Spacecraftprobe deep into moon's mysteries
Flying in formation around the moon, a pair of Nasa probes began mapping the lunar gravity field in hopes of figuring out why Earth's only natural satellite is shaped the way it is.
The probes kicked off their science campaign late yesterday, two months after arriving back-to-back at the moon over the New Year's weekend.
"Literally and figuratively, I'm over the moon," mission chief scientist Maria Zuber at the Massachusetts Institute of Technology said in an email.
Despite astronaut landings and robotic missions aimed at the moon, scientists still do not know everything about Earth's celestial companion.
A lingering mystery is why the side that always faces Earth appears flatter than the mountainous far side.
Mapping the moon's uneven gravity -- about one-sixth Earth's pull -- should provide a clue. The spacecraft will spend the next three months orbiting 35 miles above the lunar surface.