Venus mission is on

The European Space Agency (Esa) has given the final go-ahead for a mission to Venus.

The second planet is similar in size to Earth but is permanently covered in a thick atmosphere. The temperature at the surface is hot enough to melt lead.

Venus Express will use the same basic spacecraft design as the Mars Express probe that will be launched towards the Red Planet next year.

Astronomers want to understand why the Earth and Venus developed in radically different ways. Venus Express will be ready for launch in 2005.

Italian problem

Europe's mission to Venus has been on and off for two years.

The idea behind Venus Express began in 2001 when Esa issued a call for ideas to reuse the design of spacecraft that will take Europe to Mars for the first time in June.

The call for proposals resulted in a large number of ideas from scientists across Europe. Venus Express was eventually selected because of its great scientific value.

However, earlier this year, it was then placed on hold because it needed further study.

In July, it was endorsed again, but one nation, Italy, was not able to confirm its participation and was given until October 2002 to provide its final commitment.

Choking atmosphere

At the deadline, Italy could not completely commit itself to finding a share of the cost of Venus Express. So to rescue the mission, ESA and the Italian Space Agency explored new options, one of which was acceptable to all parties.

The Italian contribution to Venus Express will chiefly consist of a series of spare parts for various spacecraft components and a financial contribution.

Esa's science director Professor David Southwood said: "I'm extremely proud that we managed to bring things together. Now, we can clearly say to the scientists and industry: 'go to work to go to Venus'"

Venus is a twin to the Earth in terms of size and mass, yet has evolved in a very different direction, with a surface temperature hotter than a kitchen oven and a choking mixture of noxious gases for an atmosphere.

Venus Express will make unique studies of this atmosphere and conduct the first radar soundings of the Venusian subsurface.

The instruments on board Venus Express had been developed as back-ups for either Esa's Mars Express spacecraft or Esa's comet-chaser mission, Rosetta, due for launch in January.