Thanks to a new radar technique employed by NASA, India's first lunar probe that went missing about eight years ago has finally been found.
Chandrayaan-1
The Indian Space Research Organisation launched its first moon probe Chandrayaan-1 in October 2008 but less than a year after the spacecraft successfully entered lunar orbit, technical problems started to emerge. By August 2009, controllers lost contact with the spacecraft.
After about eight years, however, NASA found the probe again. The spacecraft was detected maintaining a lunar orbit 124 miles above the moon surface. The long-lost Indian probe was found using powerful radar beamed from Earth.
Scientists used antenna at NASA's Goldstone Deep Space Communications Complex to beam microwaves toward the lunar orb. They also used the Green Bank Telescope to study the radar echoes that bounced back to Earth, as well as observations from the Arecibo Observatory.
What made the discovery of the lost lunar probe more interesting is the size of Chandrayaan-1. It is tiny, measuring only 5 feet wide.
Besides Chandrayaan-1, scientists also found the Lunar Reconnaissance Orbiter using the the new radar technique - not necessarily because it was lost, but as a proof of concept since the LRO is an active spacecraft.
"We have been able to detect NASA's Lunar Reconnaissance Orbiter and the Indian Space Research Organization's Chandrayaan-1 spacecraft in lunar orbit with ground-based radar," said Marina Brozovic, a radar scientist from NASA's Jet Propulsion Laboratory and the test project's chief investigator.
STEREO-B Spacecraft
It is not the first time that a missing spacecraft was found. In Aug. 21, the U.S. space agency announced that it was able to re-establish contact with the STEREO-B spacecraft, which was lost in October 2014. The probe was one of the two nearly identical spacecraft NASA launched to orbit the sun.
The team behind the solar observation mission attempted to re-establish contact with the spacecraft for 22 months. Finally, with a monthly recovery operation that tapped NASA's Deep Space Network, or DSN, that tracks and communicates with space missions, scientists were finally able to re-establish communication with the probe.
Beagle 2 Lander
In 2015, A NASA spacecraft also found the European Space Agency's Beagle 2 lander, which lost contact after it set down on the red planet in December 2003. NASA's Mars Reconnaissance Orbiter, which was designed to conduct reconnaissance and exploration of the red planet from orbit, spotted the remains of the long-lost spacecraft from space. The missing lander was found lying with its solar panels partially deployed and 3 miles away from its intended landing site.
Philae Lander
Most recently, ESA's Philae lander also went missing after it made a historic landing on a comet. It was found by the camera aboard the Rosetta probe, its mothership, that was orbiting comet 67P/Churyumov-Gerasimenko. The spacecraft was found wedged into a dark crack on the surface of the comet.
"While most candidates could be discarded from analysis of the imagery and other techniques, evidence continued to build toward one particular target, which is now confirmed in images taken unprecedentedly close to the surface of the comet," ESA said after the missing lander was found.
