An oblique view of the Moon from the AMIE camera on the SMART-1 probe, a few hours before it crashed into the lunar surface. © ESA/SPACE-X (Space Exploration Institute)

After a 2-year mission to the Moon, the European Space Agency (ESA) probe SMART-1 crashed into the lunar surface at 0642 BST on 3 September 2006. The spacecraft hit the plain Lacus Excellentiae (Lake of Excellence) within a second of the scheduled time.

SMART-1 was highly successful. The probe was Europe’s first lunar mission and first spacecraft to use electric propulsion, where solar energy provided the power for an ion drive.

The probe struck the flat surface of the Moon at a glancing angle, so although its forward motion was 2 km a second or more than 7000 km an hour, this translated into a vertical descent speed of only 70 km an hour, far less than a typical meteorite.

Images of the SMART-1 impact site. The left and right hand frames show the site before and after impact. The centre frame shows the impact flash as the spacecraft hit the lunar surface. The flash probably resulted from the ignition of the remaining hydrazine fuel. © Canada-France-Hawaii Telescope Corporation Observatories in the western hemisphere (North America, South America and the Pacific) were well placed to see the impact. Astronomers used large telescopes to try to detect the impact and analyse any material thrown up from the surface. The first pictures from the Canada-France-Hawaii telescope show a bright flash at the moment of impact.

ESA scientists have also released extreme close up images of the lunar surface, sent back from SMART-1 as the probe completed its last few orbits, just a few hours before its demise.