Moog Inc. marks 25 years since the Evolved Secondary Payload Adapter (ESPA) ring completed its Critical Design Review on January 18, 2001. Development of the technology began in 1999 through collaboration between government and industry. The ESPA ring allows launch vehicles to carry multiple secondary payloads by using previously unused volume beneath primary satellites, lowering costs and increasing mission flexibility.
Over the past 25 years, the ESPA family has evolved into a modular platform supporting varied payload sizes and interface configurations. ESPA-derived designs have also served as the structural foundation for spacecraft buses. The platform supports mission planning for NASA, the U.S. government, and commercial space ventures.
Moog currently offers a family of ESPA configurations, including Standard ESPA, ESPA Heavy, and ESPA Grande, designed to accommodate evolving payload and mission requirements. The modular architecture and adaptable interfaces support rideshare missions, payload integration, and spacecraft applications.
"The ESPA ring began as a technical solution to a practical challenge: maximizing every launch opportunity," said Timothy Pargett, general manager of Moog Payload Adapters and Isolation business. "Today, it stands as a cornerstone of how missions, large and small, gain cost-effective, reliable access to orbit through rideshare."
A flight-qualified ESPA ring will be on display at the National Museum of Nuclear Science & History in Albuquerque, New Mexico, from November 7, 2026, through January 10, 2027.