CAPE CANAVERAL, Fla. (AP) _ A NASA observatory rocketed into orbit Saturday to scan the universe for the faint afterglow of creation.
Liftoff occurred right on time at 3:46 p.m., with the unmanned Delta rocket climbing through a cloudy sky.
``It's a terrific sigh of relief,'' Alan Bunner, a NASA science director, said after it reached orbit. But he said he won't relax until the spacecraft is where it needs to be this fall, 1 million miles from Earth, to conduct its ``watershed'' science work.
The $95 million MAP spacecraft will study the oldest light in the universe, that which was created within moments of the Big Bang. Astronomers expect this picture of the infant universe _ ``the ultimate baby picture'' as Bunner calls it _ to answer their most basic questions.
How old is the universe? What is it made of and how is it shaped? And perhaps most important, what is its fate?
``The whole science community is agog about this mission because it is going after such fundamental science questions,'' Bunner said.
At $145 million, including the rocket, ``it's a modest-price mission but with an enormous appeal,'' he said. He added, hopefully: ``We wish it well.''
MAP, short for Microwave Anisotropy Probe, will keep looping around Earth until it comes within 1,250 miles of the moon in early August. The observatory _ weighing not even one ton _ will use the moon's gravity to propel it out toward its final destination, a point 1 million miles from Earth.
It will take MAP three months from liftoff to reach this invisible point in space, on the side of Earth opposite the sun. For two years, it will circle this spot, the first spacecraft to do so, measuring the slight variations in temperature in cosmic microwaves that were once ultraviolet rays.
The constantly expanding universe has stretched this original ultraviolet light into microwaves over the 10 billion to 17 billion years that these rays have been traveling. That is astronomers' estimated range for when the Big Bang occurred and gave birth to the universe in a powerful explosion.
By pointing continually into deep space, MAP will avoid all the microwaves radiating from the Earth and the sun; these rays are more than 1 billion times stronger than the signals the spacecraft will seek. This location also will enable the observatory to remain at a constant temperature, essential in order for the single science instrument to track the afterglow of the Big Bang.
The afterglow is ``chock full of clues'' about the universe, Bunner said.
MAP will construct four full-sky pictures of this so-called fossil light, each one taking six months. It will measure the slight temperature differences in the microwave background with an incredible accuracy of one-millionth of a degree. The result should be much sharper pictures than those gathered by NASA's Cosmic Background Explorer spacecraft, launched in 1989.
Bunner cautions it will be 1 1/2 years before MAP's first findings are announced.
Princeton University is among the academic partners in the mission.