1. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Penetrators for Enceladus Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Dr Rob Gowen on behalf of UK Penetrator Consortium

2. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK What are Penetrators ? –Low mass projectiles ~5Kg+PDS for Enceladus –High impact speed ~ 200-500 m/s –Very tough ~10-50kgee –Penetrate surface ~ few metres –Perform science from below surface Penetrator Point of Separation Payload Instruments Detachable Propulsion Stage PDS (Penetrator Delivery System)

3. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Penetrator Payload/Science A nominal 2kg payload …  Accelerometers – Probe surface/sub-surface material (hardness/composition)  Seismometers - Probe interior structure (existence/size of water reservoirs) and seismic activity of bodies  Chemical sensors – Probe surface refactory/volatile (organic/ astrobiologic) chemicals, perhaps arising from interior.  Thermal sensors - Determine subsurface temperatures and possibly probe deep interior processes.  Mineralogy/astrobiology camera – Probe surface mineralogy and possible astrobiological material.  + other instruments – to probe surface magnetic field, radiation, beeping transmitter, etc…  descent camera (surface morphology, landing site location, etc)

4. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Science/Technology Requirements  Target –E.g. region of upwelled interior material. –2 penetrators would allow additional target, improved seismic results and natural redundancy but require 2xmass.  Lifetime –Only minutes/hours required for camera, accelerometer, chemistry, thermal & mineralogy/astrobiologic measurements. –An orbital period (~few days) for seismic measurements. (requires RHU)  Spacecraft support –~7-9 years cruise phase, health reporting  Delivery –Targetting precision. –Ejection, descent motors & orientation, pre-impact separation, communications, impact.  Operation –Power/thermal (battery/RHU), data handling, communications.

5. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Preliminary Estimated Mass Item Estimated Mass (kg) Estimated Mass (kg) Penetrator (inc. 2 kg payload) ~4.5Kg ~4.5Kg Delivery system(*) ~32Kg Spacecraft support ~2.5kg ~2.5kg Total mass ~39Kg (*) heavy penalty for Enceladus delivery: estimate ~8x(penetrator mass) with deployment from Titan with ∆V~3.7Km/sec

6. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UKHeritage  Lunar-A and DS2 space qualified.  Military have been successfully firing instrumented projectiles for many years to comparable levels of gee forces into concrete and steel.  40,000gee qualified electronics exist (and re-used).  Currently developing similar penetrators for MoonLITE.  Payload heritage: –Accelerometers, thermometers, sample drill – fully space qualified. –Seismometers (ExoMars) & chemical sensors (Rosetta) heritage but require impact ruggedizing. –Mineralogy camera – new but simple. When asked to describe the condition of a probe that had impacted 2m of concrete at 300 m/s a UK expert described the device as ‘a bit scratched’!

7. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Current Development Status Full-scale structure impact trial – Scheduled May 19-23 2008

8. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Current Development Status  MoonLITE bids in preparation for :- a)2 yr development to bring ruggedization of penetrator subsystems and instruments up to TRL 5. b)Phase-A study for MoonLITE mission, currently in discussion with BNSC and NASA.  Bids prepared for Cosmic Visions mission support. a)To study deltas to MoonLITE (impact into ice, reduced mass penetrator, long descent, communications) 3 penetrator firings Normal incidence into dry sand at 300m/s 5 inner compartments for full scale penetrator trial

9. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Main Technical Challenges  Ruggedisation to survive impact into ice (M→C)  Likely require RHUs for extended lifetime (requires good thermal model) (M→C)  Achieve proposed mass savings over MoonLITE penetrators (reduced lifetime -> power saving, lighter structure, asics) (M→C)  Optimise mass estimates of descent system (M→C)  Study descent system in detail including target ellipse (C)  Study descent and landed communications including possible trailing aerial. (M→C) (M = MoonLite, C = Cosmic Vision, M→C ∆ development for Cosmic Vision)

10. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Penetrators for Titan ?  Could be delivered from balloon or orbit.  Much smaller mass ~8.5Kg/probe  Delivery from orbit allows :- (i) deterministic targetting, and (ii) co-temporal placement of multiple penetrators for seismic network to allow investigation of subsurface oceans, interior/core, and seismic activity levels.  Multiple penetrators allows examining several different terrains (dunes, ice, lake beds)  Penetrators allow sampling from sub-surface e.g. bottom of lake beds which collect alluvial material deposits and possible astrobiologic material)

11. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK Further information and contact details email: email: rag@mssl.ucl.ukrag@mssl.ucl.uk or see penetrator web site at http://www.mssl.ucl.ac.uk/planetary/missions/Micro_Penetrators.php

12. Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008 MSSL/UCL UK - End -