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

Why Titan?

Voyager Titan Fly-By NASA

Cassini at Titan NASA

Huygens Enters Titan ESA/NASA

Huygens on Titan ESA/NASA

A Titan Shoreline NASA

Titan Lakes NASA

Peter Ward on Life in the Universe

… 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

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

Celestial Mechanics Parameters SaturnEarthTitan GM - km 3 /s E E E+03 R(planet) - km6.0268E E E+03 r(to focus) - km1.4242E E E+06

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

Earth Departure - Speed Changes

Titan Arrival – Speed Changes

Titan Departure – Speed Changes

In-Situ Propellant Production at Titan

Earth Arrival – Speed Changes

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

Mass Ratios Type Ispveve  v opt Mass Ratio skm/s OutboundReturnRound-Trip Chemical NTR GCR

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

Earth Departure - Factory

Mission Scenario Launch crew with duplicate habitat, supplies and factory years

Earth Departure - Crew with Duplicate Spacecraft

Mission Scenario Arrive unmanned habitat, supplies and factory years

Titan Arrival – Factory

Mission Scenario Arrive crew with duplicate habitat, supplies and factory years

Titan Arrival – Crew & Duplicate Spacecraft

Mission Scenario Leave crew with duplicate habitat, supplies and factory years

Titan Departure

Mission Scenario Earth entry crew years -Crew: years

Earth Arrival

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

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

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

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.