Penetrators for Enceladus

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

• Low mass projectiles 5KgPDS for Enceladus
• High impact speed 200-500 m/s
• Very tough 10-50kgee
• Penetrate surface few metres
• Perform science from below surface

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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)

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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.

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Preliminary Estimated Mass
() heavy penalty for Enceladus delivery
estimate 8x(penetrator mass) with
deployment from Titan with ?V3.7Km/sec
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Heritage

• 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!
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Current Development Status
Full-scale structure impact trial Scheduled May
19-23 2008
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Current Development Status

• MoonLITE bids in preparation for -
• 2 yr development to bring ruggedization of
  penetrator subsystems and instruments up to TRL
  5.
• Phase-A study for MoonLITE mission, currently in
  discussion with BNSC and NASA.
• Bids prepared for Cosmic Visions mission support.
• To study deltas to MoonLITE (impact into ice,
  reduced mass penetrator, long descent,
  communications)

5 inner compartments for full scale penetrator
trial

• 3 penetrator firings
• Normal incidence into dry sand at 300m/s

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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 -gt 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)
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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)

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Further information and contact details

• email rag_at_mssl.ucl.uk
• or see penetrator web site at

http//www.mssl.ucl.ac.uk/planetary/missions/Micro
_Penetrators.php
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