DARMSTADT, Germany (AP) -- A European-built probe designed to explore the hot, dense atmosphere of Venus made contact with mission control early Wednesday after blasting off on a five-month journey to Earth's neighbor, scientists said.The European Space Agency's Venus Express probe lifted off at 0333 GMT at the Russian-leased Baikonur cosmodrome in Kazakhstan, before heading northeast above the desert and into orbit around the earth in a successful launch.Mission control activated the probe's instruments after it left orbit on its trajectory toward Venus about two hours later and immediately picked up a signal to hearty applause in the observation room."Initial checks are ongoing and everything looks good," said Paolo Ferri, deputy flight operations director for Venus Express.Venus Express -- Europe's first mission to Venus -- was originally scheduled to go up October 26. However, the launch was postponed after checks revealed a problem with the thermal insulation in the upper section of the Soyuz-Fregat rocket."We have seen a successful start," said Gaele Winters, director of ESA's operations in Darmstadt on Wednesday."We are always nervous when there is a launch, you can never expect this to be a routine operation, there is always a risk," he said.The mission aims to explore the hot and dense atmosphere around the planet, concentrating on its greenhouse effect and the permanent hurricane force winds that constantly encircle it.Instruments on the probe will try to determine whether Venus' many volcanoes are active and examine how a planet so similar to Earth could have evolved so differently."Venus is still a big mystery," said Gerhard Schwehm, head of planetary missions at ESA.Not only is Venus the nearest planet to Earth within the solar system, the two also share similar mass and density. Both have inner cores of rock and are believed to have been formed at roughly the same time.Despite those similarities, the two have vastly different atmospheres, with Venus' composed almost entirely of carbon dioxide and very little water vapor. It also has the hottest surface of all the planets.It should take 163 days, or roughly five months, for the euro220 million (US$260 million) probe to reach Venus. Venus Express is expected to begin its experiments in early June.Venus Express shares many instruments with Mars Express, a sister probe launched in 2003, and the Rosetta probe, sent last year and bound for a comet.The last mission to Venus was Magellan, launched by NASA in 1989. It completed more than 15,000 orbits around the planet between 1990 and 1994.Using radar, Magellan was able to map virtually all the surface of Venus, revealing towering volcanoes, gigantic rifts and crisp-edged craters.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.