Rosetta Lander Philae

Philae is a comet nucleus lander launched in 2004 as part of ESA's Rosetta mission, after a 1-year delay and change of the target comet. See Chapter 26 for a more detailed case study (Figure 20.3).

Target Objectives

Prime contractor Launch site, vehicle Launch date Arrival date Landing site co-ordinates End(s) of mission(s)

Mass(es) Payload experiments

Comet 67P/Churyumov-Gerasimenko

To land on a comet nucleus and measure the following:

• The elemental, molecular, mineralogical, and isotopic composition of the comet's surface and subsurface material

• Characteristics of the nucleus such as near-surface strength, density, texture, porosity, ice phases and thermal properties; texture measurements will include microscopic studies of individual grains DLR/MPAe

Kourou, Ariane 5 G+ (on Rosetta orbiter) 02/03/2004

Nominal lander delivery: November 2014 To be determined based on orbiter data

First science sequence 120 h (possible with battery power only), followed by ^3 month long-term mission to 2 AU, then extended mission until lander overheats 97.4 kg mass ejected from orbiter

• APX alpha-particle-X-ray spectrometer (Rieder, Klingelhofer)

• CIVA comet nucleus infrared and visible analyser (Bibring)

• CIVA-P panoramic cameras

• CIVA-M visible/IR microscope

Delivery architecture

Thermal aspects

Power aspects

Communications architecture EDL architecture

Landing speed(s)

• COSAC cometary sampling and composition experiment

(evolved gas analyser) (Rosenbauer, Goesmann)

• CONSERT comet nucleus sounding experiment by radiowave transmission (Kofman)

• MUPUS multi-purpose sensors for surface and sub-surface science (Spohn)

• TM thermal IR radiometer

• ANC-M,T accelerometer and temperature sensor in harpoon anchors

• PEN thermal probe

• Ptolemy evolved gas analyser (Wright)

• ROMAP Rosetta Lander magnetic field investigation and plasma monitor (Auster)

• ROLIS Rosetta Lander imaging system (Mottola)

• SESAME surface electrical, seismic and acoustic monitoring experiments (Moohlmann)

• CASSE cometary acoustic surface sounding experiment

(Mohlmann, Seidensticker)

• PP permittivity probe (Laakso, Schmidt),

• DIM dust impact monitor (Apathy)

• SD2 sampling, drilling and distribution system (Finzi)

Total mass 26.7 kg

The Project Scientists are Helmut Rosenbauer, Hermann Bohnhardt and Jean-Pierre Bibring

Separation at low speed (5-52 cm s—from the Rosetta orbiter during low altitude (few km) manoeuvre

'Warm' compartment inside lander body, and 'cold' balcony for external instruments

Primary 900 Wh LiSOCl2 battery plus secondary 100 Wh Li-ion battery with body-mounted Si solar array

Two-way S-band relay via Rosetta orbiter

Ejection velocity from orbiter causes lander to fall towards surface. Momentum wheel attitude stabilisation. Landing legs unfolded. Hold-down thruster, anchoring harpoon and foot screws activated on contact with surface. Impact damping performed partly by damping mechanism in cardanic joint between landing gear and lander body

Active operations Descent and landing aspects including unfolding legs, (deployments, etc.) hold-down thruster and anchoring harpoon. Movement of lander body on landing gear via cardanic joint and rotation device. Deployment of CONSERT antennas, APXS, sampling drill, magnetometer boom and MUPUS boom

Key references Biele et al., 2002; Biele, 2002; Biele and Ulamec, 2004;

Ulamec et al., 2006; ESA SP-1165 (in preparation); Space Sci. Rev. special issue on Rosetta (in preparation)

Figure 20.3 Rosetta Lander Philae.
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