Imaging Mercury surface

The SIMBIO-SYS Experiment for the BepiColombo Mission

IASorsay

Enrico Flamini – Roma 27-2-07

SIMBIO-SYS

• SIMBIO-SYS is an integrated package for the imaging and spectroscopic investigation of the Hermean surface selected by ESA as part of the European mission to Mercury BepiColombo .

SCIENCE: Geology and Geomorphology

– Geomorphological characterization of the highly cratered units (3D)

– Origin, limit and areal extension of intracrater, hummocky and smooth plains;

– Stratigraphic relationships between highlands and plains (3D)

– Presence of layered units (HR)– Characterization of polar deposits;– Identification of aeolian deposits;– Impact crater morphologies and

degradation level (3D)– Ejecta distribution and modification

100 km

15 km

Upper crust evolution and surface processes

SCIENCE: Volcanism Styles and Deposits

– Origin of the smooth plain materials (volcanic or lobate crater ejecta?); (3D + HR + IR)

– Identification of volcanic edifices; (3D)

– Identification of volcanic deposits (i.e. lava flow vs. ejecta blanket); (3D + HR + IR)

– Definition of the type of volcanism (i.e. fissural, explosive)

Interior dynamics and crustal differentiation processes

Tectonics Evolution

– Morphological characterization of mercurian large lobate scarps; (3D)

– Identification and classification of smaller tectonic features; (3D)

– Observation of cross-cutting relationships to infer the relative age of tectonic events; (HR)

– Mapping the distribution of tectonic features

40 km

Discovery Scarp

Crustal dynamics

Surface Age– Observation of impact craters with diameter > 0.5 km;

– Mapping the different crater distribution;

– Comparison between age and the main geological units of

highlands and plains

– This would led to the definition of the impact flux in the inner Solar

System 30 km

Temporal occurrence of geologic processes

Surface Composition and Weathering

– Characterization of the bulk surface composition;

– Measure the FeO and TiO2 abundances;– Identification of recent volcanic deposits – Different composition of hermean plains respect to highlands– Identification of weathering products – Effect of surface weathering as function of the surface exposure (age)

Interior differentiation, alteration processes

Characterisation of Polar deposits

– Characterization of the polar deposits composition;

– Search for similar deposits in permanently shadowed areas of large impact crater.

Radar bright spots

Water in coldest sites

SIMBIO-SYS ScienceSummary

- Surface geology: stratigraphy, geomorphology

– Volcanism: lava plain emplacement, volcanoes identification

- Global tectonics: structural geology, mechanical properties of

lithosphere

- Surface age: crater population and morphometry, degradation

processes

- Surface composition: maturity and crustal differentiation,

weathering, rock forming minerals abundance determination

- Geophysics: libration measurements, internal planet dynamics

SIMBIO-SYS Configuration

SYMBIO-SYS, realised for the Italian Space Agency by Galileo Avionica with the partnership of France and Suisse, incorporates capabilities to perform:

• medium space resolution global mapping in stereo and colour imaging using two pan-chromatic and 3 broad-band filters Stereo Channel STC;• high spatial resolution imaging in a pan-chromatic and 3 broad-band filters High Resolution Imaging Channel HRIC;• imaging spectroscopy in the spectral range 400 2000 nm Visible Infrared Hyperspectral Imager VIHI.

HRIC

VIHISTC

High spatial Resolution Imaging Channel (HRIC)

Main Objectives

• to provide images at ground pixel size of 5 m /pxl @ 400 km*

• to provide high spatial coverage if about 20% Mercury surface

• to provide high spatial resolution images in up to 4 different bands

Type of Optics Catadioptric: Ritchey-Chretien with corrector

Type of Camera Matrix Scanner

FOV 1.47 degrees

IFOV 12.5 rad

Spectral range 400 – 900 nm

Spectral Channels Panchromatic(650) + 550, 700, 880 nm

Sensor type APS 2048x2048

*The proposed thermal design of interfaces with the S/C could lead to the reduction of the optics aperture and to a resolution of 10 m @ 400 km.

Saptial resolution: HRIC

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

-90 -70 -50 -30 -10 10 30 50 70 90

latitude (deg)

grou

nd r

esol

utio

n (m

)

Ground track and Coverage: HRIC Peri-HermGround track and coverage

-100

-80

-60

-40

-20

0

20

40

60

80

100

-3 -3 -2 -2 -1 -1 0 1 1 2 2

Longitude (deg)

lati

tud

e (d

eg

)

HRIC FOV tracks for two consecutive (red and blue) orbits of the spacecraft. Peri-herm side (adjacent tracks do not overlap at equator).

Ground track and Coverage: HRIC Apo-Herm

Ground track and coverage

-100

-80

-60

-40

-20

0

20

40

60

80

100

177 178 178 179 179 180 180 181 181 182 182

Longitude (deg)

lati

tud

e (d

eg

)

HRIC FOV tracks for two consecutive (red and blue) orbits of the spacecraft. Apo-herm side (adjacent tracks overlap).

Stereo Channel (STC)

Main Objectives

1. Global mapping in stereo mode at spatial resolution of < 110 m

2. Global mapping in three colours at spatial resolution of < 110 m

Type of Optics Petzval Design

Type of Camera Matrix Scanner

FOV 4º (32mrad)

IFOV 23arcsec (111 rad)

Spectral range 500 – 900 nm

Spectral Channels 2xPanchromatic(650) + 550, 700, 880 nm

Sensor type APS 2048x2048

Visible Infrared Hyperspectral Imager channel (VIHI)

Main Objectives

1. To produce global mineralogical mapping at spatial resolution <400 m 2. To identify mineralogical species at a 5-10% confidence level3. To correlate surface composition and surface features at a scale of

400m globally and up to 100m in selected places (> 5% surface coverage)

Type of Optics Schmidt Telescope; Littrow spectrometer

Type of Camera Pushbroom spectrometer

FOV 3.7º (64mrad)

IFOV 50arcsec (250 rad)

Spectral range 400 – 2000 nm

Spectral sampling

6.25 nm

Sensor type HgCdTe with HgCdZn substrate removal;

256x256 CMOS ROIC; 30m pixel pitch

Resource Requirements: Pointing & Alignment

*: optimised for data volume**: goal value, minimum requirement is 10 arcsec***: goal value, minimum requirement is 20 arcsec

Parameter HRIC STC VIHI (units) IFOV 2.6 23 52 arcsec AME 10 6**

(¼ of a STC pixel)

12.5*** (¼ of a VIHI

pixel)

arcsec

APE 6 (1.5*) 41 - 62 3 arcmin RPE 0.25 / 3.5

(jitter) 6 / 5 12.5 / 10 arcsec / ms

RPE 17 (short term) arcsec / s

is driving STC+VIHIAME

The in flight calibration it is of paramount importance for the removal of thermomechanical biases!

Optics Thermoelastic stability

Still under study: optomechanical tollerances not yet fixed. The following values present have to be considered as reference.

APE Absolute Pointing error;