Parachutes n Supersonic portion Hemisflo Ribbon n n
Parachutes n Supersonic portion – Hemisflo Ribbon n n Most practical for velocities up to Mach 3 Subsonic portion – Ringsail Parachutes n n Historically proven success rate Reefed for a short time to decrease max gload during deployment and increase parachute stability
Parachutes Continued n Landing parachute – Volplane n n n Developed for the Pioneer spacecraft, tested with the Gemini capsule (L/D)max = 3. 0 Provide softer landing and maneuverability
Parachute Code n n Written by Jeremy Davis for Spring 2001, modified by Jon Edwards Consists of 6 Matlab files n n subreefeom. m / supereom. m subreefdiam. m / superdiam. m supersubhm. m acceldiff. m
Parachute Sample Case n Initial Conditions n n n Altitude at Mach 3 = 17. 5 km Flight Path Angle = 45 deg Mass = 57520 kg
Parachute Sample Case Con’t n Supersonic Stage n 7 hemisflo ribbon parachutes n n n D = 25 m Total Mass = 278 kg Deployment time = 42 s
Parachute Sample Case Con’t n Subsonic Reefed Stage n 3 reefed ringsail parachutes n Reefing factor = 0. 3 n n Inflated area = 0. 3 * max inflation area Reefing time = 10 s
Parachute Sample Case Con’t n Subsonic Un-reefed Stage n 3 ringsail parachutes let open to full inflation by cutting the reefing line n n Total mass = 222 kg D = 38. 5 m Deployment time = 39 s Landing Speed = 55. 7 m/s
Altitude History
Velocity History
Acceleration History (G-load)
Propulsion Systems n Shuttle OMS Engine - Retro/Boost n n F = 6000 lbf Isp = 313 s NTO and MMH propellants (non-cryo) Mass = 134. 7 kg
Propulsion Systems Cont’d n Marquardt R-40 A – RCS System n n n F = 500 lbf Isp = 306 s NTO and MMH propellants (non-cryo) Mass = 10 kg 24 R-40 A’s – 8 in each plane Also used on Shuttle Orbiter
Engine Tank Sizing Code n tanksize. m n n Written by Casey Kirchner for Spring 2001, modified by Jon Edwards Changes n n n No descent or hovering delta v’s No heat shield OMS Isp, expansion ratio and RCS Isp Landing mass Vehicle Dimensions
Tank Sizing Sample Case n Initial Conditions n n Mass = 57520 kg Periapsis lowering/raising delta v = 20 m/s Hab length = 16. 5 m Hab diameter = 13 m
Tank Sizing Sample Case n Oxidizer tank (cylindrical w/ hemi ends) n n n Fuel tank (cylindrical w/ hemi ends) n n n Length = 0. 90 m Diameter = 1. 00 m Length = 0. 94 m Diameter = 1. 00 m Pressurant Tank (spherical) n Diameter = 1. 36 m
Tank Sizing Sample Case n Oxidizer n n n Fuel n n n Tank mass = 10. 78 kg Propellant mass = 1725. 03 kg Tank mass = 11. 00 kg Propellant mass = 1078. 14 kg Pressurant n n Tank mass = 4. 70 kg Pressurant mass = 6. 07 kg
Tank Sizing Sample Case n Structural support n n n According to Humble we add 10% of total inert mass for structural support Structural support mass = 4. 19 kg Total Mass = 3250. 54 kg
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