Bidding Adieu To The Shuttle

April 12, 1981, was an exciting day for the National Aeronautics & Space Administration: it was the day the agency first launched astronauts into space aboard the space shuttle. Billed by NASA as “humanity’s first reusable spacecraft,” the shuttle was to make travel into low Earth orbit similar to travel across the country on a jet airliner. The five shuttles—Columbia, Challenger, Discovery, Atlantis, and Endeavour—have collectively traveled beyond Earth’s atmosphere some 135 times, carrying nearly 360 people into microgravity. When the final flight of shuttle returned to Earth on July 21, the program became history.

NASA’s shuttle program hasn’t been all rosy. Fourteen astronauts perished in two shuttle disasters that drove home the inherent dangers of traveling to and from space. On the economic front, the shuttle program cost $113.7 billion in noninflation-adjusted dollars over its lifetime, according to NASA.

Was it all worth it? It depends. The early shuttle missions were key in delivering satellites into space. No other spacecraft in the world has the shuttle’s cargo capability: It can carry satellites or other cargo weighing up to 50,000 lb in its payload bay, which measures 15 feet by 60 feet. It was Discovery that launched the Hubble Space Telescope into orbit in April 1990. Subsequent shuttle missions to the telescope repaired a faulty mirror and, most recently, provided equipment to extend the telescope’s life. Hubble has yielded (and continues to yield) a wealth of information about far-off galaxies and nebulae. The magical pictures of these heavenly bodies continue to capture people’s imagination.

The shuttle’s large cargo capacity was also helpful in the construction of the International Space Station 200 miles above Earth’s surface. Since making the first delivery of huge ISS components in December 1998, the shuttles have made nearly 40 trips to the growing orbiting space lab. The station is now fully operational, but with the retirement of the shuttles, the U.S. will have limited access to it. After spending billions of dollars to build ISS, the U.S. must now rely on Russia for room in its space capsules to send U.S. crews to and from the station.

In addition to launching satellites and enabling the construction of a space station, the shuttle program has contributed to science. According to NASA, more than 2,000 experiments have been conducted on the five shuttles in the fields of earth science, biology, materials science, and astronomy . The swan-song mission, for example, includes a preclinical test of a sclerostin antibody (C&EN, July 11, page 20).

On the basis of these accomplishments, the shuttle program helped push the boundaries of science and engineering. It’s a source of pride and inspiration, and it solidified U.S. leadership in space.

Weighing against these benefits are the tragic costs of the shuttle program. Like many others, I can recall exactly where I was when I learned that shuttle Challenger had exploded shortly after takeoff on Jan. 28, 1986. The cause: a leaky O-ring seal in its right solid rocket booster that failed at liftoff. The disaster was a significant blow to NASA, which some argued had gotten complacent about the dangers of space travel. The lost crew of seven included Christa McAuliffe, who would have been the first teacher in space. Selected from more than 11,000 applicants, McAuliffe was the first and last civilian NASA would add to its shuttle crew.

After more than two years of grounding the shuttles, NASA resumed launches in the fall of 1988. Over the next 14 years, the agency completed nearly 90 missions. In fact, shuttle missions became nonevents, with little or no news coverage of launches or landings. Again, space travel began to take on an air of ordinariness—until another tragedy rocked the program.

On Feb. 1, 2003, during reentry into Earth’s atmosphere, Columbia disintegrated. The cause was a breach in the protective heat shielding, created when a piece of debris shed by the fuel tank during takeoff struck the spacecraft. Seven astronauts died, and the program was again put on hold for more than two years. Flights resumed in 2005, with 20 of the final 21 flights going to ISS and one, in 2009, to service Hubble.

In terms of dollars, the shuttle program was expensive. The cost of building the youngest of the fleet—Endeavour, which replaced Challenger—was approximately $1.7 billion, and recent launch costs approached $800 million per mission. Many worried over the shuttle’s lifetime that funding for these missions came at the cost of other, more fruitful scientific activities.

History is likely to appreciate the shuttles for the technological marvels that they are—each spacecraft has 2.5 million moving pieces— and for their contribution to science; and for the inspiration they provided the nation to think big.