The European Space Agency is planning its first mission to unveil the
mysteries of Earth’s cloud-shrouded sister planet, Venus. On Wednesday 10
April, Professor Fred Taylor (University of Oxford) will be explaining to the
UK National Astronomy Meeting why European scientists are hoping to be on
board the Venus Express in 2005.

Venus, the Earth’s nearest planetary neighbour, is remarkably similar in size
and mass to our own world. However, its atmosphere and climate could hardly
be more different. The reasons for these contrasts are proving difficult to
understand. Scientists still do not know, for example, the details of the
greenhouse effect on Venus, which keeps the surface hot enough for molten
metal to flow, despite the fact that Venus absorbs less heat from the Sun
than the Earth does.

Venus and Earth have also evolved quite differently. Venus has vast, smooth
plains, no continents and extensive volcanic activity that produces dense
cloud layers with an exotic, sulphur-rich composition.

Most puzzling of all is the atmospheric circulation which features hurricane
force winds at high levels that sweep around Venus in just four days –
remarkably rapid for a planet that only rotates once every 243 Earth days.

“The planet’s weather systems and climate characteristics cannot be
understood by comparison with Earth,” said Professor Taylor. “The failure of
extrapolated terrestrial models to account for Venus’ behaviour has wide
implications in fields ranging from solar system evolution to climate
forecasting on Earth.”

Venus Express is proposed to be launched on a direct trajectory to Venus with
a Soyuz-Fregat rocket from Baikonur in November 2005. After a flight of about
150 days, it will brake into a highly elliptical 5-day orbit around Venus.
The spacecraft will then be manoeuvred to its operational polar orbit between
250 km and 45,000 km above the planet where, for two Venus years – equivalent
to 450 Earth days – it will study the atmosphere, the surface and the plasma
environment of Venus.

In order to lower costs, Venus Express is to be based on the European Space
Agency’s Mars Express spacecraft (which is scheduled for launch in summer
2003) and it will use seven flight spare experiments from Mars Express and
the Rosetta comet chaser.

“Venus Express is a strong candidate to be part of the next wave of Venus
exploration, including Japanese and probably American space missions, which
will probe the environment of this mysterious planet,” concluded Professor
Taylor.

CONTACT DETAILS:

Professor Taylor can be contacted via the NAM press office (see above) on the
afternoon of 10 April and the morning of 11 April.

Normal contact details:

Professor Fred Taylor,

Halley Professor of Physics,

University of Oxford

Tel:: +44 (0)1865-272903

Fax: +44 (0)1865-272924

Mobile: +44 (0)794 138 2916

E-mail: fwt@atm.ox.ac.uk

Web site: http://www.atm.ox.ac.uk/user/fwt/WebPage/index.htm