Sunday, June 15, 2014

The International Sun-Earth Explorer-3

I loved this story in the weekend paper: Calling Back a Zombie Ship From the Graveyard of Space.

For 17 years, it has been drifting on a lonely course through space. Launched during the disco era and shuttered by NASA in 1997, the spacecraft is now returning to the civilization that abandoned it.

It's a wonderful story of long-term thinking and innovative use of modern technology.

Just consider this amazing outcome from a plan set in place 28 years ago:

After the successful Giacobini-Zinner flyby, ISEE-3 still had ample fuel, so three rocket burns in 1986 set it on a course to zoom about 30 miles above the surface of the moon 28 years later, on Aug. 10, 2014. The gravitational pull of the lunar flyby would swing ISEE-3 into orbit around Earth.

The astonishing thing is, it worked! Although, it may need a bit of refinement:

Mr. Wingo has now persuaded NASA to use the Deep Space Network to pinpoint ISEE-3’s trajectory, to calculate the rocket burn required to put it on a path to Earth orbit. Dr. Farquhar’s 1986 calculations were close, but not exact. Slight errors are magnified over time, and now the uncertainty is 20,000 miles, which means the spacecraft could be on course to splat into the moon.

So, in these days of frantic innovation, how do you manage to interoperate with a machine designed and launched more than 35 years ago?

Recent advances in what are called software-defined radios allowed the team to build a new transmitter and install it on the Arecibo telescope within a few weeks, much more quickly and cheaply than would have been possible a few years ago.

So cheaply, in fact, that large parts of the project were crowd-funded:

On RocketHub, a crowdfunding website, they asked for $125,000 to help pay the costs. They collected nearly $160,000, from 2,238 donors.

All in all, it's great news. You can follow the project on their Facebook page.

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