw would be hitting at 32,000 mph. An article in a recent Smithsonian went into detail about how they are designing armor for the International Space Station to try and withstand this - they've developed, for this purpose, a very high velocity gun that can shoot a projectile at about 25,000 mph. At this speed, a 1/2" diameter sphere will blow a head-sized hole in 1-inch steel.
Personally, I'm amazed at the fact that astronauts will still go on space walks. The microdebris alone could easily kill them.
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"You know your god is man-made when he hates all the same people you do."