NASA’s Kepler Space Telescope is in Emergency Mode — and it may be OK.
Interesting. Kepler’s on the blink. About three days ago, NASA mission scientists discovered that it had dropped into Emergency Mode. Now, going into a safe mode don’t necessarily mean the end. This happens to spacecraft from time to time. Even low-Earth-orbit is a hostile neighbourhood, but Kepler’s in much the same orbit as Earth, trailing it by a goodly distance, so it doesn’t benefit from the protection of the Earth’s magnetic field. It’s in open space.
Without any protection but its own shielding, being hit by everything the Sun’s throwing, plus cosmic rays and X-rays and the like from farther afield, Kepler’s in a vary harsh radiation environment, and systems do crash or fail.
Like almost all spacecraft, Kepler detects problems in its systems, and can put itself into various kinds of “safe modes”. These give Earthbound analysts a chance to download logs, and send commands to bring it back up again, system by system, until the extent of the damage (if any) is known. Then, a plan can be developed to bring it back into service or — if worst comes to worst — to decommission it.
Even if it is the end of the road, it’s been an incredible road. Operating for more than twice its original mission length, and even after two of its reaction wheels (which manage its direction) failed, Kepler has found more than a thousand confirmed planets orbiting other stars. A “K2” mission was evolved, to use the light pressure from the Sun as a kind of third reaction wheel. Kepler was about to be tasked, under K2, to look for gravitational lenses to find yet more, farther away.
Here’s hoping Kepler can be returned to an operating state, and complete its K2 mission, which finishes this year.