NASA's MAP satellite sets sail after lunar flyby
BY SPACEFLIGHT NOW
Posted: July 31, 2001
The Microwave Anisotropy Probe was successfully launched into a highly elliptical orbit around Earth on June 30 by a Boeing Delta 2 rocket.
The spacecraft made three such orbits over the past month. The loops included pre-planned thruster firings during the close approaches to Earth to systematically raise the orbital altitude in advance of Monday's lunar flyby.
MAP made the so-called "phasing loops" to wait for the moon to move into the right position. At about 12:30 p.m. EDT on Monday the spacecraft passed about 3,200 miles above the surface of the moon, receiving a boost from lunar gravity like a sling-shot to propel the 1,850-pound probe toward its final destination -- the second Lagrange Point (L2).
L2 is located a million miles from Earth in the direction opposite the Sun. MAP will become the first satellite to orbit at L2 -- a point where the combined gravity of the Earth and sun will keep the satellite in lockstep with its home planet, always forming a straight line from sun to Earth to MAP.
Controllers expect MAP should reach L2 in about two months.
MAP's $160 million mission is to paint a full-sky picture of the cosmic microwave background radiation left over from the Big Bang, which promises to help scientists answer age-old questions about how the universe formed, its structure, evolution and ultimate fate.
"L2 is a very good place for MAP because it is far from the Sun's and Earth's microwave emissions, which are a billion times stronger than the signal we are measuring," said Elizabeth Citrin, MAP project manager. "And it allows MAP to avoid night/day cycling as the solar arrays always face the Sun and the instrument is always shadowed. The instrument is cooled to about 300 degrees below zero Fahrenheit."
MISSION STATUS CENTER