Scientists at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California have found Chandrayaan-1, a lost lunar spacecraft.
A team of JPL scientists used a new radar technique to search for two spacecraft. NASA named the two spacecraft as the Lunar Reconnaissance Orbiter (LRO) and the Chandrayaan-1 spacecraft in lunar orbit.
NASA launched the reconnaissance orbiter on an Atlas V rocket on June 18, 2009. The spacecraft conducted the mapping of the moon’s surface.
On the other hand, the Indian Space Research Organization launched Chandrayaan-1 on October 22, 2008. Nearly a year later, the ISRO lost communication with the spacecraft on August 29, 2009. The agency then concluded the spacecraft’s mission.
The NASA scientists easily found the LRO since they worked with the mission’s navigators, said Marina Brozović, a radar scientists and principal investigator for the test project.
Search For Chandrayaan-1
However, spotting the ‘lost’ Chandrayaan-1 took time, Brozović said. Also, the cube-shaped spacecraft’s small size at about five feet or 1.5 meters high contributed to the delay in identifying it.
In the past, scientists used interplanetary radar to observe small asteroids several millions of miles from Earth. But researchers have yet to use radars to detect small-sized objects as far away as the moon. They then decided to locate Chandrayaan-1 to determine if they could do this. The team estimated the spacecraft’s location at around 237,000 miles (380,000 kilometers) away from Earth.
The test projects started on July 2, 2016. The project team directed an antenna from the Goldstone Deep Space Communications Complex and Green Bank’s 100-meter (330-foot) Telescope towards a location about 100 miles (160 kilometers) above the moon’s north pole. The team wanted to see if the lost spacecraft would cross the radar beam.
Using the antenna at Goldstone, scientists at NASA beamed microwaves towards the moon. The team then tapped the Green Bank Telescope in West Virginia, using it to receive radar echoes that bounced back from the lunar orbit.
Spacecraft Changed Location
The JPL team had to shift the location of Chandrayaan-1 by about 180 degrees, said Ryan Park, manager of JPL’s Solar System Dynamics group. The spacecraft’s present location appeared to be half a cycle from the old estimates from 2009, Park explained.
“But otherwise, Chandrayaan-1’s orbit still had the shape and alignment that we expected,” he added.
The test project for Chandrayaan continued for several months. It found that the radar echoes from the spacecraft agreed with the new orbital predictions.
The Arecibo Observatory in Puerto Rico, which has the most powerful astronomical radar system on Earth, also made follow-up observations to confirm the findings. The National Science Foundation, through funding from NASA’s Planetary Defense Coordination Office for the radar capability, operates the Arecibo Observatory.
Through the Chandrayaan-1 test project, the laboratory found they could use radar antennas at Goldstone, Arecibo and Green Bank to track even small spacecraft in lunar orbit.
NASA noted that ground-based radars could play a part in future robotic and human missions to the moon. Scientists could use the radars as collision hazard assessment tool. They could also tap the radars as safety mechanism for spacecraft that encounter navigation or communication issues.