NASA Radar Locates India's Missing Lunar Orbiter Chandrayaan-1 After 8 Years

A team of scientists from NASA's Jet Propulsion Laboratory claims that they have found a long lost lunar orbiter of the Indian Space Research Organization.

The lunar orbiter, named Chandrayaan-1, studied the moon from October 2008 to 2009. According to Space, India has lost contact with the tiny moon probe last August 2009. Now, scientists at NASA-JPL have successfully located the spacecraft using a new technological application of interplanetary radar.

The use of interplanetary radar in the field of astronomy is not new. However, it was only used to observe small asteroids several millions away from Earth and was not yet tested to detect much smaller objects, such as the Chandrayaan-1.

To search for the missing lunar probe, the scientists first calculated the present distance of Chandrayaan-1 from the moon's surface. Knowing that the spacecraft is in polar orbit around the moon, the scientists pointed NASA's 230-foot antenna at NASA's Goldstone Deep Space Communications Complex in California at a location about 100 miles above the moon's North Pole and blasted a powerful beam of microwave.

The NASA scientists then waited for the radar echoes bounced back from lunar orbit to be received by the 330-foot Green Back Telescope in West Virginia. Their calculations predict that Chandrayaan-1 takes about two hours and eight minutes to complete an orbit.

The researchers observed that a radar signature of a tiny spacecraft did cross the beam during four hours of observation. Furthermore, the timing of the detection matched the time it would take for the small lunar orbiter to go around the moon and return to the same position above the moon's pole. Using the data from the return signal, NASA estimated the current velocity and distance of the Chandrayaan-1.

"It turns out that we needed to shift the location of Chandrayaan-1 by about 180 degrees, or half a cycle from the old orbital estimates from 2009," said Ryan Park, the manager of JPL's Solar System Dynamics group, in a press release. "But otherwise, Chandrayaan-1's orbit still had the shape and alignment that we expected."

Follow-up observations using the Arecibo Observatory in Puerto Rico, which has the most powerful astronomical radar system on Earth confirmed that the radar echoes coming from the moon came from a small spacecraft that is in perfect sync with the new orbital predictions for the Chandrayaan-1.