First Transcontinental Return Since Columbia

When the shuttle Discovery flies home to Kennedy Space Center this week, wrapping up its over-two-week-long trip to the International Space Station, it will do so on path over the continental United States... the first time a shuttle has done so since the February 2003 loss of Columbia.

As ANN reported, Discovery's first landing opportunity at Florida's Kennedy Space Center will be at 1302 EST Wednesday. If that window is approved, the shuttle will fire its engines to deorbit at around noon.

The return will be accompanied by double sonic-boom -- which people along a southeasterly line from southwestern Canada, through the Dakotas, Nebraska, Arkansas, and Georgia should be able to hear. They may be able to see the orbiter, as well... though the daylight conditions will make that problematic.

"Landing in daylight is a safer and easier task than landing in the dark," shuttle program manager Wayne Hale told ABC News. "The commander of this flight has requested a daylight landing, with a little sleep shifting. It is an easy thing to do for us, and the crew is well rested."

Since the shuttle program resumed in 2005, orbiters have approached KSC from the south, deorbiting over the Indian Ocean; or, landed at California's Edwards AFB, approaching over the Pacific.

The "descending node" approach will give millions of people across North America the opportunity to experience, if only briefly, a part of Discovery's STS-120 mission... but in the shadow of the 2003 loss of Columbia, for many it's also cause for some concern.

Columbia followed a southern track over the US when it reentered the atmosphere. The orbiter -- compromised by a hole in the reinforced carbon-carbon leading edge of its right wing, that allowed superheated gases to compromise its internal structure -- broke up over California, Nevada, Arizona, and New Mexico. Most of the debris fell in Texas.

Since that tragedy, NASA has performed numerous, detailed inspections of the shuttle's fragile heat shield on each mission, looking for the type of damage that doomed Columbia.

The agency also keeps a close eye out during launch for falling foam from the shuttle's external fuel tank, the culprit in the loss of Columbia. NASA engineers have also redesigned sections of the tank, to reduce the chance of falling foam, with varying levels of success.

Discovery has received a clean bill of health for its return, NASA said.

(Landing track graphic courtesy of NASA)

FMI: www.nasa.gov