Transcript Penetrators for Enceladus

Penetrators for Enceladus
Dr Rob Gowen on behalf of
UK Penetrator Consortium
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
What are Penetrators ?
Detachable
Propulsion Stage
– Low mass projectiles
~5Kg+PDS for Enceladus
– High impact speed
~ 200-500 m/s
– Very tough
~10-50kgee
Point of
Separation
Payload
Instruments
– Penetrate surface
~ few metres
– Perform science
from below surface
Penetrator
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
PDS
(Penetrator
Delivery System)
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)
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.
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
Preliminary Estimated Mass
Item
Estimated Mass (kg)
Penetrator (inc. 2 kg payload)
~4.5Kg
Delivery system(*)
~32Kg
Spacecraft support
~2.5kg
Total mass
~39Kg
(*) heavy penalty for Enceladus delivery: estimate ~8x(penetrator mass) with
deployment from Titan with ∆V~3.7Km/sec
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
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’!
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
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
Current Development Status
 MoonLITE bids in
preparation for :a)
b)
5 inner compartments for full scale
penetrator trial
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.
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
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)
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)
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
Further information and contact
details
email: [email protected]
or see penetrator web site at
http://www.mssl.ucl.ac.uk/planetary/missions/Micro_Penetrators.php
Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK
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Titan Saturn System Mission Workshop - Paris, Mar 17-19, 2008
MSSL/UCL UK