Soon after 2003 WT153 was discovered by the 1.8m Spacewatch-Telescope on Kitt Peak, it became clear that the orbit of this unusual object looks much like a transfer orbit from Earth to Venus. The estimated diameter of several meters only is also compatible with a man-made object. In fact, Paul Chodas from JPL has suggested that 2003 WT153 may be the Shuttle interstage rocket that launched the Galileo space probe on its way towards Venus, taking a gravtiy assist manouver on it's way to Jupiter. That link, however, is somewhat uncertain, and there remains a 50% chance that 2003 WT153 is a natural object, whose perihelion- and aphelion-distance has been shifted close to the orbits of Venus and Earth due to multiple encounters with these planets. The objects has a small chance of colliding with the Earth during a number of future encounters with our home planet, but -- no matter if it is man-made or not -- it is probably too small do cause any damage on the ground.
The image shown here is a three minute exposure taken by Erich Meyer at the Davidschlag Observatory near Linz, Austria, witha a SBIG ST-6 CCD camera at a 0.6m f/3.3 reflector. The image was taken on 2003 November 30, just as 2003 WT153 was passing only 0.0045 AU (673.000 km) from Earth. The telescope was tracking the 18mag object, which was moving at 90"/minute, so the stars on this image appear trailed, while 2003 WT153 can be seen as a small dot in the center of the frame. The tiny object was observed over 60 hours only, and Meyer's obersvations from December 1, which show the object faded to 19mag, were the last observations before 2003 WT153 disappeared from our view.