Just shy of a full year encircling the moon, NASA’s twin lunar probes are bidding farewell on Monday, crashing in a controlled fashion into a small mountain-like formation at the moon’s north pole.
The GRAIL twins, nicknamed Ebb and Flow, are almost out of fuel and their lives would come to an end anyway--but rather than let them fall out of the lunar sky, as it were, NASA is performing a kind of spacecraft euthanasia.
“It’s kind of sad for me,” said David Lehman, GRAIL’s project manager at the Jet Propulsion Laboratory in Pasadena, in a phone call with journalists. “I’m hoping tonight a gas station will pull up next to our spacecraft, refuel it, and we can continue another 6 months. But I don’t think that’s going to happen.