17 December 2012, 06:00 AM ET
NASA TV will provide commentary, but the impact itself will probably not be visible.
13 December 2012, 01:33 PM ET
The Grail spacecraft will go out in style on Dec. 17.
11 December 2012, 10:51 AM ET
The Grail spacecraft will go out in style Dec. 17.
05 December 2012, 02:20 PM ET
The findings should shed light on the evolution of the moon and the solar system's rocky planets.
07 November 2012, 02:21 PM ET
The space agency has likely been holding off until the presidential election was decided.
08 October 2012, 06:58 AM ET
The proposed project is a joint effort of Europe and Russia.
22 March 2012, 04:45 PM ET
The Messenger spacecraft began a one-year bonus mission at Mercury, and the twin Grail probes will get 90 more days at the moon.
22 March 2012, 03:26 PM ET
The MoonKAM project is an educational outreach program for middle school students.
07 March 2012, 02:05 PM ET
The Grail probes' measurements should help scientists learn about the moon's structure and evolution.
01 February 2012, 04:58 PM ET
NASA's Grail probes have returned their first view of the far side of the moon.
19 January 2012, 07:01 AM ET
NASA's Grail spacecraft will begin mapping the moon in early March
17 January 2012, 01:10 PM ET
The names were suggested by students competing in a nationwide NASA contest.
17 January 2012, 09:45 AM ET
The new names for the twin Grail moon probes were selected from a nationwide student contest.
08 January 2012, 08:00 AM ET
From New Year's resolutions to private spaceflight, vote for your top space story of the week.
01 January 2012, 05:05 PM ET
The Grail-A spacecraft is orbiting the moon, and its twin Grail-B has joined it today.
01 January 2012, 12:33 PM ET
From New Year's moon mission to a supernova space oddity. vote for your top space story of the week.
31 December 2011, 11:46 PM ET
NASA's twin Grail gravity-mapping probes
31 December 2011, 04:22 PM ET
The Grail-A spacecraft was captured by the moon's gravity on Saturday afternoon.
31 December 2011, 12:58 AM ET
NASA's Grail mission will map the moon's gravity like never before.
30 December 2011, 06:32 PM ET
See photos of NASA's Grail moon twins, two spacecraft to map the lunar gravity like never before.
30 December 2011, 07:00 AM ET
The Grail spacecraft will start orbiting Earth's nearest neighbor on New Year's Eve and Day.
28 December 2011, 03:09 PM ET
The Grail spacecraft will enter orbit around Earth's nearest neighbor on Saturday and Sunday.
04 October 2011, 06:00 AM ET
Not satisfied with the name GRAIL, NASA is inviting kids to offer up a better name for the mission.
10 September 2011, 09:08 AM ET
NASA's Grail mission will study the inside of the moon and its gravitational field.
10 September 2011, 08:21 AM ET
High-altitude winds have once again delayed the launch of NASA's Grail mission.
10 September 2011, 12:14 AM ET
NASA will try launching its twin Grail lunar probes again tomorrow, after delays.
08 September 2011, 11:43 PM ET
The delay is the second in two days and allows time to study propulsion system data.
08 September 2011, 08:30 AM ET
Windy weather has delayed the launch of the twin Grail spacecraft on NASA's mission to map the moon's gravity.
08 September 2011, 12:19 AM ET
Students and teachers can follow along with NASA's Grail mission to investigate the moon's gravity fields.
07 September 2011, 06:09 PM ET
NASA's twin Grail lunar probes are slated to launch Sept. 8 on a mission to map the moon's gravity.
07 September 2011, 07:00 AM ET
Grail will map the moon's gravity field up to 1,000 times better than previous missions, researchers say.
06 September 2011, 03:15 PM ET
Clouds and thunderstorms may scrub the launch, but the forecast should improve over the weekend.
05 September 2011, 08:00 AM ET
The GRAIL mission will send two spacecraft to study the moon's structure.
01 September 2011, 07:00 AM ET
The GRAIL moon-studying mission blasts off on Sept. 8.
26 August 2011, 09:30 AM ET
The Gravity Recovery and Interior Laboratory (GRAIL) will use twin spacecrafts flying in tandem to study the gravity of the moon in unprecedented detail. Set to launch on September 8, 2011.
25 August 2011, 02:06 PM ET
The launch of NASA's GRAIL moon-studying spacecraft should go off as planned Sept. 8.