CAPE
CANAVERAL, Fla. - NASA engineers are poring over systems that control the space shuttle Atlantis' twin
solid rocket boosters to determine whether to once more delay the orbiter's
planned liftoff due to a powerful
lightning strike at the launch pad, agency officials said Sunday.
Atlantis
and its six-astronaut
crew could still launch toward the International Space
Station (ISS) as planned on Monday at 4:04:14 p.m. EDT (2004:14 GMT), but
if more invasive booster checks are needed a delay to Tuesday or beyond is
possible, NASA spokesperson George Diller told SPACE.com.
"We have
not officially made a decision to go for Tuesday," Diller said. "It is a
developing story."
Atlantis' STS-115
mission to deliver a $371.8-million
set of new trusses and solar arrays to the ISS has already been delayed
one day - from a planned
Sunday launch - due to a powerful bolt of lightning that struck the orbiter's
Pad 39B launch site Friday. The 100,000-amp bolt of lightning struck the pad's
lightning protecting system, though engineers registered a small spike in one
of the Atlantis' three electrical buses and a larger surge in a system that
allows a hydrogen vent arm to pull free from the orbiter's external tank just
before launch.
STS-115
Mission Management Team chairman LeRoy Cain opted Saturday to scrub the planned
space shot for 24 hours to allow the system checks necessary to determine whether
other orbiter or launch pad systems were affected by the lightning strike,
which is considered the strongest ever seen at a NASA launch pad.
While
engineers have good data on Atlantis' systems during the strike - it was that
data that showed the electrical bus spike - they do not know whether the
shuttle's two solid rocket boosters experienced a similar glitch since they
were powered down at the time, NASA spokesperson Bruce Buckingham said.
Engineers
want to determine whether the electronics associated the boosters' explosive
pyrotechnics, used to separate the rockets from the launch pad at liftoff and
from Atlantis' external tank about two minutes into flight, NASA officials
said.
Diller said
engineers are working to determine whether they have enough data on orbiter's
solid rocket booster systems. Based on that assessment, mission managers will
decide whether Monday is still a viable launch day or whether to push to a
Tuesday flight plan.
Cain's
management team assembled in an impromptu meeting late Saturday night, and will
meet again today for an update on that work.
Weather
forecasts for both Monday and Tuesday are favorable, with an 80 percent
chance of good launch conditions, shuttle weather officials have said.
NASA's
window to launch Atlantis extends
through Sept. 7, when the agency plans to stand down to allow a Russian
Soyuz spacecraft to launch toward the ISS on Sept. 14 with a new station crew
aboard.
A press
briefing is expected some time around midday, NASA said.
An added
complication in NASA's Atlantis launch preparations is Hurricane
Ernesto, which grew from a tropical storm into a full-blown hurricane one
day earlier than expected today, with current forecasts predicting a path bound
for the west coast of Florida later this week.
Space
shuttles are typically rolled back into the safe shelter of the agency's
massive, 52-story Vehicle
Assembly Building if flight controllers expect winds in excess of 70 knots
at the launch pad, according to NASA documents.
NASA continues
to watch Hurricane Ernesto's development and path to determine if it will
impact launch preparations should an extended flight delay become necessary,
NASA spokesperson Lisa Malone said.
Today's
planned midday status update will be held on NASA
TV. You are invited to follow the briefing using SPACE.com's NASA
TV, which is available by clicking
here.
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