GAIA

Gaia (Global Astrometric Interferometer for Astrophysics) is an ambitious space mission organized by the European Space Agency (ESA) and involves conducting a census of approximately one billion stars in our galaxy (1 per cent of the Galactic stellar population). Gaia will monitor each of its target stars roughly 70 times over a five-year period. Gaia is the successor to the Hipparcos mission and will rely on the proven principles from the Hipparcos mission. It is predicted that Gaia will discover hundreds of thousands of new celestial objects, such as extra-solar planets and brown dwarfs. The total cost of the mission is approximately 650 milllion euros which includes the manufacture, launch and ground operations. Gaia is scheduled to launch on October of 2013, on a Soyuz-Fregat rocket from Sinnamary, part of Europe’s Spaceport in French Guiana and will end 5 years after launch (2018).

RTEMS version 4.6.1 is used on Gaia’s Central Data Management Unit (CDMU). The CDMU is the main spacecraft computer, responsible for communication with ground and control of all other units on the spacecraft.

RTEMS version 4.6 is used on Gaia’s Payload Data Handling Unit (PDHU). The PDHU is a computer control mass memory unit that is the interface between the data arriving from the optical payload and the CDMU that passes the packetised data to the ground.

Background

ESA’s pervious Hipparcos mission cataloged more than 100,000 stars to high precision, and more than a million stars to lesser precision. Since the Hipparcos mission, technology has greatly improved and the successor mission, Gaia will provide with similar cataloguing aims as Hipparcos but with a much more ambitious payback. In response to a call for proposals for ESA’s Horizon 2000 Plus, the Gaia mission was proposed in October 1993 by Lennart Lindegren (Lund University, Sweden) and Michael Perryman (European Space Agency). Gaia was approved in 2000 as an ESA Cornerstone mission, and will be launched in 2013. The B2 phase of the project was authorized on 9 February 2006, with EADS Astrium taking responsibility for the hardware.

Features

Gaia is equipped with two optical telescopes that can precisely determine the location of stars and split their light into a spectrum for analysis. Gaia has a total mass of 2030 kg and has a focal plane containing 106 CCD detectors. There are two sections to the spacecraft, the payload module and the service module. The payload consists of the telescopes and other instruments. The service module contains the propulsion system, the communications units and other essential components that allow the spacecraft to function and return data to Earth. Beneath the service module and the payload module is the sunshield and solar array assembly.

Mission Objectives

Precisely chart selected star positions, distances, movements, and changes in brightness.
Detect and characterize of tens of thousands of extra-solar planetary systems.
Perform a comprehensive survey of objects ranging from huge numbers of minor bodies in our Solar System.
Conduct more accurate tests of Albert Einstein’s general relativity theory.
Detect of up to 500,000 distant quasars.

References and external links