Near Rectilinear Orbits around the Moon as Operational

Near Rectilinear Orbits around the Moon as Operational Orbit for the future Deep Space Gateway Carlos Sánchez Lara, Joan Pau Sánchez Cuartielles 7 th International Conference on Astrodynamics Tools and Techniques (ICATT) 6 - 9 November 2018 www. cranfield. ac. uk

GUIDELINE Introduction NRHO Orbit Maintenance Transfer Trajectories Conclusions 2/22

3/22 INTRODUCTION Credits: www. engadget. com Deep Space Gateway (DSG) Introduction NRHO Orbit Maintenance Transfer Conclusions

4/22 INTRODUCTION – LOP-G Credits: www. engadget. com Applications • Staging point • Communications • Scientific observations Orbit Requirements • Lunar poles coverage • Low orbit maintenance risks & costs • Accessibility NRHO Introduction Orbit Maintenance Near Rectilinear Halo Orbits (NRHO) Transfer Conclusions

5/22 INTRODUCTION – Dynamical Models Circular Restricted Three Body Problem (CR 3 BP) • Periodic orbits • Transfer trajectories Introduction NRHO Orbit Maintenance Bicircular Model (BCM) • Station-keeping analysis Transfer Conclusions

6/22 HALO ORBITS Near-Rectilinear Halo Orbits Introduction NRHO Orbit Maintenance Transfer Conclusions

7/22 HALO ORBITS Period Introduction NRHO Jacobi Constant Orbit Maintenance Transfer Conclusions

HALO ORBITS – 8/22 Near Rectilinear Halo Orbits (NRHO) Introduction NRHO Orbit Maintenance Transfer Conclusions

HALO ORBITS – 9/22 Near Rectilinear Halo Orbits (NRHO) Introduction NRHO Orbit Maintenance Transfer Conclusions

HALO ORBITS – Dynamical Substitutes 10/22 Introduction NRHO Orbit Maintenance Transfer Conclusions

11/22

12/22 STATION-KEEPING Errors Model Error Magnitude Model Manoeuvr e 1% execution Introduction NRHO Orbit Position 1 km Velocity 1 cm/s Minimum manoeuvr 0. 15 cm/s e Transfer - Conclusions

13/22 STATION-KEEPING – Strategies Unstable mode cancellation Cost Function Optimisation Differential Corrections Introduction NRHO Orbit Transfer Conclusions

14/22 STATION-KEEPING – Strategies Unstable mode cancellation SKS – 5 1 man/orbit SKS – 6 2 SKS – 1 SKS – 2 1 man/orbit SKS – 3 2 SKS – 9 1 man/orbit SKS – 7 3 man/orbit SKS – 8 1 man/orbit SKS – 4 3 man/orbit Introduction Cost Function Optimisation Differential Corrections man/orbit (x-axis crossing Guzzetti, Howell et al. , 2017 method) NRHO Orbit Transfer Conclusions

STATION-KEEPING – Results (CR 3 BP) 15/22 Introduction NRHO Orbit Transfer Conclusions

STATION-KEEPING – Results (BCM) 16/22 Introduction NRHO Orbit Transfer Conclusions

17/22 TRANSFER TRAJECTORIES Direct transfer from Earth to apolune Introduction NRHO Orbit Maintenance Transfer Conclusions

18/22 TRANSFER TRAJECTORIES Transfer from Earth to stable manifold Introduction NRHO Orbit Maintenance Transfer Conclusions

TRANSFER TRAJECTORIES 19/22 Introduction NRHO Orbit Maintenance Transfer Conclusions

20/22 TRANSFER TRAJECTORIES Introduction NRHO Orbit Maintenance Transfer Conclusions

21/22 TRANSFER TRAJECTORIES Transfer from NRHO to polar circular Moon orbit Orbit Distant Retrograde Orbit Introduction NRHO 830 m/s 800 m/s Orbit Maintenance Credits: Whitley et al. , 2016 Transfer Conclusions

22/22 CONCLUSIONS • Excellent lunar poles coverage • Direct line of sight with the Earth • Low escaping risks • Low maintenance costs • Direct/fast trajectories available at reasonable costs • Efficient transfer trajectories • Good accessibility to the lunar poles Introduction NRHO Orbit Maintenance Transfer Conclusion

Thank you for your attention! Any Questions?

Unstable mode evolution