Transcript lumb_ESA

European Space Agency
- developments & in-orbit
experience
SDW2005
Advanced Concepts & Science Payloads Office
Science Directorate
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Outline
Technology Development Cycle
 Technology Readiness Levels
 Instrument Development Cycle
Missions in Operation
 XMM-Newton
 Integral
 Mars Express
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Outline (continued)
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Missions in Development
Herschel / Planck
GAIA
BepiColombo
Future Missions
Solar Orbiter
Darwin
XEUS
Advanced Concepts & Science Payloads Office
Science Directorate
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Investment by Technology Domain
Investment per Technology Domain
• Increasingly complex science instrumentation
requires corresponding
investment
in Automation &
Others
AOCS & GNC
TT&C
Robotics
3%
11%
Thermalinfrastructure
10%
spacecraft
4%
4%
&
• Structure
For example
pointing stability, on-board data
Mechanism
Data Handling
processing
must improve
4%
5%
• Nevertheless the instrument funding by ESA
Propulsion
remains
the most critical
Detectors
6%
16%
Power
5%
Optics
32%
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ESA Science Programme
• 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 ……….
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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.)
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The life-cycle of a Science Instrument
ESA
Novel
Technology
R&D
Phase 2:
Improvements,
Demonstrators
Science Institutes
Instrument
National Funding Pre-development
Breadboards,
Qualification
of Technology
New instruments
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AO
Detailed
Instrument
Design,
Consortia
Instrument
Proposals
Instrument
Integration
Onto Spacecraft,
Launch,
Operation
Science
Selection
Novel
Technology
R&D
Phase 1:
New ideas,
Fishing
Instrument
Building,
Qualification,
Calibration
Instrument
Implementation
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The Catch 22
SDW2005
Innovative
Science Missions
Novel Technologies
Require Novel
Technologies:
Non-existant
Require Prospective
Science Mission
for Justification
Premature for
Science Programme
Not relevant for
Missions in B/C/D
Rejected
Rejected
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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
SDW2005
Existing, proven
Technologies
Definition Phase
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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”
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XMM
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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
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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)
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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
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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
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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
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PACS Array design
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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 bolometer
0.3K hung from kevlar to 1.7K
with 3He Sorption cooler
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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..
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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?
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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
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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
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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: 5-6 efor AF2-10
Broad-band photometry:
- 5 photometric filters
Along-scan star motion in 10 s
FoV2
FoV1
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GAIA On-board processing
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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 “?
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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
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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
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BepiColombo instruments
•
GaAs room temperature spectrometer array
• Mated to readout ASIC for 64 x 64 imager 200eV
FWHM energy resolution at 1keV
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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
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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
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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
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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
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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
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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
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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)
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