2018-2019 Science Planning Summaries
United States Antarctic Program United States Antarctic Program Logo National Science Foundation Logo
2018-2019 USAP Field Season
Project Detail

Project Title


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A-115-M Research Location(s): Williams Field (Long-Duration Balloon Facility)


Event Number:
NSF/NASA Agreement

Program Manager:
Dr. Vladimir Papitashvili

ASC POC/Implementer:
John Rand / Kaija Webster / Chad Naughton

Principal Investigator(s)

Dr. Henric S. Krawczynski
Washington University
St. Louis, Missouri

Project Web Site:


Supporting Stations: McMurdo Station
Research Locations: Williams Field (Long-Duration Balloon Facility)


X-Calibur is a balloon-borne X-ray polarimetry mission that will observe mass- accreting black holes and neutron stars in the 25-60 kiloelectronVolts (keV) energy range. X-Calibur measures the linear polarization degree and angle – two new observables relating to the uniformity and orientation of the electric field carried by X-rays. This new capability of polarimetry allows X-Calibur to obtain geometrical information about objects that are too far away and too small to be imaged. The 2018-19 balloon flight will be used to observe four to 10 sources and to measure their energy-dependent hard X-ray polarization properties. The sources will include the accreting neutron star and X-ray pulsar Vela-X1, and the results will constrain the location and physical mechanisms that accelerate particles in Vela-X1.

Field Season Overview

The X-Calibur mission will launch on a high-altitude balloon flight from near Williams Field as part of the Columbia Scientific Balloon Facility (CSBF) Long-Duration Balloon (LDB) ballooning operations. The deployment and recovery teams will reside at McMurdo Station and make day trips to the launch site. The deployment team will remain in Antarctica until the payload is out of line-of-sight communications. The recovery team will, ideally, recover the instrument in the same season. If that is not possible, they will return the following season. The most crucial payload items will be recovered on an initial Twin Otter aircraft reconnaissance flight. The rest of the payload will be recovered on subsequent Twin Otter and Basler flights. If the payload terminates far from McMurdo Station, the team may reside in a field camp for up to two weeks to facilitate disassembly of the instrument.

Deploying Team Members

  • Quincy Abarr
  • Richard Bose
  • Dana Braun
  • Thomas Gadson
  • Scott Heatwole
  • Fabian Kislat
  • Henric Krawczynski (PI)
  • Ronald McGee
  • Takahashi Okajima (Co-PI)
  • Zachary Peterson
  • Garry Simburger
  • David Stuchlik (Co-PI)
  • Hiromitsu Takahashi