Many astronomy lovers may be dreaming of stepping on the Moon's ground.

But NASA is really preoccupied by how to maximize the results of such a costly voyage.

Since the end of the Apollo program, "folks around the world have been thinking about returning to the moon, and what they would like to do there," says Jeff Volosin, strategy development lead for NASA's Exploration Systems Mission Directorate.

Now, NASA plans to send astronauts to the Earth's natural satellite no later than 2020. "So we consulted more than 1,000 people from businesses, academia and 13 international space agencies to come up with a master list of 181 potential lunar objectives."

As the moon has virtually no atmosphere and it is situated most of its 28-day orbit outside of Earth's magnetosphere, scientists could make observations which are impossible from Earth.

The moon could be a good place for radio astronomy: a radio telescope on its far side would be protected from the Earth's abundant radio noise, enabling it to catch low radio waves that cannot penetrate the Earth's atmosphere.

This could open a totally pristine domain in astronomy. The moon is also ideal for studying the high-energy particles of the solar wind or the cosmic rays from deep space, deflected by the Earth's magnetic field, so even artificial satellites can't detect them all. A complete span of solar particles would shed light on the inner solar processes, as well as galactic cosmic radiation from remote black holes and supernovas.

Moreover, the Moon's regolith, its outer layer of crushed rock and dust, records them, being like an archive explaining the changes in solar wind over billions of years. "We believe that the moon's preservation of this solar record is unique and can provide us with insights on how past fluctuations in the solar output have affected, for example, the history of life on Earth," says Volosin. More specifically, this could explain the climate change on Earth.

The Moon itself is regarded as "a fossil world”, a small, non-dynamic space body largely preserved since its emergence in the early solar system. Its interior would explain many aspects about how a planet's inner layers separate and solidify during planetary birth.

The Moon also preserves meteorite craters and a complete picture of how meteorite flow has fluctuated over time in the Earth's surroundings.

Earth has lost many of these aspects due to its active dynamics.

More than half of the list recommendations points to the challenges of living in an alien world: from keeping astronauts safe from radiation and micrometeors to setting up power and communications systems to growing food in the airless, arid lunar environment. "We want to learn how to live off the land and not depend so much on supplies from Earth," says Tony Lavoie, leader of NASA's Lunar Architecture Team at the Marshall Space Flight Center.

Experience accumulated on the moon would be used for eventually manned missions to Mars.

Amongst the commercial activities on the Moon there would be: lunar power from solar cells, protected data archives, metal mining, low gravity and high vacuum researches, tourism and television.

NASA is still receiving input from scientists at space agencies and universities around the world.