Opening Shock Factor Calculation for Orion Main Parachute Disreefing

摘要

We describe a new calculation of the opening shock factor C_k characterizing the peak inflation drag of NASA's Orion spacecraft main parachutes, while disreefing from 1st stage reefing to 2nd stage reefing, and later, from 2nd stage reefing to full-open. Here the Momentum-Impulse Theorem is used to derive new formulas that estimate C_k solely based on the knowledge of inflation time, final reefed drag area and descent rate at the beginning of each disreefing stage. These new results are validated using the trajectory and inflation performance data generated during the engineering development and qualification test drops of NASA's CPAS program, and over the full range of mass ratios in which both inflation modes have taken place.