Thu, Nov 10, 2005 - Page 6 News List

Venus Express launches successfully

GOOD START So far, so good as the European Space Agency's unmanned probe looks set to become the first spacecraft to visit Earth's closest neighbor in more than 10 years


The first space mission in over 10 years to Earth's closest neighbor Venus emitted its first signal yesterday after a successful launch from the Russian cosmodrome in Baikonur, Kazakhstan.

"The baby cried. Venus Express has begun its operational mission," said Jean-Pierre Cau, an official from EADS Astrium, the company that built the spacecraft's propulsion system, after receiving the signal.

Venus Express separated successfully from the Soyuz Fregat carrier rocket more than 90 minutes after its 03:33am launch at the start of a 163-day journey to Venus.

The European Space Agency's (ESA) first probe to the planet, Venus Express will explore its unusual stormy atmosphere and runaway global warming in the hope of better understanding Earth's greenhouse-gas problem.

Venus, the second planet from the Sun, is similar in size, mass and age to Earth but has a vastly different and ferociously hot weather system.

Also known as the Evening Star, thanks to the bright light it reflects from the Sun, the planet is blanketed by thick clouds of suffocating gas driven by often hurricane-force winds and a surface pressure and temperature high enough to crush and melt lead.

The planet's clouds reflect back 80 percent of the Sun's radiation and absorb another 10 percent, leaving just 10 percent to filter down to the surface.

But the clouds provide such effective insulation the surface zone becomes a pressure cooker capable of melting metal.

"Venus has no surface water, a toxic, heavy atmosphere made up almost entirely of carbon dioxide with clouds of sulfuric acid, and at the surface the atmospheric pressure is over 90 times that of Earth at sea-level," the ESA notes.

The planet's searing surface temperature of 477 Celsius -- the hottest in the Solar System -- and immense atmospheric pressure have caused many previous missions to fail or send data streams lasting only minutes before their instruments were crushed.

It is hoped, however, that the 1.27-tonne unmanned Venus Express orbiter will be able to use seven powerful instruments on board to map the planet's surface and weather system, looking at temperature variation, cloud formations, wind speeds and gas composition.

After a 163-day journey, the craft is scheduled to arrive off Venus in April, when it will be placed in an elliptical orbit, swooping to as low as 250km above the surface to a height of 66,000km.

The orbiter, whose total mission costs are US$264 million, has enough fuel to operate for 1,000 Earth days, the ESA says.

The first mission to Venus in 1961 saw a Soviet-made probe lose communications with ground control about 7 million kilometers from Earth.

The following year the US Mariner 2 became the first successful interplanetary mission.

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