NASA rolled out Monday a strategy and rationale for robotic and human exploration of the moon(File Photo) Photo Gallery >>>

WASHINGTON, Dec. 4 (Xinhua) -- NASA rolled out Monday a strategy and rationale for robotic and human exploration of the moon -- determining that a lunar outpost is the best approach to achieve a sustained, human presence on the moon, U.S. medias reported on Monday.

    The lunar base will be the central theme in NASA's going back to the moon effort, in preparation to go to Mars and beyond. The base would be built in incremental steps, starting with four-person crews making several seven-day visits. The first mission would begin by 2020, with the base growing over time, beefed up with more power, mobility rovers and living quarters.

    The moon base would eventually support 180-day lunar stays, a stretch of time seen as the best avenue to establish a permanent presence there, as well as prepare for future human exploration of Mars.

    NASA's senior planners detailed a global exploration strategy, outlining the themes and objectives of 21st century lunar exploration and the hardware needed to regain a foothold on the moon.

    A key technology yet to be defined is a lunar lander -- hardware that can be used in piloted or unpiloted mode to develop a capability on the moon more rapidly.

    NASA's lunar plan also encourages participation by other nations, as well as non-governmental organizations and commercial groups. NASA's lunar strategy is evolving from dialogue that has already taken place with 13 other space agencies.

    A moon outpost would yield tangible science benefits, as well as enlarge the sphere of economic activity beyond low earth orbit, said Scott Horowitz, NASA associate administrator for the Exploration Systems Mission.