Consider the following statements regarding the Gaia mission:

1. Gaia was launched in 2013 with the aim of creating a 3D map of the Milky Way galaxy and understanding its future changes.

2. The mission was designed for astrometry, specifically to map the cosmos through precise measurements of the location and movement of stars and celestial bodies.

3 . Gaia was positioned at the Lagrange point 1 (L1) to ensure an unobstructed view of the universe.

4 . Gaia used a single telescope to capture images, with a camera featuring nearly one billion pixels.

Which of the above statements are correct?