WASHINGTON D.C.: Astronomers said this week that the testing of NASA's new space telescope, the James Webb Space Telescope, is nearly completed, with scientific observations expected to begin in July.

The telescope sent back the latest test pictures of a neighboring satellite galaxy, and the results are better than the images taken by the Spitzer Space Telescope, NASA's previous infrared observatory.

Each of the 18 mirror segments on the new telescope is larger than the single mirror on Spitzer.

University of Arizona's Marcia Rieke, chief scientist for Webb's near-infrared camera, said, "It is not until you actually see the kind of image that it delivers that you really internalize and go 'wow!' Just think of what we are going to learn," as quoted by the Associated Press.

Launched in December, the $10 billion Webb, the largest and most powerful astronomical observatory ever sent into space, will look for light emitted by the first stars and galaxies, close to 14 billion years ago, as well as for possible signs of life.

Scientists are keeping the identity of Webb's first target a secret.

The telescope, positioned 1 million miles from Earth, is considered the successor to the aging Hubble Space Telescope.