An out-of-control rocket booster is set to slam into the moon.
Bill Gray, a sky-watcher, identified the booster as the upper stage of the vehicle that sent the Deep Space Climate Observatory into space.
However, after a closer look at the available data, it emerged last month that it may be part of a Long March 3C rocket launched by China's Chang'e 5-T1 moon-bound mission in October 2014, though China denies any link.
The booster is going to hit the lunar surface at 7:25 a.m. 4:30 a.m. On Friday.
The impact on the far side of the moon will make it difficult for ground telescopes to see the crash site.
If it were observable, you would see a big flash, and dust and disintegrated rocket bits and pebbles and boulders thrown out.
It could take a long time to locate the impact site, but NASA will use its LRO to find it.
A NASA spokesman told Space.com that LRO will be able to use its cameras to identify the impact site, but that the search for the crash site will be more difficult.
An exciting research opportunity for the space agency was described by the spokesman.
The impact will be the first time a man-made object crashes onto the moon. A planned impact occurred in 2009, when a NASA rocket and probe were to slam into the moon at high speed in a mission to find water on Earth.
The origin of the rocket booster may be determined by researchers with greater certainty.