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Venus Express

Venus Express, European Space Agency’s spacecraft to Venus is scheduled to lift off aboard a Soyuz rocket from Baikonur, Kazakhstan, on 26 October. When it arrives at Venus in April 2006, it will study the planet from a polar orbit stretching from an altitude of 250 to 60,000 kilometres.

The mission will focus mainly on the composition and temperature of Venus’s atmosphere. It rotates 50 to 60 times faster than the planet itself, which spins just once every 243 days and in the opposite direction to Earth. In particular, researchers will study mysterious hurricane-like vortices above the poles.

Astronomers hope to understand how a planet that has more in common with Earth than any other in terms of distance from the Sun, size and mass could have evolved into such an inhospitable world. Temperatures hover at 450°C, while the thick, carbon dioxide atmosphere produces crushing surface pressures 90 times those on Earth and sulphuric acid rains from the sky. Scientists are still struggling to understand why Venus is so radically different from Earth.

The surface will also be scanned for active volcanism, hinted at by the presence of sulphuric acid in the atmosphere, but never seen. Venus boasts the most volcanoes of any planet in the solar system. Nearly 90% of its surface is covered by basaltic lava flows. Based on the size and number of impact craters, the lava appears to be about 500 million years old.

This age suggests that, unlike Earth, Venus does not have multiple rocky plates that constantly move and collide over the hot, soft rock in the planet’s core. On Earth, plate tectonics enables heat to escape from the core.

Local volcanic activity probably goes on all the time and the gases belched out in the process would "go a long way toward explaining Venus’s extreme climate".

The mission is the first dedicated to Venus since NASA’s Magellan spacecraft mapped the surface of the planet in 1990. Venus Express is scheduled to operate for about 500 Earth days - the equivalent of two rotations of Venus - but it has enough fuel to last 1000 days.

posted by: kyawoo at 19:07 | link | comments |
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