Astronomy > In Pictures: Beyond Planet Earth

Our closest neighbor is the Moon . Did you know that only 12 people have ever set foot on its near-black, powdery surface?

No one has been to the Moon since 1972. But today, many scientists want to send people and robots back there. What do you think it would be like to live and work on the Moon?

When and if humans return to the Moon, they might want to set up a base camp. Astronauts could eat, sleep, bathe, and work in an expandable spacecraft like this one.

The Moon would be a great place to do astronomy. There is no atmosphere to block the view! Scientists can set up a liquid mirror telescope  that could detect light from the earliest days of the universe .

Scientists are also working on an idea of a lunar elevator. Secured to a cable from a space station to the Moon, it would help transport goods and people between Earth  and the Moon.

Orbiting beyond the Moon is an asteroid  named Itokawa. This space rock is huge. It's longer than 50 school buses! Itokawa is one of more than 7,000 near-Earth asteroids in our solar system .

Can humans visit these space rocks? It's definitely a possibility. Learning more about asteroids could help scientists learn to deflect ones that get too close to Earth.

Next stop: Mars . Today, this red planet is cold and dry. But millions of tons of liquid water once flowed on its surface. Could life have thrived there? Scientists want to find out.

NASA  sent the  Curiosity  rover to Mars. This robot is like a roving science lab. It can pick up samples and test them onboard. And it can fire a laser at rocks to see what they're made of!

Someday, humans might go to Mars too. The Nautilus-X spacecraft could carry a crew of nine on a two-year voyage, which is long enough to reach Mars.

Astronauts would sleep in spinning compartments. As it spins, passengers are pushed against the outer walls. The artificial gravity  would help prevent bone loss and other health problems.

Exercise machines would help astronauts keep their muscles and bones strong. Solid waste from toilets could be used as compost for plants. The plants, in turn, would provide food and oxygen.

Mars' surface is cold and barren. But the ingredients for a warm, wet, fertile environment are all there. They're just frozen underground. Could we turn Mars into a livable planet? Some scientists think so!

Transforming Mars into an Earthlike planet would take hundreds or even thousands of years. And it would be very expensive. But we could learn a lot about how climates and ecosystems work.

Further out our solar system is the giant planet Jupiter . Did you know that it has at least 50 moons? One of its moons is the ice-covered Europa.

Scientists think that there may be a deep saltwater ocean beneath Europa 's icy surface. On Earth, life exists wherever there is water. Is the same true on this moon? Future missions may find out!