PoGOLite (The Polarised Gamma-ray Observer) is a

balloon A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...

-borne astroparticle physics experiment which is to measure polarisation in hard X-rays and soft gamma-rays. It is sensitive to photons with an energy range of 25-80 keV. PoGOLite contains 217

phoswich detector Phoswich detectors were developed to detect low-intensity, low-energy gamma rays, X-rays, as well as alpha and beta particles efficiently in a higher-energy ambient background. Some detector designs can measure and separately identify all energies ...

cells (PDC) which are surrounded by a ring of side anticoincidence shield (SAS) detectors.

PoGOLite Pathfinder mission

The pathfinder instrument containing 61 PDCs and 30 SAS detectors was scheduled to be launched from the

Esrange Esrange Space Center (short form Esrange) is a rocket range and research centre located about 40 kilometers east of the town of Kiruna in northern Sweden. It is a base for scientific research with high-altitude balloons, investigation of the au ...

facility in northern Sweden during summer 2011. The flight was to be the first westward circumpolar balloon flight in the northern hemisphere in 20 years and was expected to take 17–25 days. The main targets of the pathfinder experiment are the

Crab Pulsar The Crab Pulsar (PSR B0531+21) is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054.high-mass X-ray binary X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the ''donor'' (usually a relatively normal star), to the other component, called the ''accretor'', which ...

system

Cygnus X-1 Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus and was the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the ...

, which are two of the brightest objects in the energy range of PoGOLite. The mission was launched at 1:57am Thursday 7 July 2011 (23h57 GMT Wednesday 6 July 2011) from

, Sweden. However, it was brought back down by 7:00am from an altitude of 35 km, because of a helium leak. The payload landed near

Nikkaluokta Nikkaluokta () is a Swedish Sami village in Norrbotten County. The village belongs to Gällivare Municipality, bordering Kiruna Municipality, the closest urban area some 60 kilometers away. In its vicinity lie the areas of two Sami communities, ...

just before the mountains around the Sweden-Norway border where a landing would have caused more potential damage. The payload was returned to the Esrange site on 8 July 2011 after which initial tests showed only minor damage to the payload. A second attempt was scheduled for July 2012 but was cancelled because of bad weather. The mission's third and final attempt is scheduled for July 2013.Bad news for PoGOLite once again, blog post at Oskar Klein Center by Mark Pearce
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References

{{reflist Balloon-borne telescopes X-ray astronomy X-ray telescopes Balloons (aeronautics)

PoGOLite Pathfinder mission

See also

References