The RKW Group is bringing film manufacturing to a new level by producing high-performance technical films for the stratospheric balloons of the French space agency CNES.
The balloons are made with RKW film at Site RKW Remy in France, and are used for missions at heights of up to 40 km and therefore depend on special material properties and high quality.
© CNES/GRIMAULT Emmanuel, 2015
With a diameter of up to 148 metres and volume capacities from 3000 to 1,200,000 metres cubed, the development of the envelope for the CNES stratospheric zero pressure balloon (ZPB) or BSO (Ballon Stratospherique Ouvert) posed several challenges to the experts at RKW.
François Nelias, R&D Engineer and Product Manager at RKW Remy, said: We were required to produce a very thin high-performance film for the balloon envelope that had to be absolutely tear and perforation resistant.”
“It also had to carry a weight of up to 1750 kg in the harsh environmental conditions of the stratosphere over several hours of even a few days.”
“The film is made from a high-impact and puncture resistant polyethylene resin. The use of any additive such as polymer processing aids is out of the question, as we have to prevent any contamination from a second raw material. This of course makes the extrusion process even more difficult.”