Purpose of the flight and payload description
BIOPAUSE is a research project carried out by the Planetary Exploration Research Center (PERC) at Chiba Institute of Technology in Japan. The aim of Biopause is to conduct a series of bioaerosol sampling in the stratosphere, in order to determine the location of "biopause", the upper boundary of the biosphere. Determining it's location and the biological flux across the biopause are key to understand the universality, distribution, origin, and evolution of life in the universe. It is widely accepted that the tropospheric atmosphere contains bioaerosol, although the flux of microbes from the troposphere to the stratosphere is small and dynamical and biological lifetime in the stratosphere are short. However, the presence of microbes in the stratosphere has been recorded in previous experiments using balloons, aircraft, and rockets. The most direct information available that can be used to investigate the biopause is the distribution and dynamicity of life in the middle atmosphere.
For this purpose PERC developed the world's first descending inertial impactor-style sampling device. This apparatus is sent to the stratosphere under a high altitude balloon and once at required ceiling, the sampler is released from the balloon. Sample collection is conducted as the sampler falls back to earth on his own parachute. The stratospheric atmosphere is introduced into the sampler using its descending velocity and atmospheric aerosol particles are collected on the impactor plates. Gate valves for the vacuum are placed at the entrance and exit of the atmospheric pathway in the sampler and operated via a control unit. This procedure reduces biological contamination from particles that adhere to the balloon surface or the wall of the sampler as they cannot enter the sampler during the descent because the descent velocity of the particles (as determined by Stoke's law) is less than the descent velocity of the sampler. Once completed the collection, the valves are closed and samples secured. After the flight the samples are cultivated and analyzed to make a quantitative comparison between culturable and unculturable stratospheric microorganisms.
Details of the balloon flight
Balloon launched on: 6/23/2017 at 4:47 jst
Launch site: Multipurpose Aviation Research Field, Taiki-Cho, Hokkaido, Japan
Balloon launched by: Institute of Space and Astronautical Science (ISAS) / Japan Aerospace Exploration Agency (JAXA)
Balloon manufacturer/size/composition: Zero Pressure Balloon model B30 30.000 m3
Flight identification number: B17-02
End of flight (L for landing time, W for last contact, otherwise termination time): 6/23/2017 at 6:50 jst
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 2 h 53 m
Landing site: In the Pacific Ocean 40 km ESE of Taiki, Japan
The balloon was launched from the Taiki Aerospace Research Field on June 23, 2017, at 4:47 a.m. Japan Standard Time (JST). After released, the 30.000 m3 balloon ascended at 330 meters/minute about 6:15 JST it reached float altitude of 28 kilometers above the Pacific Ocean, approximately 40 kilometers east south-east of the Research Field. At 6:50 JST, following the separation command, the balloon and control equipment started descent and fell at a point 15 kilometers south east off the origin of flight, offshore the Pacific Ocean. Then, by 7:40 JST pickup was done by a ship that JAXA dispatched to the site.