Europa Surface Element
Penetrators
MSSL
Rob Gowen (MSSL/UCL) on behalf of The Penetrator Consortium
ESA Europa Penetrators Study Results
Introduction
• Low mass, high speed impacting projectiles, performing
science investigations from below surface.
• Objectives: ground truth, unique science not possible from
orbit, future missions support
• Science capabilities: geophysics, chemistry, astrobiology,
environment.
Developments Update
• ESA ‘Jovian Moons Penetrators’ study performed.
• Paper (‘Penetrators for in situ subsurface investigations of
Europa’ ) written and accepted for publication
(http://dx.doi.org/10.1016/j.asr.2010.06.026)
• Engaged in ESA Instruments TDA (Technical
Development Activities) Program.
ESA Jovian Moons Penetrator
Study - Context
• ESA study with special provision for UK.
• Astrium UK [prime](descent system), MSSL(penetrator),
QinetiQ UK(shell, comms), UCL(impact sites & materials)
• Initially focused on Ganymede then on Europa
• Study did not include science instruments development
• Study constraints: 2 planetary orbits operational lifetime,
battery only power, high TRL solutions, 100 kg total mass
limit.
→Included model payload selected from candidate
instruments PDD (Payload Definition Document)
→Just within ~100 kg mass limit for single penetrator for
Ganymede (too high for inclusion in JGO reference
payload)
→Performed evaluation to determine minimum mass solution
(using ‘floor’ single instrument payload micro-seismometer
only payload for Europa)
•
•
•
•
Impact materials characterisation and hazards assessment
Impact survival testing of all elements
Assess impact crater morphology
Batteries (low temperature performance, bespoke design)
Abutment
Ring
Penetrator
Back Plate
Communications
Bay
Instrument
Bay
Battery & Control
Electronics Bay
• Shell: Detailed modelling shows Steel
or Titanium alloy shell can survive
impact into 40Mpa solid
polycrystalline ice (cf baseline 10MPa
compressive strength). Broader body
design reduces over-penetration into
more porous ice. (QinetiQ, UK)
Europa Penetrator Conceptual Design
• Inner: Vacuum flask concept limits thermal losses to enable 1 week lifetime with
batteries only power; and decouples thermal environment which could enable
feasible use of RHU to extend lifetime or reduce mass.
• Communications system: rear mounted UHF (High TRL) with 10dB margin for
transmission through pure ice; proximity-1 enables large range of dynamic signal
attenuation. 120 cone patch antenna allows for considerable range of post impact
orientations.
• Power: Potentially suitable primary battery alternatives identified, but require
detailed low temperature and impact assessment.
Release stud
Radome housing
antenna
Spacecraft
interface
Rear axial snubbers
(not visible)
Penetrator Shell
Radial snubbers positions
Front snubber
support system
Descent System
• Delivers penetrator to surface from orbiter
• Monopropellant system
• Orbiter visible throughout descent
Estimated Mass
Europa Penetrator Descent Module
[Design by Astrium Ltd.]
- Includes maturity and system margins
- micro-seismometer only payload (penetrator mass not particularly sensitive to
payload)]
Europa SEP
Mass
(a) For steel shell penetrator. (see Table)
Penetrator
~14.3 kg
(b) Minimum Mass System: ~60 kg
Descent Module
~49.8 kg
(Titanium alloy shell reduces penetrator
mass to 10.8 kg)
Total system mass ~64.1 kg
Additional mass saving options possible
Estimated Penetrator System Mass
(packing, RHU, bespoke batteries)
(steel penetrator), including margins
Way
Forward
• Develop TRL for science instruments
• Develop TRL for access to external materials
• Detailed study of planetary protection and radiation assessment
EJSM 4th Workshop, July 26-29 2010. Universal City, LA. U.S.A.