Despite two catastrophic failures in a little more than 100 flights, NASA and the space-faring world that relies on it are unlikely to see a replacement for the space shuttle any time soon.
This stasis is not the result of a lack of vision for how you might improve upon the "flying brick" technology, whose basic operating design was signed off by Richard Nixon in the early 1970s.
Over the years, the National Aeronautics and Space Administration has enunciated what it desired in a next-generation rocket ship.
It wanted a genuine capacity for the crew to escape and survive an emergency during ascent and descent -- the lack of this ultimately made Challenger and Columbia death traps for the astronauts.
It wanted rocket engines that lasted for at least 50 missions and not the present 10. It desired a long-lived lightweight air frame that would endure for 500 missions (the present shuttle's projected operational lifetime is 100 missions).
It wanted to advance beyond today's brittle, heat-resistant tiles, which fall off regularly, and maybe come up with what it calls an "advanced thermal protection system" that might build heat absorption into the body of the plane.
It wanted to cut the cost of transporting material from roughly $20,000 (U.S.) a kilogram to about $2,000 a kilogram. It wanted faster turnaround times and a concomitant cut in the $500-million to $1-billion each shuttle flight costs.
It wanted to reduce the risk of a fatal accident from the shuttle's predicted 1 in 250 flights to 1 in 10,000.
But most emphatically it wanted the shuttle replacement to take off and land from ordinary facilities with the whoosh and winged lift of the Millennium Falcon in Star Wars rather than the present rocket piggyback up and air-brake glide down.
The most famous expression of this dream of a better rocket ship was given in 1986 by U.S. president Ronald Reagan in what is sometimes called the "New Orient Express" speech.
Mr. Reagan described a plane -- later officially dubbed the X-30 -- that was going to fly at 29,000 kilometres an hour, take off from Dulles Airport and have the capacity to dock with a space station. The space flight experience would become routine -- "almost like taking off from Washington to London," in the president's words.
What followed were at least five ultimately failed efforts to change space travel from a ride on what shuttle detractors have termed the world's least fuel-efficient bus to a truer spaceship experience.
The X-30, which was supposed to fly by 1995, died in the mid-1990s. The X-33, which Bill Clinton predicted would launch by 2004, was killed by George W. Bush in 2001 as part of setting NASA's financial house in order. The X-38 was put on the development back burner last November.
On many levels, the reasons why the shuttle has not been replaced with anything significantly better is simple. "The technology is not there. We cannot today produce an economically viable alternative to the present shuttle," says Charles Vick, a U.S. space and strategic studies analyst with GlobalSecurity.org.
The biggest technological stumbling blocks to making a true spaceship are quite fundamental. "There have been no significant discoveries in the last 30 years that have changed fuel-thrust-to-weight ratios significantly," says Brian Thompson, an engineering professor at the University of Western Ontario. That means present motors and present fuels cannot lift single-stage spaceships made with present materials off the Earth.
Neither have there been major breakthroughs in heat shielding or in getting astronauts quickly off a ship that is in peril.
In some sense, Prof. Thompson notes, the problem is the inverse of NASA's famous argument that space development is important because it has spun off technology -- Kevlar and computer miniaturization, for example -- that can be used on Earth.
Earth-oriented developments don't spin off things needed in the harsh environs of space. "There have been very little improvements in the brittleness of tiles because there is no crying need for less brittle tiles except on the shuttle," Prof. Thompson says.
A second obvious reason for the lack of rocket ship advancement is financial. "They are flat-out expensive . . . and NASA's budgets have always been based on economic falsehoods," says Donna Shirley, former manager of the Mars Exploration Missions for NASA.
As an example of pie-in-the-sky economics, the X-38's dramatic cutback came when a re-analysis allegedly found that its $10-billion price tag was more likely going to be $30-billion.
Moreover, there has been a continual impetus to shift money required for advanced research into simply keeping existing shuttles flying.
Before Columbia's disintegration, it was fair to say the shuttle of the future was a version of the present shuttle, only a lot smaller.
Last month, NASA announced its proposals for the Orbital Space Plane, which if all went according to plan, might be ready for service by 2010. Its purpose would be to ferry astronauts to the International Space Station and back, as well as serve as a lifeboat.
In announcing it, NASA administrator Sean O'Keefe played down expectations about the new craft. "This is not based on a dream sheet flight of fancy. We want to make this a simple and basic crew-transfer vehicle."
Still, a human ferry doesn't answer the question of how NASA will send up materials to build or repair or launch things.
"The prognosis from the inside is that we are expecting to get another 20 years' life out the shuttle program and in the meantime will do research and hope for breakthroughs," Prof. Thompson says.
And what to do with the hole the Columbia's explosion leaves in the space program?
"Build another shuttle," he says.
Stephen Strauss writes on science for The Globe and Mail.