MPR News Chief Meteorologist Paul Huttner signs off

MPR News helps you turn down the noise and build shared understanding. Turn up your support for this public resource and keep trusted journalism accessible to all. 

Turn Up Your Support


      CAPE CANAVERAL, Fla. (AP) — A pair of spacecraft rocketed toward
the moon Saturday on the first mission dedicated to measuring lunar
gravity and determining what's inside Earth's orbiting companion -
all the way down to the core.


      "I could hardly be happier," said the lead scientist, Maria
Zuber. After two days of delays and almost another, "I was trying
to be as calm as I could be."


      NASA launched the near identical probes - named Grail-A and
Grail-B - aboard a relatively small Delta II rocket to save money.
It will take close to four months for the spacecraft to reach the
moon, a long, roundabout journey compared with the zippy three-day
trip of the Apollo astronauts four decades ago.


      Grail-A popped off the upper stage of the rocket exactly as
planned 1½ hours after liftoff, followed eight minutes later by
Grail-B. Both releases were seen live on NASA TV thanks to an
on-board rocket camera, and generated loud applause in Launch
Control.


      The pair are traveling independently to the moon, with A
arriving on New Year's Eve and B on New Year's Day.


      "Grail, simply put, is a journey to the center of the moon,"
said Ed Weiler, head of NASA's science mission directorate,
borrowing from the title of the Jules Verne science fiction
classic, "Journey to the Center of the Earth."


      The world has launched more than 100 missions to the moon since
the Soviet Union's Luna probes in 1959. That includes NASA's six
Apollo moon landings that put 12 men on the lunar surface.


      NASA's Grail twins - each the size of a washing machine - won't
land on the moon but will conduct their science survey from lunar
orbit.


      Beginning in March, once the spacecraft are orbiting just 34
miles above the moon's surface, scientists will monitor the slight
variations in distance between the two to map the moon's entire
gravitational field. The measurements will continue through May.


      "It will probe the interior of the moon and map its gravity
field 100 to 1,000 times better than ever before. We will learn
more about the interior of the moon with Grail than all previous
lunar missions combined," Weiler said.


      At the same time, four cameras on each spacecraft will offer
schoolchildren the opportunity to order up whatever pictures of the
moon they want. The educational effort is spearheaded by Sally
Ride, America's first spacewoman.


      The entire Grail mission costs $496 million.


      Zuber, the mission's principal investigator and a planetary
scientist at the Massachusetts Institute of Technology, said the
precise lunar gravity measurements will help her and other
planetary scientists better understand how the moon evolved over
the past 4 billion years. The findings also should help identify
the composition of the moon's core: whether it's made of solid iron
or possibly titanium oxide.


      Another puzzle that Grail may help solve, Zuber said, is whether
Earth indeed had a smaller second moon. Last month, astronomers
suggested the two moons collided and the little one glommed onto
the big one, a possible explanation for how the lunar highlands
came to be.


      Knowing where the moon's gravity is stronger will enable the
United States and other countries to better pinpoint landing
locations for future explorers, whether robot or human. The gravity
on the moon is uneven and about one-sixth Earth's pull.


      "If you want to land right next to a particular outcrop (of
rock), you're going to be able to do it," Zuber said. "There will
be no reason to do another gravity experiment of the moon in any of
our lifetimes."


      Zuber said the Grail findings should eliminate cliffhangers like
the Apollo 11 landing in 1969 by Neil Armstrong and Buzz Aldrin.
They overshot their touchdown site in part because of the subtle
gravity changes in the moon's surface below; they almost ran out of
fuel before safely touching down on the Sea of Tranquility.


      "It will be easier next time," Zuber promised.


      For now, NASA has no plans to return astronauts to the moon,
Earth's closest neighbor at approximately 240,000 miles away. That
program, called Constellation, was canceled last year by President
Barack Obama, who favors asteroids and Mars as potential
destinations in America's future without the shuttle.


      This is the second planetary mission for NASA since the space
shuttle program ended in July, and attracted a large crowd to Cape
Canaveral. NASA expected as many as 6,000 to 7,000 guests for the
morning liftoff, about half the throng that jammed Kennedy Space
Center for the Juno launch to Jupiter at the beginning of August.


      Grail was supposed to soar Thursday, but high wind interfered.
Then NASA needed an extra day to check the rocket after engine
heaters stayed on too long. High wind almost stopped NASA again
Saturday; the launch team had to skip the morning's first
opportunity, but the wind dissipated just in time for the second.


      The year's grand finale will be the launch of the biggest Mars
rover ever the day after Thanksgiving.


      "NASA is still doing business even though the shuttles stopped
flying," Weiler told reporters earlier this week.


      Grail is the 110th mission to target the moon, according to NASA
records. Missions have been launched by the United States, Soviet
Union, Japan, China and India.


      The previous moonshot was two years ago: NASA's Lunar
Reconnaissance Orbiter. Just last month, the moon-circling probe
beamed back the sharpest pictures yet of some of the Apollo
artifacts left on the moon from 1969 through 1972 - and even
moonwalkers' tracks. NASA released the photos earlier this week.
    

Gallery

Science

A pair of spacecraft rocketed toward
the moon Saturday on the first mission dedicated to measuring lunar
gravity and determining what's inside Earth's orbiting companion -
all the way down to the core.

Twin NASA craft launched to study insides of moon

Go Deeper.

Like this?

News you can use in your inbox