After a
week of launch
scrubs, poor
weather and other delays, two NASA satellites successfully reached orbit Friday
to begin their mission to scan the Earth's clouds in three dimensions.
NASA's CloudSat
and CALIPSO spacecraft successfully launched spaceward atop a Boeing Delta
2 rocket at 6:02:16 a.m. EDT (1002 GMT) from Vandenberg Air Force Base in California. The space shot comes after six days of delay caused by glitches, refueling
plane schedules, high winds and poor weather.
"When we
lifted off you could just feel the release," NASA launch director Chuck Dovale
said after CloudSat's deployment. "Not only in watching the vehicle on the pad,
but the release of the folks here in the launch center."
The two
spacecraft are expected to produce unprecedented views of Earth's clouds and
aerosols - fine particles suspended in the atmosphere - that can be used to
track climate change and improve weather forecasts, mission scientists said.
Clouds
and climate change
CloudSat's $185
million mission calls for the probe to peer through Earth's clouds using a
powerful radar 1,000 times more sensitive than typical instruments to identify individual
particles of clouds, rain and snow.
"Clouds
fundamentally influence the greenhouse [effect] of the climate," said Graeme
Stephens, CloudSat's principal investigator at Colorado State University in Fort Collins, before today's launch, adding that Earth's water cycle sets the
pace for greenhouse gases and global warming. "CloudSat is trying to get a
handle on the key aspects of that water cycle."
The $223
million CALIPSO - short for or Cloud-Aerosol Lidar and Infrared Pathfinder
Satellite Observations - carries a laser ranging, or lidar, instrument and two
other tools to identify and characterize aerosol distribution in the Earth's
atmosphere. The spacecraft is a cooperative effort with the French Space Agency
(CNES).
CloudSat
and CALIPSO were deployed - CALIPSO first - in a 438-mile (705-kilometer) orbit
where they are expected to join three other spacecraft already in orbit.
Together with NASA's Aqua
and Aura
satellites, as well as France's PARASOL
spacecraft, CloudSat and CALIPSO will make the "Afternoon Train" (A Train)
of Earth-observation, mission managers said.
Rocky
road to space
Friday's space
shot not only marked the beginning of the joint CloudSat and CALIPSO missions,
but also the end to almost a week of flight delays for the beleaguered
satellite pair.
"It was a
quite difficult mission almost from start to finish," Dovale said of the
launch. "We had quite a few scrubs and in between we days where we called
things off early."
An initial
April 21 launch attempt was
thwarted with just 48 seconds left before liftoff after CALIPSO lost
communications with its support center in France. Flight controllers quickly
reestablished the communications link, but missed the split-second launch window
that day.
Launch
opportunities on Saturday and Sunday were plagued by a different ailment: the
unavailability of a refueling plane needed to supply a radar tracking aircraft
that monitored today's liftoff as the Delta 2 rocket carried CloudSat and
CALIPSO out of range of flight controllers on the ground.
High
winds cropped up four minutes before a Tuesday launch attempt, scrubbing
the attempt, while a poor weather outcast prevented a Wednesday launch
outright.
The final
scrub occurred early Thursday, when a temperature sensor returned errant
readings that prompted engineers to call off the launch and look into the
matter. The issue was later resolved and the launch attempt shifted to Friday.
"This was
technically the fourth attempt...a great success," Dovale said.
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