DRO-A and DRO-B
DRO-A and DRO-B — two Chinese Academy of Sciences satellites launched together on 13 March 2024 to test a distant retrograde orbit around the Moon, a large, stable orbit that circles the Moon in the opposite direction to its motion around Earth. Their rocket's upper stage failed and left them far short of their target and tumbling; still joined, they recovered, raised their own orbit and reached the Moon's distant retrograde orbit in July 2024 on a long, fuel-saving route. After separating in August they linked by radio with a satellite in Earth orbit to test navigation between the two. (The size of their orbit has not been published; it is drawn representatively, at DRO-A's position.)
Key facts
Mission & specifications
Mission
- Operator
- Chinese Academy of Sciences
- Launched
- March 13, 2024
- Status
- Active
Trajectory
- Distance from the Sun
- 1 AU
- Computed from the cached position
- Distance from Earth
- 0.295 AU
- Computed from cached positions
- Distance from Venus
- 0.333 AU
- Computed from cached positions
Mission
A distant retrograde orbit circles the Moon at tens of thousands of kilometres, in the opposite direction to the Moon's own motion around Earth, and the pull of Earth keeps it stable for years with little fuel. The Chinese Academy of Sciences launched DRO-A and DRO-B, still joined together, on a Long March 2C from Xichang on 13 March 2024 at 12:51 UTC to test using one. The rocket's upper stage failed: the pair reached an apogee of only 134,000 km instead of 292,000 km, tumbling fast, with solar wings damaged. Controllers stopped the tumble within hours and, over the following weeks, raised the orbit with the satellites' own engines. Then, using the pull of Earth and the Moon on four passes of each, they reached the distant retrograde orbit on 15 July 2024, about 123 days and 8.5 million km after the failure, the Academy said, on about a fifth of the usual fuel. The two separated on 28 August 2024 and photographed each other, and on 30 August linked by radio with DRO-L, a satellite launched into Earth orbit a month before them, to form the first network of its kind: three hours of links between the satellites fixed their orbits as well as two days of tracking from the ground. DRO-A stayed in the distant retrograde orbit; DRO-B later moved to other orbits between Earth and the Moon for further tests.
- 2024DRO-A and DRO-B launch on a Long March 2C rocketLaunch
The upper stage fails, leaving them far short of their target orbit.
- 2024In the Moon's distant retrograde orbitArrival
123 days after the failure, on a long, fuel-saving route.
- 2024The two satellites separateMilestone
And photograph each other.
- 2024Linked with DRO-L in Earth orbitMilestone
The first network of its kind.
Images
No openly licensed image of DRO-A or DRO-B has been found.