The satellite

The Gaia satellite consists of three modules (see the diagram of the satellite below to find out how the main components are put together):

• The Payload Module, which is the instrument used for the survey. It includes the twin telescopes (read why two telescopes), the entire Focal Plane Assembly, and the electronics needed for their operation and processing of the raw data.
• The Mechanical Service Module, which provides the support for the payload and the satellite's electronics. It takes care of the sunshield deployment shortly after launch and the thrusters used for attitude control and orbit corrections, and includes:
  • micro-propulsion system,
  • deployable sunshield,
  • payload thermal tent,
  • solar arrays,
  • harness.
• The Electrical Service Module (built by Astrium Stevenage), which is responsible for a wide range of tasks, from storing and transmitting the science data to monitoring of the payload and controlling the pointing of the satellite.

More information about the satellite, including mass budget and energy consumption, can be found on Spacecraft page on ESA's Gaia website. You can find description of both service modules on Service Module page on ESA's website.

Exploded diagram of Gaia spacecraft. The diagram shows the main components of the satellite. Reading from bottom to top they are: Fixed Solar Array Panels, Equipped Phase Antenna Panel, Propulsion Ring, Propellant and Pressurant Tanks, Equipped Service Module Structure, Launch Lock Bipods and In-Orbit Bipods, Payload Module Focal Plane Assembly and Payload Module Optical Bench, Deployable Sunshield Assembly (DSA) Ring with six Deployable Solar Panels, Deployable Sunshield Assembly and Thermal Tent. (Image courtesy of EADS Astrium.) View larger image.

The animation below (animation courtesy of ESA) shows the deployment of Gaia's unique sunshield and solar array. (Skip video.)

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