US plans for Moon base

US space agency Nasa says it is planning to start work on a base on the Moon after astronauts begin flying back there in 2020. The maps and graphics below show how and where man could live on the Moon.

Nasa scientists say the best approach is to develop a solar-powered Moon base and to locate it near one of the poles of the moon - such as the Shackleton Crater in the south.

The poles offer moderate temperatures and a high percentage of sunlight which means greater potential for solar power.

Nasa says they are also exciting options as they are not as well known as other areas, and offer "unique, cold dark craters".

Nasa wants to have returned to the Moon by 2020, with 30-day residential missions by 2024, increasing to six months by the end of that year.

Nasa says the global space community has identified six key aims for lunar exploration:

• to extend human presence to the Moon to enable eventual settlement.

• to pursue scientific activities that address fundamental questions about the history of Earth, the Solar System and the Universe.

  MOON TIMELINE 2008: Launch Lunar Reconnaissance Orbiter 2010: Last Space Shuttle missions 2014: Deadline for Crew Exploration Vehicle 2020: Return to Moon

• to test technologies, systems, flight operations and exploration techniques to reduce the risks and increase the productivity of future missions to Mars and beyond.

• to provide a challenging, shared and peaceful activity that unites nations in pursuit of common objectives.

• to expand Earth's economic sphere, and conduct lunar activities with benefits to life on the home planet.

• to use a vibrant space exploration programme to engage the public, encourage students and help develop the high-tech workforce that will be required to address the challenges of tomorrow.

By 2025, Nasa hopes to have developed the capabilities required to enable further steps into space - possibly expanding lunar exploration and/or manned missions to Mars.

(1) The heavy-lift Ares 5 rocket blasts off from Earth carrying a lunar lander and a "departure stage"

(2) Several days later, astronauts launch on an Ares 1 rocket inside their Orion vehicle (CEV)

(3) The Orion docks with the lander and departure stage in Earth orbit and then heads to the Moon

(4) Having done its job of boosting the Orion and lunar lander on their way, the departure stage is jettisoned

(5) At the Moon, the astronauts leave the Orion and enter the lander for the trip to the lunar surface

(6) After exploring the lunar landscape for seven days, the crew blasts off in a portion of the lander

(7) In Moon orbit, they re-join the waiting robot-minded Orion and begin the journey back to Earth

(8) On the way, the service component of the Orion is jettisoned. This leaves just the crew capsule to enter the atmosphere

(9) A heatshield protects the capsule; parachutes bring it down on dry land, probably in California