Rita Schulz

Rosetta Project Scientist

The ROSETTA MissionExploring Solar System Formation

Rosetta

One Comet rendezvousTwo Asteroid fly-bys

• Launch: 2 March 2004 with Ariane 5

• Journey:

3 Earth gravity assists Mar 2005, Nov 2007, Nov 2009

1 Mars gravity assist Feb 2007

2 Asteroid flybys 2867 Steins: Sep 2008, 21 Lutetia: Jul 2010

Comet Rendezvous maneuver May 2014 m(4 AU)

Lander delivery: Nov 2014 (3 AU)

Perihelion Passage: Aug 2015 (1.24 AU)

End of Nominal Mission: Dec 2015 (1.9 AU **)

Rosetta Milestones

11 Orbiter Instruments/ (Instrument Packages) 18 Experiments

Payload Mass: ~170 kg+ Lander: ~110 kg

10 Lander Instruments/ (Instrument Packages)=> 16 Experiments

Rosetta

Scientific PayloadScientific Payload

Payload Mass: ~27 kg

Rosetta Scientific PayloadThe Rosetta Orbiter:

Remote sensing ALICE, OSIRIS, VIRTIS, MIRO

Composition analysis ROSINA, COSIMA

Nucleus large-scale structure CONSERT

Dust flux and physical properties GIADA, MIDAS

Comet plasma environment RPC

Radio science RSI

The Lander Philae

Imaging CIVA, ROLIS

Composition analysis APX, COSAC, Ptolemy

Physical properties MUPUS, SESAME

Nucleus large-scale structure CONSERT

Magnetic field and plasma ROMAP

Drill and sampling device SD2

The Journey

Rosetta Mission Scenario includesRosetta Mission Scenario includesTwo Asteroid Fly-bysTwo Asteroid Fly-bys

(2867) Steins (21) Lutetia Closest approach:5 Sept. 2008 18:38:19 UT

r = 2.14 AU, Δ = 2.41 AURelative velocity: 8.62 km/sMin. flyby distance: 802.6 km

Closest approach:10 July 2010 15:44:57 UT

r = 2.72 AU, Δ = 3.05 AURelative velocity: 15 km/sMin. flyby distance: 3160 km

Asteroid (2867) Steins

1 km 1 km

60 % of surface resolved

Overall dimensions: 6.67 × 5.81 × 4.47 km3

Spherical equivalent radius: 2.65 km

Phase function -> surface roughness

(2867) Steins – Opposition Effect

Geometric albedo near 0 phase image: 0.40 ± 0.01

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(2867) Steins – Cratering History

Crater number & size -> age of surface

Age: 0.154 ± 0.035 Ga (NSL) or 0.49 to 1.6 Ga (HSL)

Crater scaling laws

Crater density not saturated

Steins’ surface younger than mean collisional age (2.2 Ga)

Reshaping due to YORP spin up(Yarkovsky-O’Keefe-Radzievskii-Paddack)

YORP effect can modify the rotation rate and spin-axis orientation of small asteroids.Important process driving their physical and dynamical evolution. Material sliding towards the equator.

YORP Effect and Geology

Catena with 7 pits on one side & large fault on the opposite side likely produced by large impact creating 2.1-m sized crater. Steins not a monolith, but strongly fractured (may be a rubble pile).

(21) Lutetia – approach phase

Overall dimensions: 123 × 103 × 93 km3

Pixel size: 60 m