Radar imagery acquired of the Chandrayaan-1 spacecraft as it flew over the moon’s south pole on July 3, 2016.NASA/JPL-Caltech
NASA’s Jet Propulsion Laboratory (JPL) has found two missing unmanned spacecraft orbiting the Moon. NASA has successfully located India’s first lunar satellite, the Chandrayaan-1, which lost contact with Earth control eight years ago and the Lunar Reconnaissance orbiter.
As explained by experts, finding spacecraft and space debris orbiting our planet is a technological challenge, and this task is even more complicated when we talk about our moon. This is due to the brightness of the Moon, which prevents optical telescopes from identifying smaller objects.
In order to easily detect this type of objects lost in space, NASA has developed a new interplanetary radar that has allowed researchers to find the two spacecraft in lunar orbit.
The unmanned spacecraft are the Lunar Reconnaissance Orbiter (LRO), launched by NASA in 2009, and the Chandrayaan-1, which belongs to the Indian Space Research Agency, their first mission to the Moon which launched in 2008.
In addition to the time that passed since the last contact with the Indian probe, the size of the probe has also not been of help to the researchers which say that spotting the Chandrayaan-1 was a difficult task. The Chandrayaan-1 is only around 1.5 metres (5 feet) on each side, so from Earth it would be less than a tiny speck around the Moon.
“Finding LRO was relatively easy, as we were working with the mission’s navigators and had precise orbit data where it was located,” said Marina Brozovic, a radar scientist at NASA’s Jet Propulsion Laboratory (JPL).
“Finding India’s Chandrayaan-1 required a bit more detective work because the last contact with the spacecraft was in August of 2009.”
To make the discovery, experts first came up with their best predictions as to where the Chandrayaan-1 might have been located. Based on data where the spacecraft was last heard from, their best guess was that the Chandrayaan-1 would be some 200 km above the Moon, situated in a polar orbit.
After estimating its position, experts ‘beamed microwaves towards the moon’s north pole, some 380,000 kilometers away, using the huge antenna at NASA’s Goldstone Deep Space Communications Complex in California, and waited for them to bounce back, reports Science Alert.
Experts say that if any small spacecraft crossed the path of the microwaves, they could detect them. Luckily, this is exactly what happened—the team detected a small spacecraft crossing the microwaves twice in around four hours, the same orbital period that Chandrayaan-1 was predicted to have.
Experts continued tuning into the radars in order to understand the spacecraft’s current orbit and position. They found that it barely had shifted in the almost eight years it had been adrift by itself.
“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, manager of JPL’s Solar System Dynamics group.
“But otherwise, Chandrayaan-1’s orbit still had the shape and alignment that we expected.”
NASA scientists believe that this new technique could play an important role in future missions to the Moon as both a tool to assess the danger of collision and a safety mechanism for spacecraft encountering navigation or communication problems .