BERLIN (AP) - Scientists
were counting down Tuesday for the blast off of a Russian booster rocket
carrying a European-built probe aimed at exploring the hot, dense atmosphere
around Venus.
The launch
of the European Space Agency's Venus
Express probe is planned for 10:33 p.m. EST (0333 GMT) Wednesday at the
Russian-leased Baikonur Cosmodrome in Kazakhstan.
Venus Express was
originally scheduled to go up Oct. 26, but the launch was postponed
after checks revealed a problem with the thermal insulation in the upper
section of the Soyuz-Fregat rocket. Once it separates from the rocket,
scientists at ESA's mission control in Darmstadt, south of Frankfurt, plan to
make contact with the probe.
"We've just had the pre-launch
briefing and everything is in the green zone," said ESA spokeswoman Jocelyne
Landeau. "Everything is ready for go."
The mission, Europe's first
to Venus, is aimed at exploring the hot and dense atmosphere around the planet,
concentrating on its greenhouse effect and the permanent hurricane force winds
that constantly encircle it.
In addition, instruments on
the probe will try to discover whether Venus' many volcanoes are active, and
look at how a planet so similar to Earth could have evolved so differently.
"Venus is still a big
mystery," Gerhard Schwehm, head of the planetary missions at ESA, said Monday.
Not only is Venus the nearest
planet to Earth within the solar system, but the two share also roughly the
same mass and density. Both have inner cores of rock and are believed to have
been formed at roughly the same time.
But despite these similarities,
the two have vastly different atmospheres, with Venus' composed almost entirely
of carbon dioxide with very little water vapor. It is also the hottest surface
of all the planets and lacks atmospheric pressure.
It will take 163 days, or
roughly five months, for the $260 million (220 million Euros) probe to reach
Venus. As a sister probe to ESA's Mars Express, launched in 2003,
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.
Venus Express is expected
to begin its experiments in early June.
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.
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