The report into the Columbia space shuttle disaster has far-reaching implications for Nasa and will shape the future of human space flight for decades to come.
By Helen Briggs
BBC News Online science reporter
It could herald the biggest shake-up in policy since the end of the Apollo Moon missions, when the US space agency first set its sights on building the space shuttle.
Columbia's left wing was fatally damaged during lift-off
Perhaps the most serious implication for the US space agency is the criticism of its culture and management.
Similar concerns were raised after the 1986 Challenger disaster and the reverberations look set to run even deeper this time around.
Howard McCurdy, a space policy expert at American University, Washington DC, expects the report to influence policy for at least the next 30 years.
"The experience of the shuttle programme has shown how difficult it is to maintain a high performance space programme within the government for extended periods of time," he told BBC News Online.
"Heavy investment in a direct replacement for the space shuttle could condemn the US to remain in low Earth orbit for the next 30 years."
Nasa's policy after Apollo was to design and build a reusable spacecraft. Columbia was the first such space shuttle to fly, lifting off in 1981.
Challenger, Discovery and Atlantis were put into service in the early 1980s but disaster struck in 1986 when Challenger was lost together with its crew of seven astronauts.
The loss of Challenger shocked the nation and left Nasa's shuttle programme in disarray.
The subsequent Presidential Commission report blamed a faulty seal within the O-ring of a rocket motor for the accident.
It criticised internal communications within Nasa and called for stricter safety controls.
During the Challenger inquiry, it emerged that Nasa managers had failed to respond to last-minute warnings from engineers on risks.
Similar concerns surfaced during the Columbia investigations when it was disclosed that ground engineers had sent e-mails warning about the consequences of damage from foam striking the wing.
Columbia broke up 15 minutes before landing
The Columbia Accident Investigation Board has placed the blame for the accident largely on flawed practices at Nasa.
It is convinced that the management practices overseeing the Space Shuttle Programme were "as much a cause of the accident as the foam that struck the left wing".
Peter Bond, space science advisor for the Royal Astronomical Society in the UK, says the Columbia report is a milestone in the agency's history.
"This is a major landmark from which Nasa has to adapt and evolve and change the way it does things," he said.
"The future of Nasa's space programme will never be the same again."
Nobody is expecting the US to abandon human space flight altogether. But there is bound to be renewed soul searching over its commitment to the International Space Station (ISS) and the shuttles that take astronauts and cargo into low-Earth orbit.
The shuttle is expected to take off again next summer, but under strict constraints.
Engineering modifications will have to be carried out so that astronauts will be able to repair any damage caused to the shuttle during the flight.
Missions will have to lift off during daylight hours, to allow photographs to be taken to assess the risk of damage, and the shuttle will have to be capable of docking with the ISS to allow the crew to be rescued, if need be.
Construction work on the orbiting outpost is likely to remain on hold for the foreseeable future and Nasa will have to think again about how it will eventually replace the shuttle.
Nasa had planned to keep the remaining shuttles in operation until 2020 but this strategy has been heavily criticised by the board.
It says it has no confidence that the space shuttle can be safely operated for more than a few years.
There is no doubt that the Columbia report makes painful reading for Nasa and its chief administrator Sean O'Keefe.
It will require a broader discussion of budget, policy and how to replace the shuttle fleet.
Tough engineering and management challenges lie ahead. But like any large organisation it is perhaps the question of internal culture that will be the hardest for Nasa to address.