Japanese Probe Returns to Earth

This probe gathered a lot of attention, at least on the Japanese interwebs in the past few months as it neared its delayed and much awaited return.
To sum it up in a sentence, the story of this probe can be said to be the Apollo 13 of unmanned probes.

After a successful launch, it suffered
- the breakdown of 2 out of its 3 reaction wheels (weighted wheels that spin inside to change the orientation of the craft)
- loss of all chemical thrusters including a burst fuel tank that spilled it all over the innards of the probe.
- 4 of 11 lithium battery banks
- loss of communications for a 2 month stretch
- temporary loss of 3 out of 4 ion engine units

But somehow, the folks of JAXA (Japan Aerospace eXploration Agency) coaxed it back to life through crazy improvisation and the craft held together due to the insane redundancy built into it during design. Tricks like expelling xenon propellant for the ion engines from a side valve to stabilize the tumbling craft, using radiation pressure from solar light on the solar panels (pioneering principles with solar sails) to orient the craft, very gradually nursing the discharged batteries back to life (lithium batteries are light and powerful but tend to explode when charged improperly), using cross-connected back-up circuits to bypass failed components and keeping the ion engines alive, were some of the more remarkable feats.

The craft was originally scheduled to drop off the capsule containing the asteroid sample in the Australian desert and then be recovered in orbit. But all the roadblocks forced it to change its trajectory and delay its return by years, which in turn left no option but to burn up on reentry after releasing the capsule.

With the dramatic cliff-hangers and successful (but tragic) ending returning home, the story of this probe really caught the imaginations and empathy of many people.

Here’s a nice video that sums it up made back in January (and translated into Engrish). The Space Battleship Yamato (Starblazers) theme is a nice touch.
http://www.youtube.com/watch?v=nDbc3AcBHIM