Issue 42

Chinese Spacecraft is Testing Out a New Lunar Orbit

15 Feb 2022: Amateur satellite tracker Scott Tilley (noted previously) and others, have been following Chang'e-5's travels through space and provide evidence for the new lunar orbit following months of observations. See Video on Scott. - A spacecraft involved in China's 2020 Chang'e-5 lunar sample-return mission (…

15 Feb 2022: Amateur satellite tracker Scott Tilley (noted previously) and others, have been following Chang’e-5’s travels through space and provide evidence for the new lunar orbit following months of observations. See Video on Scott.

– A spacecraft involved in China’s 2020 Chang’e-5 lunar sample-return mission (Video) is now in a unique orbit around the Moon, more than a year after completing its primary mission.

– The service module, which played a large part in delivering 1.731kg of fresh lunar samples to Earth in December 2020, is now in a distant retrograde orbit (DRO) of the moon.

– A distant retrograde orbit allows a spacecraft to interact with two gravitationally stable areas in front of and behind the moon with respect to the Earth. The spacecraft’s distance from the moon means it orbits only once every couple of weeks.

– Such an orbit has not been used before but is planned for NASA’s upcoming Artemis 1 mission later this year.

– After releasing the capsule containing samples collected from Oceanus Procellarum, the orbiter itself continued its journey away from Earth, heading for the Sun-Earth Lagrange point 1, roughly 1.5 million kilometers away. The spacecraft is using extra fuel due to the precise initial orbital injection by the Long March 5.

– It is unclear what China is planning with the DRO test, but Chang’e lunar missions have earlier been sent on extended missions to add value or even as important tests for later missions.

– Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center, stated that he believes China is probably using the Chang’e-5 spacecraft gaining experience with astrodynamics. “They are using it as a toy to play around with. It is clearly useful as a stable lunar orbit for future missions, I just don’t think it’s a specific precursor.”

– Currently the Chang’e-5 is orbit has a an apogee of 456,772km and a perigee of 190,986km.

Most lunar orbits can be rather unstable due to the moon’s mass concentrations, and require periodic station keeping (fuel). A DRO offers a stable (decades+), low cost place to park spacecraft or an asteroid (for future mining) for that matter.

Chang'e 5 Family Photo.

Earth & Moon as viewed from Sun-Earth Lagrange Point, April 2021.

Chang'e 5 Orbiter as viewed from Equator (Geostationary Orbit also depicted).

Chang'e 5 Orbiter as viewed from Pole (Geostationary Orbit also depicted).