The Columbia accident report called on NASA to develop a shuttle replacement as soon as possible. As a result, the space agency is taking a new look at spacecraft designs that were once intended to supplement the shuttle strictly as a crew transfer vehicle for the space station, but now might have to serve as a bridge between the shuttle and some next-generation spacecraft based on technology that might not emerge for decades. NASA could have to live with its choice for some time, and that gives the capsule and its ability to leave Earth orbit a big boost. "There's clearly a lot of interest in the capsule design,” said Michael Kostelnick, NASA's number two space-flight official. “When you look at whether we should develop a winged spacecraft or a capsule, the opportunity to do other things beside fly in low Earth orbit weighs very heavily."
Astronauts, designers and Congressional watchdogs who embrace the idea usually talk of an Apollo-style capsule, and to some that means putting the Apollo back into production. But even those who want to design a new ship acknowledge the final product will look and feel essentially the same. Crews of at least six, optimally seven, will be needed to fully staff the ISS, and while the old Apollos never carried more than three astronauts, they were capable of carrying as many as six. Since the onboard electronic systems would take up much less space today than they did nearly 40 years ago, seven may be possible.
Before the Columbia disaster, the capsule plan "wasn't getting a lot of support," says one Congressional source. "The idea of fishing men and women out of the ocean, after we'd been landing people on the runway at the Kennedy Space Center for so many years, just seemed like we were going backwards."
But the loss of Columbia and its crew of seven on Feb. 1 would shake NASA more deeply than the public was generally aware. While NASA administrator Sean O'Keefe was quick to promise, just four hours after the crash, that shuttles would resume normal flight operations as soon as possible, some of the program's staunchest backers were soon nursing doubts about the long term viability of winged spacecraft. With just three orbiters remaining Discovery, Atlantis and Endeavour one more catastrophic accident would mean the program could not support enough flights to keep the space station operating. And an orbital space plane would share many of the same limitations as the shuttle. What if a rocket were about to explode and the commander tried to abort at supersonic speed? The force would simply rip the wings off a space plane. And leaving one docked to the station for months at a time, the way Soyuz lifeboats are today, would expose its thermal tiles and wingpanels, essentially the same system that failed on Columbia, to hits from space debris, perhaps dooming another crew on re-entry.
Suddenly, people remembered that the Russians, despite a reputation for clunky hardware and slipshod workmanship, had been flying capsules with a perfect safety record since 1971, and the U.S. had never lost a capsule crew in flight, though it had lost the Apollo 1 crew to a launch-pad fire and nearly lost Apollo 13 on its way to the moon. Though a capsule was no guarantee of safety, and nothing really could be in an inherently dangerous business, the laws of physics that govern inertia and aerodynamics favor a five-ton bell-shaped capsule over a 100-ton winged shuttle. Among the early supporters of a capsule idea were many of the pilots and commanders in the astronaut corps, even though the shuttle has had no more enthusiastic constituents. "Would I fly a capsule?” says Brian Duffy, a recently retired shuttle commander. “Absolutely."
Expediency is another factor; with the shuttle fleet vulnerable, NASA cannot afford to spend 10 years developing a space plane, as it had planned to before February. The agency would like to test a new vehicle by 2006.
NASA and its Congressional allies will have an easy time pitching a quick return to space to the public, which continues to support space exploration by impressive margins. Safety is a harder sell, since NASA has been touting the shuttle system as safe since the very beginning, and superior to every other spacecraft ever flown. As one Congressional source put it, "If NASA goes with the capsule design, you'll hear a lot about our ability to return to the moon. This may take us there, but that's secondary. Safety is the number one issue. Safety is driving the design."
There are some jobs only the shuttle can do. Its ability to carry large payloads into space will keep the remaining fleet in operation at least until the space station is completed. And its ability to bring large payloads back to Earth is unique. But the space shuttle, while magnificently brawny and brilliantly engineered, emerged from a series of compromises and budget cuts dating back to the Nixon Administration. The most critical mistake: designing a spaceship to fly horizontally like an airplane but launching it vertically like a rocket. That one decision saved $5 billion in the 1970s but led directly to the loss of both the Challenger and Columbia. "The problem is that once the shuttle is a meter or two off the ground, there is nothing you can do to save it if something goes wrong," says Corin Segal, an aerospace scientist at the University of Florida. NASA sponsors Segal's research into developing a launch system that would allow for horizontal takeoffs. He estimates that technology could be 15, even 20 years away. In the meantime, if NASA wants more giant leaps, it may have to start with a small step back.