Approximately how much propellant is required for attitude control?
ANSWER from Bryan Lunney on April 2, 2000: There are two types of thrusters, vernier thrusters (25 pounds of thrust) and the primary thrusters (875 pounds of thrust). Both types of thrusters fire in 80 millisecond (0.080 sec) increments. The duration is dependent on how much the autopilot determines is required. A single pulse every few minutes on verniers is usually sufficient to maintain a stable attitude, but the actual frequency and duration is highly dependent on the commanded attitude, the particular autopilot variables being used, and a few other factors. The vernier thrusters have a steady state flow rate of 0.0923 pounds/second. Thus, a single pulse (80 ms) will use about 0.0073 pounds of propellant (oxidizer and fuel). The primary thrusters have a steady state flow rate of 3.14 pounds/second. Thus, a single pulse (80 ms) will use about 0.25 pounds of propellant (oxidizer and fuel). Return to top.
