Session
Swifty Session 2
Abstract
ESPA is established launch infrastructure for small satellites on Atlas V, Falcon 9, and Delta IV. Auxiliary payloads* (APLs) mount to ESPA on Ø15-inch† ports subject to limits on spacecraft mass and center of gravity (CG). ESPA Grande has increased payload capacity compared to the original ESPA due to larger diameter (Ø24-inch) ports and having fasteners every 10° compared to 15° spacing on ESPA. The small satellite standard Ø15-inch port referred to as ESPA class,‡ which has become a standard interface for small satellites, was redefined in 2016 with a delta qualification (static load) test. New ESPA APL limits, including introduction of an alternate version of the interface, referred to as ESPA Heavy (with Ø5/16” instead of Ø1/4" fasteners), are the following: 1. ESPA class: 220 kg at 51 cm (485 lb at 20 in), an increase of 21% compared to heritage ESPA class, 2. ESPA Heavy class: 322 kg at 51 cm (710 lb at 20 in), a mass increase of 77%. These increased payload capabilities for ESPA were documented in a paper at the 2017 Small Satellite Conference.1 In 2018, ESPA Grande, with its more capable Ø24-inch ports, was tested for the first time despite having flight heritage based on analysis and similarity to the ESPA Ø15-inch port. Prior to testing, the advertised capability of the Ø24-inch port was 318 kg at 51 cm (700 lb at 20 in). This paper documents the results of ESPA Grande qualification testing, and it describes the use of the ESPA Mass Acceleration Curve (MAC) which was implemented for this test program. The ESPA MAC provides design load factors for the range of APL mass available with the new, tested capabilities for both ESPA and ESPA Grande.
ESPA Grande Qualification
ESPA is established launch infrastructure for small satellites on Atlas V, Falcon 9, and Delta IV. Auxiliary payloads* (APLs) mount to ESPA on Ø15-inch† ports subject to limits on spacecraft mass and center of gravity (CG). ESPA Grande has increased payload capacity compared to the original ESPA due to larger diameter (Ø24-inch) ports and having fasteners every 10° compared to 15° spacing on ESPA. The small satellite standard Ø15-inch port referred to as ESPA class,‡ which has become a standard interface for small satellites, was redefined in 2016 with a delta qualification (static load) test. New ESPA APL limits, including introduction of an alternate version of the interface, referred to as ESPA Heavy (with Ø5/16” instead of Ø1/4" fasteners), are the following: 1. ESPA class: 220 kg at 51 cm (485 lb at 20 in), an increase of 21% compared to heritage ESPA class, 2. ESPA Heavy class: 322 kg at 51 cm (710 lb at 20 in), a mass increase of 77%. These increased payload capabilities for ESPA were documented in a paper at the 2017 Small Satellite Conference.1 In 2018, ESPA Grande, with its more capable Ø24-inch ports, was tested for the first time despite having flight heritage based on analysis and similarity to the ESPA Ø15-inch port. Prior to testing, the advertised capability of the Ø24-inch port was 318 kg at 51 cm (700 lb at 20 in). This paper documents the results of ESPA Grande qualification testing, and it describes the use of the ESPA Mass Acceleration Curve (MAC) which was implemented for this test program. The ESPA MAC provides design load factors for the range of APL mass available with the new, tested capabilities for both ESPA and ESPA Grande.
