1. Nuclear Thermal Propulsion for Robotic and Piloted Titan Missions Brice Cassenti University of Connecticut

2. Why Titan?

3. Voyager Titan Fly-By NASA

4. Cassini at Titan NASA

5. Huygens Enters Titan ESA/NASA

6. Huygens on Titan ESA/NASA

7. A Titan Shoreline NASA

8. Titan Lakes NASA

9. Peter Ward on Life in the Universe

10. … on Piloted Missions to Titan “Unfortunately chances are that any humans hazarding the long trip to the Saturnian system would be embarking on one –way trips. As dangerous as a mission to Mars would be, it pales in comparison with what would be required of the humans and machines leaving on the seven-or-more-year trip just to get from the earth to Titan.” p. 251

11. Nuclear Thermal Propulsion for Robotic and Piloted Titan Missions The Astrodynamics Some Propulsion Alternatives In-situ Propellant Production A Mission Scenario Conclusions

12. Celestial Mechanics Parameters SaturnEarthTitan GM - km 3 /s 2 3.7931E+073.9860E+059.0400E+03 R(planet) - km6.0268E+046.3568E+032.5750E+03 r(to focus) - km1.4242E+091.4960E+081.2220E+06

13. Hohmann Transfer Description Elapsed Time years Depart Earth0.00 Arrive Saturn6.03 Depart Saturn7.00 Arrive Earth13.03 *Synodic Period: 1.04 years

14. Earth Departure - Speed Changes

15. Titan Arrival – Speed Changes

16. Titan Departure – Speed Changes

17. In-Situ Propellant Production at Titan

18. Earth Arrival – Speed Changes

19. Speed Changes  v - km/s Earth Departure7.3 Titan Departure5.7 Round-Trip13.0

20. Mass Ratios Type Ispveve  v opt Mass Ratio skm/s OutboundReturnRound-Trip Chemical4754.667.454.83.416.32 NTR9509.3114.92.191.844.04 GCR190018.6229.791.481.362.01

21. Mission Scenario Launch unmanned habitat, supplies and factory - 0 years

22. Earth Departure - Factory

23. Mission Scenario Launch crew with duplicate habitat, supplies and factory - 1.03 years

24. Earth Departure - Crew with Duplicate Spacecraft

25. Mission Scenario Arrive unmanned habitat, supplies and factory - 6.03 years

26. Titan Arrival – Factory

27. Mission Scenario Arrive crew with duplicate habitat, supplies and factory - 7.06 years

28. Titan Arrival – Crew & Duplicate Spacecraft

29. Mission Scenario Leave crew with duplicate habitat, supplies and factory - 8.03 years

30. Titan Departure

31. Mission Scenario Earth entry crew -14.06 years -Crew: 13.03 years

32. Earth Arrival

33. Mass Estimate From Mars mission study –Dry mass in LEO is approximately 250 tons –Includes habitat, factory, reactor and supplies –With propellant mass is 550 tons There are three identical spacecraft –Total mass in LEO is 1,650 tons International Space Station is 300 tons

34. Conclusions Titan is of immense scientific interest Bimodal nuclear thermal propulsion –is the right specific impulse –is high thrust –provides power Titan can provide abundant resources for the return trip

35. Future Work Accurate mass estimates Exam fast transfers/gravity assists to reduce: –cosmic ray exposure & solar flares –effects of weightlessness Add artificial gravity to eliminate effects of weightlessness

36. It’s hard, but maybe not as hard as Peter Ward believes NASA/JPL If we use bimodal nuclear thermal rockets and in-situ propellant production.