NASA announced its Kepler mission has discovered two new planetary systems, including three super-Earth-size planets in a "habitable zone."

Of late, NASA's Kepler mission has been very successful in discovering new planetary systems and earth-like planets. The latest additions to this list of achievements include a recent discovery of two new planetary systems, including three super-Earth-size planets in a "habitable zone."

The first planetary system has been named Kepler-62 and consists of five planets namely 62b, 62c, 62d, 62e and 62f. The other planetary system discovered has been named Kepler - 69 and consists of two planets namely 69b and 69c. Planets 62e and 62f from the planetary system Kepler-62 and planet 69c from planetary system Kepler-69 are the three super-Earth-size planets.

Among these newly discovered planets, two of them orbit a star that is cooler and smaller than the Sun. Kepler-62f is said to be the exoplanet closest to the size of the Earth as it is only 40 percent larger than the size of our planet. Though the size of this planet has been stated, scientists are yet to measure its mass and composition. It is believed to have a rocky composition, according to NASA.

"The detection and confirmation of planets is an enormously collaborative effort of talent and resources, and requires expertise from across the scientific community to produce these tremendous results," said William Borucki, Kepler science principal investigator at NASA's Ames Research Center at Moffett Field, California and lead author of the Kepler-62 system paper in Science. "Kepler has brought a resurgence of astronomical discoveries and we are making excellent progress toward determining if planets like ours are the exception or the rule."

Planet 62e is 60 percent bigger than the Earth while Kepler-69c is 70 percent larger than the size of Earth. Both these planets orbit in the habitable zone of a star similar to our Sun.

"The Kepler spacecraft has certainly turned out to be a rock star of science," said John Grunsfeld, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. "The discovery of these rocky planets in the habitable zone brings us a bit closer to finding a place like home. It is only a matter of time before we know if the galaxy is home to a multitude of planets like Earth, or if we are a rarity."

Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate.