Enhanced Feasibility Assessment of Payload Adapters for NASA's Space Launch System

The first flight of NASA's new exploration-class launch vehicle, the Space Launch System (SLS), will test a myriad of systems designed to enable the next generation of deep space human spaceflight, and launch from Kennedy Space Center no earlier than December 2019. The initial Block 1 configuration for Exploration Mission 1 (EM-1)will be capable of lofting at least 70 metric tons (t)of payload and send the Orion crew vehicle into a distant retrograde lunar orbit, paving the way for future crew missions to cislunar space and eventually Mars. A Block 1B version of SLS will lift at least 34 t to trans-lunar injection (TLI)in its crew configuration and at least 37 t to TLI in its cargo configuration no earlier than 2024. For Mars-class payloads, larger fairings and payload adapters for the Block 2 cargo vehicle are under consideration. For missions beyond the Earth-Moon system, SLS offers greater characteristic energy (C3)than any other launch vehicle, enabling shorter transit times or heavier payloads with more robust science packages for missions to the outer solar system. Indeed, the unmatched combination of thrust, payload volume and departure energy that SLS provides opens new opportunities for human and robotic exploration of deep space. To support the delivery of infrastructure on all of these flights, a family of SLS Payload Adapters (PLA)is being developed to provide ELV class (1575-mm, 2624-mm, 4394-mm)and larger spacecraft/payload interfaces for both crewed (Orion)and cargo (fairing)missions. These PLAs also provide the potential of accommodating various configurations of 6U, 12U and 27U Secondary Payloads (SPL). Work on demonstrating the manufacturing of these 8.4-m diameter composite structures is already in progress at Marshall Space Flight Center in Huntsville, Alabama, which manages the SLS Program. Because of the many potential configurations required to support SLS missions ranging from sending Europa Clipper to Jovian space to establishing a lunar orbiting Gateway, there is a critical need for establishing the fewest PLA designs that can accommodate the most SLS payloads possible. This paper will summarize applications from a NASA Engineering and Safety Center (NESC)led Model Based Systems Engineering (MBSE)pathfinder activity to develop a “digital” PLA feasibility assessment approach. This approach will help potential users optimize their interface to SLS by providing analysts with the means to reduce PLA feasibility definition cycle time/effort by over 75%. This also allows more feasibility assessment “turns” available to single and multiple payload elements on a single SLS launch. This translates into providing users with options that allows them to optimize upmass available to payload versus being required for PLA structure.