If you dream of seeing regularly scheduled missions to the Moon, you're not alone. While some companies are taking a more conventional approach, like developing rockets specially-designed to lower launch costs, other space-bound firms are pursuing less traditional means. Enter LiftPort: a company that hopes to build a space elevator system designed to greatly simplify missions to the Moon.
LiftPort President Michael Laine was working with NASA's Institute for Advanced Concepts in the early 2000s when he first began exploring the idea of a mechanism that could get people and cargo to space while remaining tethered to Earth.
The concept is pretty straightforward, at least in theory. Imagine you have a ball on a string and you spin it around your head. Get it spinning fast enough and the string will stay taut. Now imagine that string is around 500 kilometers long and is anchored to the Earth's surface rather than your hand. The other end is in anchored in orbit, attached to a spacecraft. You'd get the same taut string between the two points, and it'd be possible to build a system to climb up a taut string. That's the space elevator.
But we don't have the material means to build a space elevator just yet. What we do have, Laine told me, is the capability to build a version of a space elevator connecting the Earth and the Moon. Just add about 238,000 kilometers to our string above. About two and a half years ago, Laine struck out to try and bring this idea to reality.
WHILE IT WILL EXTEND TOWARDS THE PLANET, IT WILL NOT ACTUALLY TOUCH IT
The concept behind the Moon elevator is still similar to the ball on the string, but a little more complicated because of the Moon's slow orbit around the Earth. The solution lies in Lagrangian points. These are the points of gravitational equilibrium between two bodies. It's here that the gravitational pull of both bodies are equal, and so they cancel each other out. Lagrangian point L1 is about 55,000 kilometers from the Moon, and that's the one Laine hopes to take advantage of.
After anchoring one end of the "string" on the Moon's surface, it will extend to L1, then from L1 towards Earth. While it will extend towards the planet, it will not actually touch it. At the end of the string will be a counterweight made up of all the spent pieces of rocket that launched the initial mission to get the spike into the Moon. The counterweight will be in the right place for the Earth to pull on it gravitationally, but it will be anchored, through the Lagrange point, to the Moon. The force on both halves of the "string" will keep it taut. And that taut string will be a space elevator to the Moon.
What's more, said Laine, is that the Moon elevator can be built off-the-shelf, with readily available technology. A prototype could be built and deployed within a decade for as little as $800 million, according to him. It would be a small version exerting just a few pounds of force on the anchor on the Moon, but it would lay the groundwork for larger follow-up systems that could transport more cargo and eventually astronauts.
There's a lot of work to do before LiftPort can launch its Moon elevator. Up next for the company is a proof-of-concept demonstration that will see a robot climb the tallest freestanding human structure in existence.
WHAT'S MORE, SAID LAINE, IS THAT THE MOON ELEVATOR CAN BE BUILT OFF-THE-SHELF, WITH READILY AVAILABLE TECHNOLOGY
Using three large helium balloons held together on a tripod, Laine's team will unroll a giant spool of Vectran fiber into the air. Vectran, the same material NASA used to make the airbags that cushioned Spirit and Opportunity's landings on Mars, is a material that gets stronger as it gets colder, making it ideal for a high altitude test. The thread will be just an eighth of an inch think but able to support 1,400 pounds and withstand strong winds.
This high altitude test will be LiftPort's 15th experiment and the 20th robot to attempt an ascent. It will also be the first test using a Moon elevator-type string rather than an Earth elevator-type ribbon. Ribbons offer a larger surface area for the robot to grip, so preparing a test using a string has been a technological balancing act to find a motor large enough, robotic wheels strong enough, and a battery powerful enough to climb the string. This is not to mention the logistical balancing act of clearing airspace for the test.
Laine doesn't have a prospective date for when this test will happen. "We'll fly when we're ready," he said, stressing that he's unwilling to go prematurely. Failure in a public arena would set the project back years, and this test will be very public because Ben Harrison has been filming the whole thing for a new documentary.
Harrison found out about LiftPort by chance; he stumbled upon the company's 2012 Kickstarter campaign and, as a space fan, donated to the project. He was also working for Engadget at the time and ended up filming a brief ten-minute spot about Laine for the website. But he wanted to tell more of the story, and so he approached Laine with a pitch for a documentary about the space elevator. Laine agreed.
Harrison's is an independent project with independent vision, and he's been lucky to get very deep and generous access to Laine's project. That also means he's been able to capture the humanity behind LiftPort, because while some companies might hide failures, Laine hasn't. Harrison has seen, and caught on film, some pretty interesting technical foul-ups.
But Laine doesn't mind. With crowdfunding behind a significant source of money for LiftPort, he feels transparency and honesty are key. And besides, big technologies rarely, if ever, go from concept to execution without some problems, and this documentary isn't a story about Laine, it's about the project.
Harrison and his team plan to ask for public support via Kickstarter so they can finish the documentary, called Shoot the Moon, and share it with the world.