An Arianespace Soyuz ST-B rocket successfully launched the impressive Gaia space observatory from the Kourou Spaceport in French Guiana on Thursday the 19th of December. The launch marks the beginning of an ambitious project to map a billion stars in our Milky Way galaxy. The Spacecraft: The Gaia spacecraft is a successor to the Hipparcos satellite that was launched by Arianespace in 1989. Gaia will be placed into deep space in an orbit that will be of a Lissajous-type around the second Lagrange point (L2). Gaia’s main goal is to create a highly accurate 3D map of our Milky Way Galaxy by repeatedly observing a billion stars to determine their precise positions in space and their motions through it. The resulting census will allow astronomers to determine the origin and the evolution of our Galaxy. Gaia will also uncover tens of thousands of previously unseen objects, including asteroids in our Solar System, planets around nearby stars, and exploding stars – supernovas – in other galaxies. The mirrors of the 2 telescopes have an unusual curved shape, which is calculated using a very precise mathematical formula so that there will be no distortion of the incoming light across the telescopes’ field of view and at all wavelengths from blue to red. GAIA has been built by Astrium, and it is expected to enjoy a five-year mission, with its full archive to exceed 1 petabyte in size – providing enough information to tackle many important problems related to the origin, structure and evolutionary history of the galaxy. This mission has been participated by GTD as well. GTD and University Polytechnic of Catalonia (UPC) have developed and implemented the internal algorithm (onboard) in charge of lossless data compression. An Arianespace launch at the service of science Today's mission was the second successful Soyuz launch from CSG in 2013, and was the launcher’s sixth successful mission overall from CSG. Also in 2013, Arianespace used a Soyuz rocket to orbit the first four satellites for the O3b constellation in June. Arianespace has always supported the world's leading scientific missions, enabling humankind to better understand our Universe. Gaia is the 25th scientific satellite tobe launched by Arianespace, bringing a real breakthrough in understanding our galaxy, and create a 3D map of the Milky Way. The launch of Gaia continues a long-standing and steady cooperation between Arianespace and ESA: it also is the 40th payload sent into orbit for the space agency, 28 years after the launch of Giotto – ESA's first scientific satellite in July 1985 on an Ariane 1 (Flight 14). In 2013, Arianespace carried out four Ariane 5 launches, orbiting the ATV Albert Einstein with supplies for the International Space Station and six telecommunications satellites, as well as the second Vega launch with satellites dedicated to sustainable development (Proba-V, VNREDSat-1 and ESTCube-1). The "Soyuz at CSG" program that brought Soyuz to French Guiana carries on the long-standing space collaboration between Europe and Russia, and gives Europe a medium-lift launcher that perfectly complements its heavy Ariane 5 and light Vega launchers. Arianespace and its Starsem subsidiary also performed a Soyuz launch from the Baikonur Cosmodrome (Kazakhstan) in February 2013, orbiting six satellites in the Globalstar constellation. GTD AT KOUROU SPACE CENTER Each time an Ariane 5, a Soyuz or a VEGA are launched from the spaceport in Guiana, as well as the payload, many hours of work are required from GTD’s technical teams. GTD supplies services and software in practically all steps of an Ariane 5 mission – from the launcher's flight program to the responsibility of ground systems that control the launching operations, as well as the radars, telemetry and mission control systems. Each launch is also a challenge for GTD’s team, who is responsible for all the computer systems at the launch site. Each launch is a fresh new project; there is no routine, which means our engineers always embark on an adventure than goes beyond technical jobs that require a lot of responsibility. Countdown: The campaign to prepare a launcher takes about 22 - 30 working days, and a campaign to prepare the payload (satellite) takes from 4 weeks to 5 months (depending on the mission and its magnitude). Our teams are currently able to launch up to seven double Ariane 5, up to four soyuz and up to two Vega per year, that is, 14 telecom satellites and 4 to 6 EO and scientific spacecraft every year. Launch day: The end of the countdown is near. The final operations to fill the liquid propellants on the Ariane 5, and then the ground operation tests are carried out on the launcher. During this stage, gtd's staff is working hard all round the Spaceport. In the launch site's bunker, the technical centre, in Des Pêres Mountain where the radar and telemetry installations are, in the meteorological centre where the last conditions before the launch is authorised. At the same time, a support team is configuring a backup of the computer systems in Barcelona, 8,000 km away from the Ariane 5, which is already letting out oxygen steam. Ariane is launched: Once the launcher is in the air, it is controlled on board (by the embedded computer) and from the Jupiter Control Centre (CDC). These two systems were also designed by GTD’s engineers and are currently being operated by GTD’s engineers, too. Once the launcher releases the payloads (at a height of 500 - 600 km), everyone breathes a sigh of relief and starts clapping and cheering and congratulating each other; but our engineers are already thinking about the next mission that starts the following morning…
