NASA prepares search for Earth-like planets

Posted by Wolfgang Gruener

Cape Canaveral  (FL) – NASA said it is set to launch a Delta II rocket carrying the Kepler space telescope. The device will survey 100,000 sun-like stars over a period of three years in a quest to find Earth-like planets that may be able to support life as we know it.

According to NASA, the Kepler mission is undergoing final preparations and is scheduled for takeoff tomorrow from Pad 17-B at Cape Canaveral Air Force Station in Florida. There will be two launch opportunities, one from 10:49 to 10:52 pm and  the other from 11:13 to 11:16 pm EST.

The Kepler mission is expected to last for about three years and will include the survey of more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy. NASA hopes the telescope will identify hundreds of planets that are at least the size of Earth orbiting distance stars which are much like our own sun in energy output, luminosity and mass. The telescope will focus on the potentially habitable zone within their space and "could find dozens of worlds like ours." However, NASA also mentioned that Kepler may not find any such "Earths" - especially if they are rare.

"This mission attempts to answer a question that is as old as time itself - are other planets like ours out there?" said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA Headquarters in Washington. "It's not just a science question - it's a basic human question."

The first two stages of the Delta II rocket will take the telescope into a circular orbit 115 miles above Earth less than 10 minutes after launch. After coasting for 43 minutes, the second-stage engine will fire again, followed by second-stage shutdown and separation. The third stage will then burn for five minutes. Sixty-two minutes after launch, Kepler will have separated entirely from its rocket and will be in its final Earth-trailing orbit around the sun, an orbit similar to that of NASA's Spitzer Space Telescope, NASA said. "We are very excited to see this magnificent spacecraft come to life when it reaches space," said James Fanson, Kepler project manager at NASA's Jet Propulsion Laboratory, in Pasadena, Calif.

The vast majority of the approximately 300 planets known to orbit other stars are much larger than Earth and not one is believed to be habitable. The majority that we've been able to detect so far are more like extremely large Jupiters - gas giants.

The Kepler telescope is specially designed to detect the periodic dimming of stars caused by transiting planets, NASA explained. Some star systems are oriented in such a way that their planets cross in front of their stars as seen from our Earthly point of view. As the planets transit, they cause their star's light to slightly dim, or wink. β€œThe telescope can register changes in brightness of only 20 parts per million,” NASA said. In late 2006, when NASA was able to detect Fomalhaut-b, the variation between the sun's brightness and the planet itself was that the planet was over 20 billion times less luminous.

"We will monitor a wide range of stars; from small cool ones, where planets must circle closely to stay warm, to stars bigger and hotter than the sun, where planets must stay well clear to avoid being roasted," said William Borucki, science principal investigator for the mission at NASA's Ames Research Center at Moffett Field, Calif.
 
Borucki has been working on the mission for 17 years. "Everything about the mission is optimized to find Earth-size planets with the potential for life, to help us answer the question - are Earths bountiful or is our planet unique?"

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