![p8
3 instruments sharing the same focal
plane• Photometry & RVS: spectral dispersion is produced in the image
space, in front of the focal plane => common detection & processing
Blue & red photometry
with 2 prisms in the FPA
& dedicated CCDs:
Chromaticity correction
simultaneous to astrometry
Medium Band Photometry
[330-1000 nm]
Radial Velocity Spectrometer
with grating & afocal corrector
& 12 dedicated CCDs:
Spectrometry in [847-874nm]
Radial Velocity measurement](https://image.slidesharecdn.com/prsentationgaiaspaceup-130602124120-phpapp02/75/GAIA-SpaceUpParis-8-2048.jpg)
Uploaded byIsabelle Desenclos
GAIA @SpaceUpParis
1. GAIA is a European Space Agency satellite launched in 2013 to create a 3D map of the Milky Way galaxy. 2. It contains three instruments - photometers, spectrometers, and astrometers - that precisely measure the positions, motions, distances, and physical properties of over 1 billion stars. 3. To observe the entire sky, GAIA spins and precesses, taking measurements of each star approximately 80 times over its 5 year mission lifetime. The satellite's measurements enable astronomers to understand the composition, formation, and evolution of our galaxy.
GAIA @SpaceUpParis
- 1. 1 All thespace you need GAIA Crédit:©ESA GAIA a science satellite for 3D dynamic mapping of the Milky Way
- 2. Some observables todescribe objects B d d ≈ B / α Comparative analysis of distances and physical properties => Get rid of distances => Perform high accuracy measurements Crédit:©F.Mignard/Cheveu(BornBadRecords2008) The position of the image of a star depends on its color, the measurement of the color of the star is needed => chromaticity => astrometry
- 3. •Several successive observationsof the celestial sphere enable to measure relative motions between stars, but in 2D => 2D dynamics mapping •Radial distance and radial velocity (along observer line of sight) are missing to complete a complete 3 D dynamics measurement Radial distance: Parallax measurement Radial velocity: Doppler effect (light spectrum of a star is shifted toward blue (short wavelength) when star is coming closer and shifted to the red when star is moving away) => spectrometry
- 4. p4 Gaia main objective Improvestar positioning knowledge by a factor 100, stars up to magnitude 20 Observe more than one billion of objects, without any a priori Position => astrometry + chromaticity correction Distance => astrometry Proper motion => astrometry + HR spectrometry Physical properties => photometry + HR spectrometry => 3 instruments on board the spacecraft
- 5. In order toobserve all the sky • 2 view directions with a 106.5 deg basic angle • Spin of the satellite in 6 hours •Modification of the spin axis At the end of GAIA life, each object should be have been seen 80 times Crédit:©F.Mignard,UNS&ObservatoiredelaCôted'Azur/ESA
- 6. p6 1,5 millions kmfar away from Earth There are 5 equilibrium positions for a 3 body system, one of them being provided with a marginal mass. Soleil+Earth+spacecraft Lagrangian point L2 is well suited for cosmos observation = Stability
- 7. 16 years fromconcept to launch Proposal Concept & Technology Study Mission Selection Re-Assessment Study Phase B1 Scientific operation Launch 2013 Final Studies Data Processing Implementation Data Processing Definition Operation Mission Products Intermediate Selection of Prime Contractor (EADS Astrium SAS) Phase B2 Phase C/D Software Development (DPAC)
- 8. p8 3 instruments sharingthe same focal plane• Photometry & RVS: spectral dispersion is produced in the image space, in front of the focal plane => common detection & processing Blue & red photometry with 2 prisms in the FPA & dedicated CCDs: Chromaticity correction simultaneous to astrometry Medium Band Photometry [330-1000 nm] Radial Velocity Spectrometer with grating & afocal corrector & 12 dedicated CCDs: Spectrometry in [847-874nm] Radial Velocity measurement
- 9. The focal plane 106CCD, ~ 1 Gpixel
- 10.
- 11. p11 Two telescopes combinedon the same focal plane • 2 Three Mirror Anastigmat telescopes M1-M3 aperture 1450x500 mm², focal length f = 35 m angular separation = basic angle Common folding mirrors M1 M3 M2 M1 M3 M2 M4 M’ 4 M1 M3 M4 - beam combiner M2 Intermediate image used for field discrimination Beam combiner at their exit pupil => common FPA M’1 M1 LOS 2 LOS 1 M’2 M2 M3 M’3 M4/M’4 (combiners) M5 M6 Common FPA LOS1 LOS2M1 M2 M3 M’1 M’2 M’3 Beam combiner Common FPA
- 12. p12 A stable opto-mechanicaldesign • Full silicon carbide architecture • Passive thermal design • Decoupling by release of launch bipods M’3 M’2 M1M’1 FPA with radiators Isostatic mounts PLM optical bench Folding optics structure with RVS optics M5 M6 M’4 M4 (CDR design status)
- 13. The payload inassembly
- 14.
- 15. p15 •A nanostructure network(grating plate) spectrometer provides the required resolution (0.25 Å/pixel) Spherico-prismatic lenses Nanostructure network (grating plate) Radial velocity measurement
- 16. The overall satellite Instrument ServiceModule Thermal Tent Sun Shield
- 17.
- 18. 30/07/2010 Service Module(SVM) arrival in Toulouse Carbon fiber structure (made by CASA, Spain), Propulsion elements (CPS system made by ASTRIUM UK, and part of MPS system made by TAS Italy), electrical harness (CASA), previously assembled and tested in Stevenage (UK) 22/10/2010, first switch ON of the SVM electrical first equipments : power, calculator, interfaces and first central software October 2011, the SunShield (DSA) is delivered by SENER (Spain)
- 19. Deployment test ofthe sunshield in clean room
- 20. Autumn 2011 :Mechanical tests Vibrations, acoustics noise are simulated to the Spacecraft to verify if the structure and the differents fixations could resist to the future launch The missing equipments are simulated by loads (for example, the Payload). The tanks are full of Helium, Nitrogen or Isopropylic alcohol to simulate the future propellant gaz. Beginning of 2012, new DSA deployment to verify if it passed successfully the mechanical tests = successful launch
- 21. Test de vibrationsmécaniquesBeginning 2012 : mechanical tests of the Payload Acceleration up to 10G !
- 22. April 2012, deliveryof the Phase Array Antenna This antenna will allowed to send the data recorded on board to the Earth A new step to the complete Spacecraft !
- 23. Summer 2012, SVMThermal Vacuum With captors inside, the SVM is placed into a vacuum chamber to simulate the temperature into Space. The objectives is to verify that all the equipments are well running onto vacuum and that thermal predictions are confirmed. December 2012, Payload Thermal Vacuum The performance of the 3 instruments are verify in vaccum and low temperature (stability, good images, …)
- 24. February 2013 Payloaddelivery GAIA became a complete satellite ! In order to avoid any contamination on mirrors and CCD, the assembly is done in a class 100 clean room (less than 10000 particles of 0,1µm or less than 30 particles of 1µm in 1m3 air).
- 26. March 2013, beginningof the final verifications The spacecraft is measured : weight, Center of gravity, inertia moment
- 27. EMC TEST inanechoic chamber Verification that all equipments are not « noisy » to others, in particular the PAA
- 29. Automn 2013: launchon Soyouz from Kourou, french Guyana
- 30. Key Numbers Massspacecraft at launch : 2 100 kg Mass propellant : 300 kg Diameter of the Sunshield in orbit configuration : 10 m Primary mirrors : 1.45 m x 0.5 m Focal Distance : 35 m CCD : 1 Gpixels @ 160 K Mass memory : 1 Tb Science Telemetry : 10 Mbits/s With about 100 Go of data each day, 1 Peta-octet (1000 To) of data at the end of the GAIA mission !
- 31. News about GAIAon my blog : http://idariane.wordpress.com On ESA page : http://sci.esa.int