A mission to two of the biggest asteroids in the solar system has been reprieved by Nasa just weeks after they cancelled it.
The project’s delighted chief scientist believes that one of the mini-worlds, Ceres, is one of the best places to look for alien life.
The Dawn space mission to Vesta and then Ceres was dropped after costs escalated from around £205million to £255million.
It was scrubbed in a bid to save money to keep the shuttle flying, complete the International Space Station and prepare for manned flights to the Moon and Mars.
Now Nasa has changed its mind after howls of protest from scientists who said the mission would allow them to learn about how the solar system formed 4.6billion years ago.
They also argued that it was vital to learn more about asteroids because of the danger that some could collide with the Earth.
Both Vesta and Ceres are safely out of harm’s way in orbits between Mars and Jupiter.
Dawn is now expected to be launched in summer next year from Cape Canaveral, Florida.
It will swing past Mars in early 2009 and reach Vesta in October 2011 where it will go into orbit for six months.
Vesta is 330 miles wide and the brightest asteroid visible from Earth.
The spacecraft will then head for 600-mile wide Ceres, the largest known asteroid and first to be discovered in 1801, going into orbit around it in August 2015.
Nasa spokeswoman Colleen Hartman said yesterday: “Vesta and Ceres have basically remained intact since their formation.
“Understanding the major asteroids is a critical part of our exploration program as it is the only way to piece together what happened 4.6billion years ago.”
Dawn’s chief scientist Chris Russell said. “Vesta is a rocky planet with an iron core like the Earth. It is one of the building blocks that formed the terrestrial planets.
“Ceres we now know is an ice planet over a rocky core. The water ice may be liquid inside. Thus it is probably a better place to find life than Jupiter’s moon Europa.”

© Paul Sutherland. Unauthorised reproduction forbidden.