1. BepiColombo GW Fraser Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH 1. The BepiColombo Mission 2. The challenge of Mercury 3. MIXS 4. In anticipation – results from MESSENGER

2. Professor Giuseppe “Bepi” Colombo (1920-1984) (University of Padua) explaining Mercury’s 3:2 orbital resonance.

3. Mercury Timeline 1974Mariner 10 flybys 1993Proposal for mission to Mercury by A. Balogh (ICSTM) 2004NASA MESSENGER launched 2008ESA Cornerstone BepiColombo mission finally confirmed dual spacecraft – ESA MPO and JAXA MMO Ariane V launch, now beyond August 2015 mass 4.2 tonnes six years cruise phase, one year nominal mission, one year entension Astrium DE prime contractor Astrium UK for S/C structures, electric and chemical propulsion mission cost capped at 980 Meuro UK involvement in MIXS/ SIXS and MERMAG instruments 2011MESSENGER orbital insertion 2021BepiColombo arrives at Mercury

4. Science Questions Origin/Composition? Anomalous density? Exosphere/Magnetosphere ?

5. MMO (JAXA) MPO (ESA) Nadir Instrument Platform MTM BepiColombo

6. Solar Coronal Primary X-ray Flux X-ray fluorescent and backscattered flux Direction of MPO motion Planetary X-ray Remote Sensing

7. NASA Mercury probe MESSENGER Launched 3 rd August 2004 Mercury orbital insertion 18 th March 2011 X-Ray Spectrometer (XRS) Collimated gas proportional counter X-ray fluorescence spectrometer. Three GPCs equipped with filters to overcome resolution limitations and resolve Al, Mg and Si fluorescence lines GPC1 4.5 μm Mg filter GPC2 6.3 μm Al filter GPC3 unfiltered Heritage of Design – Apollo 15, NEAR Shoemaker (never before in an active magnetosphere)

8. Suprathermal electrons in the MESSENGER XRS ? First MESSENGER flyby, January 14 th 2008. [Ho et al. Planetary and Space Science (2011) Schriver et al Planetary and Space Science (2011)] Schriver et al Planetary and Space Science (2011)]

9. Astronomy with the MESSENGER XRS ! Observation of possibly the first ever occultation of a cosmic X-ray source by any other solar system object than the Moon XRS field-of-view at 08:37:00 UTC on October 6 th 2008.

10. Charged particle populations in the Mercury Magnetosphere MESSENGER magnetometer and energetic particle spectrometer (EPPS) findings indicate the existence of a quasi-trapped charged particle population in magnetosphere MESSENGER magnetometer and energetic particle spectrometer (EPPS) findings indicate the existence of a quasi-trapped charged particle population in magnetosphere MESSENGER XRS encounters these particles ~ every orbit. MESSENGER XRS encounters these particles ~ every orbit. 27 March 201210

11. Observed by MESSENGER –Targets for MIXS

12. MIXS 12

13. Science requirements for the mapping of the elemental composition of Mercury on global, intermediate and local scales dictate two complementary X-ray channels Science requirements for the mapping of the elemental composition of Mercury on global, intermediate and local scales dictate two complementary X-ray channels Wide field-of-view – Non-Imaging Collimator MIXS-C Wide field-of-view – Non-Imaging Collimator MIXS-C Narrow field-of-view – Imaging Telescope MIXS-T Narrow field-of-view – Imaging Telescope MIXS-T Common Detector Format for programmatic simplicity Common Detector Format for programmatic simplicity Common Enabling Technology – low mass, microchannel plate (MCP) optics Common Enabling Technology – low mass, microchannel plate (MCP) optics

14. ModuleMass MEB2.741Kg FPA - MOM interface0.07Kg x 2 MOM-T2.02Kg MOM-C0.52Kg Base-plate2.25Kg FPA1.33Kg x 2 Total no contingency10.354Kg (previous value 10.0Kg) Total with 10% contingency 11.39Kg

15. MIXS-T X-ray results from Optically-Representative Sextant

16. An X-ray Lens – the Square-Pore MCP Incident X-rays Double reflection (2-axes, true focus) Diffuse background Single reflection (1 axis, line focus)

17. MCP Geometries 20-100 μm pores 20-100 μm pores Unit size 40 x 40 mm Unit size 40 x 40 mm 0.9 mm square multifibres 0.9 mm square multifibres Channel aspect ratio 10:1 -500:1 Channel aspect ratio 10:1 -500:1 60% open area 60% open area Planar (point-to-point focus) Planar (point-to-point focus) Radially packed, spherically slumped Wolter Type 1 approximation (top) Radially packed, spherically slumped Wolter Type 1 approximation (top) Square packed, spherically slumped Lobster Eye geometry Square packed, spherically slumped Lobster Eye geometry Square packed, cylindrically slumped Kirkpatrick Baez geometry Square packed, cylindrically slumped Kirkpatrick Baez geometry K : few grams per square cm effective area, K : few grams per square cm effective area, Manufactured by Photonis France Manufactured by Photonis France Key technology for LOFT..... Key technology for LOFT..... Optical microscopy of multifibres

18. MIXS Optical Elements MIXS-TMIXS-C Microchannel formatSquare pore PackingRadialSquare Channel size20 μm Channel pitch26 μm Aspect ratio L:DVariable55:1 CoatingIridium Optic diameter / side length210 mm80 mm FocussingYN Optic-detector separation1000 mm550 mm Detector typeMacropixel APS Detector size19 mm x19 mm FOV1.1°10° FWZM Angular resolution limit2`10°

19. MIXS-C and MIXS-T MIXS-C has a high X-ray throughput and 10° angular resolution / field of view, with a flat-top response and small detector, produced by a spherical collimator geometry, radius of curvature 55 cm MIXS-C has a high X-ray throughput and 10° angular resolution / field of view, with a flat-top response and small detector, produced by a spherical collimator geometry, radius of curvature 55 cm MIXS-T is a true focusing telescope, one metre focal length MIXS-T is a true focusing telescope, one metre focal length

20. MIXS-C MIXS-T Calculated count rates in each channel for various solar states

21. MIXS-C collimator response MeasuredRay Trace

22. MIXS-C Collimator Response Simulation at 8.4 keV 22

23. Synthetic X-ray Image from Full Aperture Illumination Scales : Axes in “pixels” ~0.28 mm

24. Optics module vibration testing at RALSpace 2 nd Eigen-Frequency – MCP optic Measured 2394 Hz Predicted 2133Hz.

25. Shock test on STM+ Shock input Accelerometers Ringing plate

26. MIXS Status FM delivery soon All DEPFET detectors manufactured All coated and filmed MCPs delivered to Leicester delta Instrument Critical Design Review completed

27. How do you know MIXS-T will work?

28. Comparison of X-ray fluorescence model with Chandra ACIS data