The moon is about to become crowded.

In the next few years a slew of countries, including China, India, and Japan, are looking to put unmanned probes on the lunar surface. But more unprecedented are the 26 teams currently racing to win the Google Lunar X Prize – a contest that will award $20 million to the first private company to land a robot on the lunar surface, travel a third of a mile, and send back a high-definition image before 2015.

With all this activity, NASA is somewhat nervous about its own lunar history. The agency recently released a set of guidelines that aim to preserve important heritage locations such as the Apollo landing and Ranger impact sites. The report, available since 2011 to members of the private spaceflight community, was publicly posted at NASA’s website and officially accepted by the X Prize foundation on May 24.

“NASA has recognized that these sites are important to mankind and have to be protected to make sure there’s no undue damage done to them,” said John Thornton, president of Astrobotic Technology Inc., a company competing for the prize.

Though NASA has no way of enforcing the requirements, they are designed to protect materials and scientific equipment at historical lunar sites as well as future landing sites. The guidelines have been made available internationally, and the agency welcomes other nations to participate in and improve upon them, said NASA spokesperson Joshua Buck in an e-mail.

NASA is asking anyone that makes it to the lunar surface to keep their landing at least 1.2 miles away from any Apollo site and about 1,600 feet from the five Ranger impact sites. The distance should keep the old equipment safe from a terrible accident or collision. It will also would put the new equipment “over the lunar horizon” relative to the relics, and prevent any moon dust – known to be a highly abrasive material – from sandblasting NASA’s old machines.

The Apollo 11 and 17 sites – the first and last places visited by man – are singled out in particular for extra care and respect. Robots are prohibited from visiting both sites and are requested to remain outside a large radius (250 feet for Apollo 11 and 740 feet for Apollo 17) to prevent a stray rover from accidentally harming hardware or erasing any footprints.

“Only one misstep could forever damage this priceless human treasure,” reads the report.

Looking toward a possible high-traffic lunar future, the report also warns that frequent and repeated visits would have a cumulative and irreversible degrading effect on the historical sites. Other guidelines ask that rovers avoid kicking dust onto existing scientific experiments, like the laser-ranging lunar reflectors that are used to measure the distance between the Earth and moon.

Once a team has successfully landed, both the guidelines and the Google Lunar X Prize actually encourage them to go near some of the historic landing sites. The X Prize will award an extra $4 million to any company that can snap photos of a man-made object on the moon, including the Soviet Lunokhod rovers. And NASA has placed less restrictive protective radii around their other Apollo-era sites and artifacts, asking that robots merely remain three to nine feet from flags, tools, storage bags, and other pieces.

There is currently little data on what sitting for 40 plus years on the lunar surface does to man-made objects. The moon is an extreme environment, with wild temperature swings and full-on exposure to solar radiation, dust, and micrometeorites, all of which could severely weather materials.

Scientists and engineers are eager to obtain some before and after shots of artifacts that have been exposed to the elements for so long. It could give them insight into building future long-term structures on the moon, such as manned bases or mining operations.

Though the guidelines come from NASA, the agency worked with members of the private spaceflight community before releasing them, said Robert Richards, founder of two companies competing for the Lunar X Prize, Moon Express, Inc. and Odyssey Moon Limited.

“It’s not a decree, we were able to participate and comment,” he said. Richards added that the instructions simply reflect common sense, decency, and respect for other people’s property on the moon.

Images: 1) NASA's proposed radius around the Apollo 17 landing site, which would prevent damage to any historical artifacts from future missions. 2) Scientists and engineers would like to obtain updated photos of the Apollo 15 rover to see how it has weathered after nearly 40 years on the lunar surface. NASA