More Delays For Dawn?

NASA's trouble-plagued Dawn spacecraft may suffer yet another delay to its launch, as agency administrators announced Tuesday the planned July 7 target date may be overly optimistic due to continuing glitches with the Delta II launch rocket, and difficulties with coordinating launch support.

The Whittier (CA) Daily-News reports engineers at Cape Canaveral, FL are racing against the clock to meet the planned launch date. As ANN reported, that date was already moved off once, after a crane used to stack segments of the Delta II booster broke down. A worker's wrench also fell on the spacecraft's solar panel during a procedure to prepare the spacecraft for spin-balance testing, though it did not damage any cells.

If NASA isn't able to send Dawn skyward by July 12, the next opportunity would be in October. Dawn must be off the pad by then, to make room for the booster carrying the Mars Phoenix rover, which needs to blast off by August 25 in order to make its once-every-two-years launch window.

Dawn -- slated to eventually study the twin asteroids Ceres and Vesta, between Mars and Jupiter -- doesn't face such strict launch constraints, as its novel ion propulsion system offers greater manueverability after launch to correct its trajectory. But a delay would be yet another blow to the program nonetheless.

"There are other options for Dawn, but they come at a fairly large cost," said NASA deputy administrator Todd May. "If we were to jump over the Phoenix launch at this point, first of all you get into hurricane season, but second of all it's a fairly large budget hit to do that -- and frankly there's no guarantee to get off at that time either."

Such a delay could add another $25 million to the nearly half-billion cost of the mission, which was (increasingly ironically) cancelled by NASA in early 2006 due to cost overruns. NASA reinstated the mission after the scientific community protested.

"If we move to September or October, I'm very confident we could do a terrific scientific mission that would be every bit as good as we could do if we launched in July," said Marc Rayman, the mission's project systems engineer at the Jet Propulsion Laboratory. He added, however, that "by late October, even with the tremendous propulsion of the ion propulsion system, we wouldn't be able to make it to the two bodies in the asteroid belt."

Stay tuned...

FMI: http://dawn.jpl.nasa.gov/