ESA's Gaia Mission Is Beginning To See Things More Clearly

Lee Rannals for redOrbit.com – Your Universe Online

The European Space Agency’s (ESA) billion-star surveyor mission is slowly beginning to see more clearly.

ESA’s Gaia launched on December 19, 2013, and since then it has been preparing for its mission to gather loads of data on stars that surround us. Gaia took a test image of a dense cluster of stars in the Large Magellanic Cloud as part of a “fine tuning” test to get the spacecraft into focus.

The new image is allowing ESA engineers to tune up the behavior of Gaia’s instruments, and it is the first “proper image” to be seen from the spacecraft, according to the space agency. While the image may be the first proper one, ESA said that it will also be one of the last because Gaia’s main objective does not involve sending full images back to Earth.

Gaia’s goal is to create the most accurate star map of our Milky Way Galaxy by making precise measurements of the positions and motions of about a billion stars. Although a billion is a big number to map, this represents just 1 percent of the Milky Way’s 100 billion star population. Scientists believe this map could help to explain the origin and evolution of our Galaxy.

In order to make its map, Gaia will be observing each of the billion stars an average of 70 times each over the next five years. The spacecraft will be making measurements of physical properties of each star, including brightness, temperature and chemical composition.

Gaia will be using two telescopes to scan the entire sky, focusing the light from their separate fields simultaneously onto a single digital camera. ESA said that this is the largest camera to ever be flown in space, boasting nearly a billion pixels. Before Gaia’s telescopes can begin accurately measuring our neighboring stars, the instruments must be aligned and focused, which could take several months.

The latest image, featuring NGC1818, shows less than 1 percent of what Gaia will be able to see when fully equipped. This image is just an example of how the Gaia team is making progress on understanding the behavior and performance of the instruments.

ESA said all one billion of Gaia’s target stars will have been observed during the first six months of operation, but the extra five years is needed to measure these stars’ tiny movements. This measurement will allow astronomers to determine the stars’ distances and motions through space.

Gaia’s map will not be released until three years after the end of the five-year mission, according to ESA. However, the space agency did say that it will be releasing intermediate data sets. Moreover, if Gaia detects any rapidly changing objects, such as supernovae, then alerts will be made within hours of data processing.

Ultimately, Gaia will be gathering more than a million gigabytes worth of data, the equivalent of all the data that can be stored on 200,000 DVDs.