Description: The Space Manufacturing and Assembly of Revolutionary Thermoplastic Composites (SMART-C) ACO is an unfunded Space Act Agreement (ACO-2022-0007) between the National Aeronautics and Space Administration (NASA) and Lockheed Martin Corporation and was executed under the Space Technology Announcement of Collaboration Opportunity 2022 on April 27, 2023. The key objective of this project is to demonstrate that in-space manufacturing of thermoplastic composites can achieve an order-of-magnitude improvement in volumetric packaging efficiency over state-of-the-art deployable space structures. SMART-C focuses on screening and evaluating thermoplastic and thermoplastic-metallic welding technology suitable for future application in-space. Thermoplastic composites (TPC) manufactured in space are a low-cost and low-energy alternative to in-space manufacturing approaches using thermoset composites or metallic materials. TPC components manufactured in space ultimately require assembly to create large structures. Therefore, the focus of this effort is on ground test and evaluation of various welding technologies that can enable in-space assembly for TPC structures. The NASA team is welding samples using electron beam (e-beam) welding and evaluate different welded configurations. To our knowledge, this effort is the first-time e-beam welding is performed on thermoplastic composite substrates. Other welding methods included for evaluation include laser welding and friction stir welding. Welded joint configurations being evaluated include generic lap shear welds and tube-node welds representative of a design for truss structures. The evaluations of welded samples include photo microscopy, coefficient of thermal expansion (CTE), mechanical testing for stiffness and strength. The overall goal is to demonstrate welded joint technology that is suitable for high-precision space structures with a near zero CTE for dimensional stability.

Benefits: The advanced manufacturing technologies developed under SMART-C provide enabling capability for many future NASA missions including structural trusses for a Mars Transit Vehicle's Nuclear Thermal Propulsion system as well as trusses for a future >20-meter diameter in-space assembled telescope. Commercially, in-space manufacturing of thermoplastic composites enables reflector antenna trusses and solar array booms to be produced and launched at a 30-50% lower mass and cost. In-space manufacturing reduces mass, cost, and schedule savings for most space applications and enables new scalable, modular, and sustainable solutions not possible with current state-of-the-art systems. Thermoplastic composites are fully chemically reacted and processable with heat and pressure alone enabling faster manufacturing time with shorter cycle time. Thermoplastic composites can be reheated, remolded, and cooled as necessary without causing any chemical changes, and their joining processes are more straightforward than chemical bonding. Thermoplastic composite welds allow for joining thermoplastic composite substrates and thermoplastic composite to metal. The weld methods under consideration (laser, friction stir, and e-beam) show promise in terms of low power requirement.