Monday, December 8, 2008

Endeavour up close and personal

The East Kern had an unexpected visitor on November 30th as the Space Shuttle Endeavour was forced to land at Edwards Air Force Base due to bad weather at its Kennedy Space Center primary landing site. The landing was the culmination of STS-126, a servicing mission to the International Space Station, being needed supplies. Because this is generally a rare event, and especially with so few missions left on the schedule, the Dryden Flight Research Center's Public Affairs Office went out of their way to accommodate the media's desire to document the shuttle turn-around process.

Endeavour’s arrival in the East Kern was the 52nd shuttle landing at Edwards. The decision to land a space shuttle at Edwards is typically made only when the weather at Kennedy Space Center in Florida precludes a landing there, and the weather is not expected to improve within the time frame that accommodates the spacecraft’s orbits. In the five years from 1995 to 2000, 31 shuttle missions were able to land at Kennedy without the back-up Edwards site being needed, so with only nine shuttle flights remaining until the fleet is scheduled to be retired, it is quite possible that this is the last operable shuttle that the East Kern will see.

Because Edwards' main runway is undergoing a major upgrade program, Endeavour became the first and only shuttle to use the base's temporary Runway 04. This runway is 3,000 feet shorter than the regular one, and so the braking forces were more intense, and the shuttle program engineers had the main wheels removed for analysis; in their place, for weight and balance purposes, the crews installed yellow-painted ground handling wheels. 

After landing at Edwards, a complicated process is required to prepare the orbiter for a ferry flight back to Florida on the back of the Shuttle Carrier Aircraft (SCA), a specially modified Boeing 747. All of the hazardous fluids and fuels onboard the shuttle are purged in the process, the aerodynamic tailcone is mounted over the engine nozzles and the spacecraft is hoisted up and mated to the back of the 747. Because of the tight time schedule, crews work around the clock.

While the media was being allowed access to the processing area, other VIP tours were underway as well, including astronaut (STS-3 and STS-51) Gordon Fullerton and his family. "Gordo" as the NASA regulars refer to him, is also one of the shuttle carrier 747 pilots.

When a shuttle has to land at Edwards, the diversion costs the program upwards of $1.8 million, about $1.4 million of which is expended bringing the United Space Alliance spacecraft servicing personnel out from Florida, paying for their overtime and local lodging and meals, so while such an event is a burden to the shuttle program, it is a boon for the local East Kern and Antelope Valley economies.

The ferry flight back to Florida itself costs about $350,000, and is accomplished typically over a period of two days. A “pathfinder” aircraft will always fly a couple of miles ahead of the SCA to scout the route for weather. The shuttle is not supposed to be flown through any precipitation, and even flight through clouds is avoided, because of the damage it can cause to the orbiter. The flight is flown at only 15,000 feet altitude, and at about 275 knots, much lower and slower than a 747 typically flies. Due to this flight profile, along with the limited fuel weight capacity of the SCA, at least one refueling/overnight stop is planned, and there are 21 Air Force bases that can be selected from. According to NASA’s Alan Brown, typically the fuel stop location is not selected until right before the departure from Edwards, both for security purposes and for weather planning.

One of the many tasks required to be accomplished is to do a detailed inspection of the heat shield tiles for damage.

To reduce drag while the shuttle is carried on the 747, the main rocket engine nozzles are covered with a large aerodynamic tailcone (NASA has two of these). The cone is trucked from Florida to Dryden disassembled in 14 pieces, and then reassembled.

(A very big thanks goes out to NASA PAO Alan Brown and his staff for their wonderful hospitality!)


Anonymous said...

Wonderful set of historic photographs. I wonder how much that spare set of "ground handling wheels" costs?

Anonymous said...

Awesome look into something that the average Joe would never see.