NASA delays Dawn again

Brief Dawn, NASA's mission to the asteroids, has been postponed again - this time until September. Mission managers had hoped to launch on Monday, but the final decision to delay was taken on Saturday.

Bad weather and fears of lightning strikes meant that the mission, which was originally set to launch on July 4, was postponed a couple of times last week, with engineers hopeful that things would come together on the Sunday.

But late on Friday, NASA said difficulties with a downrange telemetry aircraft and the lack of an available tracking ship mean the launch could not take place before July 9.

Having missed this deadline, NASA said the remaining launch windows in July are too narrow, while an August launch could have interfered with the start of the Phoenix Mars lander mission.

Dawn is set to explore the asteroid belt, particularly two of the largest bodies, Vesta and Ceres. NASA says it wants to study the asteroid belt to help understand the processes that went on as our solar system formed. ®