1. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
2. Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
3. Department of Physics, Catholic University of America, Washington, District of Columbia 20064, USA
4. Denali Scientific, Healy, Alaska 99743, USA
5. AS and D, Inc., Greenbelt, Maryland 20771, USA