Just a day after US President Barack Obama was re-elected, rumours began to fly that he will back NASA plans to build a hovering moon base. This lunar outpost would be parked in orbit, about 60,000 kilometres from the moon鈥檚 far side, in a gravitational haven called a Lagrange point.
There, the combined gravity of Earth and the moon would tug on a spacecraft with exactly the force needed for it to hover near the moon without spending fuel. Putting a spaceport at the Earth-moon Lagrange point 2 (EML-2) might assist human missions to an asteroid or to Mars 鈥� both on the list of NASA goals Obama announced in 2010.
Buzz about NASA鈥檚 vision for an EML-2 outpost has been swirling since September, when the newspaper obtained documents detailing how such a craft could be built using parts left over from the International Space Station.
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NASA has probably already cleared plans for the craft with the Obama administration, space policy expert John Logsdon of George Washington University in Washington DC told on 7 November, and has been waiting until after the election to announce them.
Asked about the spaceport, NASA officials would only say the agency is working towards sending a capsule to loop around the moon in 2017 and a manned mission to lunar orbit in 2021.
The president鈥檚 plan
鈥淣ASA is executing the President鈥檚 ambitious space exploration plan that includes missions around the moon, to an asteroid and eventually to Mars,鈥� spokesperson Rachel Kraft said in an email to New 杏吧原创. 鈥淭here are a variety of routes and options being discussed to help build the knowledge and capabilities to get there, and other options may be considered as we look for ways to buy down risk.鈥�
The hovering moon base plan sounds plausible, although NASA will probably wait until the new federal budget is announced in February to confirm anything, says of the University of Texas at Austin, who has served on NASA policy committees.
鈥淲ith all these rumours, I haven鈥檛 heard anybody at NASA who鈥檚 denying it. I think that says a lot,鈥� he says.
EML-2 is farther from Earth than astronauts have ever ventured, and is not shielded from radiation by Earth鈥檚 magnetic field. That makes it a good testing ground for deep space life-support systems, Lester says.
鈥淚f you want to get people out of low-Earth orbit, you want to test how well they can do in deep space, and you want to have some useful things for them to do when they鈥檙e out there, maybe the first thing to do is to send them to a Lagrange point rather than sending them to an asteroid,鈥� he says.
Scuba on Titan
An EML-2 spaceport could also allow astronauts on the base to explore the moon using robots controlled in real time. The three-second delay for radio signals to travel round-trip between Earth and the moon makes directly controlling a lunar rover from our home planet impractical. 鈥淚t鈥檚 as if you were driving drunk,鈥� says Lester. But EML-2 is close enough to the moon to erase that obstacle.
Last week NASA completed a test of such technology when an astronaut on the International Space Station drove a toy rover on Earth via the agency鈥檚 interplanetary internet.
Similar strategies could be used on Mars, as either a prelude to or a substitute for landing humans on the surface. Having a telepresence in space could also take human minds to places where our bodies can鈥檛 go.
鈥淲e could send human beings into orbit around [Saturn鈥檚 moon] Titan and they could do virtual scuba diving in the methane lakes,鈥� Lester says. 鈥淲hen you think about doing exploration that way, all of a sudden there are many more destinations for human spaceflight than there were before.鈥�
