The ISS is pretty cool and all, and it's got a sweet view of Earth, but you know what? We live on Earth. Let's do some exploring! The Orlando Sentinel is reporting that NASA may have its eye on a more exotic location for the successor to the ISS: out beyond the orbit of the Moon, serving as a gateway to Mars and beyond.
The station, which so far exists only as a "leading candidate" for NASA's next major mission, would be located at the L2 Earth-Moon Lagrange Point (or EML-2), approximately 277,000 miles from Earth, or about 276,800 miles farther from Earth than the ISS is currently. A Lagrange Point is a spot in an orbital system where the gravitational forces of two massive bodies (like the Earth and the Moon) combine to create areas where a much less massive body (like a space station) can park out while not moving relative to the other bodies in the system. There are five of these points, as illustrated below, and once you get to one and stop moving, you can just sit there indefinitely.
NASA is looking to build a relatively small outpost at EML-2, probably with bits and pieces left over from the ISS to keep costs down. The new Orion launch system would be used to get stuff out there, and construction could start as early as 2019. The station would be an ideal spot for observing the Moon, and would also make a departure point to asteroids or even to Mars.
Apparently, NASA is quite serious about this, and while there isn't a huge amount of detail, the agency's report concludes with the following:
"Placing a spacecraft at the Earth-Moon Lagrange point beyond the moon as a test area for human access to deep space is the best near-term option to develop required flight experience and mitigate risk."
For the record, this would be the farthest that humans have ever been from Earth. Ever. The increase in distance alone vastly increases the inherent risk, and leads to other issues, including significantly increased radiation danger as astronauts would be well outside the Earth's protective magnetic field. NASA gets this, but there's only so much that's reasonable to do about it: according to the agency, a mission like this would need a "culture change" that includes the "acceptance of risk significantly different" from the shuttle program. And by different, we're talking much higher. But you know what? Space travel is a risky business, and any expectation of safety has to be tempered by reality. Astronauts do know this, and my guess is if NASA offers up some seats on a risky mission like this, there will be no shortage of volunteers excited to be a part of it.