Ulysses A Scientific Odyssey

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UlyssesA Scientific Odyssey
Exploring the Heliosphere in 4 Dimensions Richard
G. Marsden
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Ulysses 1990 - 2009
U. ODysseus
18 years in orbit!!
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The Odyssey

• Introduction
• What is the heliosphere?
• Putting a space probe in a solar-polar orbit
• The scientific instruments on board Ulysses
• Selected scientific results ...
• Solar wind
• Ulysses and the Interstellar Medium
• Cosmic rays and energetic particles
• Jupiter revisited
• Recent results

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What is the Heliosphere?

• The Sun and its heliosphere are located in the
  Orion spiral arm of the Milky Way galaxy,
• 26,000 light-yrs (2.5 x 1017 km) from the centre
  of the galaxy
• During the lifetime of the solar system (4.5
  billion yrs), the Sun has circumnavigated the
  galaxy 20 times

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What is the Heliosphere?
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What is the Heliosphere?
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What is the Heliosphere?
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What is the Heliosphere?
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What is the Heliosphere?
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What is the Heliosphere?
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What is the heliosphere?

• The sphere of influence of the Sun
• The bubble in interstellar space carved out by
  the solar wind
• Our shield against the galactic environment

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Ulysses Milestones

• Launch
• 6 Oct 1990 by space shuttle Discovery
• Jupiter fly-by
• 8 Feb 1992
• Polar Passes
• 1994 (south) / 1995 (north)
• 2000 (south) / 2001 (north)
• 2006/7 (south) / 2007/8 (north)
• End of Prime Mission
• 30 Sep 1995

• ESA Extensions of Scientific Operations
• Jun 1993 SPC 1 Oct 1995 31 Dec 2001 (6.2 yrs)
• Jun 2000 SPC 1 Jan 2002 30 Sep 2004 (2.8 yrs)
• Feb 2004 SPC 1 Oct 2004 31 Mar 2008 (3.5 yrs)
• Nov 2007 SPC 31 Mar 2008 31 Mar 2009 (1 yr)

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Ulysses
Launch preparations
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Orbitwhere are we today?
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Scientific Payload

• Solar Wind
• SWOOPS/BAM (solar wind ions electrons)
• SWICS/GLG (solar wind ion composition)
• Magnetic Field
• MAG/HED (vector magnetic field)
• Radio Plasma Waves
• URAP/STO (electromagnetic waves up to 1 MHz)
• Energetic particles
• HI-SCALE/LAN (low-energy ions electrons)
• EPAC/KEP (low-energy ion composition)
• COSPIN/SIM (energetic particles cosmic rays)

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Scientific Payload

• Gamma-Ray Bursts
• GRB/HUS (15-150 keV)
• Neutral Interstellar Helium
• GAS/KEP (neutral He atoms))
• Cosmic Dust
• DUST/GRU (dust particles 10-16 to 10-6 g)

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Scientific Payload
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Principal Investigators
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Ulysses Highlights

• First exploration of the 3-D heliosphere over the
  solar magnetic cycle
• First in-situ measurements of interstellar dust
  and gas (neutral He)
• First measurements of rare cosmic-ray isotopes
• First in-situ detection of comet tails at large
  distances from the Sun
• First observations of energetic particles from
  solar storms over the solar poles
• First measurements of cosmic ray fluxes over the
  solar poles
• 1874 cosmological gamma-ray bursts detected, 165
  bursts from Galactic magnetars, and 1545 solar
  flares
• gt1450 scientific publications

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Ulysses and the solar cycle
Ulysses in orbit
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The changeable Sun
Solar minimum
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Solar wind overview
Yellow regions mark polar passes and fast
latitude scans
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Ulysses First Southern Excursion
McComas, et al., GRL, 2000
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Ulysses and the 4-D solar wind
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Ulysses and the 4-D solar wind
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Ulysses and the 4-D solar wind
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Ulysses and the 4-D solar wind
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Ulysses and the Interstellar Medium
Ulysses is exploring the Local Interstellar
Medium by measuring directly the neutral
component of the Interstellar Gas (with the GAS
instrument) and Interstellar Pickup Ions (with
SWICS)
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Characteristics of the Local Interstellar Cloud
(LIC)
First in situ measurement of neutral interstellar
Helium velocity, density and temperature
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Characteristics of the Local Interstellar Cloud
(LIC)
Physical characteristics of the LIC neutral
Helium gas were determined using the first direct
detection and measurements of helium atoms with
the GAS instrument
The composition of the neutral components of the
LIC gas at the Termination Shock was determined
using measurements of pickup H, He, He, N,
O, and Ne with SWICS.
Model calculations are used to find the densities
of the neutral and ionized components in the LIC.
Measurements of interstellar dust by the Dust
instrument on Ulysses are used to estimate the
dust fractions for N and O.
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Interstellar Dust particles
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Interstellar Dust particles
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Energetic particlesCosmic rays
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Energetic particlesCosmic rays
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Cosmic Rays
Galactic Cosmic Rays
The expected increase in cosmic ray flux over the
solar poles at solar minimum was NOT observed gt
Latitudinal transport of charged particles is
much more efficient than predicted
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Energetic Particles
Energetic Particles
Energetic particles accelerated at low latitudes
seen at high latitudes at solar minimum and solar
maximum gt Latitudinal transport of charged
particles is much more efficient than predicted
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Jupiter Distant Encounter2004
Quasi-periodic (QP) radio bursts
Courtesy R.J. MacDowall
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Jupiter Distant Encounter2004
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Solar wind at its weakest since the start of the
space age!

• Compared with previous solar minimum
• Solar wind pressure reduced by 20
• Magnetic field 35 weaker
• Possible consequences
• Boundaries of the heliosphere move inwards
  (Voyagers 1 2 may reach interstellar space
  sooner than expected, i.e. within 5 years)
• Increase in cosmic ray flux in inner heliosphere

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Data return amazing!
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Ops team outstanding!
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Ops teamAbove and beyond the call of duty!
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Ulysses
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31 March 2009 - THE END OF THE ODYSSEY
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THANKS!
On behalf of the science teams, thanks to
everyone who

• Conceived, Designed, Built, Tested

• Stored, Tested (again)

• Stored (again), Tested (yet again)

• Launched

• Operated

OOE/ISPM/Ulysses A great spacecraft and a great
mission!
(and no, we never did detect Bertottis
gravitational waves )