Delta II finally launches with Dawn

by Chris Bergin

A United Launch Alliance (ULA) Delta II launch vehicle has launched with the Orbital Sciences built Dawn spacecraft – en route to the asteroids Vesta and Ceres. Launch was at 7:34am Eastern, from Pad 17B at Cape Canaveral, slightly delayed by a ship entering the downrange field. covered the launch as a live event, with extensive background, live updates, images and free video (available now), on the links below (read more).


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‘Dawn has risen, and the spacecraft is healthy,’ said the mission’s project manager Keyur Patel of JPL. ‘About this time tomorrow [Friday morning], we will have passed the moon’s orbit.’
‘Dawn will travel back in time by probing deep into the asteroid belt,’ said Dawn Principal Investigator Christopher Russell, University of California, Los Angeles. ‘This is a moment the space  science community has been waiting for since interplanetary spaceflight became possible.’

‘After over four years of designing, building and testing the Dawn spacecraft, Orbital’s entire staff is very excited that it is now on its way to completing a historic, first-of-its-kind mission to rendezvous with and study the asteroids Vesta and Ceres, which will help us understand how our solar system was formed. We are delighted to be a key member of the team that is carrying out such an important scientific investigation,’ said Mr. Carl Marchetto, Executive Vice President and General Manager of Orbital’s Space Systems Group.

Marchetto also noted, ‘After a picture perfect launch into the early morning Florida sky, Orbital has entered a new market for our satellite business. With the Dawn mission, we have an excellent opportunity to display our deep space capabilities and look forward to participating in future spacecraft programs that support NASA’s Vision for Space Exploration.’

“With the launch of Dawn, ULA is continuing to show its dedication to
providing safe, cost-effective, reliable access to space for U.S.
government missions,” said Mark Wilkins, vice president of Delta Programs.

“ULA has brought together the most talented professionals in the launch
industry and we are honored to launch spacecraft, such as Dawn, supporting
NASA’s critical national mission to explore the universe.”

Mission background:

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).

It was during mating of those boosters that engineers were forced to cease processing of the Delta II launch, after the crane – used to hoist the solids into place along the outside of the Delta II’s first stage – broke down with a bushing problem. That was just one of many delays to getting this mission off the ground.

Shortly after, Dawn suffered accidental damage by a technician during processing, while the spacecraft was on the ‘spin table’. The damage was caused by a torque wrench slipping off the bolt head while torquing the clamp bandas, on to the power generating panel.

However, contractors managed to carry out repairs on the damaged panel. (A full presentation of the damage is available on L2).

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.

Full mission background is available on the live event page – linked above.

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