The activity is split into two phases. This preliminary phase, is aimed at ensuring all necessary (long lead) manufacturing items and knowledge are available in time for a follow-on activity (in which actual manufacturing of a number of inter-stages will be performed). The activity is highly time sensitive; for the technology to be viable for use as an inter-stage by an interested end-user an adequately mature inter-stage should be available on time (Q3 2022).

Grid stiffened structures are a type of CFRP structure that is created by arranging multiple ribs in a type of lattice network. Each rib is created from unidirectional pre-preg plies and is joined together in nodes. For this particular application/technology also a skin is foreseen to close the gaps left in the grid structure. This type of configuration allows for structures with a very high specific strength and specific stiffness. The activity seeks to further develop the technology for use in a launcher inter-stage application. The foreseen mass savings are perceived to be of great benefit to this domain.

All objectives of the activity have been completed. In particular this means: An inter-stage design has been developed in line with interested end-user needs. Material characterization tests have been performed and their results post-processed. Trial panels have been manufactured. CFRP material and necessary manufacturing equipment (a.o. a mandrel) are available on premises.

Further development of grid-stiffened technology for launcher (inter-stage) applications will achieve further launcher mass reductions. The realized reductions can be converted in increased useful launcher performance.

A follow-on GSTP activity is planned to bring the technology up to TRL 7. In the follow-on activity a number (3) of inter-stages will be manufactured. The second of these inter-stages will be mechanically qualified, so that the third manufactured inter-stage may be considered as a viable candidate for use as a flight inter-stage by the end-user by Q3 2022.