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.

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. ®

Related stories

• Dawn on its way to the asteroid belt (27 September 2007)
• NASA postpones Dawn (25 September 2007)
• NASA names the day for Dawn raid on asteroid belt (18 September 2007)
• UK plans surveillance for Earth-menacing asteroid (31 August 2007)
• NASA ponders manned near-Earth asteroid visit (1 August 2007)
• The hunt for water on Mars goes nanoscale (31 July 2007)
• NASHA ashtronauts too fly to drunk (26 July 2007)
• Brief Dawn mission hiding out after lightning threat (6 July 2007)
• Solar-powered ion drive asteroid probe set for launch (4 July 2007)
• Pluto's curse named at last (14 September 2006)
• Asteroid may carry more water than Earth (8 September 2005)