The Ariane 5 launcher, which delivers satellites into space under the responsibility of the European Space Agency ESA, is now making use of Basotect®. The Swiss company Contraves Space AG employs this BASF melamine resin foam in the payload fairing at the top of the rocket in order to protect the sensitive satellites against the high sound pressure to which the launcher is exposed during lift-off. The decisive factors for the use of this thermoset material include three of its properties: it is lightweight, has a high sound-absorbing capacity and is very flexible. A first Ariane test flight with this material has shown that Basotect performs well, meeting the exacting requirements of space flights in this particular configuration.
Specific network structure
Owing to its open-cell structure consisting of very thin filaments, Basotect is instrumental in reducing the high vibration frequency and thus lowering the sound pressure during the first stage of flight. After having left the earth’s atmosphere, when sound pressure can no longer damage the satellite being transported, the payload fairing is separated at an altitude of approximately 110 km. The filigree network structure of Basotect also accounts for the high elasticity of the material, which is hard and brittle by nature. Thus, on each launcher the foil-coated Basotect plates are mounted so as to precisely match the conically shaped inside of the payload fairing. The foam retains its flexibility without becoming brittle, even when exposed to high as well as low temperatures ranging from +200 C to –200 C.
Comprehensive material tests
The development phase, starting with the material selection and qualification testing, going all the way to production, took about one year. “The raw material passed our comprehensive test programme and demonstrates consistent behaviour during on-going production testing. An on-site visit at BASF established that BASF can reliably and flexibly deliver the raw material at a constant level of high quality,” explains Joseph Moran, Manager Technology R&D at Contraves Space. The Swiss company is the world leader in the design, development and manufacture of payload fairings for launchers in composite technology. It built its first fairing in 1979 for the first European launch system, the Ariane 1. Since then, approximately 175 Ariane rockets with payload fairings made by Contraves Space have taken off from the space port Kourou in French Guiana (on the northeastern coast of South America) with outer space as their destination.
The thermoset foam Basotect belongs to BASF’s Styrenics division. It has been in use for some time in aircraft construction for airplane seats as well as for the insulation of the cabin walls and piping. Up to now, this foam has been mainly employed for sound insulation in buildings such as acoustic test facilities, movie theatres and VIP lounges as well as in vehicle construction.