Europe's sophisticated space freighter, Johannes Kepler, is set to dock with the International Space Station (ISS).
The unmanned robotic truck is delivering new supplies of fuel, food, air, and equipment to the orbiting platform's astronauts.
Kepler is totally automatic - it will use its own computerised systems to make the attachment.
Ground controllers and the station's astronauts will not intervene unless there is a problem.
Contact with the Zvezda module on the rear of the ISS is timed for about 1549 GMT.
A successful docking will clear the way for the American space shuttle Discovery to lift off from Earth.
It, too, has a date with the ISS, and will carry up six visiting astronauts and a smart humanoid robot.
http://www.bbc.co.uk/news/science-environment-12554470
Note: 24 February 2011 Last updated at 15:00 GMT