December 19, 2013
ESA Gaia Mission Lifts Off For Five-Year Galaxy Mapping Mission
[ Watch the Video: Gaia Milky Way Mission Lifts Off ]
Lawrence LeBlond for redOrbit.com - Your Universe Online
The long-anticipated mission of ESA’s Milky Way mapper has finally launched. Set to image the galaxy with its billion-pixel camera, Gaia lifted off on Dec 19 at 09:12 GMT (4:12am EST) from Europe’s Spaceport in French Guiana, carried into space on a Russian Soyuz rocket operated by Arianespace.
Gaia was developed with the goal of creating the most accurate map of the Milky Way to date. Scientists expect the mission to make accurate measurements of the positions and motions of roughly one percent of all the stars in the night sky; it is estimated that about 100 billion stars call Milky Way home. Gaia will also answer questions about the origin and evolution of our Galaxy.
At roughly ten minutes after launch, and after separation of the first three stages, the Fregat upper stage ignited and delivered Gaia into a temporary orbit at an altitude of about 100 miles. A second firing of the Fregat, 11 minutes, later took Gaia to its transfer orbit. About 42 minutes after liftoff, Gaia separated from the upper stage, and soon after that, ground control was established by ESA operators in Darmstadt, Germany. Shortly thereafter the spacecraft began activating systems.
At 88 minutes post-launch, Gaia’s sunshield, which keeps the spacecraft at a working temperature and carries solar cells to power the craft, was deployed in a 10-minute automatic sequence. With everything up and running as expected, Gaia is now on its journey to orbit around a gravitationally-stable virtual point in space called L2, about 900,000 miles above and beyond Earth.
[ Watch the video: ESA's Gaia Launch ]
To help Gaia get to its new home in space, engineers will command it to perform two critical thruster burns. This first burn will take place tomorrow and help ensure the satellite finds its appropriate trajectory toward L2. Then, about 20 days post-launch, the second critical burn will insert the satellite into operational orbit.
As Gaia soars toward L2, it will begin a four-month commissioning phase, during which all of the onboard systems and instruments will be turned on, checked and calibrated to ensure the craft is fully functional by the time it reaches operational orbit. Once it arrives at its new home, it will begin its intended five-year science mission, imaging hundreds of millions of stars in greater detail than ever before.
“Gaia promises to build on the legacy of ESA’s first star-mapping mission, Hipparcos, launched in 1989, to reveal the history of the galaxy in which we live,” Jean-Jacques Dordain, ESA’s Director General, said in a statement.
“It is down to the expertise of Europe’s space industry and scientific community that this next-generation mission is now well and truly on its way to making ground-breaking discoveries about our Milky Way,” he added.
[ Watch the video: Gaia From Launch to Orbit ]
Designed and built by Astrium, Gaia is so sensitive that it could measure a person’s thumbnail from the moon, or the equivalent of detecting a human hair from 620 miles away, according to the telescope developers.
Astrium says that the aim of the Gaia mission is to create a three-dimensional picture of the galaxy, measuring the precise distances to a billion stars. It is also expected to log a million quasars beyond the Milky Way, as well as a quarter of a million objects in our own solar system, including comets and asteroids.
"It can do it with incredible accuracy. It's the biggest camera ever put into space," Ralph Cordey, head of science and exploration at Astrium, told CNN’s Dave Gilbert in an interview.
If successful, Gaia will add immense knowledge to that which has already been garnered from NASA’s Hubble Space Telescope and ESA’s Hipparcos satellite. Hubble is still in operational mode today, but the Hipparcos mission ended in 1993.
Robert Massey, from the UK’s Royal Astronomical Society, said, “Gaia is an amazingly ambitious mission.”
"Until now astronomers have relied on very indirect methods to gauge the distance to all but the nearest stars, meaning that the foundation on which we build a map of the universe is surprisingly weak,” said Massey, who has championed the goal of putting this billion-pixel imager into space.
"Building on the work of the pioneering Hipparcos satellite that mapped the stellar neighbourhood in the 1990s, Gaia will be used to carry out work analogous to the cartographers who surveyed the Earth in the 19th and 20th centuries, building up the first accurate charts of the cosmos and helping us better understand the structure, history and fate of the galaxy we live in," he told CNN.
MOUNTAIN OF DATA
Over the five year mission, Gaia will repeatedly observe each of a billion stars some 70 times, measuring their positions and key physical properties, including brightness, temperature and chemical makeup.
Gaia will take advantage of the slight change in perspective that occurs during its orbit of the sun to measure distances between it and the stars in observance, as well as the motions across the heavens. And it will do this by watching them patiently over the course of the five-year-long mission.
By building data about the position, motion and composition of each of the stars, Gaia will provide clues about their histories and that data will help scientists piece together a “family tree” for our Milky Way galaxy.
By constantly mapping the motions of the stars, scientists will be able to “rewind” the data to learn more about where they came from and how the galaxy was assembled. By moving “fast forward,” they will learn about the ultimate fate of these stars.
“Gaia represents a dream of astronomers throughout history, right back to the pioneering observations of the ancient Greek astronomer Hipparchus, who catalogued the relative positions of around a thousand stars with only naked-eye observations and simple geometry,” Alvaro Giménez, ESA’s Director of Science and Robotic Exploration, said in a statement.
Add to this the tens of thousands of supernovae Gaia is expected to discover during the mission, as well as the possibility of discovering planets around wobbly stars and the countless new asteroids and comets in our own Solar System, this satellite could make history. If anything, scientists do believe it could make precise tests of Einstein’s theory of General Relativity.
After the mission wraps up in 2019, experts believe that Gaia’s data archive will exceed a million gigabytes (one petabyte) of information – the equivalent of 200,000 DVD’s worth of data. Processing and analyzing this mountain of data will fall into the hands of the Gaia Data Processing and Analysis Consortium, which is made up of more than 400 individuals across several scientific institutions across Europe.
“After years of hard work and determination of everyone involved in the mission, we are delighted to see our Gaia discovery machine on the road to L2, where we will continue the noble European tradition of star charting to decipher the history of the Milky Way,” Giuseppe Sarri, ESA’s Gaia project manager, said in a statement.
Image Below: Soyuz VS06, with Gaia space observatory, lifted off from Europe's Spaceport, French Guiana, on 19 December 2013. Credit: ESA