Cameras overseen by an Arizona State University professor have captured the sharpest images ever taken from orbit of three Apollo landing sites.

NASA scientists say the photos clearly show tracks made by lunar rovers and equipment left behind from the famous Apollo missions of the late 1960s and early 1970s.

Images taken of the Apollo 17 site, the last manned mission to the moon in December 1972, also show the astronauts' foot trails.

ASU professor Mark Robinson, the lead scientist on the orbiter's cameras, called the new images "spectacular" in a NASA news briefing on Tuesday.

The cameras are attached to the Lunar Reconnaissance Orbiter, an unmanned spacecraft that has been circling the moon for more than two years. Its goal is to map the moon's surface, record temperatures and measure radiation.

The cameras previously photographed the same sites but from much farther away.

To capture the newest images, the minivan-size orbiter dipped from its usual path 31 miles above the surface of the moon to nearly 13 miles for a month.

"The images are clearer and sharper that you're getting at this low altitude," Robinson said.

Scientists targeted three Apollo landing sites up close: Apollo 12, 14 and 17. Not all the Apollo sites could be photographed so closely because of the position and lighting of the moon in relation to the orbiter. The site where humans first landed on the moon, during Apollo 11, wasn't able to be captured up close.

Scientists also looked for evidence of American flags planted by astronauts during the missions but didn't see any. Robinson said it's unlikely they would be visible because the nylon flags were battered by the moon's extreme temperatures and ultraviolet radiation.

At the Apollo 14 landing site, scientists looked for signs of astronauts famously having fun while carrying out their mission in 1971. Astronaut Ed Mitchell threw a sampling instrument as a javelin, while mission commander Alan Shepard hit golf balls across the surface. But those details are likely too small to spot from orbit, scientists said.

The images do show equipment left over from the missions, including lunar rovers and backpacks jettisoned by astronauts as they got ready to blast off from the Apollo 14 and 17 missions.

"Obviously, they didn't need the backpacks anymore so they were unceremoniously thrown out on the surface, and they're still sitting there," Robinson said.

Scientists plan to spend the next few months poring over the 1,500 new images.

The images will be used to map the moon in more detail and could be used to identify future landing sites for either human or robotic missions.

Although the United States has no plans to send humans back to the moon, unmanned missions are scheduled.

On Thursday, NASA plans to send up a pair of space probes, each the size of a washing machine, to study the moon's structure and gravity from orbit. NASA also has a 2013 mission aimed at studying the moon's atmosphere and lunar dust.

"We have a lot of plans for the moon from a scientific perspective, and it really provides us a rich opportunity to look at the origin and evolution of the Earth-moon system," said Jim Green, director of NASA's Planetary Science Division in Washington, D.C.

Reach the reporter at anne .ryman@arizonarepublic.com.