CAPE CANAVERAL - NASA's shuttles are free to resumenight launches.
Senior managers decidedlate this week to evaluate daytime or nighttime launch requirements on amission-by-mission basis based on the kind of pictures and video its engineersneed of the shuttle and its external tank during the first minutes of flight.
For NASA, the decision gives managers theflexibility they need to fly 15 or so more missions necessary to finishbuilding the InternationalSpace Station by 2010.
For the rest of us, thechange offers a chance to once again witness the unique spectacle of anighttime shuttle launch turning darkness to daylight along the Space Coast.
The first night launch willbe the nextshuttle mission, set to blast off at 9:38 p.m. on Dec. 7. Kennedy SpaceCenter launch crews remain on track to make that target.
Launching at night poses nothreat to the safety of the shuttle or its astronaut crews, according to anagency document summarizing the decision.
NASA imposed daylightlaunch restrictions after the 2003 Columbia catastrophe.
The goal was to get clearphotographs and video of the launching shuttle and of the external tank as itfalls away from the orbiter in space. Engineers needed the images to helpdetermine if changes made to the external tank stopped its foam insulation frompeeling off in flight and smashing into the orbiter, the long-neglected problemthat was blamed for the loss of Columbia and seven astronauts.
NASA always planned to liftthe restriction after twoflights.
Instead, it took threeflights for the agency to gain confidence that the tank foam will no longercome off in large enough chunks to damage the shuttle's heat-shielding.
Once Atlantis landedsafely, NASA managers said they were confidentthey would be able to eliminate the daylight launch restrictions.
However, managers waitedfor experts to analyze all of the available data before making an officialdecision.
The restrictions not onlyrequired the shuttle to launch during daylight on the ground at KSC, but attimes when the external tank [image]would be illuminated by the sun as the orbiter dropped it in space.
That way, astronaut photographers and digitalcameras mounted in the spaceship's belly could snap pictures to see if any bigpieces of foam were missing.
The requirement createdshort windows several times a year when a shuttle could launch and meet therules.
Being able to launch atnight makes most days of the year available.
NASA will look at missionsindividually and could impose the restriction on particular flights if there isa specific need for certain kinds of launch imagery.
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