1. NASA Marshall Space Flight Ctr. (United States)
2. Harvard-Smithsonian Ctr. for Astrophysics (United States)
3. Harvard–Smithsonian Ctr. for Astrophysics (United States)
4. NASA Goddard Space Flight Ctr. (United States)
5. The Pennsylvania State Univ. (United States)
6. Northwestern Univ. (United States)
7. Massachusetts Institute of Technology (United States)
8. Reflective X-Ray Optics LLC (United States)