Search for Earth-like planets delayed by satellite crash

The launch of a Nasa telescope that will search the Milky Way for planets with the same life-sustaining characteristics as Earth has been postponed for at least a day by the crash, shortly after blast-off, of the space agency's "Carbon Observatory" satellite last week.

Originally set for this Thursday, the lift-off from Cape Canaveral in Florida of the Kepler space vehicle and the super-powerful telescope it will carry will now not happen before late Friday at the earliest, officials said. They also need approval for the new blast-off window from the US air force.

Kepler's 95 mega-pixel telescope will survey as many as 100,000 stars in the Cygnus-Lyra region of the Milky Way. Specifically, however, it will be hunting for planets orbiting alien stars. The mission, one of the most ambitious in Nasa's history, should last three years.

The agency took a harsh knock early last week, when a satellite designed to map the distribution of carbon dioxide in the Earth's atmosphere plummeted into the ocean near Antarctica minutes after blasting off from California.

Announcing the delay of the Kepler launch, Nasa said that it needed to study all possible "areas of commonality" with the technology used in the CO2 satellite launch. These appeared limited, though. Most importantly, while the doomed satellite was lifted by a Taurus XL rocket, Kepler will be carried on a Delta II.

When it begins its census of the distant stars, the telescope will attempt to identify "winking" stars. Their luminosity dims when orbiting planets pass in front of them. Kepler will then look specifically for planets orbiting in the habitable zone of stars, where temperatures would permit the existence of water in a liquid state, the first indicator of possible life.