Darmstadt, Germany Europe's Mars Express went into orbit around the Red Planet early Thursday, flight officials said, as controllers awaited word on whether the craft's companion, a surface probe dubbed Beagle 2, had landed safely on the Red Planet.
Flight director Michael McKay said controllers received a signal from a small antenna aboard the Mars Express as it emerged from behind Mars on schedule at 5:11 a.m. today. He cautioned that the signal did not reveal if the spacecraft was working.
Mars Express reappeared after a maneuver in which it fired its engine to slow it enough for Mars' gravity to pull it into orbit. The craft will relay data from the Beagle 2 when -- and if -- it starts transmitting from the planet's surface.
The signal "was the first good indication that the burn went well," McKay said.
Confirmation that the maneuver was successful was expected early this morning as controllers turned the main antenna on Mars Express, which was reversed for the orbit maneuver, to face Earth.
Mission controllers sent the last commands to Mars Express Wednesday morning, telling it to heat its fuel tanks and switch off nonessential equipment so it won't interfere with the maneuver.
The first chance to hear from Beagle 2 -- named for the ship that carried naturalist Charles Darwin on his voyage of discovery in the 1830s -- comes when the U.S. spacecraft has a chance to pick up and relay a signal.
If that doesn't work, the Jodrell Bank Observatory in Britain will try to pick up Beagle's signal later today.
Mars Express' entry to orbit was critical for the mission, since the mother craft will relay Beagle's scientific data back to earth.
It won't be in position to make contact with Beagle until Jan. 3 because its initial orbit is too high and will have to be corrected.
Beagle is designed to use a robotic arm to sample surface rock and soil for signs of past or present life.
Meanwhile, Mars Express will orbit overheard for at least a Martian year, or 687 Earth days, probing as deep as 2.5 miles below the surface with a radar to look for underground water. It will also map the surface with a high-resolution stereo camera.
If all goes well, Beagle is expected to transmit its first pictures from Mars as early as Monday. The first radar pictures from Mars Express are expected in the spring.