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Parachutes

Parachutes. Changed Supersonic portion of descent 0.9 < M < 3 Changed Cd of Hemisflo Ribbon Chutes Curve fit so Cd is a function of M More accurate for computerized analysis. Parachutes Continued. Subsonic Parachute change Ringslot instead of Ringsail

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Parachutes

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  1. Parachutes • Changed Supersonic portion of descent • 0.9 < M < 3 • Changed Cd of Hemisflo Ribbon Chutes • Curve fit so Cd is a function of M • More accurate for computerized analysis

  2. Parachutes Continued • Subsonic Parachute change • Ringslot instead of Ringsail • Ringslots are applicable for velocities in the range of 0.1 < M < 0.9 • According to Knacke Cd = 0.60 has been measured for ringslots in the wake of a large aircraft

  3. Parachutes Continued • Parasail Deployment • Parasail instead of Volplane • Knacke has Cd and Cl values • Need to code

  4. Parachute Sample Case • Without parasail part of descent • Initial Conditions • Altitude at Mach 3 = 17.5 km • Flight Path Angle = 45 deg • Mass = 57520 kg

  5. Parachute Sample Case Con’t • Supersonic Stage • 7 hemisflo ribbon parachutes • D = 25 m • Total Mass = 278 kg • Deployment time = 50 s

  6. Parachute Sample Case Con’t • Subsonic Reefed Stage • 6 reefed ringslot parachutes • Reefing factor = 0.3 • Inflated area = 0.3 * max inflation area • Reefing time = 10 s

  7. Parachute Sample Case Con’t • Subsonic Un-reefed Stage • 6 ringslot parachutes let open to full inflation by cutting the reefing line • Total mass = 668 kg • D = 50 m • Deployment time = 71 s • Landing Speed = 25 m/s

  8. Altitude History

  9. Velocity History

  10. Acceleration History (G-load)

  11. Tank Sizing • Instead of trying to calculate the delta V’s needed to do spin up we are going to use the delta V’s listed in Table 4.4.2 of the Spring’s Final Report

  12. Tank Sizing Example Case • Mars Orbit DV: 20.00 • Entry Angle Change DV: 146.43 • Spin-up DV: 99.51 • Enroute RCS/Maneuvering DV: 102.00 • Total DV: 445.14

  13. Tank Sizing Example Case • Landing Mass of 57520 kg • Total Propulsion mass = 6109.43 kg • Combines all inert masses with propellant and pressurant masses

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