WT1190F

WT1190F (9U01FF6, UDA34A3, or UW8551D) was a small temporary satellite of Earth that impacted Earth on 13 November 2015 at 06:18:21.7 (± 0.1 seconds) UTC. It is thought to have been space debris from the trans-lunar injection stage of the 1998 Lunar Prospector mission. It was first discovered on 18 February 2013 by the Catalina Sky Survey. It was then lost, and reacquired on 29 November 2013. It was again discovered on 3 October 2015 by astronomer Rose Garcia with the Catalina Sky Survey 60-inch telescope, and the object was soon identified to be the same as the two objects previously sighted by the team, who have been sharing their data through the International Astronomical Union's Minor Planet Center (MPC). An early orbit calculation showed that it was orbiting Earth in an extremely elliptical orbit, taking it from within the geosynchronous satellite ring to nearly twice the distance of the Moon. It was also probably the same object as 9U01FF6, another object on a similar orbit discovered on 26 October 2009.

WT1190F had been orbiting Earth as a temporary satellite (named UWAIS) since mid-2009, if not longer. While it has not been positively identified with any known artificial satellites, its estimated density of 0.1 g/cm³ was much lower than would be expected of a natural object as even water has a density of 1 g/cm³. Hence, European Space Agency astronomers have concluded that the object was likely a fuel tank of some sort.

After more observations, astronomers determined that the object would impact Earth on 13 November 2015 at 06:18 UTC (11:48 local time), south of Sri Lanka. Due to its small size, it was expected that most or all of the object would burn up in the atmosphere before impacting, but would be visible as a bright daytime fireball if the sky was not badly overcast.

A ground-based observational campaign was organized as a possible test for future collision events involving also natural bodies. Provided by Wikipedia