After its three-month journey through space, NASA's Microwave Anisotropy Probe arrived at its observation station a million miles from Earth on Monday to measure the oldest light in the cosmos.

An artist's concept of MAP. Photo: NASA

"We can now begin the process of observing the remnants of the early Universe," said Dr. Charles L. Bennett, MAP Principal Investigator from NASA's Goddard Space Flight Center in Greenbelt, Md. "There is great anticipation within the astronomy community about this mission because of the potential it has to give us key clues to the content, shape, history and the ultimate fate of our Universe."

Called MAP for short, the satellite was launched by a Boeing Delta 2 rocket from Cape Canaveral on June 30, arriving in a highly elliptical orbit around the Earth. From there, the spacecraft team executed a series of maneuvers using onboard thrusters to send MAP looping around the Earth three times and positioning it for a gravity-assist boost from the Moon. The lunar swing-by occurred a month after launch, on July 30.

Since then, MAP has cruised toward L2, a quasi-stable position one million miles from Earth in the direction opposite the Sun. While previous missions have passed through the L2 neighborhood, MAP is the first mission to use an L2 orbit as its permanent observing point.

Illustration shows MAP's journey from Earth to L2. Photo: NASA

All of MAP's spacecraft and instrument systems are performing admirably, NASA said. "Both the operations team and the science team are ecstatic because of MAP's outstanding performance," added Bennett. "Everything is going extremely well."

MAP will scan the skies over two years, collecting information on the faint cosmic glow in five distinct wavebands of light. The data will be analyzed and made into a full sky map for each waveband. The first sky map results are expected about December 2002.

The space probe will collect the information needed to make a map of the entire sky in the microwave light left over from the Big Bang. The entire universe is bathed in this afterglow light. This is the oldest light in the universe and has been traveling for 14 billion years. The patterns in this light across the sky encode a wealth of details about the nature, composition and destiny of the universe.

The images of the infant universe are viewed by measuring tiny temperature differences within the microwave light, which now averages 2.73 degrees above absolute zero. The extraordinary design of MAP allows it to measure the slight temperature fluctuations to within millionths of a degree. The unprecedented accuracy of MAP has the potential to revolutionize current views of the universe.

MAP was produced in partnership between Princeton University, N.J., and Goddard. Goddard and Princeton University produced the MAP hardware and software. In addition to Goddard and Princeton, science team members are located at the University of Chicago, the University of California, Los Angeles, Brown University, Providence, R.I., and the University of the British of Columbia, Vancouver.

MAP, an Explorer mission, is managed by Goddard for NASA's Office of Space Science in Washington at a cost of about $95 million.