Updates on NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission to measure the moon’s gravitational field and determine what lies beneath the surface are at the public’s fingertips thanks to a free Apple Store App which helps students and users.

The twin washing-machine-sized probes will enter the moon’s orbit on New Year’s weekend and more information will be available on the GRAIL application as the mission progresses.

The GRAIL App gives an overview of the mission, explains the mission objective, describes the spacecraft, links users to news about the GRAIL mission, has a countdown of the time it will take each probe to enter the Lunar orbit, and features videos and photos.

NASA said that the GRAIL Mission carries the “MoonKAM payload, operated by Sally Ride Sciences, which will engage middle schools across the country in the GRAIL mission lunar exploration.”

The MoonKam will be able to take photos from the probes.

Organizers expect thousands of fifth to eight grade students will select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center (MOC).

Photos of the target areas will then be sent back by the GRAIL satellites and made available in the Images section of the MoonKam website. (https://moonkam.ucsd.edu/)

Students can use this information to study lunar features such as craters, highlands, and maria also known as the lunar “seas,” which are the dark spots on the moon.

The twin GRAIL probes were launched from Cape Canaveral Air Force Station on Sept. 10, 2011.

According to NASA, GRAIL-A is set to arrive in lunar orbit on Saturday December 31 at 4:21 p.m. EST and GRAIL-B will enter orbit 24 hours later at 5:05 p.m. EST on Sunday January 1 2012.

Data collection won’t begin until May.