kepler

NASA has launched a spacecraft with a mission to help determine something that has been the theme for many Hollywood movies over the years: whether Earth-like planets might exist elsewhere in space.

The 15-foot tall, 2,320-pound Kepler satellite lifted off yesterday at 10:50 p.m. Eastern time atop a Delta II rocket from the Cape Canaveral Air Force Station in Florida for a three-and- a-half-year mission to find other planets that may support life, according to a NASA statement distributed by PR Newswire.

Kepler carries a photometer, a device made up of 42 highly sensitive digital light sensors that will monitor a patch of 100,000 stars to detect planets that may orbit them. Its findings will be essential in determining the course of future missions looking for extraterrestrial life, said David Koch, Kepler’s deputy principal investigator.

“In terms of finding Earth-like planets, this is the only mission that can do it,” he said.

The launch came 10 days after another NASA satellite failed to reach orbit and crashed into the ocean near Antarctica. NASA officials said the fairing, which covers the satellite during the launch, didn’t come off as expected. The weight of the fairing prevented the satellite from reaching its orbit. Without enough power to carry it into orbit, the satellite plunged back to Earth.

Tests After Mishap

In the mishap’s aftermath, Kepler’s fairing was tested and approved for the new mission, which will cost $591 million. The Kepler satellite was built by Boulder, Colorado-based Ball Aerospace & Technologies Corp. United Launch Alliance, a joint venture of Boeing Co. and Lockheed Martin Corp., constructed the rocket.

Koch said scientists expect to find about 50 planets roughly the size of Earth and as many as 500 that are slightly larger. Once a planet is found, scientists can calculate whether its size and distance is conducive to the presence of water, an essential component for supporting life.

Kepler is the first U.S. mission to seek planets in the galaxy that may support life. Scientists will conduct two months of tests on Kepler’s systems before the planet search begins.

The satellite will be able to examine a broad swath of the Milky Way for a longer period of time than Corot, a spacecraft sent up by the European Space Agency two years ago, Koch said.

Star Brightness Tested

By focusing on the same group of stars, Kepler will allow scientists to measure changes in brightness, which can occur when planets orbit around them, he said.

Astronomers need to measure three brightness changes, known as transits, to confirm that a planet is causing the light fluctuation.

To have water, a planet has to be at a distance “just right” from the star, an area known as the “Goldilocks Zone,” Koch said. Too close, the planet will be a “roaster” and too hot; too far, a planet would be too cold, he said.

The right distance varies depending on a star’s temperature.

A planet’s mass also is an important factor in whether it’s a place hospitable to life. If the planet is less than half Earth’s mass, it won’t have the gravitational pull to maintain an atmosphere. If it is more than 10 times the mass of Earth, it will become a “cosmic vacuum cleaner,” sucking in elements like hydrogen and helium, creating a planetary surface with the firmness of a soap bubble, Koch said.