India's Moon orbiter was shifted suddenly to avoid Korea's and NASA's craft
Apparently there's not enough space in space
The Indian Space Research Organisation revealed late last week that its Chandrayaan-2 moon orbiter has twice maneuvered to avoid potential collisions with similar craft.
The Indian craft raised its orbit on September 19 – two weeks before it would have made an uncomfortably close encounter with Korea's Danuri spacecraft, according to the Indian space agency’s monthly summary report [PDF].
While the collision-avoidance maneuver successfully allowed the space agencies to escape a very expensive fender-bender, a second maneuver was necessary – and was made on October 1 – to avoid collision with NASA's Lunar Reconnaissance Orbiter (LRO).
The three spacecraft all use orbits that pass over the Moon’s poles.
The LRO’s orbit is highly elliptical around the Moon, with an average altitude of about 50km, as it circulates to survey the entire lunar surface and search for water, ice and other resources.
Danuri studies the lunar surface, also looking at water and ice, from around 100km.
Chandrayaan also operates at 100km, from where it maps the lunar surface and conducts thermal imaging. Again, the goal is gathering data on water and ice.
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There's no formal protocol for when the orbits intersect. Dodging impacts relies on collaboration between the space orgs – in this case NASA, ISRO and Korea Aerospace Research Institute (KARI).
And near collisions do occur.
ISRO carried out another maneuver just days before it lowered Chandrayaan-2. The agency’s report also reveals that on September 16 it moved its Cartosat-2A Earth observation satellite to avoid a close approach with Russian rocket body SL-14.
As for Danuri, also often known as the Korea Pathfinder Lunar Orbiter (KPLO), it racked up over 40 potential collision warnings between February 2023 and May 2024.
"We monitor collision possibilities daily through the Multimission Automated Deepspace Conjunction Assessment Process (MADCAP) report provided by NASA JPL," explained [PDF] KARI earlier this year.
"Collision avoidance maneuvers require fuel consumption and temporary suspension of some payload missions, which may lead to differences in opinion regarding who should carry them out," the agency added. ®
Biting the hand that feeds IT
