SpaceX upper stage expected to strike Moon near Einstein Crater; scientists urge observations

A SpaceX Falcon 9 upper stage is expected to unintentionally collide with the Moon on Wednesday, striking the lunar northern hemisphere near the Einstein Crater at approximately 2:35 am Eastern (8:35 SA time).

What scientists and observers expect

Researchers and amateur stargazers are preparing to watch for a sunlit plume of rubble and debris that could follow the impact. “It might be possible for folks with a telescope to observe the plume of ejecta created by the impact,” said Benjamin Fernando of Los Alamos National Laboratory, lead author on a recent paper about the event. “It is unclear how bright it will be, which is one of the reasons why we are looking to study this event,” he told AFP.

Projected impact details

The paper’s authors estimate the upper stage weighs approximately 4,000 kilograms, assuming all propellant is spent. It is expected to strike at about 8,690 kilometres per hour.

Origins of the upper stage

The Falcon 9 mission launched last January carrying two lunar landers. The booster returned to Earth, but the upper stage remained in space to push the landers onward.

How the impact course developed

At a Monday news conference, Julianna Scheiman, director of NASA Science and Dragon Programs at SpaceX, said that for “high-energy missions” SpaceX performs a maneuver to ensure the second stage “is safe per the appropriate rules and regulations.” She said, “We did that,” and added that “what has happened is essentially a mixture of solar activity and gravity forces have put it on a path towards the Moon.”

Official responses and scientific purpose

NASA emphasised there is no risk to Earth. “There is no danger to Earth,” said NASA spokesperson Jimi Russell in a statement. “NASA will continue to track the booster for training purposes, as well as later observe the impact site for scientific purposes.”

The research team encouraged both professional and amateur astronomers to attempt to observe or record the collision. They wrote that the event “provides an opportunity to test a pipeline for localizing impacts on the lunar surface for future seismic experiments, investigating the dust and plume dynamics from impact events on the Moon, and considering hazards from artificial space debris impacts.”

Context on lunar impacts

The Moon regularly experiences impacts from space debris including meteoroids. The article notes that artificial collisions are less common and recalls that in the 1970s, NASA carried out deliberate crashes during its Apollo programme to collect seismic data.