The European Space Agency's Venus Express mission will study the atmosphere and clouds of the planet nearest to Earth.
Scientists hope the probe will beam back the clearest-ever images of the planet and provide new insight into its atmosphere.
VENUS EXPRESS PROBE
1. MAG: Magnetometer - measures magnetic, field strength and direction
2. Virtis: (Visible and Infrared Thermal Imaging Spectrometer)imaging spectrometer that operates in the near ultraviolet, visible and infrared parts of the electromagnetic spectrum
3. Planetary Fourier Spectrometer - measures atmospheric temperature and concentration of known and unknown minor atmospheric constituents
4. Spicav/Soir (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) Imaging spectrometer which detects ultraviolet and infrared radiation. Soir (Solar Occultation at Infrared) will observe the Sun through Venus's atmosphere at infrared wavelengths
5 . VMC wide angle camera which captures ultraviolet, visible and near infrared images
6. VeRa (Venus Radio science) Radio-sounding experiment which will examine the ionosphere, atmosphere and surface of Venus by means of radio waves transmitted from the spacecraft
7. Aspera (Analyser of Space Plasmas and Energetic Atoms) will study energetic neutral atoms (ENAs), ions and electrons in Venus' atmosphere
The spacecraft shares its design and manufacturing team with the Mars Express mission. This reduced the amount of time and money required in the preparatory stages.
The mission blasted off atop a Soyuz rocket from Baikonur Cosmodrome in Kazakhstan on 9 November. After a 153-day journey, the probe is set to enter orbit around Venus on 11 April 2006.
Once there it will manoeuvre itself into an orbit that takes it looping round the planet's poles.
It is a peculiarity of Venus that the planet orbits the Sun much faster than it rotates, meaning a "day" lasts roughly 250 Earth days.
Its atmosphere consists mainly of carbon dioxide with a small amount of nitrogen and other trace gases.
Abundant CO2 has led to runaway greenhouse warming on Venus, with temperatures of approximately 460C on the surface.
Atmospheric pressure is some 90 times that of Earth. Standing on the surface of Venus, a hypothetical visitor would experience the same pressure as they would diving below 1km of water on Earth.
1. Launch from Baikonur, Russia, at 0443 UT on 26 October 2005
2. First burn of Fregat rocket booster propels probe from suborbital trajectory into a circular parking orbit
3. Second Fregat burn sends the probe into an interplanetary flight trajectory
4. Its fuel spent, Fregat detaches; spacecraft continues to Venus