The Air Force Space Shuttle Program: A Brief History

(NASA)

The Air Force Space Shuttle Program: A Brief History

E. J. Tomei

The Air Force had high hopes for its West Coast shuttle complex. But despite years of preparation, this state-of-the-art facility never saw a shuttle launch.

On January 1, 1986, the maiden flight of the Air Force space shuttle program was just six months away. This flight, mission 62-A, would mark the beginning of the Air Force's shuttle launch service from Vandenberg Air Force Base in California. The crew—which included Edward "Pete" Aldridge Jr., then Secretary of the Air Force—was completing preflight training at Johnson Space Center in Houston, Texas. The space shuttle Discovery had accomplished its latest mission in August 1985 and was being serviced at Kennedy Space Center in Florida prior to its shipment across the country. The external tank, which carries the fuel and oxidizer for the orbiter's main engines, was being certified in the checkout facility at Vandenberg, and the solid-rocket booster segments were in prestack processing at the solid-motor facility. The first payloads were nearly set to go, pending final integration. Vandenberg's flight-hardware processing facilities were ready, and Space Launch Complex 6 (SLC-6), where the space shuttle would launch, was nearing the end of its operational readiness testing. Meanwhile, Aerospace personnel were wrapping up their training at Kennedy Space Center, Johnson Space Center, and Vandenberg to support launch operations. Among its many firsts, the launch of mission 62-A was to be the first human spaceflight into polar orbit.

Flight crew for the inaugural Air Force space shuttle flight 62-A, planned for Vandenberg Air Force Base. Clockwise from top left: Edward "Pete" Aldridge Jr., Robert Crippen, Brett Watterson, Dale Gardner, Jerry Ross, Mike Mullane, Guy Gardner. Not shown is Randy Odle, who was backup on 62-A. (NASA)

A Long Road

These final preparations marked the culmination of a long and intense development process that included extensive Aerospace support. In fact, the Air Force space shuttle program dates back to 1971, when the first conceptual studies concerning payload capability, upper stages, and launch sites were initiated. The Air Force began these studies in concert with NASA, but each organization had somewhat different priorities. NASA, for example, was most concerned with planetary exploration and scientific missions using satellites inserted in equatorial orbits. The Air Force, on the other hand, needed to launch critical defense and reconnaissance satellites, primarily into polar orbits.

Aerospace participated in early studies that showed a West Coast launch site for Air Force missions would be needed to complement NASA's East Coast launch site at Kennedy. Launch-site studies in 1974 led to the selection of SLC-6 at Vandenberg, which was well situated for launching classified satellites into polar orbits. The complex had been built in 1969 to launch the Air Force's Manned Orbiting Laboratory, but was never used because the program was canceled before first flight. By modifying the existing structures on this site, the Air Force hoped to save $150 million in construction costs.

These cost savings never materialized. Instead, the launch complex went through an extensive series of redesigns to satisfy changing requirements. Some of these changes reflected new Air Force mission requirements, while others arose to meet changes in the space shuttle itself, which was still evolving in response to NASA testing, which was proceeding in parallel with SLC-6 construction.

Aft solid-rocket booster segment and pallet (weighing 200 tons) on its state-of-the-art 100-ton elevating and leveling transporter.

Aerospace oversaw facility design studies that led to the unique features of SLC-6 needed for Air Force missions, such as a secure payload processing facility within 300 meters of the launchpad. Aerospace was responsible for developing system and facility specifications, supporting contractor selection, evaluating designs, developing activation plans, and overseeing the final construction and activation testing of SLC-6 and other facilities for flight hardware processing, control, and crew operations.

Special attention and analyses were necessary to adapt the existing site to the special requirements of the space shuttle. These included small-scale test programs and extensive analyses of liftoff loads and dynamics, ice formation, launch vibro-acoustics, orbiter handling and space shuttle assembly, flight crew emergency egress, sonic booms, and hazards to the closely spaced facilities and surrounding environment.

Groundbreaking Work

Modification of the abandoned SLC-6 for space shuttle operations began in January 1979 (see sidebar, Space Launch Complex 6). A small contingent of Aerospace engineers was stationed onsite from the start of construction; a larger complement would follow afterward, when the entire program office would be moved from Los Angeles to the launch site at Vandenberg.

Most of the refurbishment focused on the main launch complex, though SLC-6 itself was not the only challenge. The Air Force space shuttle program also required a landing strip nearly 5 kilometers long and various specialized facilities—for mating and demating the orbiter and its 747 carrier aircraft, orbiter maintenance and checkout, flight crew preparation, logistics and supply, processing the external tank, refurbishing the solid-rocket booster, and recovering the solid-rocket booster. Aerospace oversaw the design, construction, activation, and operational readiness testing of all these installations, including the commissioning and sea trials of the naval vessel for retrieving the solid-rocket boosters after launch.

External fuel tank for the inaugural Air Force space shuttle flight 62-A arriving at the checkout facility at Vandenberg.

While assisting the facility development, the Vandenberg team also participated in space shuttle testing at Johnson Space Center, Marshall Space Flight Center, and Kennedy Space Center leading up to the first NASA launch in April 1981. Aerospace helped formalize the lessons learned from these efforts, reported them to the Air Force, and ensured that they were implemented into the systems at Vandenberg.

Partly because of the location, and partly because of the different nature of Air Force missions, the new facilities at Vandenberg required capabilities that the NASA complex at Kennedy did not provide. For example, SLC-6 had a 4000-ton moveable wind screen standing 70 meters tall to shelter the orbiter during mating with the external tank. Sound suppression was enhanced through a 3-meter-diameter underground water system flowing nearly 3.8 million liters per minute. This water system absorbed the launch acoustics generated by the rocket thrust and prevented its reflection into the flight systems and payloads. A water-treatment facility reclaimed nearly 1.9 million liters of this sound-suppression water, which was contaminated with exhaust products from the solid motors after each launch. A unique hot-gas heating system powered by a pair of turbofan engines was used to prevent ice formation on the external tank. The payload processing facility (which was designed to handle three 4.5 X 18-meter satellites simultaneously) was equipped with state-of-the-art electromagnetic shielding. A 15-megawatt power plant provided dedicated power for all these facilities. The whole complex employed a seismic design capable of withstanding a severe earthquake.

The first planned payload for the inaugural Air Force space shuttle flight consisted of five experiments for modeling Earth's upper atmosphere. It is shown in the payload bay of the Columbia, which brought it into space in April 1991. (NASA)

Artist's rendering of Teal Ruby, the second payload planned for the inaugural Air Force space shuttle. This experiment was intended to test infrared sensor arrays for detecting aircraft from space. It was never flown in space. (U.S. Air Force)

With construction nearly complete, the Aerospace program office was transferred to Vandenberg in early 1982 to support formation of a site-activation task force. Operational verification testing began in 1984, and a joint NASA/Air Force operations team was formed, with Aerospace in the lead technical support role for the government. Facility verification tests using the orbiter Enterprise (an unpowered experimental model that was deployed from a jumbo jet, not launched from a launchpad) were completed in March 1985. All systems were go for an auspicious first launch in the summer of 1986.

All Systems Stop

That first launch never happened. On January 28, 1986, the Challenger accident resulted in the death of seven astronauts and the demise of the Air Force's space shuttle plans. The White House rescinded its 1982 mandate requiring all government payloads to fly on the space shuttle and instructed the Air Force to restart the expendable launch vehicle production lines. The space shuttle facilities at Vandenberg were once again abandoned, partly because the investigation into the Challenger failure resulted in design changes that rendered the shuttle incapable of lifting the satellites planned for polar flights out of Vandenberg. The Aerospace space shuttle program office was disbanded, and its personnel were reassigned to the new expendable launch vehicle programs and advanced launch studies. The primary payload flew on a later space shuttle mission out of Cape Canaveral; however, the second payload, Teal Ruby, never flew in space. The remaining DOD shuttle payloads planned for Vandenberg were placed on the manifest for the older Titan 34D and the new Titan IV launch systems. No human spaceflight has yet taken place in polar orbit.