Gaia's main instrument is being slowly brought online

Feb 8, 2014 10:10 GMT  ·  By

Officials with the European Space Agency (ESA) have recently released the first test image collected by their new space telescope, called Gaia. The purpose of this mission is to survey more than 1 billion stars in our galaxy over the next 5 years, and its main instrument is only now being brought online. 

Gaia was launched into space aboard a Russian-built Soyuz ST-B delivery system, sporting a Fregat-MT upper stage. Takeoff occurred on December 19, 2013, from the ESA Kourou Spaceport, in French Guiana, South America.

The 1,392-kilogram (3,069-pound) spacecraft was manufactured by ESA contractors EADS Astrium and e2v Technologies and will conduct its survey from a Sun-Earth L2 Lissajous orbit, with an apoapsis of 707,000 kilometers (439,000 miles), and a period of 180 days.

After spending five years in space, Gaia will have sufficient data to map the positions and motions of nearly 1 percent of all stars in our galaxy. This will enable astronomers to determine where each of these stars is going, in effect producing a 3D map of the Milky Way.

Before that happens, however, the telescope needs to open its eyes, and then calibrate its main instruments. The image attached to this article is one of the first test photos, which ESA mission controllers will use to focus its future spectrophotometric measurements.

Gaia is an astrometry mission, meaning that it will study physical characteristics of stars, such as luminosity, effective temperature, gravity, and elemental composition. It features an astrometric instrument (ASTRO), a photometric instrument (BP/RP), and a radial velocity spectrometer (RVS).

The image above is centered on a dense stellar cluster called NGC1818, located in the Large Magellanic Cloud, one of the several dwarf galaxies orbiting the Milky Way. Interestingly, this will also be one of the last photos the telescope sends back to Earth, as its main operations mode involves sending only data to Mission Control, not full images.

While conducting its survey, the spacecraft will scan each of the stars it targets a total of 70 times over 5 years. This will enable it to determine the speed at which these objects travel, as well as whether or not any variations occur in their velocities on account of external factors.

ESA estimates that focusing and calibrating the science instruments on Gaia will take a few more months, though it is impossible to know exactly how long.