NASA’s Kepler space telescope, the world’s first mission to hunt for extra solar Earth-like planets, has reached its orbit, NASA said.

A United Launch Alliance Delta 2 rocket is prepared for the launch of the Kepler Telescope for NASA Kepler, from Pad 17-B at Cape Canaveral Air Force Station in Florida, March 6, 2009. (Xinhua Photo/Reuters)

Sixty-two minutes after launch, the 591-million-U.S.-dollar Kepler separated entirely from its rocket and were in its final Earth-trailing orbit around the sun, an orbit similar to that of NASA’s Spitzer Space Telescope.

After the clock ticks down to liftoff, the Delta II’s first-stage main engine and six strap-on solid rocket boosters ignited, the NASA TV shows.

Three remaining boosters ignited 65.5 seconds later, and the first-stage main engine continued to burn for 4.5 minutes. The second stage then ignited, carrying Kepler into a circular orbit 115 miles above Earth less than 10 minutes after launch.

After coasting for 43 minutes, the second-stage engine fired again, followed by second-stage shutdown and separation. The third stage then burned for five minutes.

The spacecraft is designed to find Earth-size planets orbiting stars in habitable zones — regions where water could pool on the surface of the planets. Liquid water is believed to be essential for the formation of life. It will watch a patch of space for 3.5 years or more for signs of Earth-sized planets moving around stars similar to the Sun. The patch that Kepler will watch contains about 100,000 stars like the Sun.

“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, before Kepler’s liftoff.

“It’s not just a science question — it’s a basic human question,” Weiler said.

Using special detectors similar to those used in digital cameras, Kepler will look for slight dimming in the stars as planets pass between the star and Kepler. The Kepler’s place in space will allow it to watch the same stars constantly throughout its mission, something observatories like Hubble Space Telescope cannot do.

“We are very excited to see this magnificent spacecraft come tolife when it reaches space,” said James Fanson, Kepler project manager at NASA’s Jet Propulsion Laboratory, Pasadena, California.

After a commissioning period lasting about two months, Kepler will begin its job of looking for planets. Its isolated perch behind Earth will give the telescope an unobstructed view of a single, very large patch of sky near the Cygnus and Lyra constellations.

“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, California. 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?”

Kepler will find planets through the transit method. Planets that happen to pass directly in front of their stars from Earth’s point of view cause the stars to dim by almost imperceptible amounts. Kepler’s powerful camera, the largest ever flown in space, can see the faintest of these “winks.”

“Trying to detect Jupiter-size planets crossing in front of their stars is like trying to measure the effect of a mosquito flying by a car’s headlight,” said Fanson. “Finding Earth-sized planets is like trying to detect a very tiny flea in that same headlight.”

VietNamNet/Xinhuanet