The Development of a 100-ft Drogue Parachute for the X-38 Spacecraft

Abstract

§The NASA X -38 program was developing a Crew Return Vehicle (CRV) for the International Space Station (ISS). The primary parachute system for the CRV consisted of a mortar -deployed pilot, drogue parachute, and parafoil. This pa per describes the design, development, and testing of the 100 -foot drogue parachute, which was designed to slow and stabilize the CRV, provide the desired deployment conditions for the parafoil, and extract the parafoil when the drogue was released from th e vehicle. The drogue was a continuous ribbon, quarter -spherical canopy with a vent hoop instead of vent lines. Zylon was incorporated into the design to reduce weight, however, Zylon suffered strength degradation when exposed to light, requiring close mon itoring of each parachute’s condition prior to reuse. The total loads for the maximum deployment dynamic pressure of 350 psf were minimized by using 5 reefed stages. Stability improvement was achieved by incrementally reducing suspension line length to ret ain the desired drag coefficient while improving stability. Drop testing was conducted to validate the design.