CAPE CANAVERAL - NASA's shuttles are free to resume
night launches.
Senior managers decided
late this week to evaluate daytime or nighttime launch requirements on a
mission-by-mission basis based on the kind of pictures and video its engineers
need of the shuttle and its external tank during the first minutes of flight.
For NASA, the decision gives managers the
flexibility they need to fly 15 or so more missions necessary to finish
building the International
Space Station by 2010.
For the rest of us, the
change offers a chance to once again witness the unique spectacle of a
nighttime shuttle launch turning darkness to daylight along the Space Coast.
The first night launch will
be the next
shuttle mission, set to blast off at 9:38 p.m. on Dec. 7. Kennedy Space
Center launch crews remain on track to make that target.
Launching at night poses no
threat to the safety of the shuttle or its astronaut crews, according to an
agency document summarizing the decision.
NASA imposed daylight
launch restrictions after the 2003 Columbia catastrophe.
The goal was to get clear
photographs and video of the launching shuttle and of the external tank as it
falls away from the orbiter in space. Engineers needed the images to help
determine if changes made to the external tank stopped its foam insulation from
peeling off in flight and smashing into the orbiter, the long-neglected problem
that was blamed for the loss of Columbia and seven astronauts.
NASA always planned to lift
the restriction after two
flights.
Instead, it took three
flights for the agency to gain confidence that the tank foam will no longer
come off in large enough chunks to damage the shuttle's heat-shielding.
Once Atlantis landed
safely, NASA managers said they were confident
they would be able to eliminate the daylight launch restrictions.
However, managers waited
for experts to analyze all of the available data before making an official
decision.
The restrictions not only
required the shuttle to launch during daylight on the ground at KSC, but at
times when the external tank [image]
would be illuminated by the sun as the orbiter dropped it in space.
That way, astronaut photographers and digital
cameras mounted in the spaceship's belly could snap pictures to see if any big
pieces of foam were missing.
The requirement created
short windows several times a year when a shuttle could launch and meet the
rules.
Being able to launch at
night makes most days of the year available.
NASA will look at missions
individually and could impose the restriction on particular flights if there is
a specific need for certain kinds of launch imagery.
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