I'm excerpting this because it's a long article. Go to the link to read the whole sordid story. "About a year ago, Orbital's Launch Division changed the stage two igniter in the Pegasus launch vehicle that would be used to launch DART. They eventually determined that the launch environment would be different and that it would present a larger launch load - one which would have damaged the DART spacecraft. At the time of the change NASA asked Orbital Launch Division for information on this change and how it would affect the mission. Orbital Launch Division dragged their feet and...