Europe's first space probe to Venus slipped smoothly into orbit on Tuesday in a mission designed to send back data from a planet whose extreme atmosphere conceals important similarities with the Earth.
The Venus Express sent back its first signal at just after 0900 GMT confirming that the orbital entry phase had been successfully completed after a brief period when the craft passed behind the planet and was out of contact with Earth.
"Everything went as it was planned, clearly, without difficulties," Gaele Winters, European Space Agency (ESA) director of operations, told a news conference. "This is a great success," he said.
The 1.3 tonne spacecraft took off on a Soyuz rocket from Baikonur in Kazakhstan last November, travelling 400 million km (250 million miles) on a mission scheduled to last 486 days.
Priced at a relatively modest 220 million euros ($265 million) and built by firms from 14 countries, the Venus Express underlines the ambition of European scientists to be at the cutting edge of exploring the scope and origins of the universe.
"It all comes back to the basic question that I'm sure just about everybody has asked -- how did we turn up here out of all that?" said David Southwood, director of science at ESA.
Venus Express will take another four weeks to reach its operational orbit before sending back data from an atmosphere of carbon dioxide and clouds of sulphuric acid where temperatures average 450 degrees Celsius (842 degrees Fahrenheit).
But in other respects, including size, mass and composition, Venus closely resembles Earth and scientists will use the data to look for answers as to why a planet so near has evolved so differently over the last 4,600 million years.
Shrouded by a layer of clouds 20 km (12 miles) thick and buffeted by extremes of temperature and pressure, Venus is Earth's closest planetary neighbour but is an enigma to science.
Its dense atmosphere creates a supercharged greenhouse effect, as it spins round the planet in four days in a "super rotation" phenomenon that scientists cannot explain.
Some researchers have said there may once have been life on Venus. They hope to obtain clues about greenhouse conditions on Venus and whether any comparisons about global warming on Earth can be drawn.
Beyond that, the scientists are hoping that Venus Express, a virtual twin of the Mars Express craft which has been providing spectacular images of the Red Planet since 2003, will be the stepping stone to further European space missions.
"We (Europe) aren't finished with the planets," said Southwood. "We're planning to go back to Mars and we're planning also to go to Mercury, one of the most mysterious of planets very close to the Sun," he said.
Officials at the ESA's Space Operations Centre in Darmstadt, Germany, said the Venus probe had completed a braking operation that will place it into a position that will allow it to be dragged into orbit around the planet.
Full reactivation of the craft will take place over the next two days with the second of two major antennas due to come on stream on April 13. Several more delicate manoeuvres will be required before final orbit is reached on May 7.
The ship will orbit the planet's poles well above the cloud cover from a distance of 250 to 66,000 km, collecting data with instruments designed to build on observations from around 20 previous US and Soviet missions to the planet since 1962.
One Venus day is the equivalent of 243 Earth days, due to its slower rotation.