PoGO+ stratospheric balloon mission from Esrange, Sweden, to Victoria Island, Canada
Abstract
PoGO+ was a stratospheric balloon project with a cosmic ray experiment from KTH, Stockholm, Sweden, that was launched on July 12th, 2016 for a 7 day flight from Sweden to Canada. The payload mass was 1728 kg and an Aerostar SF-39.57 balloon was used to reach the float altitude of 40 km. In 2013 a similar experiment flew from Esrange to Norilsk in Russia in a circumpolar flight that lasted 2 weeks. That balloon was called PoGOLite.The experiment on PoGO+ was a balloon-borne hard X-ray polarimeter operating in the 25 - 240 keV energy band from a stabilised observation platform. Observations were conducted from a stabilised stratospheric balloon platform at an altitude of approximately 40 km. The primary targets were the Crab - a pulsar and associated wind nebula in the constellation of Taurus, 6500 light years from Earth, and Cygnus X-1 - a black hole binary system. A custom attitude control system kept the polarimeter field-of-view aligned to targets of interest, compensating for sidereal motion and perturbations such as torsional forces in the balloon rigging.After a launch at 03:17 UTC, the balloon reached float altitude after almost 10 hours, due to a cold stratosphere with slow ascent. A slower than anticipated wind took the balloon over the Atlantic for a landing in Canada on July 18th at 22:26 UTC. Landing latitude was 71.84747 N, longitude 110.885 E on Victoria Island. The mission was very successful with all systems both scientific and support and balloon systems working nominal during the complete flight. A huge amount of scientific data was collected during the flight that will be analysed. The flight lasted 7 days and this was longer than expected resulting in more scientific data. The landing and recovery was performed nominal and the scientific data were recovered and delivered to the science team within 12 days after landing. The mission was managed by SSC and SSC was also responsible for the gondola structure, housekeeping and communication systems, power systems and part of the balloon flight systems. SSC was handling the launch, flight and recovery operations. KTH was responsible for the instrument, X-ray polarimeter, including all subsystems for controlling and monitoring the systems including thermal management. DST Control, Sweden was responsible for the dual axis pointing system. New Mexico State University, USA, was responsible for part of the balloon flight systems.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E..13A