Extreme Ultraviolet Explorer Runs Out Of Time

VCP writes: "NASA has decided that the Extreme Ultraviolet Explorer (EUVE) astronomical observatory is to be deactivated and de-orbited even though it is still working flawlessly and gathering valuable information. Why? Because NASA can't come up with $1M per year to support it. Shuttle launches cost what, $20-50M. It shouldn't be that hard to come up with $1M per year."

Comments

Not just money....

[bph]

The question is money well spent.

Most people don't realize how old some of these systems are. The EUVE was flown a long time ago and there are now two different instruments that provide similar capability, the Space Telescope Imaging Spectrograph on HST, and the Far Ultraviolet Spectroscopic Explorer.

The EUVE has been running for like 10 years, it is probably a good time for it to end (and Stu Bowyer to find something else to do).

Re:Why not bring it "up"?

[tesserae]

Not that easy, and here's why:

There are actually five points you are referring to, known as the Lagrangian points; they're where Earth's gravity and the Moon's gravity are equal, providing what's known as an equilibrium point. Three of them are in a line: one between the Earth and Moon, but much closer to the Moon than to Earth; one on the far side of the Moon from Earth; and one on the far side of Earth from the Moon. All three of these points are "unstable" equilibrium points, however -- the equivalent of balancing a marble on a basketball... there's an equilibrium point there, but the marble's not gonna stay put long.

The other two Lagrangian points are along the Moon's orbital path, but 60 degrees ahead of and 60 degrees behind the Moon's position; these are also knows as "Trojan" points, after the Trojan group of asteroids 60 degrees behind Jupiter in its orbit. These positions are stable: in fact, there's stuff there already, in slow orbits around the Lagrange points. These two points, BTW, are sometimes called "L4" and "L5", and there have been several proposals to put manned colonies there (too long a discussion for here, though).

L4 and L5 are stable, and are the ones you're talking about; but the problem is they're way out at the Moon's orbit, and that's almost as far energetically as putting the EUVE in a solar orbit. It's often been said (and very truthfully) that when you've made it to Lunar orbit, you're halfway to anywhere in the Solar Syatem. The bottom line is, EUVE can't get there.

A further comment: it's not so much that the EUVE needs to be reboosted to keep it going -- the $1M/year is for operational funding, just to support the people and hardware to track EUVE, keep it aimed at the desired targets, receive the data it transmits and suchlike. I remember when NASA decided to do the same with one of the Viking Mars landers after it'd worked for years past its funded lifetime: it upset enough people that some group (the Planetary Society, IIRC) collected the funding to keep it going privately, even though NASA gave up...

EUVE just doesn't have the same publicity pull, though -- too bad for UV astronomy.

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