Shuttle Lessons Applied To Commercial Crew

From Aviation Week: Shuttle Lessons Applied To Commercial Crew
CAPE TOWN, South Africa — Space Exploration Technologies Inc. (SpaceX) and other companies developing commercial crew transportation for the International Space Station (ISS) are applying the hard-won lessons of the space shuttle era as they develop their new vehicles, according to John Shannon, NASA’s last shuttle program manager.

The reason, in part, is that the commercial companies have hired experienced shuttle engineers away from NASA to help with the new vehicles being developed under the agency’s Commercial Crew Development (CCDev) seed-money effort.

“I’m very saddened, but I feel very comfortable,” Shannon told the 62nd International Astronautical Congress (IAC). “I’ve lost three of my most senior shuttle people that were in the program, that I would trust doing anything, to commercial companies.”

Shannon presented engineering lessons learned during the 30-year shuttle program in a special hour-long IAC session moderated by his boss, William Gerstenmaier, associate NASA administrator for human exploration and operations. Taking four examples from the shuttle program — the digital flight control system, space shuttle main engine, thermal protection system (TPS) and external tank — Shannon says the program had the best results in those areas where testing and the search for improvements were continuous.

Engineers working flight software and the main engine continued to probe for the edge of the engineering envelopes in their systems throughout the life of the program, he says, using real software in simulations run with real crews and flight controllers, and pushing the boundaries of engine operations in hot-fire tests at Stennis Space Center in Mississippi.

As a result, the engines and flight software got better and better, overcoming inevitable development glitches to become extremely reliable in the later years of shuttle operations. By contrast, the TPS and tank projects did not have that “stay hungry” approach, with tragic results in the Columbia accident.

“If you think you can just design a rocket system and walk away from it, you’re wrong,” says Shannon, who advised the Columbia Accident Investigation Board before overseeing the return-to-flight efforts to prevent the tank from shedding foam, and to develop TPS inspection and repair techniques.

Shannon says it is “a little unfair” to suggest that the commercial companies working on new vehicles under CCDev may let their hunger for profits overshadow the stay-hungry approach he advocated.

“I love the fact that SpaceX, for example, is testing at McGregor [Texas] daily,” Shannon says. “They are doing propulsion testing like you ought to do propulsion testing. . . They’ve got a very hungry attitude in that they want to have problems that they can go correct and make the system more robust.”

SpaceX and Orbital Sciences Corp. both plan to fly cargo to the ISS commercially as early as next year, under NASA’s $500 million commercial orbital transportation services development cost-sharing program. Orbital suffered a setback when a fuel leak damaged an AJ26 engine during a test in June. Testing has resumed, and Shannon says that company, too, is taking the right approach.