Scientists watching out for Earth-threatening asteroids have spotted the ExoMars spacecraft streaking towards Mars at more than 20,000mph.
Remarkable images captured by ground-based telescopes in Australia, New Zealand and Brazil just after the vehicle broke free from Earth orbit show a rapidly moving bright blob.
The first stage of the joint European and Russian ExoMars mission to search for life on Mars was successfully launched on Monday.
A Russian Proton heavy-lift rocket blasted two unmanned probes, Trace Gas Orbiter (TGO) and the lander Schiaparelli, into space from the Baikonur Cosmodrome in Kazakhstan.
Flying together as a combined "stack", the craft are now coasting on a trajectory that will cause them to rendezvous with Mars in October after a journey of 300 million miles.
A final engine burn sent the spacecraft on its way at a speed of 33,001kph (20,506mph).
For asteroid hunters, ExoMars offered a perfect practice target since its departure mimicked in reverse the approach of a small near-Earth object (NEO).
The European Space Agency (Esa) NEO co-ordination centre in Italy organised an international hunt for the spacecraft.
Rapidly identifying a fast-moving object whose location is only known within a short time window is similar to the process of discovering a nearby asteroid on collision course with Earth.
ExoMars's predicted path was supplied by Esa mission control in Darmstadt, Germany, and converted at the NEO centre into aiming data for telescopes.
The information was shared among Esa's network of collaborating telescopes in the southern hemisphere, from where ExoMars was observable.
In the images, the spacecraft appears as a bright object surrounded by at least six other fainter spots. These are elements of the Proton rocket's discarded upper stage moving together across the sky.
TGO will sniff the atmosphere of Mars looking for traces of methane, and has instruments that can show if the gas is likely to have been generated by geology or living microbes.
Schiaparelli will parachute down on a Martian plain and test the technology for landing a British-built rover during the second stage of the mission, due to launch in 2018. It will also study Martian surface weather.