The big expense in getting people to orbit or the moon or any other space destination is the cost of escaping the Earth’s gravity. One often-proposed solution involves building a giant space elevator from some point on the Earth to orbit. That sounds great, but the reality is the materials needed to make a giant stalk reaching from the ground to orbit don’t exist today. Cables or other structures for such an elevator would have to be so impossibly thick as to break under their own weight. However, a recent paper from a researcher at Cambridge and another at Columbia suggest that while you can’t build an elevator from the Earth’s surface to orbit, we may have the technology to build a tunnel that anchors on the moon and lets out in Earth’s orbit.

Before you dismiss the idea out of hand, have a look at the paper. A classic space elevator proposal has one point on Earth and the far end balanced with a counterweight keeping the cables under tension. The proposed lunar elevator would minimize these problems by having most of the bulk in space and on the moon.

Honestly we aren’t good enough with physics to tell how serious this might be, though it does capture the imagination. However it may work though, it isn’t a panacea. With current building materials, such a construction could in theory go from the moon to a geostationary orbit. It would be possible to come closer, at the expense of paying a higher price for the weight and force on the thing. There really isn’t any free lunch.

Then again, a lot of the cost of getting into space is getting out of the Earth’s gravity well, so this isn’t as attractive as some proposed elevators that go from the surface to orbit. However, going to the moon or anywhere along the elevator would be easy and inexpensive. In particular, the paper identifies a Lagrange point base camp which would essentially be part of the way along the elevator.

This isn’t the first time we’ve looked at elevators to the sky. If we could get a handle on carbon nanotubes, we could be in business. Maybe a future Hackaday prize will be a ride on a space elevator.