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Probe Separation Analysis Daniel Rummel UCB

Probe Separation Analysis Daniel Rummel UCB. Overview. Overview • Linear Separation Analysis • 3D Re-Contact Analysis • Early Attitude Maneuvers • Long-Term Monte Carlo Simulation. Linear Separation Analysis Separation Events Summary. 3rd Stage Burn Out. Probe A Release.

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Probe Separation Analysis Daniel Rummel UCB

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  1. Probe Separation Analysis • Daniel Rummel • UCB

  2. Overview • Overview • • Linear Separation Analysis • • 3D Re-Contact Analysis • • Early Attitude Maneuvers • • Long-Term Monte Carlo Simulation

  3. Linear Separation AnalysisSeparation Events Summary 3rd Stage Burn Out Probe A Release Probes B-E Release 3rd Stage Chuffing

  4. Linear Separation Analysis Probe A to 3rd Stage Separation (Springs) Using mass properties and the details of the separation system, a nominal and low separation velocity can be calculated between Probe A and the Launch Vehicle.(LV = Star 48 3rd Stage + Probe Carrier)

  5. Linear Separation AnalysisResidual Thrust Error Sources Four3sigma Error Sources contribute to velocity imparted by residual thrust: • Mass of 3rd Stage • Probe A Separation time • 3rd Stage Burn time • Residual Thrust in 3rd stage (initial thrust & decay rate define the thrust curve)

  6. Velocity Imparted by 3rd Stage Chuffing: Linear Separation AnalysisResidual Thrust Integration Results Nominal + 3sigma Velocity =

  7. Linear Separation AnalysisResults/Margins Subtracting the residual thrust velocity from the spring separation system velocity yields separation margins. • Nominal margins remain high. • 3sigma margins remain positive.

  8. 3D Re-Contact AnalysisSummary 3D Re-Contact Analysis • Utilized GTDS using the full high-fidelity force model for 3D orbit propagation. • Short-term analysis at 1 sec. resolution for the first 20min after release. • Long-term analysis at 1 min. resolution for 7 days.

  9. 3D Re-Contact AnalysisShort-term Results: Probe A Nominal Separation Probe A obtains ~900m in first 20 min. In 3sigma case Probe A still maintains ~100m after first 20 min. Nominal Separation 3Sigma Low Separation

  10. 3D Re-Contact AnalysisShort-term Results: Probes B-E Nominal Separation Probes B-E obtain ~2000m in first 20 min. As expected residual thrust has little effect on Probes B-E. Nominal Separation 3Sigma Low Separation

  11. 3D Re-Contact AnalysisLong-term: Probe A to LV • General trend: A Linear increase in separation at each successive orbit node. • Nominal separation yields ~170km at the first node. Nominal Separation +3Sigma Separation

  12. 3D Re-Contact AnalysisLong-term: Probe A to LV - Close Up • General trend: Linear increase in separation at each successive orbit node. • Nominal separation yields ~170km at the first node. • +3Sigma Separation yields ~15km at the first node. +3Sigma Separation Close Up

  13. Early Attitude ManeuversEarly Attitude Maneuvers and the Imparted dV Within ~14hours after release the probes will need to be placed in a power positive attitude. (From the LV attitude to any sun normal attitude). Modeling these maneuvers in GMAN indicates that they impart ~1 m/s of dV partially in the direction of separation and out of release formation. Residual dV Reorientation

  14. Early Attitude Maneuver Sequence D E C B A Probe Release Early Attitude ManeuversEarly Attitude Maneuver Sequence Spacing these maneuvers out over ~8 hours can aid in probe separation. (*Night 3 is a lunar shadow.)

  15. Early Attitude ManeuversProbe A-> LV Nominal Release w/ Early Attitude Maneuvers Nominal release shows benefit of ~50km after the first 20 hours.

  16. Early Attitude ManeuversProbe A-> LV 3sigma Release w/ Early Attitude Maneuvers 3sigma release shows benefit of ~45km after the first 20 hours.

  17. Early Attitude ManeuversProbeA -> ProbeB separation w/ Early Attitude Maneuvers Probe A maneuver @ Release+9hours Probe B maneuver @ Release+13Hours The green line indicates additional separation due to the attitude maneuvers.

  18. Early Attitude ManeuversProbe A->Probe B Long-term Sep. w/ Early Attitude Maneuvers Probe A maneuver @ Release+9hours Probe B maneuver @ Release+13Hours • Long-term separation continues. • Trends are similar for all other probes.

  19. Monte Carlo SimulationRandom Dispersion of Velocity Vectors Dispersions Applied: • All Velocity & timing dispersions from Linear Analysis. • Rotation of the launch vehicle 15 +/-3 RPMs. • 0.5 sec release window for Probes B-E. • 2 deg/sec tip off rate of Launch Vehicle.

  20. Early Attitude Maneuver Sequence D E C B A Monte Carlo SimulationMore Details • In Addition to the new dispersion the simulation also includes modeling of the ‘Early Attitude Maneuvers’. • 18,000 cases completed for each probe. (1000 cases for every 5° of a 90° phase of the launch vehicle.) • Run at 1 min resolution in GTDS

  21. Monte Carlo SimulationResults For each Probe and the LV post-release minimum approach distance to any of the other objects was tracked:

  22. Summary & Conclusions Linear separation analysis of separation springs and residual thrust. - Nominal margins remain high. - 3sigma margins remain positive. 3D re-contact analysis - Nominal and 3sigma separation checks out. Early attitude maneuvers - Effects are minimal but are beneficial to separation. Monte Carlo simulation - 3 sigma dispersions show no re-contact due to orbital perturbations.

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