European Space Agency - developments & in-orbit experience

1. European Space Agency - developments & in-orbit experience

2. Outline • Technology Development Cycle • Technology Readiness Levels • Instrument Development Cycle • Missions in Operation • XMM-Newton • Integral • Mars Express

3. Outline (continued) • Missions in Development • Herschel / Planck • GAIA • BepiColombo • Future Missions • Solar Orbiter • Darwin • XEUS

4. Investment by Technology Domain • Increasingly complex science instrumentation requires corresponding investment in spacecraft infrastructure • For example pointing stability, on-board data processing must improve • Nevertheless the instrument funding by ESA remains the most critical

5. ESA Science Programme • Missions arebased onexisting technologies, or technologies whichmight require some modest evolutions or modifications(relatively high TRL level) • New and more efficient, or ever more demanding Science Missions have torely oninnovative and novel technologies, on thespacecraft and also particularly the payload side (Optics and Sensors). • An innovative technology program is therefore the required base for any creative and productive long-term science programme. • But currently the funding base is being eroded ……….

6. How are technologies selected? • Astronomy: typically <1 mission / decade per wavelength domain, • Planetary science missions to different destinations, with remote and in situ follow-ups implies <1/decade/planet • Solar observatories are weakly motivated to exploit the 11yr natural cycle for the next generation instruments • Next mission is always beyond current science programme lifecycle. [Current programme is fixed to 2014] • Frequently a mission’s science goals evolve[priorities and themes change with other science discoveries including those of other agencies] • Can forecast only generic technology challenges for any major enhancement of capability (~order magnitude improvement performance) or the introduction of a new techniques(image/spectroscopy/polarimetry/timing/particle species etc.)

7. The life-cycle of a Science Instrument ESA Novel Technology R & D Phase 1: New ideas, Fishing Novel Technology R & D Phase 2: Improvements,Demonstrators Instrument Integration Onto Spacecraft, Launch, Operation Science AO Selection Science Institutes National Funding Instrument Pre-development Breadboards, Qualificationof Technology New instruments Detailed Instrument Design, Consortia InstrumentProposals Instrument Building, Qualification, Calibration InstrumentImplementation

8. The Catch 22 Innovative Science Missions Novel Technologies Require NovelTechnologies: Non-existant Require Prospective Science Missionfor Justification Premature for Science Programme Not relevant for Missions in B/C/D Rejected Rejected

9. TRL 1-3 TRL 4-10 TRP CTP-A CTP-B GSTP Existing, proven Technologies Definition Phase Creative, innovative Technologies Pre/Assessment Phase Technology Readiness Levels and ESA Funding Programmes

10. Despite the best laid plans….. • Qualification for vibration, thermal environment and radiation may limit preferred design options • Inevitably resourcing of flight instruments through PI-led consortia can be hostage to delays • Testing and calibration time come under severe time pressure • The cost of running the spacecraft contract is huge – therefore pressure to launch on-time prevents the full testing of instrument • We examine here some cases of operational “surprises”

11. XMM

12. XMM • Lessons learned concern the in-orbit environment • Pre-launch concerns about environment (eccentric 100,000 km) Moveable shutter for belt passage protons (cf. CHANDRA) • Contamination to be mitigated with out-gassing chimney/cold-trap. • Soft protons flares ~ 20% of operation (soft 10’s keV) • Micrometeorites – 1/yr/camera, they scatter at grazing incidence off mirrors. Local damage and worse ….. • Enhanced charged particle background - GEANT 4 modeling? • User interaction – flat field set up 100’s –1000’s seconds • CCD electronics infant mortality

13. Integral • Ge detectors – cryogenic spectrometer at 80K. Radiation damage factor 2 worse than expected, Requires annealing every 6 months – a loss of observing time (and suspected loss of diodes through thermal cycling?) • Background also twice expected, spectral lines and showers reduce sensitivity • JEM-X – contamination in glass strips – breakdown in gas exacerbated by high backgound rates, gain had to be reduced (poor calibration)

14. Mars Express • High Resolution Stereo Camera • 9 CCD lines of 5100 pixels, 32kg • The ultimate resolution of 2m at orbit height 250km has not been achieved • Complex optics train, requires exceptional thermal stability and control • Suggests more comprehensive testing and calibration should be considered

15. Herschel • Discovering the earliest epoch of proto-galaxies, cosmologically evolving AGN-starburst symbiosis, and mechanisms involved in the formation of stars and planetary system bodies. • 3.5 metre diameter passively cooled telescope 60 - 670μm. • The science payload complement - two cameras/medium resolution spectrometers (PACS and SPIRE) and a very high resolution heterodyne spectrometer (HIFI) - will be housed in a superfluid helium cryostat. • Herschel will be placed in a transfer trajectory L2, 2007 3 yrs

16. PACS • Photoconductor Array Camera & spectrometer • 3 Ge:Ga photoconductor linear arrays for spectroscopy & 2 Si bolometers • 50 passive & active optical elements 4 precision mechanisms • 3 photometric bands with R~2. • `blue' array covers the 60-90 and 90-130 µm bands, while the `red' array covers the 130-210 µm band. • Field of view of 1.75x3.5 arcmin • An internal 3He sorption cooler will provide the 300 mK environment needed by the bolometers. • Spectroscopy covers 57-210 µm in three contiguous bands, with velocity resolution in the range 150-200 km/s • The two Ge:Ga arrays are stressed and operated at slightly different temperatures

17. PACS Array design

18. SPIRE • 3-band imaging photometer (simultaneous observation in 3 bands) • Wavelengths (μm): 250, 350, 500 • Beam FWHM (arcsec.): 71, 24, 35 • Field of view (arcmin.): 4 x 8 • 3He cooler • Imaging Fourier Transform Spectrometer (FTS) • Wavelength Range (μm): 200-400 (req.) 200-670 (goal) • Simultaneous imaging observation of the whole spectral band • Field of view (arcmin): 2.0 (req.) 2.6 (goal) • Max. spectral resolution (cm-1): 0.4 (req.) 0.04 (goal) • Min. spectral resolution (cm-1): 2 (req.) 4 (goal) • Spider web NTD Ge bolometer0.3K hung from kevlar to 1.7K • with 3He Sorption cooler

19. HIFI • Heterodyne Instrument for the Far-IR a spectrometer • 480 – 1250 GHz and 1410 – 1910 GHz • 134 kHz – 1 MHz frequency resolutions • 4 GHz IF bandwidth • 12 – 40" beam dual polarization  sensitivity & redundancy • Superconductor/insulator/superconductor & hot electron bolometers • New technology for mixers and local oscillators etc..

20. HERSCHEL • Combination of large He observatory cryostat and complex thermal interface with instrument coolers has been a huge programme risk • HERSCHEL also to launch with PLANCK – developments tied to another platform (to reduce launch cost $150M) • All instruments require substantial development and qualification (thermal design, vibration) • In future Agency may prefer to take on load of the cryo developments from PI – reduce risk but testing interface more complex?

21. Gaia • Astrometry (V < 20): • completeness to 20 mag (on-board detection)  109 stars • accuracy: 10-20 arcsec at 15 mag (Hipparcos: 1 milliarcsec at 9 mag) • scanning satellite, two viewing directions • Radial velocity (V < 16-17): • third component of space motion, perspective acceleration • dynamics, population studies, binaries • spectra: chemistry, rotation • Photometry (V < 20): • astrophysical diagnostics (5 broad + 11 medium-band) + chromaticity

22. GAIA Payload and Telescope Rotation axis SiC primary mirrors 1.4  0.5 m2 at 99.4° Superposition of fields of view SiC toroidal structure Combined focal plane (CCDs) Basic angle monitoring system

23. GAIA Astrometric Focal Plane Total field: - active area: 0.64 deg2 - number of CCD strips: 20+ 110+40 - CCDs: 4500 x 1966 pixels - pixel size = 10 x 30 µm2 Sky mapper: - detects all objects to 20 mag - rejects cosmic-ray events Astrometric field: - readout frequency: 55 kHz for AF2-10 - total detection noise: 5-6e- for AF2-10 Broad-band photometry: - 5 photometric filters Along-scan star motion in 10 s FoV2 FoV1

24. GAIA On-board processing

25. GAIA – CTI concern • Mass limitation dictated rather thin exterior light shades – gave very large proton dose • Now measuring prototype CCD performance after 109 protons/cm2 • Smeared response would prevent centroids being accurately calculated • Performance depends upon history of stars within a column – need “thin zero “?

26. BepiColombo • Determination of mineralogy at spatial scale of large craters requires combination of visible, IR and X-ray imaging • Payload must sustain environment of solar irradiation, and cruise period of several years • X-ray instruments map high resolution fluoresence only at times of high solar flare fluence! • Optical and IR instruments require APS technology, room temperature operation, radiation hard • Uncooled broadband IR arrays – Si MEMS technology

27. BepiColombo instruments • Si MEMS technology to produce micro-bolometer • ¼ cavity for good response, produced with polymer lift-off technique • ~256x320 array mated to ASIC to allow pushbroom readout

28. BepiColombo instruments • GaAs room temperature spectrometer array • Mated to readout ASIC for 64 x 64 imager 200eV FWHM energy resolution at 1keV

29. Solar Orbiter • Observations at 0.2 AU – 25 Solar constants load • Active Pixel Sensors - CCD would suffer un-tolerable radiation damage at 0.2 AU and CMOS based APS are a key need for the mission (all Remote Sensing instruments). • Heat rejecting entrance window / EUV filters -The need to reject the heat before it reaches the S/C is a key requirement for the SolO instruments (foils and grids) • Fabry-Perot filters - select a narrow and tunable spectral band baseline is a double Fabry Perot followed by a band pass interference filter. The spectral tuning of both Fabry Perot is achieved by applying high voltage • Liquid Crystal polarisers- to select 4 independent input polarisation states using Liquid Crystal Variable Retarders • Solar-blind detectors – wide band gap needs development or use intensified CMOS APS

30. Darwin • 4 spacecraft at L2 orbit, 2m class telescopes • Nulling interferometry to reject primary star light by ~108 • Maintain baselines from 50m – 200m, with rotation - by formation flying • OPD established to 20nm within the beam combiner S/C • Require integrated optics & detectors for 4-20μm for spectroscopy

31. Darwin • Detectors could rely on JWST for 5-20μm • Eg linear array of BIB Si:As, but these need 8K temperature cf. optics 40K • Possible problem with vibrations from additional cooler

32. XEUS • X-ray astronomy observatory with 10m2 effective area via. novel silicon mirror plates modules • L2 orbit, MSC and DSC in formation flying 50 m apart • Imaging and spectroscopy requires new detectors developments

33. XEUS • Wide Field Imager – Si class energy resolution, and 100μm pixels • Huge mirror area means for photon counting that fast readout required • Use a DEPFET version of APS technology

34. XEUS • Cryogenic sensors to achieve non-dispersive spectroscopy λ /δλ ~ 1000 • STJ or TES readout of bolometers • Requires ADR coolers (50mK) and efficient light and IR-blocking filters, RF SQUID multiplexors

35. Summary Required Developments • Larger focal planes, with APS-like readout at all wavelengths • Europe lacks heritage in readout ASICs cf. HEP vertex detectors • Investment in novel optics and mechanical coolers will be as important (cryogen lifetime) • Early identification of technology, investment, early testing in appropriate environment • Common location for observatories is L2 – radiation damage and prompt effects are important (background/cosmic ray removal)