10 Apr 2002
(Source: Royal Astronomy Society)
Royal Astronomical Society Press Notice
Ref. PN 02/13 (NAM 7)
Issued by: RAS Press Officers
Peter Bond (Except 8 - 12 April)
Tel: +44 (0)1483-268672
Fax: +44 (0)1483-274047
Mobile phone: +44 (0)7711-213486
Dr Jacqueline Mitton (Except 7 - 13 April)
Tel: +44 (0)1223-564914
Fax: +44 (0)1223-572892
Mobile phone: +44 (0)7770-386133
NAM PRESS ROOM (9 -12 April only):
+44 (0)117 928-4337
+44 (0)117 928-4338
+44 (0)117 954-5913
+44 (0)117 928-7901
UK National Astronomy Meeting Web site: http://www.star.bris.ac.uk/nam/index.html
CONTACT DETAILS ARE LISTED AT THE END OF THIS RELEASE.
The European Space Agency is planning its first mission to unveil the mysteries of Earth's cloud-shrouded s ister 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 lev els 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 Ta ylor. "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 trajec tory 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 k m 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 Spa ce 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 V enus exploration, including Japanese and probably American space missions, which will probe the environment of this mysterious planet," concluded Professor Taylor.
Professor Taylor can be contacted via the NAM press offic e (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
Web site: http://www.atm.ox.ac.uk/user/fwt/WebPage/index.htm