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
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."