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Huge Balloon Lofts New Telescope
Science Daily is reporting that a new solar telescope has been launched via an enormous balloon filled with helium. Dubbed project "Sunrise" the National Center for Atmospheric Research (NCAR), NASA, Germany's Max Planck Institute for Solar Physics, Spain's Astrophysics Institute of the Canary Islands, and the Swedish Space Corporation all partnered to launch the balloon in order to view never before see features of the Sun. "The project may usher in a new generation of balloon-borne scientific missions that cost less than sending instruments into space. Scientists also can test an instrument on a balloon before making a commitment to launch it on a rocket. The balloon, with its gondola of scientific instruments, was launched successfully on the morning of October 3 from the Columbia Scientific Balloon Facility in Fort Sumner, New Mexico. It flew for about 10 hours, capturing stable images of the solar surface and additional data from the various instruments of the sophisticated payload. The gondola then separated from the balloon and descended with a parachute, landing safely in a field outside Dalhart, Texas."
Though this sounds like a very interesting project, the use of balloons (and sounding rockets) for instruments that might later fly in space is not new. Cosmic ray studies have been using balloons for since 1912.
What may be new here is using balloons for instruments that need to be aimed precisely. Detectors on previous balloons were usually omni-directional, or could make measurements over large surface angles. Their Sun-tracking technology aiming sounds interesting, and I look forward to reading about their results
Preventive War is like committing suicide for fear of death. - Otto Von Bismarck
The payload (SUNRISE) is designed to carry a 1-meter telescope with a full complement of scientific instruments. This flight had a small (30 cm) stand-in telescope, to test the active pointing system, and a camera with a small array of narrowband filters, to see what wavelengths are visible from the flight altitude.
Strangely enough, some the components of sunlight at 120,000 feet altitude are not well known. Some interesting ultraviolet lines (the "h" and "k" lines from Magnesium) are thought to be visible there, that are not visible on the ground -- but nobody has yet characterized the ultraviolet absorption spectrum from the very upper layers of the stratosphere and from the mesosphere. Most telescopes that have flown so high were rocketing through on their way to space, rather than floating under a balloon. So this first flight was both to test the pointing (and other flight control) systems, and to double check that some desired wavelengths are present and usable at the target altitude.
Even the test flight of SUNRISE was a real accomplishment: it is far from the ideal of small, cheap, lightweight, quick-and-dirty payloads under scientific balloons, and is run more like a space mission both in terms of payload complexity and in terms of team management. The team is multinational and the payload is subject to rigorous engineering and testing.
The balloon flight environment is in some ways more harsh than the vacuum of space: payloads are subjected to wild temperature swings on climbout, and the thermal environment is not nearly as controllable as it is in empty space. On the other hand, launch and flight are very gentle compared to unmanned space shots.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
While the scope and precision of this project appears to be admirable and new, the idea of using balloons to loft telescopes is most certainly not, though the summary and article may both give that impression. They launch balloons in Antarctica all the time for astronomical observations (remember BOOMERANG?) and much of the initial attempts to view the universe through non-optical, non-radio wavelengths (the ones where our atmosphere is basically opaque) was done with balloons in addition to the sounding rockets.
Actually NASA still flies them occasionally for research. Or they did up until a few years ago at least. I suppose they could have been retired for real by now though. And even if your data is accurate about altitude (none of the SR-71 pilots I met ever confirmed anything higher than 85K) that's still 20,000 shy of the altitude the balloon reached. I don't know how much difference it makes because you can see space fairly clearly from anything above 80 or so.
"Growing old is inevitable; growing up is optional."
There are renewable resources (trees, etc.) and non-renewable resources (oil, etc.). But at least the raw elements of these resources stay around on Earth, and can conceivably be used again in the future for something else. In essense, the elemental composition of the earth has remained mostly constant for the past few billion years; it's only the molecules that the elements are bound up in and where that changes over time. Put it this way, if humans die off tomorrow, there'll be plenty of new oil for the insect overlords that evolve in a billion years, because the raw material for the oil is still churning around in the Earth's biological and geological systems.
But helium... well, helium is special. It has two interesting properties. Firstly, it is a very light element. Hydrogen and helium are so light that as individual atoms they freely escape the Earth's gravitational system and leak out into space. That means forever. Secondly, it is completely inert. It does not and cannot bind to any other molecule to weigh it down. This is in contrast to hydrogen, which is almost always bound up in a molecule of some sort. Thus, helium is the ONLY element that, when released into the atmosphere, will eventually leak out into space and be lost to the Earth forever. The only reason we have helium on Earth now is because a bunch of it is trapped in sand particles (that's where we mine it from). But once we mine it and use it, it's gone. And I mean gone gone. Deep space gone. Helium is the second-most abundant element in the universe (and the sun has a lot of it), but unless it's available on Earth, that fact is completely useless to us. We can't make new helium, other than through nuclear fusion of two hydrogen atoms. And that's not a manufacturing process we (or the future insect overlords) are ever going to undertake.
And this is all a great shame, too, since helium, being the lightest inert gas, is incredibly useful. I can't help but think that in a few hundred years (yes, I realize that it's probably that far away) humans will be kicking themselves for having blown helium in such great quantities in complete disregard for the fact that it could never, for the rest of humanity and beyond, be used again.
Think about that the next time you order a dozen helium balloons for your kid's next birthday party!