Enlarge image The Soyuz Fregat rocket carrying Venus Express launches from the Baikonur Cosmodrome in Kazakhstan (Image: ESA)
Europe's first mission to Venus was successfully launched from the Baikonur Cosmodrome in Kazakhstan in the early hours of Wednesday.
The Venus Express probe blasted off at 0333 GMT and separated from its Soyuz Fregat carrier 90 minutes later. It then emitted a signal to mark the start of its 163-day journey to the turbulent planet.
"Venus Express has begun its operational mission," said Jean-Pierre Cau of EADS Astrium, which built the spacecraft's propulsion system.
Venus Express is the first expedition to Earth's closest planetary neighbour in over 10 years. The probe will explore the planet's stormy atmosphere and runaway global warming.
Pressure cooker
Venus is similar in size, mass and age to Earth but has a vastly different, ferociously hot, weather system. The planet is blanketed by thick clouds of suffocating gas driven by often hurricane-force winds and experiences surface pressures and temperatures high enough melt lead.
Venusís clouds reflect 80% of the Sun's radiation and absorb 10%, leaving just 10% to filter down to the surface. But the clouds also provide such effective insulation that the surface zone becomes a red-hot pressure cooker.
Venus has no surface water and a toxic atmosphere made up almost entirely of carbon dioxide and sulphuric acid. Atmospheric pressure at the surface is over 90 times that of Earth and the planet's surface temperature is 477įC - the hottest in the solar system.
These extreme atmospheric conditions pressure have caused many previous missions to fail or to send data streams lasting only minutes before their instruments were crushed.
Elliptical orbit
It is hoped, however, that the 1.27-tonne Venus Express orbiter will be able to use its seven powerful instruments to map the planet's surface and weather system from orbit, looking at temperature variation, cloud formations, wind speeds and gas composition.
Venus Express was originally scheduled to launch from Baikonur on 26 October but pieces of an insulating blanket that covered the inside of the Fregat upper stage were found on the probe. Workers used special UV lights to find the pieces and then removed them with tweezers, vacuum cleaners and nitrogen gas airbrushes.
The craft is scheduled to arrive off Venus in April 2006, when it will be placed in an elliptical orbit, swooping to as low as 250 kilometres (156 miles) above the surface to an altitude of 66,000 kilometres (41,250 miles). The orbiter has enough fuel to operate for 1000 Earth days.
The first successful landing on Venus came in 1970 when Soviet probe Venera 7 parachuted a capsule of scientific instruments onto the Venusian surface. The first television pictures were provided by a sister probe, Venera 9, in 1975.
European Space Agency's probe to  was successfully launched on Wednesday, November 9, at 0333  from the  in Kazakhstan. The , entitled , separated from its  carrier 90 minutes after the launch, after which it emitted a signal marking the start of its journey to Earth's closest planetary neighbour.

Venus Express is to arrive at Venus in April 2006. The probe will spend at least 15 months—two Venusian days—studying the planet. The orbiter, however, has enough fuel to operate for 1000 Earth days.

The 220 million € (260 million US$) probe is set to examine the turbulent  and intense  of Venus. The probe will study the planet's temperature variation, cloud formations, wind speeds and gas composition. It is hoped that the results will help scientists understand Earth's  better.
Venus express is a clone of Mars Express which has been orbiting Mars since December 2003.