Image credit: NASA/JPL-Caltech/MIT

Image credit: NASA/JPL-Caltech/GSFC/ASU

Their fate is now sealed.

NASA’s twin Gravity Recovery and Interior Laboratory (GRAIL) spacecraft are en route to a ruinous ending.

The trajectory of both spacecraft have been modified, with each slated to impact the moon on Monday afternoon, Dec. 17, at about 2:28 p.m. PST (5:28 p.m. EST).

On trajectory now, the two probes – named Ebb and Flow — will slam into an unnamed mountain near the moon’s north pole. Both spacecraft will hit the surface at 3,760 mph (1.7 kilometers per second).

No imagery of the impact is expected, because the region will be in shadow at the time.

The GRAIL spacecraft have been orbiting the moon since Jan. 1, 2012. The duo’s successful primary mission yielded the highest-resolution gravity field map of any celestial body.

Lockheed Martin Space Systems in Denver built the spacecraft.

The event will be broadcast on NASA Television and streamed on the agency’s website.

NASA TV streaming video, schedule and downlink information:

http://www.nasa.gov/ntv

By Leonard David