The US Government Accountability Office says NASA should not have completed preliminary design reviews for its Constellation programme's vehicles because it did not have the data to allow it to meet planned delivery dates with confidence.

Neither the Orion crew exploration vehicle nor its Ares I crew launch vehicle should have progressed, says the GAO. In its September report on Constellation the GAO highlights NASA's decision to delay Orion's PDR from mid-2008 to third quarter 2009 and the fact that it closed the Ares I review, while deferring resolution of the launcher's thrust oscillation issue until the Constellation programme design milestone in March 2010.

Constellation has already slipped its first crew flight from September 2014 to March 2015 and has 192 identified risks that represent an additional $2.4 billion or more in costs to resolve. One such risk is thrust oscillation, which threatened to violently shake Orion and its crew on ascent.

NASA disagrees with GAO and says: "The Constellation programme and project preliminary design reviews fully comply with the NASA guidance. In every case, the review was declared successful by...independent reviewers."

Yet NASA's Constellation programme may never reach its own March 2010 milestone. Later this month President Barack Obama's review of US human spaceflight plans committee is expected to submit its full report on which NASA administrator Charles Bolden will base a new human spaceflight policy proposal by the end of the year.

Source: Flight International