CAPE
CANAVERAL, Fla. - NASA's chances of launching the shuttle Atlantis toward the International Space
Station (ISS) Sunday have dropped slightly due to impending thunderstorms,
weather officials said Friday.
Shuttle
weather officer Kathy Winters said Atlantis now has a 60 percent chance of
rocketing spaceward at 4:29:57 p.m. EDT (2029:57 GMT) Sunday, down from 70
percent Thursday, because of stormy weather and thick clouds expected during
the spacecraft's countdown.
"We'll
probably go red during the countdown," Winters said, referring the weather
status near Atlantis' Pad 39B launch site.
The main
concern for launch involves anvil clouds, electrically charged clouds
associated with thunderstorms, which could be within 20 nautical miles (37 kilometers),
of the Kennedy Space Center (KSC). The clouds can spawn lightning during
shuttle flight and must be clear of NASA's
Shuttle Landing Facility should Atlantis be forced to make an emergency
landing.
Weather
willing, Atlantis' STS-115 astronaut crew will carry a new pair
of solar arrays and a 17.5-ton set of trusses to be installed on the port
side of the ISS.
NASA has
four opportunities to launch Atlantis in five days beginning with the Aug. 27
attempt. The shuttle's launch window extends through Sept. 7.
Winters
said weather experts are also watching Tropical Depression 5, which is moving
through the Caribbean. The storm may strengthen into Tropical Storm Ernesto
soon and become a Category 1 hurricane by next week, as it builds strength in
the Caribbean. While the depression is not expected to impact the launch of
Atlantis, it could affect the KSC launch site or even NASA's Houston, Texas-based
shuttle and ISS mission control operations at Johnson Space Center.
"It could
be a threat to any of those locations," Winters said, adding that the next few
days will shed more light. "Everybody's just monitoring the situation."
Stormy
weather has already impacted Atlantis' launch preparations, though it appears
to be the only concern facing launch controllers at this time.
"There are
no smoking guns that I'm aware of, so to speak," NASA test director Pete
Nickolenko said during the briefing. "Technically, the vehicle is in great
shape."
Flight
controllers began the shuttle's launch countdown six
hours early Thursday in order to load the cryogenic liquid oxygen and
liquid hydrogen used to power the orbiter during its planned
11-day mission. Engineers began pumping the super-cold propellant into
Atlantis' fuel tanks at about 9:30 a.m. EDT (1330 GMT) this morning, and hope
to finish by 2:00 p.m. EDT (1800 GMT), though afternoon thunderstorms - an
ever-present concern this time of year at the launch site - could delay the
process.
Nickolenko
said heavy rain, lightning and thunderstorms Thursday afternoon also prevented
pad workers from closing Atlantis' payload doors - originally slated for noon -
until about 9:45 p.m. EDT (0145 Aug. 25 GMT).
Aside from
weather, no technical issues have popped during the STS-115 launch countdown.
One leftover item - final analysis of an auxiliary power unit (APU) glitch on
Atlantis' sister ship Discovery - will be presented to the spaceflight's
Mission Management Team (MMT) during a launch readiness review later today. The
issue is expected to be cleared at that time, shuttle officials said.
"All of our
teams are ready and their focused," Nickolenko said. "We're all looking forward
to launch on Sunday and the return to [ISS] assembly."
advertisement
