The interns of the 2012 Lunar and Planetary Science Academy overseen by the Goddard Space Flight Center prepare to explore the Grand Canyon, one of the best places to study Mars without leaving Earth.
This image was taken June 27, 2012 during NASA's annual trip. See more photos from the "Martian" look at the Grand Canyon in this gallery.
The Grand Canyon's sculpted layers reveal two billion years of natural history, a result of long-term etching by the Colorado River and its tributaries. This image was taken June 27, 2012.
Intern Allison Duh takes in the canyon on June 27, 2012.
Though not the longest or deepest canyon on Earth, the Grand Canyon stretches an impressive 277 miles (446 kilometers) long and is up to 18 miles (29 kilometers) wide and more than a mile (1.8 kilometers) deep. This image was taken June 27, 2012.
The fun begins for intern Jillian Votava. This image was taken June 27, 2012.
The colored rock layers, buttes and mesas at the base of Mars' Mount Sharp look like they belong in the Grand Canyon. The image was taken Nov. 14, 2012.
For Avinash Misra, it's all about the rocks. This image was taken Jan. 3, 2009.
The Grand Canyon's layers provide the perfect resting place for weary intern Nicole Thom. This image was taken Jan. 3, 2012.
Break time for Adam and April Frake, Aaron Silver and Chet Gnegy (in back). This image was taken in Jan. 4, 2009.
Near Sedona, Rachel Kronyak studies the wave patterns preserved in a flat, Mars-colored landscape that was once under water. This image was taken June 25, 2012.
A 50,000-year-old Meteor Crater, near Winslow, Arizona. Although it was long thought to have been formed by volcanic activity, it is actually the result of a meteorite impact that had the force of 20 million tons of dynamite. This image was taken Nov. 14, 2012.
Sebastian Fischer crouches in front of Meteor Crater. Scientists come here to get a close-up view of what an impact crater on Mars or another planet or moon might look like. This image was taken June 26
Meteor Crater is an analog site for the moon. This Apollo command module (a "boilerplate," meaning it did not fly) serves as a reminder that Apollo astronauts trained here in the 1960s to prepare for their missions. This image was taken June 26, 2012.
Unlike Meteor Crater, Colton is a volcanic crater. Called a maar, it was formed by a "giant steam bomb," in the words of intern Ryan Jackson, of hot lava mixed with ground water. This image was taken June 25, 2012.
Kyle Leaf checks out Colton Crater from the bottom.
Interns Rachel Kronyak, Antonio Aguirre and Alisa Bochnowski (front row, left to right) and Amber Keske and John Gemperline (back row) relax at Colton Crater. This image was taken June 25, 2012.
When seen from above, it's easy to see why SP Crater, with its nearly perfect symmetry, is considered a textbook example of a cinder cone volcano. Also prominent is SP's distinctive tongue of black lava. This image was taken Nov. 14, 2012.
SP Crater is one of about 600 small volcanoes in Arizona's San Francisco Volcanic Field. Scientists think these volcanoes, like the ones on Mars, are hotspots—places where excessive heat below the surface melts the crust. This image was taken Jan. 1, 2012.
Melissa Gaddy gets a closer look at SP Crater's black lava. This image was taken June 24, 2012.
Arizona's Painted Desert, located between the Grand Canyon and the Petrified Forest National Park, is a good model for the badlands terrain found on Mars. The image was taken on June 25, 2012.
The petrified logs scattered around Petrified Forest aren't the park's only fossils. Other fossils include dinosaurs, reptiles, fish and amphibians. The oldest fossils date back more than 200 million years. This image was taken June 25, 2012.
The 2012 Lunar and Planetary Science Academy (LPSA) interns and trip leaders in a group photo taken July 9, 2012.
