NASA has moved back the launch of one of the most eagerly-anticipated spacecraft for some time, in order to check out concerns regarding its launch rocket. The Kepler telescope, expected by many to discover evidence of habitable worlds orbiting other stars, will wait until March 6 while engineers re-examine elements of its launcher.

NASA's Orbiting Carbon Observatory (OCO) CO₂-measuring sat crashed into the ocean off Alaska last week after the payload fairing on its Taurus XL rocket failed to separate as planned. Kepler will use a Delta II launcher rather than a Taurus, but the two rockets have certain parts in common. It is these which have caused concerns.

Engineers are reviewing all common hardware between the Delta II rocket carrying the Kepler telescope and the Taurus XL launch vehicle. On Tuesday, a Taurus carrying NASA's Orbiting Carbon Observatory failed to reach orbit. Managers want to confirm there will not be similar issues with Kepler's Delta II.

Kepler's original March 5 target launch date was moved one day later to accommodate the additional time for analysis. The March 6 target date still must be confirmed by the U.S Air Force, which manages the eastern launch range.

Kepler, once in orbit, will survey 100,000 stars to see if they have planets orbiting in their "habitable zones" - the spaces around them where a planet could have liquid water on its surface. The presence of liquid water is considered essential for life to arise along the same lines as it did on Earth. Roughly Earth-sized planets in a star's hab zone, even if uninhabited by indigenous life, would also be potentially habitable for Earthly life if it could get there.

At least one serious boffin in America is sure that many such potentially-habitable worlds will be discovered by Kepler, and thus that the existence of life elsewhere in the universe - even if only basic, microbe-level life - is a racing cert. Heavyweight British boffins have also backed this view. ®

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