According to MSNBC, NASA planners are looking at two of the Lagrange points where the gravity of the Earth and the moon cancel one another out at initial destinations for the first human explorers beyond low Earth orbit.
What are the Earth-Moon Lagrange Points?
The Lagrange points are areas in space where the gravity of two celestial bodies cancel one another out. There are five Lagrange points in the Earth-Moon system. L1 lies between Earth and the moon. L2 is beyond the lunar farside. L3 is on the opposite side of Earth from the moon. L4 and L5 make equilateral triangles with Earth and the moon.
Of the Lagrange points, L4 and L5 seem to be the most stable. L1, L2, and L3 are less so, though a space craft could park at either of those places using a “halo orbit,” which is not technically an orbit at all, but a repeating path near the Lagrange point in question. Some station keeping with rocket engines would be required.
Why go to a Lagrange Point?
In the first case, they are easy to get to, even more so than lunar orbit and especially more so than the lunar surface. Lockheed Martin proposed an early space flight to the Earth-Moon L2 point with an Orion spacecraft for long term observations of the lunar farside. This was meant to be a test of the system before more ambitious missions were undertaken to Earth approaching asteroids and eventually Mars.
The idea is to establish small space stations at L1, which faces the lunar nearside, and L2, which faces the lunar farside. These would serve as bases to use tele-operated robots to explore the lunar surface and to build infrastructure for an eventual human return.
It is claimed tele-presence has advanced to a degree that they could provide “avatar-like” access to environments that humans would ordinarily be unable to go to. People in a nearby space station would use such robots as eyes and hands to explore the moon or another planet.
Such a scheme would fit neatly into a plan advanced to use precursor robots to build a lunar base for human astronauts advanced by Paul Spudis of the Lunar and Planetary Institute and Tony Lavoie of NASA’s Marshall Space Flight Center.
Long-Term Implications
One aspect of using tele-operated robots on the moon is that it would serve as a test run for using such machines in more human-hostile environments such as the surface of Venus or in the Titan methane lakes.
If the idea is actually put into effect, the “humans vs. robots” controversy which ranged from the dawn of the space age until the 2004 study by the Royal Astronomical Society that demonstrated the scientific utility of human astronauts will be revived. Tele-operated robots, it will be argued, combine the flexibility of humans and the durability of machines. Human space exploration advocates will counter that there is still no substitute for a human mind and human eyes on the scene to explore a place properly. Finally, space settlements cannot be inhabited by robots. Those need human beings.
Mark R. Whittington is the author of Children of Apollo and The Last Moonwalker . He has written on space subjects for a variety of periodicals, including The Houston Chronicle, The Washington Post, USA Today, the L.A. Times, and The Weekly Standard.
Source: http://us.rd.yahoo.com/dailynews/rss/science/*http%3A//news.yahoo.com/s/ac/20120111/sc_ac/10822043_nasa_mulls_missions_to_earthmoon_lagrange_points
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