Comets as cosmic time capsules: Rosetta’s scientific goals

SCIENCE AND ROBOTIC EXPLORATION

Rosetta wake-up and the year aheadESOC, 10 December 2013

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Prof Mark McCaughreanSenior Scienti!c AdvisorEuropean Space Agency

Comets as cosmic time capsules:Rosetta’s scienti!c goals



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Comet McNaught as seen from Cerro Paranal in 2007 / ESO



Comet ISON is (probably) no more

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ESA-NASA SOHO / LASCO C3, C2 coronographs, 27–30 November 2013



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Old ISON has "zzled away,To many astronomers’ dismay.But fret not, my friends,Fresh starts follow ends,Rosetta will soon be at play.

She’ll be waking in January, you see,To drop off her lander, Philae,Down onto the ice,Info in a trice,All about comet 67P.

Limericks courtesy of the Frost*ies



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Comet 1P/Halley in 1066, as recorded on the Bayeux tapestry



Hartmann 6

Artist’s representation of a protoplanetary disk / Hartmann



Origins of the solar system and life

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The Rosetta stone, discovered in 1799 at Rosetta (Rashid) in Egypt; now in British Museum, London



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Comet Halley in 1986, seen from the Kuiper Airborne Observatory



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ESA Giotto launched on an Ariane 1 on July 2, 1985



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Giotto at Comet 1P/Halley, March 14, 1986 / ESA



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Comet 103P/Hartley-2 taken at 700 km during EPOXI "y-by, November 4, 2010 / NASA, JPL, Caltech, UMD



ESA Herschel far-infrared astrophysics observatory, launched 2009

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Hartogh et al. (2011, Nature, 478, 4638)

Comets as the origin of Earth’s water?



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Composite of images Comet 9P/Tempel 1 taken by NASA’s Deep Impact impactor spacecraft on 4 July 2005



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Impact on Comet 9P/Tempel 1 as seen by NASA’s Deep Impact "y-by spacecraft on 4 July 2005



Huygens lander at Titan

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ESA Huygens lander deployed from NASA-ESA-ASI Cassini mission at Saturn, January 2005



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ESA Rosetta mission, launch 2004, arrival at Comet 67P/Churyumov-Gerasimenko in 2014



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Rosetta orbiter and Philae lander at Comet 67P/Churyumov-Gerasimenko in 2014



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Rosetta launch on Ariane 5G+ from Kourou, March 2, 2004 / ESA, CNES, Arianespace



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Rosetta on its !rst Earth "y-by, March 4, 2005 / ESA, reprocessed by Emily Lakdawalla



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Rosetta at Mars, as seen at 240,000km, one day before "y-by on February 25, 2007 / ESA



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Rosetta at Mars near closest approach at 1,000km, February 25, 2007 / ESA



Asteroid 2867 Šteins

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Fly-by on September 5, 2008



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Rosetta on its third Earth "y-by, November 13, 2009 / ESA



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Rosetta’s 2010 "y-by of asteroid 21 Lutetia, released May 30, 2012 / OSIRIS, ESA



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Asteroid 21 Lutetia during Rosetta’s "y-by on July 10, 2010 / ESA, OSIRIS



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67P/C-G



Target: 67P/Churyumov-Gerasimenko

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Mars EarthVenus

Mercury

Orbit ofJupiter

Plot showing orbits of inner planets, Jupiter, and Comet 67P/C-G on February 26, 2004

DiscoveryPerihelionAphelionSemi-major axisEccentricityInclinationOrbital period

19691.2458 AU5.6839 AU3.4648 AU0.640437.0424°6.45 yr

Klim Churyumov, Jean-Jacques Dordain (ESA), & Svetlana

Gerasimenko at Rosetta launch

Sun



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67P/C-G at 5.683AU, one month before aphelion, April 25, 2012 / Faulkes Telescope North / N. Howes, E. Guido



Hubble Space Telescope, NASA-ESA UV-optical-near-IR astrophysical observatory, launched 1990

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What does 67P/C-G look like?

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Reconstruction of Hubble Space Telescope light-curve data taken in 2003Distance from Sun: 2.5 AU Distance from Earth: 1.5 AU

In 2014, we will start to see 67P/C-G in much more detail

Lamy et al. 2006, A&A



Activity in 67P/C-GNeed to predict activity

Deployment of Philae in Nov 2014 predicated on low activity state

Reconstruct activity vs phase from last 3 orbits

67P/C-G period 6.45 yrAphelion 5.6839AUPerihelion 1.2458AU

Comet active earlier than previously thought

Onset of activity predicted for Mar 2014But still within operational constraints by Nov 2014

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Snodgrass et al. 2013, A&A



Activity in 67P/C-GSpeci!c active regions

Analysis of ground-based images from 2003–2009Provides spin axis, locations of most active regions

Model: consistent with three active regions

No evidence for change in number or location of regions, or of spin orientation

Activity localised to equatorial & mid-latitudes

Exposed on sunlit hemisphere during perihelion

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Vincent et al. 2013, A&A



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CONSERTROSINACOSIMA

MIDAS

Philae

VIRTIS

RPC

OSIRISALICE

GIADA

MIRO

ROSINA

Radio scienceRSI



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Imaging & spectroscopy inthe optical, UV, IR, millimetreOSIRIS, ALICE, VIRTIS, MIRO

Gas & dust mass spectroscopyROSINA, COSIMA

Dust structure, distribution,sizes, & microscopyGIADA, MIDAS

Plasma experimentsRPC

Imaging during descent,surface panorama, &

microscopyROLIS, ÇIVA

Gas, dust, organics, & plasmaCOSAC, MODULUS PTOLEMY,

APXS, ROMAP

Analysis of surface & sub-surface

SD2, MUPUS, SESAME

Tomography of the nucleus

CONSERT



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Comet Hale-Bopp in 1997 / Jerry Lodriguss

It’s time to unlock the treasure chest!



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Technology

Comets as cosmic time capsules: Rosetta’s scientific goals