March 6, 2009

Successful Launch for Kepler Planet Finding Mission

NASA reports a successful launch on Friday night for a revolutionary new space telescope that will seek out other Earth-like planets in the Milky Way galaxy. Scientists hope Kepler will find planets potentially hospitable to life.

At 0348 GMT (10:48pm), the Kepler telescope liftoff marks the agency's first mission to seek out life-sustaining planets. Kepler launched via a United Launch Alliance Delta II rocket from Cape Canaveral Air Force Station in Florida. The Delta II rocket used nine solid-fueled booster rockets and three stages to lift Kepler to its proper vantage point.

"Kepler is a critical component in NASA's broader efforts to ultimately find and study planets where Earth-like conditions may be present," Jon Morse, astrophysics division director at the US space agency's Washington headquarters, told a press conference last month.

"The planetary census Kepler takes will be very important for understanding the frequency of Earth-size planets in our galaxy and planning future missions that directly detect and characterize such worlds around nearby stars," he added.

"There is now clear evidence for substantial numbers of three types of exoplanets; gas giants, hot-super-Earths in short period orbits, and ice giants," NASA said.

"The challenge now is to find terrestrial planets (i.e., those one half to twice the size of the Earth), especially those in the habitable zone of their stars where liquid water might exist on the surface of the planet."

NASA unveiled Kepler in late January. The telescope is equipped with a 0.95-meter diameter photometer, or light meter, with a large field of view for an astronomical telescope. It is equipped with a 95 megapixel camera "“ the largest ever flown in space.

"The photometer is composed of just one "Ëœinstrument,' which is, an array of 42 CCDs (charge coupled devices). Each 50x25 mm CCD has 2200x1024 pixels," NASA said. "The CCDs are read out every three seconds to prevent saturation."

"If Kepler were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front," Kepler project manager James Fanson told AFP.

NASA hopes to determine the distribution of sizes and shapes of the orbits of larger planets in or near the habitable zone of a wide variety of planets.

"Kepler finds planets by looking for tiny dips in the brightness of a star when a planet crosses in front of it"”we say the planet transits the star," said NASA.

"Once detected, the planet's orbital size can be calculated from the period (how long it takes the planet to orbit once around the star) and the mass of the star using Kepler's Third Law of planetary motion."

"The size of the planet is found from the depth of the transit (how much the brightness of the star drops) and the size of the star. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated. From this the question of whether or not the planet is habitable (not necessarily inhabited) can be answered," the space agency added.

To find a planet like Earth, scientists will need to catch at least four transits, a process that will take about 3 1/2 years. Its gaze will be fixed on a patch of sky between the constellations Cygnus and Lyra. Ground-based telescopes will be used to verify results, according to Reuters.

More than 330 planets have been observed circling stars in other solar systems, but none of them have had the size or properties suitable for sustaining life.

NASA says Kepler's objective will be to explore the structure and diversity of planetary systems through viewing a large sample of stars in order to determine the percentage of terrestrial and larger planets that are in or near the habitable zone of a wide variety of stars; determine the distribution of sizes and shapes of the orbits of these planets; estimate how many planets there are in multiple-star systems; determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets; identify additional members of each discovered planetary system using other techniques; and determine the properties of those stars that harbor planetary systems.

"A null result is as important as finding planets," Michael Bicay, director of science at NASA's Ames Research Center in California, told reporters in January.

"There's several astrophysical phenomena that masquerade as planets," Bicay said. "We're going to have to sort them out."

NASA said its engineers are analyzing the Delta II rocket to determine if it shares any commonality with the Orbital Sciences' Taurus launch vehicle, which resulted in last month's failed attempt to launch the agency's Orbiting Carbon Observatory (OCO).

The OCO failed to reach orbit after liftoff from Vandenberg Air Force Base in California on Feb. 24. NASA said the Taurus XL launch rocket's fairing - a clamshell structure that encapsulates the satellite as it travels through the atmosphere - failed to separate. The OCO landed just short of Antarctica, in the ocean, according to John Brunschwyler, Taurus project manager for Orbital Sciences Corp.

Astrophysicist Alan Boss said he expects Kepler or the French-owned COROT satellite to find Earth-like planets.

"I will be absolutely astonished if Kepler or COROT didn't find any earth-like planets, because basically we are finding them already," astrophysicist Alan Boss was quoted by AFP during a February science conference in Chicago.


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