The International X-Ray Observatory (IXO) is a joint mission including participation from NASA, the European Space Agency (ESA), & the Japanese Aerospace Exploration Agency (JAXA). The IXO mission will incorporate the joint experience gained from NASA’s Constellation-X (Con-X) and the ESA/JAXA X-ray Evolving Universe Spectroscopy (XEUS) mission concept into a single mission. IXO will perform high resolution X-ray spectroscopy with 100 times the throughput of previous X-ray observatory missions.

After launch, IXO will operate from an orbit around the Sun-Earth L2 libration point. Flight Dynamics support during FY08 was focused on the Con-X (prior to the collaborative agreement) visit to the Mission Design Laboratory (MDL) during July of 2008. During the MDL study, Flight Dynamics engineers re-evaluated the delta V budget and again discussed the delta V implications related to maneuvering Con-X into an L2 orbit that stays within the Earth’s magnetosheath to shield the observatory from high energy cosmic particles. Additional work included providing a qualitative evaluation of the navigation concept given Con-X’s momentum unloading strategy. The decision was made to proceed with a sequential orbit determination architecture given the expectation that Con-X expects to unload momentum roughly every 3 days. Further analysis of the orbit determination architecture will leverage the experience gained through similar work done for the James Webb Space Telescope (JWST) mission which employs a similar architecture due to frequent momentum unloads in its L2 libration point orbit. Finally, a full lifecycle cost estimate was prepared during the MDL study for Con-X.

Future efforts will include working with GSFC IXO team to understand the new roles and responsibilities in this new international collaborative effort.