Europe is poised to send a spacecraft to Venus, our closest planetary neighbour and a hothouse world that has been described as Earth's "evil twin".
Venus Express will blast off aboard a Russian rocket from Baikonur Cosmodrome in Kazakhstan on 26 October.
It will slip into orbit around Venus next year, using science instruments to study the planet from space.
Venus underwent runaway greenhouse warming, so experts think it may offer clues to how Earth will evolve.
At face value, Venus and Earth would seem to be similar; they are of comparable size and mass and were born out of the same cloud of stellar gas.
But that is more or less where the resemblance ends.
Ground temperatures on Venus can reach 460C and the thick atmosphere generates surface pressures similar to those found one kilometre down in Earth's oceans.
Fire and brimstone
Venus Express will carry out the first global investigation of Venus' atmosphere, to shed light on how the planet evolved its hellish climate.
The highly reflective layer of clouds, which rain sulphuric acid, absorbs less heat from the Sun than does the Earth, despite the fact Venus is a third closer to our star.
But once absorbed, solar energy is trapped by an atmosphere that is 96% carbon dioxide (CO2). This has led to an extreme greenhouse effect with volcanism perhaps contributing to the warming.
The mission will shed light on the planet's hellish environment
"Venus has developed in quite a different way to our own planet," said Dr Andrew Coates, a co-investigator on the Aspera science instrument.
"In some ways it could be thought of as an evil twin of Earth."
The US Magellan probe, sent to map Venus, revealed extensive volcanic flows on the planet's surface.
"I suspect that Venus is very volcanically active but we don't know that for certain," said Oxford University's Professor Fred Taylor, an interdisciplinary scientist on the mission.
The European Space Agency (Esa) mission will investigate this question and others in a mission that lasts two Venusian days, equivalent to about 500 of our own.
Venus has undergone runaway greenhouse warming
British industry has played a significant role in the mission. Stevenage-based company EADS-Astrium built the propulsion system and SciSys, based in Wiltshire, built mission control systems.
Venus Express will lift-off from the Baikonur Cosmodrome in Kazakhstan aboard a Soyuz rocket. An upper "Fregat" stage with the orbiter mounted on top will then enter a sub-orbital trajectory.
After two burns, Fregat will launch the spacecraft into an escape trajectory that takes it directly to Venus.
After about five months, Venus Express will reach its target and enter an elliptical polar orbit.