advanced concepts & science payloads office science directorate sdw2005page 1 european space...

Advanced Concepts & Science Payloads Office Science DirectorateSDW2005

European Space Agency

- developments & in-orbit experience


Outline

Technology Development Cycle Technology Readiness Levels Instrument Development Cycle

Missions in Operation XMM-Newton Integral Mars Express


Outline (continued)

Missions in Development Herschel / Planck GAIA BepiColombo

Future Missions Solar Orbiter Darwin XEUS


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

Investment per Technology Domain

Structure & Mechanism

4%

Thermal4%

TT&C10%

Others3%

Power5%

Optics32%

Detectors16%

Data Handling5%

AOCS & GNC11%

Propulsion6%

Automation & Robotics

4%


• Missions are based on existing technologies, or technologies which might require some modest evolutions or modifications (relatively high TRL level)

• New and more efficient, or ever more demanding Science Missions have to rely on innovative and novel technologies, on the spacecraft 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 ……….

ESA Science Programme


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.)


The life-cycle of a Science Instrument

Novel Technology

R & DPhase 1:

New ideas,Fishing

Novel Technology

R & DPhase 2:

Improvements,Demonstrators

ESA

AO

Selection

Science InstitutesNational Funding Instrument

Pre-developmentBreadboards,Qualification

of TechnologyNew instruments

DetailedInstrument

Design,ConsortiaInstrumentProposals

InstrumentBuilding,

Qualification,CalibrationInstrument

Implementation

InstrumentIntegration

Onto Spacecraft,Launch,

OperationScience


The Catch 22

Innovative Science Missions

Require NovelTechnologies:Non-existant

Novel Technologies

Require Prospective Science Missionfor Justification

Premature for Science Programme

Not relevant for Missions in B/C/D

Rejected Rejected


Technology Readiness Levels and ESA Funding Programmes

TRL 1-3 TRL 4-10

TRP

CTP-A CTP-B

GSTP

Creative, innovative Technologies Pre/Assessment Phase

Existing, proven TechnologiesDefinition Phase


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”


XMM


XMMLessons 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


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)


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


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


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


PACS Array design


SPIRE3-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


HIFI HIFI

• Heterodyne Instrument for the Far-IR a Heterodyne Instrument for the Far-IR a spectrometerspectrometer

• 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..


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?


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


GAIA Payload and TelescopeSiC primary mirrors

1.4 0.5 m2 at 99.4°

Superposition offields of view

SiC toroidalstructure

Basic anglemonitoring system

Combinedfocal plane (CCDs)

Rotation axis


GAIA Astrometric Focal Plane

Along-scan star motion in 10 s

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: 5-6 e- for AF2-10

Broad-band photometry: - 5 photometric filters

FoV2

FoV1


GAIA On-board processing


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 “?


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


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


BepiColombo instruments

• GaAs room temperature spectrometer array

• Mated to readout ASIC for 64 x 64 imager 200eV FWHM energy resolution at 1keV


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


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


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


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


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


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


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)

advanced concepts & science payloads office science directorate sdw2005page 1 european space...

Documents

operation science slide

innovative science missions

demanding science missions

esa science programme

prospective science

instrument funding

critical slide

existing technologies