NASA’s Deep Impact spacecraft has extended its mission to include a search for exosolar planets (planets orbiting other stars). This part of the mission is called Epoxi. Deep Impact has already completed part of its original mission at comet Tempel 1 on July 4, 2005. NASA recently extended the mission to include a flyby of comet Hartley 2 on October 10, 2010.

Using its largest telescope, Deep Impact will study five nearby stars with transiting exosolar planets, which are planets crossing the face of or are in front of its star. The five planets were discovered already, now they can be studied further. They are giant planets with massive atmospheres, like Jupiter in our solar system. These giant stars have orbits closer to their star than Earth is to the sun, so they are very hot. They have been nicknamed “Hot Jupiters.”

Other planets in the same solar systems as the giant planets may be discovered in this search. Scientists believe they can find Earth-sized planets using different methods, including gravity and a timing technique. Scientists may be able to observe the atmospheres of the planets using light emissions. They subtract the known light of the star, and the rest of the light is reflected off the planet.

Deep Impact will look back at Earth and observe it in visible and infrared wavelengths. Later the data can be used to compare with future discoveries of Earth-like planets.