ESA revives plans for mission to Venus

A runaway greenhouse effect makes Venus the hottest planet in our solar system.

(CNN) -- The European Space Agency is moving forward with plans to send a spacecraft to Venus, using designs from another unmanned mission that will visit Mars.

The Venus Express would include a suite of instruments that could study our nearest planetary neighbor from below its super-hot surface to the highest reaches of its incredibly dense atmosphere, according to ESA.

The agency's Science Program Committee agreed last week to start work on the probe project, which would include instruments developed for the Mars Express mission.

ESA budget cuts in recent years almost killed the project. But after considering numerous other scientific proposals, the agency decided the Venus mission was valuable, and achievable at a reasonable cost with surplus ESA equipment.

"The Venus Express mission has now taken a big step toward realization. However, there is much work to do," said ESA scientist David Southwood. "Everyone has to be ready if it is to fly in time."

The departure deadline would be November 2005, an ideal time to launch a probe from Earth to Venus because of the position of the two planets. For similar reasons, ESA expects to launch the Mars Express in June 2003.

But the Venus Express must overcome another major obstacle before ESA moves ahead with its development. Italy, a member nation of the agency, has yet to confirm its participation in the Venus project. The country has until mid-October to decide.

Venus resembles Earth in size and mass, but it evolved into a scorching inferno with a poisonous atmosphere that cloaks the surface and temperatures that can melt lead.

The planet probably had water when it formed 4.5 billion years ago but lost its liquid reserve to evaporation when a runaway greenhouse effect overwhelmed it, whereby it absorbed more solar energy than it reflected back into space, scientists theorize.

The Venus Express, by making atmospheric observations and conducting subsurface radar readings, could help explain what led to the hellish conditions on the planet.