Robert Stevens, chief executive of NASA's Orion crew exploration vehicle developer Lockheed Martin, has called for sustained funding of the US space agency's exploration programme, at the Space Foundation's National Space Symposium.

NASA's budget for its fiscal year 2007 saw a $577 million cut in its exploration systems funding that includes the Orion and its launcher Ares I crew launch vehicle. NASA's fiscal year is from October to September.

Speaking on 10 April at the symposium Stevens said, "Funding...goes beyond one company, it is at the centre of being able to do what needs to be done. There have been tough trade offs [due to funding pressure] and more will be needed."

NASA administrator Michael Griffin has told the US Congress that that funding cut has pushed the deployment of Orion back by six months from September 2014 to March 2015. The block one version of Orion is for International Space Station (ISS) crew transportation. The currently agreed end of the station's certified life is 2016.

Stevens added that the US must renew its tolerance of risk, pointing to the US military's support for the Lockheed designed Corona spy satellite throughout the 12 failures it suffered during its development before it became a success. The space industry fears that Congress and NASA will drop the Constellation programme that includes Orion and Ares if their development became troubled.