POGOLITE mission aborted a few hours after launched - 7/15/2011
Esrange, Sweden.- The maiden flight of Pogolite, the most important Swedish balloon-borne instrument developed in the last years in the country, ended prematurely on July 7th, a few hours after launched from the stratospheric balloon base of ESRANGE, east of Kiruna.
POGOLITE stands for Polarised Gamma-ray Observer - Light-weight version and is an astronomical soft gamma-ray polarimeter optimised for point-like sources. It measures polarisation in the energy range 25-80 keV by using the azimuthal angle anisotropy of Compton-scattered photons. It was developed by the Particle and Astroparticle Physics group of The Royal Institute of Technology and the Stockholm University from Sweden along with a wide international collaboration that included institutions from USA and Japan. During this first mission a reduced amount of 61 detector units would be included as a "pathfinder" experience to proof the accuracy and sensitivity of the instrument. The final goal of the project is to open a new obervational window on high-energy astrophysics, with the promise of clarifying the emission mechanism of many sources.
The mission started under the bath of the rays of the semi-covered midnight sun at 23:57 utc on July 6 -corresponding to 1:57 local time on July 7- but according to a brief statement published yesterday by Mark Pearce principal investigator of the project "...it became clear that the altitude of the balloon had leveled out to about 35 km - a few kilometres short of the target altitude. The altitude then started to slowly decrease, implying that the balloon had sprung a leak allowing helium gas to escape..."
Decision was taken to finish the flight once the balloon reached a safe landing zone, thus precluding the scientific team from even take a look at their primary science target, The Crab pulsar, as still it was bellow the horizon of the instrument. The termination command was sent at 5:21 utc while the balloon was flying, west of Kiruna. The payload separated from the balloon whitout problems and started to descent on his own parachute. While the balloon impacted near the Kebnekaise mountain station the scientific team was a bit worried as the GPS track showed the gondola resting on a lake, but a better inspection of the data bringed some relief to the group, as the payload was instead lying on dry soil not far from the town of Nikkaluokta.
The following day, the recovery team located the gondola lying on his back (as can be seen in the image at right) but mostly intact. It was returned to Esrange where the Pogolite team made some preliminary tests of the telescope and attitude control system. After discovering some issues to work on, the payload was delivered back to their lab in Stockholm, and the campaign was called off.
Althought the flight ended prematurely, the scientific team was able to start up the instrument during the ascent phase of the mission and obtained data from Cygnus X-1. The pointing system of the instrument worked flawlessly, but as the balloon was too low in altitude was not possible to obtain valuable scientific data. Also the pointing system and the star trackers performed very well.
The POGOLite pathfinder was originally scheduled to fly in mid-August 2010 during the so called "turnaround" period, allowing a maximum flight time of 24 hours, with little displacement from the launch site, but this flight was cancelled in the aftermath of the failed launch of the NCT payload at Alice Springs in April 2010 as several parts of the balloon train would be provided by the NASA balloon program. Thereafter, the PoGOLite flight was rescheduled for July 2011 changing the flight profile to a circumpolar flight -the first one to be performed at these latitudes since late 90's- of 20 days, traveling over the Atlantic Ocean, Greenland, Canada, Alaska and crossing east-to-west the Russian territory, if granted the overflight permission of the former government.
The mission will be launched probably from the same place the next year.
Lawsuit that stoped Red Bull Stratos effort resolved - 7/6/2011
As occured in October, a small publication in the website of the Red Bull Stratos effort informed the public of the end of the legal action that endangered the continuation of the project to send a man to the stratosphere to beat the high altitude parachute record jump set by Joe Kittinger back in the 60's.
"...The legal action filed by Daniel Hogan and PerDan, LLC in the Superior Court for the State of California for the Country of Los Angeles entitled Per Dan, LLC, et al. v. Red Bull GmbH, et al., Case No. BC 436456 has been mutually resolved by the parties out of court and the lawsuit has been dismissed..."
On his personal Blog, the parachutist Felix Baumgartner wrote that "...I am struggling to find the right words to express my happiness, how relieved and motivated I am that it has finally come to an end..." and also appreciated the support provided by family, friends and fans of the project.
Probably we will have more news on the project soon. Stay tuned!
