NASA finds missing spacecraft using ground-based radar

Two unmanned probes lost in space have been located by NASA’s Jet Propulsion Laboratory in Pasadena, California. Too small to be seen with optical telescopes, NASA’s Lunar Reconnaissance Orbiter (LRO) and the Indian Space Research Organization’s Chandrayaan-1 spacecraft were found by ground-based radar stations using a pioneering radar technique that could help in planning future missions to the Moon.

OK, that’s a relief, The Lunar Reconnaissance Orbiter LRO wasn’t missing in the first place.

> The second spacecraft, Chandrayaan-1, went silent in 2009 and though the specifications of its orbit were well known, finding it was another matter.

I didn’t know that it was missing.

Any large spacecraft that went missing in Earth Orbit has already been spotted by radar. Anything that went missing beyond the Moon’s orbit and influence would be too far away.

So the breakthrough is in finding missing manmade objects near the Moon.

> Using the 70-m (230-ft) antenna at NASA’s Goldstone Deep Space Communications Complex in California, the JPL team fired a tight, high-powered radar beam at the Moon that was strong enough to send back meaningful signals across 237,000 mi (380,000 km) of space.

As radar pioneers know, the radar signal strength is proportional to the inverse fourth power of distance, not the inverse square law. Which makes using radar to find objects further away than the Moon Very tricky indeed. By way of contrast, communications with the Apollo mission on the Moon followed an inverse square law with distance so was very much easier.

How “tight” was this radar beam?

Anything missing near Mars?