Goals: The Spitzer Space Telescope is an orbiting observatory that uses infrared technology to study celestial objects that are either too cool, too dust-enshrouded or too far away to be seen otherwise. After depleting its instrument coolant as planned during its 5 1/2-year primary mission, Spitzer was recalibrated to continue studying the cosmos at warmer temperatures.

Accomplishments: Spitzer was the first telescope to detect light from an exoplanet -- a planet orbiting a distant star. The telescope's infrared instruments were also able to split the exoplanets' light into various wavelengths, revealing information about the distant worlds' atmospheres. Spitzer also was able to pinpoint hundreds of distant black holes previously shrouded in dust and capture a stunning portrait of the center of our galaxy.