Saturday's loss will raise questions on cost-cutting at NASA and its effect on safety, writes Leo Enright
The space shuttle Columbia began life as an engineering blueprint in 1972, but its fate may already have been sealed before the first spaceship's keel was laid on June 4th, 1974: most of the compromises that were to haunt America's shuttle programme were made on the drawing board long before a single rivet was punched.
Investigators probing the Challenger disaster of 1986 exposed a culture of denial and deceit that sought to hide the shuttle's limitations by compromising safety. But it was not until November of 1988 that America's failure of will at the heart of the shuttle programme became fully apparent.
On that windswept morning, into the teeth of a blizzard, the then Soviet Union launched a space shuttle that did "exactly what it says on the tin".
Buran was in many ways the reusable spaceplane that the United States had intended to build. It is perhaps the richest irony of the Space Age that the bankrupted Buran shuttle became, quite literally, a fairground attraction in a Moscow theme park, while its flawed American cousin continued to fly - until now.
Almost everything that the shuttle could do, Buran could do better. The shuttle's pencil-shaped booster rockets, once lit, could not be extinguished; this contributed to the Challenger disaster and continues to pose a mortal threat to crews throughout the first two minutes of flight. Buran, meanwhile, had boosters that could be shut down in an emergency.
Shuttle crews have no ejector seats. Buran had two-man couches that could be blasted clear in an emergency. The shuttle cannot fly through the smallest rain shower, for fear of damaging its heat protection tiles. Buran's maiden launch was during a snowstorm.
Why did the Russians build Buran? It is now generally forgotten that the United States's decision to build a space shuttle in the first place was viewed in Moscow as a major provocation: it was seen as signalling an intention to break treaties on the peaceful uses of outer space, much as concerns about the threat from Iraq and Korea have raised tensions today.
The Soviets were worried about intelligence reports of American work on X-ray lasers, nuclear bomb-pumped devices which could have been capable of destroying dozens of Russian nuclear missiles simultaneously.
In fact, the first laboratory demonstration of an X-ray laser did not happen until 1984, by which time the idea of a military space application was apparently quietly dropped by the leaders of president Reagan's so-called "Star Wars" initiative.
But the reality is that much of the US shuttle's design was driven primarily by US Air Force requirements that the shuttle be able to enter a polar orbit. Most satellites are launched into orbits that venture no further north than the Inishowen Peninsula.
However, a US military shuttle would need to be able to overfly the entire planet from pole to pole, launching from Vandenberg Air Force base north of Los Angeles, completing one orbit of the earth, and returning back to Vandenberg in less than two hours if necessary.
The military also insisted that the shuttle should be able to manoeuvre within the atmosphere with enough leeway to ensure it did not have to land on hostile territory.
Meeting these stringent military requirements left the civilian space agency with a shuttle designed by a committee and a legacy of compromises that significantly eroded the safety margins.
The loss of Columbia revived a long-simmering debate in Congress about the human spaceflight programme, and is certain to lead to new hearings in the Congress. It renewed questions about whether cost-cutting and management problems at NASA might have compromised astronauts' safety.
With Buran, however, the Russians showed that a safer shuttle was possible, and appeared to confirm suspicions that America's shuttle programme was forced to make critical safety compromises to win military support for a programme that might otherwise not have been funded on its civil merits.
Some in NASA have long dreamed of escaping this Faustian nightmare which America's shuttle fleet has been flying for twice as long as its builders envisioned. Some parts were made so long ago that they are no longer available. Shuttle engineers have had to turn to Internet auction site eBay for desperately needed hardware and electronics.
Columbia, the oldest and heaviest of the shuttle orbiters, was nearly mothballed in the late 1990s, as NASA tried to trim the shuttle programme budget.
A series of reports from the General Accounting Office, the National Academy of Sciences and NASA's own advisory boards all called for upgrades to improve the shuttle's safety. In 1996, NASA's associate administrator for the space shuttle programme resigned abruptly, saying the shuttle faced unacceptable risks.
Shuttle programme manager Mr Ron Dittemore said on Saturday he did not think age was a factor in the loss of Columbia. The shuttles were built to fly 100 times each and Columbia was on its 28th voyage. But no one knows how gracefully the shuttles will age as they endure violent launches and re-entries at many times the speed of sound.
Shrinking budgets, experts said, have undercut the agency's ability to maintain its shuttle fleet and, more importantly, to design and build a new generation of safer and cheaper reusable aircraft that should have replaced the shuttle years ago. In a perfect world, a replacement would get 80-90 per cent of its business from outside NASA but would still meet all of the space agency's requirements.
The goal was to replace the space shuttle by 2010 with a vehicle that would reduce the cost of launching by 90 per cent.
But the technologies needed for such a low-cost spaceship remain challenging. So, in the meantime, America's space agency has taken another fateful step: it has abandoned detailed consideration of such high-tech options.
With no replacement on the horizon, NASA extended the lifespan of the shuttle, saying an intensive upgrade programme would permit "safe and efficient flight to 2012 and beyond". More recent estimates have suggested the shuttle fleet could be in use until 2020. And some have said it could fly safely for decades - but that was before Saturday's tragedy over Texas.