My understanding is that we had a launch contract with Boeing. It was going to be launched by the Americans. Our technical team came to a certain milestone, and at that milestone the launch vehicle did not meet the vibration requirements of our spacecraft. It would have destroyed it. We made the tough decision to switch contractors, which cost us money and time, and we moved over to a Russian launch. The American government understood that and granted all the agreements that were required to do that, and we went to space.
On April 1st, 2008. See this statement in context.