Ebb and Flow, two spacecraft that have been investigating the moon's gravitational field, will end their existence by smashing into the moon's north pole next week. The event is not likely to be visible from Earth, but the Lunar Reconnaissance Orbiter may catch a glimpse.
After nearly a year circling the moon, NASA's Ebb and Flow will meet their demise when they crash — on purpose — into the lunar surface.
Just don't expect to see celestial fireworks. Next week's impact near the moon's north pole by the washing machine-sized spacecraft won't carve a gaping crater or kick up a lot of debris. And it'll be dark when it happens.
"We are not expecting a big flash or a big explosion" that will be visible from Earth, said mission chief scientist Maria Zuber of the Massachusetts Institute of Technology.
Still, it'll mark a violent end to a successful mission that has produced the most high-resolution gravity maps of Earth's closest neighbor. On Friday, engineers will turn off the science instruments in preparation for Monday's finale.
Previous unmanned trips to the moon have studied its lumpy gravitational field, but Ebb and Flow are the first ones dedicated to this goal. Since entering orbit over New Year's weekend, the formation-flying spacecraft have peered past the craggy surface into the interior.
Initially, the spacecraft flew about 35 miles (56 kilometers) above the surface and later dropped down to 14 miles (22 kilometers). About an hour before Monday's impact, they will fire their engines until they run out of fuel and slam at 3,800 mph (6,115 kph) into a predetermined target — a mountain near the north pole that's far away from the Apollo landing sites.