The Dawn mission won’t be delayed past it’s July 7 launch date target, despite news of damage occurring on part of the spacecraft.
Believed to be a solar array that was damaged when – as later confirmed “damage caused by the torque wrench slipping off the bolt head while torquing the clamp bandas” on to the power generating panels – engineers are carrying out evaluations on Dawn to find out what is the full extent of the damage.
**Dawn mission – Live Update Pages** – L2 Members can download a presentation full of images of the damage.
The damage occurred during processing for the July 7 launch, when the spacecraft was on the ‘spin table’ on Monday. Delta II engineers and managers have been conducting a series of teleconferences to ascertain the status of the launch date.
The Dawn mission recently saw its launch date slip when United Launch Alliance (ULA) engineers were orced to cease processing of the Delta II launch vehicle, which is set to carry the Orbital Sciences spacecraft from LC-17B at Cape Canaveral Air Force Station.
That happened when a crane – used to hoist the solids into place along the outside of the Delta II’s first stage – broke down with a bushing problem.
The problem occurred during the mating of the first of nine solid rocket motors, with the process ceasing due to noise being heard from the top of the crane, which was followed by troubleshooting, as exclusively revealed by this site at the time. This caused a week’s delay to the launch date.
The Delta II being used to launch Dawn is the 7925-H version, the heavier-lift model of the standard Delta II that uses larger solid rocket boosters (GEM-46).
Dawn was originally set to launch in June of 2006, before a program review of the mission – to explore two of the largest bodies in the asteroid belt, Vesta and dwarf planet Ceres – was subsequently cancelled due to technical issues and cost-growth.
However, the mission was then reinstated for the June, 2007 launch, following protests from planetary scientists.
The Dawn spacecraft is powered by an Ion engine, which, at its maximum thrust, can expend only about 0.25 kg of xenon per day, changing the spacecraft’s velocity by 10 m/s.
The spacecraft is destined to rendezvous and orbit both Vesta and Ceres in 2011 and 2015, respectively. The trip from Earth to Vesta is about 2 billion miles, while the journey from Vesta to Ceres is about 1 billion miles.
Further information on the status of Dawn will be updated in this article when available.