NASA prepares to crash probes into moon’s surface
A year-long mission to learn what lies beneath the lunar surface will culminate next week with Nasa crashing a pair of small robotic science probes into the moon, reports daily mail.
The twin Gravity Recovery and Interior Laboratory, or GRAIL, spacecraft will plunge into a mountain near the moon's north pole, a site selected to avoid hitting any of the Apollo or other lunar relics.
The impacts, which are not expected to be visible from Earth, will take place about 20 seconds apart at 10.28pm UK time on Monday.
'They're going to be completely blown apart,' GRAIL project manager David Lehman, with Nasa's Jet Propulsion Laboratory in Pasadena, California, told reporters on a conference call.
Almost out of fuel and currently flying just 7 miles above the lunar surface, the probes will make a final steering manoeuvre on Friday and shut down their science instruments in preparation for Monday's crash.
The two spacecraft, known as Ebb and Flow and each about the size of a small washing machine, have been flying in close formation around the moon for nearly a year to map the lunar gravity.
Scientists precisely measure the distance between the two, a figure that slightly changes as they fly over denser regions of the moon. The gravitational pull of the additional mass causes first the leading probe and then the following one to speed up, altering the gap between them.
Gravity maps from the first part of the mission, collected between March and May 2012 when the spacecraft were about 34 miles above the lunar surface, revealed the moon has a shallower and much more fractured crust than expected - the result of asteroid and comet impacts billions of years ago.
'We know that the moon had been bombarded by impacts but what we found is just how broken up and fractured the crust of the moon is,' said lead scientist Maria Zuber, with the Massachusetts Institute of Technology.
Similar bombardments happened on all the solid bodies of the inner solar system though the evidence on Earth has been erased by erosion, plate tectonics and other phenomena.
'With Mars, there's a questions about where did the water that we think was on the surface go,' Zuber said. 'These fractures provide a pathway deep inside the planet and it's very easy to envision now how a possible ocean on the surface could have found its way deep into the crust.' daily times monitor