X-Calibur is ready for launch as of today! We successfully passed the “compatibility test” in which the experiment is fully configured for launch, and put on the “boss” – a giant launch vehicle. The boss will hold the experiment while the balloon inflates with helium. Once the balloon is sufficiently filled, it starts rising into the sky, and the launch vehicle holds onto the payload until the balloon straightens out and moves above the experiment. At that time, the payload is released for a hopefully perfectly vertical launch. During the compatibility test the functionality of all payload components and the various telemetry channels are tested.
We are now second in the flight queue, right after the SuperTIGER Cosmic Ray experiment which may be launched on Friday or Saturday. Our prime observation target will be Vela X-1, a neutron star in binary orbit with a supergiant star. Although the mass of the neutron star exceeds that of the sun by a factor of almost two, its radius is only about 10km! We have scheduled simultaneous observations of Vela X-1 with X-Calibur and various other X-ray satellites, in particular with NASA’s Neil Gehrels Swift observatory, and Nuclear Spectroscopic Telescope Array (NuSTAR), and ESA’s Iternational Gamma Ray Astrophysics Laboratory (INTEGRAL). The results from these different observatories will be combined to constrain the physical conditions close to the neutron star, and thus to use Vela X-1 as a laboratory to test the behavior of matter and magnetic fields in truly extreme conditions.
The X-Calibur team after the successful compatibility test (from left to right: Fabian Kislat, Hiromitsu Takahashi, Henric Krawczynski, Richard Bose, David Stuchlik, Thomas Gadson, Dana Braun, Scott Miller, Scott Heatwole, Zach Peterson, and Brian Rauch).