Space shuttle: home coming options.

Space shuttle: Homecoming options

Though getting the space shuttle up and into orbit for the first time in 2 1/2 years is the main focus of attention - the launch is now scheduled for Aug. 4 - NASA is also working to ensure that there is a choice of safe places for the craft to land.

The primary site is still runway 17 at Edwards Air Force Base in California, where 18 of the 24 successful shuttle flights ended. Rain can be a factor even in the Mojave Desert, however, and five shuttles have descended directly from orbit to Kennedy Space Center (KSC) in Florida. Since this is where the shuttles are launched, landing at KSC eliminates the need to bolt the craft atop a Boeing 747 jet and fly it back east so it can take off again. But direct KSC landings stopped with Mission 16 on April 19, 1985, when the shuttlecraft Discovery blew a tire and suffered brake damage as it touched down on the rough-surfaced runway. KSC's 15,000-foot runway is also less than half as long as the one at Edwards, and much narrower, making the West Coast facility the strong preference of the astronauts who must bring the shuttle safely back from space. In addition, KSC is often beset by rains on short notice, so that its landing strip is sometimes unavailable.

As a result, the Florida facility is not even NASA's second choice. The agency has now designated "White Sands Space Harbor" (formerly known as Northrup Strip) in New Mexico as the backup site for at least the next three shuttle missions, with KSC to be used only if needed for emergencies. The one shuttle mission that ever landed at White Sands, No.3 in March of 1982, was sent there because of rain that had left the Mojave strip-a dry lake bed-muddy.

Even so, work was begun on Jan.29 to modify the shuttle landing strip at KSC, smoothing 3,500 feet of the surface at each end and replacing a series of grooves that run across the strip with narrower ones that are aligned lengthwise like a "corduroy road". The primary purpose of the alterations, according to KSC officials, is to reduce tire wear, though another goal is to hasten the disappearance of water from the frequent rains. In addition, landing-light fixtures are being modified, and markings are being repainted on the entire runway. Although the KSC strip will initially serve only as a "backup backup" shuttle landing site, NASA says the landing site options "will be reassessed after the next three missions."