When the crew members of the Space Shuttle Discovery lift off later this year from NASA's Kennedy Space Center, Fla., they'll be supported by two years of hard work by tens of thousands of people determined to make the Space Shuttle safer. NASA has upgraded flight hardware, as well as visual tracking and inspection equipment, to ensure the Return to Flight mission is successful.The Columbia accident revealed a major problem with the insulating foam that covers the External Tank. Investigators found that foam falling off the tank had damaged Columbia's left wing, letting superheated gases inside. Redesigning the External Tank became a top priority in the Agency's Return to Flight work.
NASA engineers made dozens of changes to the tank design, including one to a key mechanism that joins the External Tank with the orbiter. Jutting from the upper third of the tank, the "bipod fitting" is susceptible to icing due to the ultra-cold fuel that tank contains. Until the Columbia accident, the part was protected from ice buildup using thick sheets of foam. The improved bipod design now excludes using foam and instead relies on electric heaters to keep the area clear. The new fitting design is currently being retrofitted to the 11 existing tanks -- including the one chosen for Discovery's flight -- and will be included on those produced in the future.
Another key change to the tank involves equipment known as the LOX Feedline bellows. The bellows are expansion joints which allow the liquid oxygen (LOX) feedline to expand and contract as it carries fuel from the External Tank to the Orbiter. Because they move, the bellows aren't insulated with foam, which means ice could build up from the minus-297 degree fuel, creating a debris risk. NASA is adding a heater to the area and installing a foam "drip-lip" that prevents condensati
on from building up and freezing.Another major safety improvement to the Space Shuttle fleet is the expanded use of enhanced imaging equipment to record the launch of Discovery as it roars into the sky and glides through space.
At Kennedy Space Center, NASA has upgraded the short-, medium-, and long-range tracking camera system around the Center's launch pads 39A and 39B, along with those lining the nearby Atlantic coastline. The addition of nine more camera sites will provide unprecedented views of Discovery's launch, allowing engineers to clearly observe the flight high into the sky.
Discovery itself also received new imaging equipment with the installation of a digital External Tank camera and new "Canadarm" inspection boom.
Making the most of current consumer photography equipment, the orbiter's External Tank camera has been switched from film to a digital model. Located in the rear underbelly of the orbiter, the camera is similar to a standard 35 mm model and snaps a series of photos as the tank separates from the orbiter. With the previous film camera, flight engineers had to wait until Discovery landed to retrieve the negatives and develop photos. With the simplicity and increased speed of a digital system, the image files will be easily transmitted back to Earth shortly after Discovery reaches space.
