On February 11, 2015, NASA’s DSCOVR spacecraft (originally nicknamed GoreSat) was launched to the Sun-Earth L1 point by a SpaceX Falcon 9 v1.1 rocket. The Falcon 9’s upper stage inserted DSCOVR into a lunar flyby trajectory which would assist it in reaching L1, performed a short avoidance burn to guard against re-contact with the payload, and shut down, leaving it in an unstable high Earth orbit subject to perturbations from the Earth, Moon, and Sun.
DSCOVR upper stage
Further analysis by Bill Gray shows that the DSCOVR mission’s Falcon 9 upper stage, abandoned since 2015, will actually impact the lunar farside at around 1222 UTC Mar 4.
NOAA’s DSCOVR space weather mission was launched on 2015 Feb 11 to the Sun-Earth Lagrange 1 point (SEL1). The SpaceX Falcon 9 upper stage injected it to a 190 x 1244000 km x 37.0 deg transfer orbit and then made a small avoidance burn which left it on a lunar flyby trajectory, At this point the stage’s batteries would run out and it’s been space junk ever since. It flew 18242 km from the Moon at 2037 UTC 2015 Feb 13, which swung it into a 350000 x 565000 km x 57.4 deg deep Earth orbit in the outer part of the Earth-Moon system. The perigee was close to lunar distance, making eventual further lunar encounters inevitable. Orbits like this are somewhat chaotic, their orbital parameters strongly affected over time by lunar and solar gravity as well as the Earth. Further lunar flybys occurred: 23573 km on 2016 Jan 17, and 9312 km on 2022 Jan 5. This last flyby sent the Falcon 9 stage on an elliptical orbit that came as low as 25000 km from the Earth, on Jan 21, then out again to lunar distance. It will come back in to 45000 km perigee on Feb 9 on a path for a fatal last apogee at 688000 km on Feb 23 from which it will fall back in to hit the Moon on Mar 4.
The stage is about 4 tonnes and it will hit the Moon at 2.5 km/s.
We know lots of junk from lunar missions has ended up hitting the Moon, for example upper stages from lunar missions and junk left in lunar orbit. The LCROSS mission deliberately smashed a Centaur stage (similar size) into the Moon on 2009 Oct 9, with a special spacecraft following behind it to study the impact.
This is the first time that something not explicitly targeted at the Moon has been noticed to accidentally hit it, but that’s mainly because we weren’t paying attention until recently. Thanks to Bill Gray and a few other people who have spent their own time keeping track of the space junk that’s too far out for SpaceForce to care about, we can now spot events like this. Amazingly it is no one’s paid job to do. SpaceX haven’t paid attention to the object since Feb 2015, and neither has NASA or anyone else official.
There are about 30 to 50 lost deep space objects like this that have been missing for years — 50 years in some cases — that haven’t been picked up by asteroid searches, and probably some of them hit the moon without us noticing. This is not ‘SpaceX did something bad’ — it’s perfectly standard practice to abandon stuff in deep orbit — this is ‘none of the space agencies care about leaving stuff out beyond the Moon’.
Traffic in deep space is increasing. And it’s not just the USA and the USSR sending stuff to deep space, it’s many countries and even commercial companies like SpaceX. So I think it’s time for the world to get more serious about regulating and cataloging deep space activity.