Developments on Low Cost Manufacturing Methods for Cylindrical Launch Vehicle Structures

Due to the increasing international competition and growing pressure to lower the cost of launch vehicles, enhanced technologies and competences for efficient, low cost manufacturing have to be developed. In this paper, an innovative manufacturing technology for launch vehicle applications is presented that was developed over the last few years at MT Aerospace AG (MTA) in collaboration with NASA Langley Research Center, the European Space Agency (ESA), Lockheed Martin Corporation (LMCO), Leifeld Metal Spinning and Scot Forge. The Integrally Stiffened Cylinder (ISC) manufacturing method was first investigated in 2010. Early results indicated a high mass saving potential for cylindrical structures for launch vehicle systems, such as cryogenic tank barrels and intertanks, produced using the ISC method. Cost-benefit studies conducted at NASA and MTA estimated up to 50% reduction in manufacturing costs is possible compared to conventional multi-piece, welded fabrication methods. Associated reductions in manufacturing lead times have shown that a 40% faster production rate is possible by the ISC process. Following proof of concept and process development efforts, a cylindrical structure manufactured using the ISC method had its maiden flight in 2015 on a Black Brant sounding rocket at NASA Wallops Flight Facility. Further collaboration between ESA, NASA, MTA, LMCO, and Scot Forge led to manufacturing test campaigns at MT Aerospace in 2017 and 2018 that successfully demonstrated ISC fabrication at a scale representative of commercial launch vehicles. This paper summarizes the status and relevant results of the development sequence of the ISC cylinder manufacturing method. Results of cost / benefit and structural performance analyses are also summarized. Moreover, an outlook will be given on further planned activities and development steps.