Is the shuttle worth it?
By Richard Stenger
(CNN) -- The space shuttle Atlantis was to roll out to the launch pad this week for a trip to the international space station. Instead, NASA must decide when the grounded fleet should fly again, and the nation whether it should fly at all.
Since the shuttle Columbia broke up as it re-entered the atmosphere Saturday with seven hands on deck, many committees, panels and task forces, staffed by engineers, generals and senators, have begun the slow, sober process of figuring out what went wrong and what to do next.
Their discussion of the future of the shuttle will likely include a reexamination of its original role and whether it has lived up to expectations.
Will NASA ground the fleet more than two years as it did after the Challenger disaster in 1986? Possibly not, considering the international space station is currently the home of three men and requires frequent visits from shuttles.
"We're still flying in space. We have a crew that's on orbit right now. And we have a space station on orbit. And they deserve our full attention to make sure that they have a safe and productive mission," said Bob Cabana, NASA director of flight crew operations.
The two Americans and one Russian have tons of food, fuel, air and supplies, enough to last until June, three months longer than they expected to live more than 200 miles high in a string of modules linked like metal sausages.
Should the fleet remain grounded for many months, a completely different kind of ship could swap out station crews, one that is spartan, reliable, and built by the Russians, who in a roundabout way helped bring about the shuttle.
The Apollo program, which helped the United States overtake the Soviet Union to claim the ultimate prize in the manned space race, safe roundtrips to the moon, generated many of the engineering concepts used to build shuttles.
A legacy of Apollo
The orbiters still blast off from the same launch pads that shuddered under the Apollo mission rockets of the 1960s and 1970s. Problem is, critics contend, those technologies are outdated, unsafe and expensive.
The computers run with older microchips and software. The engines have far more moving parts than newer rocket motors. And the thermal protection tiles predate advanced material discoveries.
The shuttle is based on "old, outmoded and obsolete technology," said Rep. James Sensenbrenner, R-Wisconsin, a veteran of House science and space committees.
"We have to be forward-looking in how we explore space," Sensenbrenner said.
NASA initially touted the shuttle as a reusable launch vehicle that would provide a cheap way to place satellites into orbit. The proposed and actual numbers have proved quite different.
"The [original] numbers that NASA gave to the White House were that shuttle would cost about $5.5 million per launch and the launch rate would be anywhere between 50 and 60 launches a year," said John Logsdon, director of the Space Policy Institute at George Washington University.
Shuttles have instead averaged about five launches a year, and NASA was way off on the cost.
"Most people use a figure like $400 [million] or $500 million [per launch]," Logsdon said. "Anyway you look at it, it's a lot of money."
After Columbia became the first shuttle in space in 1981, shuttle crews became, in effect, human couriers to do deliveries that unmanned rockets could do at the same or lower cost, and without human risks.
The program needed another reason for being and found it in the space station. A dream hatched in the 1980s by the United States, it eventually enlisted the support of 15 nations and became the most extensive, expensive engineering undertaking ever.
The first crew did not arrive until 2000. In the interim, NASA astronauts often busied themselves with experiments.
In recent years most shuttle crews flew with giant pieces of hardware and attached them to the station, but the fatal Columbia mission was a rare throwback to the science days.
Man vs. machine
Is there a better way? Theodore Postol of the Massachusetts Institute of Technology thinks so.
"Is the shuttle well-suited for manned space flight and is it technically well-suited for science exploration? It seems to me, it's not technically suited for either," the physics professor said.
Expendable launch vehicles with simple return capsules would be safer and cheaper to fly in the long run, Postol suggests.
"We're spending a lot of money to return 150,000 pounds of shuttle home and make it safe for another human sojourn into space," he said.
"On re-entry, a vehicle should simply bring the crew back. It shouldn't be an enormous plane-like vehicle with all these tiles."
NASA is considering alternatives to the shuttle. In 2001, after sinking more than $1 billion into an advanced prototype, the X-33, the agency scuttled the project because of engineering obstacles.
In December, NASA chief Sean O'Keefe presented another shuttle successor, this one a scaled-down "space orbital plane," a glider really, that would ferry astronauts to the space station for a fraction of the price of a shuttle trip.
NASA estimates it would take $12 billion and at least seven years to develop.
Postol argues against sending humans into space at all, saying we should be leaving the inhospitable void to unmanned craft.
"I could do an enormous amount of science with robotics. That is much safer and doesn't risk lives," he said.
Gerard Faeth, a University of Michigan scientist who sent an experiment on Columbia objects for reasons of science.
"Robots work best for observational science, where a satellite looks at the terrain and reports back the images. On the shuttle, we had an active laboratory. Humans are necessary," he said.
"Robots are rarely used in labs here on Earth. I don't think they would be very effective in space."
Others object for more complex reasons. Humans are hardwired to explore, take risks, sail uncharted waters. It's no coincidence that the shuttles -- Endeavour, Atlantis, Discovery -- were named for sailing ships with daring crews.
The original Columbia was the first American vessel to circumnavigate the globe. The shuttle Columbia equaled the feat, only a little higher.
"Curiosity is the essence of human existence and exploration has been part of humankind for a long time," said Gene Cernan, the Apollo 17 astronaut who in 1972 was the last man on the moon.
"The exploration of space, like the exploration of life, if you will, is a risk. We've got to be willing to take it."
CNN's Charles Feldman and Kate Tobin contributed to this report.