Adapter Ring for Small Satellites on Responsive Launch Vehicles

A modular multi-payload adapter for small launch vehicles based on the ESPA ring is presented. The "Small Launch ESPA" is a scaled version of the EELV Secondary Payload Adapter (ESPA). This adapter ring for small launch vehicles features a 38.8-inch-diameter primary interface and is sized for Minotaur IV, Falcon 1e, Taurus, and Delta II. Modular features of the ring provide flexibility for a range of missions. Small-launch ESPA accommodates radial mounting for up to six low-profile small satellites on standard 8-inch or 15-inch-diameter interfaces. This "little ESPA" is particularly suited for CubeSats and the satellite class between CubeSats and "ESPA-class" spacecraft (180 kg). Launches with the ring on Minotaur IV and Delta II can accommodate secondary payloads up to 100 kg. A mission could be configured with multiple secondary satellites and no primary satellite. In a primary/secondary configuration, the Small Launch ESPA is compatible for flight with an ORS-Sat- class spacecraft mounted on top of the ring. Benefits to Operational Responsive Space (ORS) include simultaneous launch of several small payloads or testing of new technologies on responsive spacecraft missions. Adapter rings stored at the Chile Works would provide launch infrastructure for quick-turn missions. Propulsion and avionics built into the ring increase options for modular mission design. Launch load mitigation with SoftRide spacecraft vibration and shock isolation can be integrated from depot-stored components using a rapid coupled-loads-analysis software tool currently in development. The Small Launch ESPA design is based on the flight proven ESPA ring, and costs for flight validation will be low with qualification by analysis or utilization of existing test facilities. The paper describes launch stack configurations for two representative launch vehicles including payload volumes available based on fairing dynamic envelopes.