The Gaia Mission

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The Gaia Mission

• A stereoscopic census of our Galaxy

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Aims of the mission

• To observe the 6D phase-space map of our galaxy
  with sufficient accuracy to enable the first
  detailed reconstruction of its history
• Positions and kinematics of objects to distances
  of several tens of kpc need to be studied to
  enable this parallaxes, proper motions and
  radial velocities required
• Classification of each object from photometry

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How can this be done?

• One large survey of all 109 stars brighter than
  V20, over 5 to 6 years, covering each object on
  average about 80 times, providing
• Astrometry, using the Hipparcos principle
• Photometry, using dispersion spectra
• Radial velocities, medium-resolution spectrograph

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The payload

• Telescope
• 35-m focal length telescope with two apertures,
  folded up in a 3m diameter satellite
• Focal plane
• 0.5 square meter covered with 103 CCDs
• Operating in TDI mode (Time-delayed integration),
  following images passing over the CCDs

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Scientific potential

• Solar system census of smaller bodies
• Nearby stars Detection of planets
• Star clusters observational isochrones
• Galactic structure history of the galaxy
• Distances globular clusters, LMC SMC
• Fundamental physics reference frames

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Planet detection
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Double-star detections
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ObservationalIsochrones
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The SMC
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The schedule

• Phase B2 has started
• Phase C will start end 2006
• Launch scheduled for end 2011
• Operations at L2
• Mission duration 5 to 6 years
• Final mission products around 2020

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Schedule
2000
2004
2008
2012
2016
2020
Concept Technology Study ESA SCI 2000(4)
Acceptance
Re-Assessment Ariane ? Soyuz
Technology Development
Design, Build, Test
Launch
Start of Phase B2
To L2
Observations
Analysis
Catalogue
Early Data
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The data processing

• The Gaia Data Processing and Analysis Consortium
  is in the process of being created
• Consists of 8, relatively independent,
  coordination units, assigned to specific tasks
• 3 data processing, 3 data analysis, and 2 support
  units
• DPAC executive for coordination and planning of
  activities

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The size of the job

• We expect of order 1012 observations
• Calibration is in first instance towards an
  internally defined system
• Extensive iterations required in astrometry,
  photometry and radial velocities
• Processing requirements of order 100000
  observations per second

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UK involvement

• Photometric data processing
• Software developments and implementation
• Cambridge, Leicester, Edinburgh
• Radial velocity data processing
• Software developments
• MSSL
• Gaia Science Team
• Floor van Leeuwen, IoA Cambridge
• Mark Cropper, MSSL
• Industry E2V will manufacture all CCDs