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Private Efforts Fill Gaps In Earth's Asteroid Defenses
Hugh Pickens sends us to Seed Magazine for an update on Earth's defenses against collisions with near-earth objects (NEOs). The bottom line is that government is moving slowly on cataloging NEOs but private bodies are picking up some of the slack. "In 2005, the US Congress directed NASA to catalog 90 percent of potentially hazardous NEOs greater than 140 meters in diameter by the year 2020 but NASA has yet to allot funds to the project. Increasingly, coordinated private efforts are working to fill the gap in Earth's NEO defenses. Earlier this year, Bill Gates and Charles Simonyi donated a combined $30 million to the Large Synoptic Survey Telescope (LSST), keeping it on track for first light in 2014. LSST will survey the entire visible sky deeply in multiple colors every week with its three-billion pixel digital camera, probing the mysteries of Dark Matter and Dark Energy and by opening a movie-like window on objects that change or move, the LSST will also detect and catalog NEOs."
Check out Orbital Debris Quarterly News at http://orbitaldebris.jsc.nasa.gov/newsletter/newsletter.html They have back issues in pdf
Known near misses are published.
Not as bad as it sounds. The primary reflector is stationary, but the primary collector is movable. If you look closely, you'll notice that the Arecibo main dish isn't a perfect parabolic shape. Depending on where the rays are coming from, they're focused in different spots... move the collector, and presto - different part of the sky. No, it isn't quite as flexible as a fully movable one, but it isn't fully stationary either.
Those who can, do. Those who can't, sue.
In 2005, Congress Directed NASA to go do the work. No, they didn't just sit on the money. As a part of this work, Congress sent a few million to the Air Force to manage the University of Hawaii's NEO detector project, PanSTARRS.
The planning kicked off at about the same time as the LSST, but being significantly cheaper and using off the shelf optics with custom gigapixel detectors, a testbed has already been deployed on Maui. When the full system is deployed atop Mauna Kea on the island of Hawaii, it'll include four scopes ganged together, putting 4 X 1.4GPix on a patch of sky. The redundant detectors allow for added error correction from bad pixels, cosmic ray strikes, and whatnot.
Now that the LSST has some significant seed money, we may soon be able to reap the benefits of two panoptic sky survey systems. That's going to be a hell of a lot of near-real time data processing.
Luke, help me take this mask off
Except that you wouldn't find all of them in that survey. They're only easy to spot when they're nearby; for the dangerous ones, in orbits similar to Earth's, that only happens every few years. For the rest, you'd have to hope that it happened to be close by when you were surveying the right piece of sky. You also have to get several images of an asteroid to start computing even an approximate trajectory -- 3 images is a minimum, but that would give awful error bars. Sure, you can go follow up on everything that moved, but it would be nice if your original survey could distinguish at least something about how relevant the asteroid is.
Also, this is a job that's reasonably well suited to terrestrial telescopes, AIUI. No need for a special orbiting scope when you can get better pictures for less money from the ground.
It's a lot of money compared to spending nothing, but as a percentage of the budget it's less than almost any other developed nation spends.