Possible Probes and Scientific Instruments for Titan, Enceladus and the Saturnian system

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Possible Probes and Scientific Instruments for
Titan, Enceladus and the Saturnian system
Kinetic Penetrators - R. Gowen Space Plasmas
- A. Coates X-ray Observations - G.Branduardi

MSSL/UCL
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Mullard Space Science Laboratory
Hinode Launch 22-9-06

• Part of University College London
• 140 Staff
• Astrophysics (..XMM, Swift), Solar physics
  (..Yokhoh, Soho, Hinode) Space Plasma Physics
  (Cluster, Cassini,) Planetary Physics (Beagle2,
  Exomars)Climate Physics
• In-house mechanical and electrical engineering
  design, manufacture and test
• Provided hardware or calibration facilities for
  17 instruments on 12 spacecraft currently
  operating

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PenetratorConsortium

• MSSL
• Consortium lead, payload technologies, payload
  system design
• Birkbeck College London
• Science
• Imperial College London
• Seismometers
• Open University
• Science and geochemistry instrumentation
• QinetiQ
• Impact technologies, delivery systems
  technologies
• Southampton University
• Optical Fibres
• Surrey Space Science Centre and SSTL
• Platform technologies, delivery system
  technologies

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Penetrator Science

• Probe sub-surface chemistry (organic,
  astrobiological content ?)
• Probe sub-surface hardness/composition via
  accelerometers/chemical sensors
• Probe interior structure and seismic activity of
  bodies via seismometers, beeping transmitter
• Probe interior geothermal and chemistry via
  heat flow measurements
• Probe surface magnetic field, radiation,
  atmosphere, descent camera (surface morphology),
  etc

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Technology

• Deploy from orbit or balloon
• Deploy from orbit 15-18Kg for a 2 probe system
  (Enceladus,Titan) - De-orbiting and attitude
  control systems to decelerate probes to
• provide near vertical axially oriented impact
  300m/s at 10kgee. - deterministic landing
  zones.- For Titan need to study effects of
  atmospheric winds.
• Deploy from balloon 5Kg/penetrator (less mass)
  (Titan)- Gravitational acceleration and aero
  fins to provide axially oriented
  impact.(Balloon penetrator probes -gt powerful
  science combination)
• - Can sample more landing zones (icy, dunes,
  lakes,)
• - Landing site not deterministic - determined by
  balloon drift path. - Could soften landing
  impact, reduced penetration.- Deployment
  optimisation by selecting low atmospheric winds ?
• - Penetrator mass could double as ballast (if do
  not need seismic instruments else need early
  coordinated deployment)
• (Lunar-A 13.6 Kg, DS2 3.6Kg penetrators).

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Technology

• Scientific payload 2Kg for each penetrator.
• Probes to penetrate down to few metres under
  surface.
• Lifetime batteries provide 1 year on Moon, but
  rhus required for extended operations on cold
  worlds.
• Heritage Space penetrators DS2 and Lunar-A
  fullyspace qualified. TRL 6.
• No great history of failure DS2 only penetrators
  to have been deployed, though failed alongside
  lander.
• Defence sector regularly fires instrumentedmissil
  es at these speeds at concrete and steel and
  survive.
• Precede by Lunar Technical Demonstrator
  Mission.UK recently announced MoonLITE
  penetrator mission (2010-2011).

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Examples of electronic systems

• Have designed and tested electronics for high-G
  applications
• Communication systems
• 36 GHz antenna, receiver and electronic fuze
  tested to 45 kgee
• Dataloggers
• 8 channel, 1 MHz sampling rate tested to 60 kgee
• MEMS devices (accelerometers, gyros)
• Tested to 50 kgee
• MMIC devices
• Tested to 20 kgee
• TRL 6

MMIC chip tested to 20 kgee
Communication system and electronic fuze tested
to 45 kgee
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MSSL plasma interests at Titan

• Titan plasma interaction being explored by
  Cassini
• Plasma environment important for upper atmosphere
  heating
• New results show that plasma environment is
  relevant to atmosphere via negative ion formation
  (Coates et al, Waite et al, 2007)
• Important consequences for surface
• Need to be explored at lower altitudes is this
  the link needed for heavy organic formation ?

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MSSL plasma interests at Enceladus

• Flow deflection near Enceladus (Tokar et al,
  2006) due to neutral particle environment
• Accompanied by electron cooling due to neutrals
• Magnetosphere nearby important in affecting
  surface and as part of the environment of
  Enceladus
• Need to explore closer and with good electron,
  ion, composition measurements

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X-rays from Saturn

• Clear detections with XMM-Newton and Chandra
• Disk and polar cap X-ray emissions have similar
• spectra (unlike Jupiter)
• ? scattering of solar X-rays and
• fluorescent oxygen line emission
• ? no obvious X-ray emission from the
• aurorae (unlike Jupiter too faint?)
• Flux variability (flares) suggests X-ray
  emission controlled by the Sun
• Oxygen Ka line (0.53 keV) detected from the
  rings
• ? fluorescent scattering of solar X-rays
• from oxygen in H2O icy material
• ? consistent with Cassini detection of
• photo-produced tenuous atmosphere
• above the rings

Chandra ACIS
Bhardwaj et al. 2005
Chandra ACIS
Bhardwaj et al. 2005
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An X-ray imaging spectrometer for the Saturnian
system

• Unprecedented opportunity to combine in-situ
  X-ray observations with
• particle measurements
• 
  Scientific objectives
• Search for X-ray aurorae and correlate with UV
  emission
• - what fraction of X-ray emission is of
• magnetospheric origin?
• - what mechanisms may be at work?
• e.g. ionic charge exchange,
• electron bremsstrahlung, as on Jupiter?
• - how do auroral X-rays, and so the
  magnetosphere,
• respond to solar activity?
• Explore in detail the X-ray emission from the
  rings
• - how is it distributed along and
  above/below the rings?
• - how correlated with chemical properties
  of rings atmosphere?
• - how correlated with solar irradiation
  (aspect and intensity)?

Jupiter (XMM-Newton)
Branduardi-Raymont et al. 2007
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An X-ray imaging spectrometer for the Saturnian
system

• Scientific
  objectives (cont.)
• Investigate the response of Saturns upper
  atmosphere to solar X-ray
• irradiation albedo, time and spectral
  variability
• X-ray measurements of other solar system bodies
  en route to the
• planet, exploration of the Saturnian satellites
  (especially Titan)
• and their relation to Saturn
• ? X-ray imaging spectrometer is under study
  at MSSL
• Low mass, low power, 2o FOV micropore
  optics,
• CCD-type energy resolution (0.1 ? few
  keV)

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Summary
Kinetic Penetrators - Interior body and
geochemistry - R. Gowen Space Plasmas
- Magnetospheres/atmospheric links - A.
Coates X-ray Observations - Saturn rings and
atmospheric physics - G.Branduardi
Rob Gowen rag_at_mssl.ucl.uk Andrew Coates
ajc_at_mssl.ucl.ac.uk Graziella Branduardi
gbr_at_mssl.ucl.ac.uk