Session
Technical Session V: University Student Scholarship Competition
Abstract
Small satellites create unique challenges in the design of deployment mechanisms and attachments to launch vehicles. The SAPPHIRE satellite, designed and built by students at Stanford University, is 35 pounds and is designed to be launched as a secondary payload on any of a variety of launch vehicles. The design of the interface and separation system is intended to optimize simplicity, size, weight, and cost. The SAPPHIRE design uses a single hold down bolt with a single separation spring. Deployment is achieved through the use of a Frangibolt (TiNi Alloy Co.). This device utilizes properties of the shape memory alloy Nitinol which forcefully expands when heated in order to fracture a quarter inch Titanium bolt. The Frangibolt was used previously on the Clementine mission to the moon to deploy solar arrays but has not been proven yet to actually deploy a satellite. The power requirement of the Frangibolt (60 Watts minimum) is met through the use of a thermal battery designed for use with ejection seats. The interface between the satellite and the launch vehicle provides four attachment points to the rocket, supports the satellite and separation system components and isolates the satellite from high frequency vibrations during launch and ascent. This paper describes the design and testing of the SAPPHIRE separation system and launch vehicle interface.
The Design of the SAPPHIRE Separation System and Launch Vehicle Interface
Small satellites create unique challenges in the design of deployment mechanisms and attachments to launch vehicles. The SAPPHIRE satellite, designed and built by students at Stanford University, is 35 pounds and is designed to be launched as a secondary payload on any of a variety of launch vehicles. The design of the interface and separation system is intended to optimize simplicity, size, weight, and cost. The SAPPHIRE design uses a single hold down bolt with a single separation spring. Deployment is achieved through the use of a Frangibolt (TiNi Alloy Co.). This device utilizes properties of the shape memory alloy Nitinol which forcefully expands when heated in order to fracture a quarter inch Titanium bolt. The Frangibolt was used previously on the Clementine mission to the moon to deploy solar arrays but has not been proven yet to actually deploy a satellite. The power requirement of the Frangibolt (60 Watts minimum) is met through the use of a thermal battery designed for use with ejection seats. The interface between the satellite and the launch vehicle provides four attachment points to the rocket, supports the satellite and separation system components and isolates the satellite from high frequency vibrations during launch and ascent. This paper describes the design and testing of the SAPPHIRE separation system and launch vehicle interface.
