WHY THIS MATTERS IN BRIEF
The cost of getting astronauts and cargo into space is still astronomical, a space elevator could eliminate the need for costly rocket launches and democratise access to space.
Let’s be honest, launching things into space with rockets is a pretty inefficient way to do things, after all you wouldn’t ever, for example, dream of taking a rocket to the top of a tall skyscraper. Not only are rockets expensive to build they also need a ton of fuel, and, flipping back to getting things into space, while the costs of individual launches are being dramatically reduced thanks to concepts like reusable rockets and space planes from Aerodyne and SpaceX, a better and more cost effective solution could be to build a Space Elevator.
However, while such a project of mega-engineering is simply not feasible right now, there are many scientists and companies around the world that are dedicated to making a space elevator a reality within our lifetimes, and now a team of engineers from Shizuoka University in Japan have created a scale model of a space elevator that they will be launching to the International Space Station (ISS) for first trials later this week. And it’s the first trial of its kind.
The concept for a space elevator is quite simple. Basically, it calls for the construction of a space station in Geosynchronous Orbit (GSO) which is tethered to Earth by a “tensile structure,” or cable to you and I. A counterweight would be attached to the other end of the station to keep the tether straight while the Earth’s rotational velocity ensures that it remains over the same spot, and astronauts and cargo would travel up and down the tether in cars, like elevator cars, that would eliminate the need for rocket launches altogether.
For the sake of their scale model, the engineers from Shizuoka University created two ultra-small CubeSats, each of which measures 10 cm (3.9 inches) per side. These are connected by a roughly 10 meter long (32.8 ft) steel cable, a container that acts like a space elevator moves along the cable using a motor, and cameras mounted to each satellite monitor the container’s progress.
The microsatellites are scheduled to be launched to the ISS in September where they will then be deployed in space to be tested. Along with other satellites, the experiment will be carried by H-IIB Vehicle No. 7, which will launch from Tanegashima Space Center in Kagoshima Prefecture. While similar experiments where cables were extended in space have been conducted before, this will be the first test where an object is moved along a cable between two satellites.
“It’s going to be the world’s first experiment to test elevator movement in space,” said Yoji Ishikawa, an engineer on the project, “in theory, a space elevator is highly plausible. Space travel may become something popular in the future.”
If the experiment proves successful, it will help lay the groundwork for an actual space elevator. But of course, many significant challenges still need to be resolved before anything approaching a full size space elevator can be built. Foremost among these is the material used to build the tether, which would have to be both lightweight, so as not to collapse, and have incredible tensile strength to resist the tension induced by the centrifugal force acting on the elevator’s counterweight.
On top of that, the tether would also have to withstand the gravitational forces of the Earth, the Sun and the Moon, not to mention the stresses induced by Earth’s atmospheric conditions. These challenges were considered insurmountable during the 20th century, when the concept was popularised by such writers as Arthur C. Clarke. However, by the turn of the century, thanks to the invention of Graphene Carbon Nanotubes, a wonder material that’s already helped reverse paralysis, and that could also one day be used to create the first generation of batteryless electric hypercars and next generation semiconductors and electronics, scientists began to reconsider the idea.
However, manufacturing nanotubes on the scale needed to reach a station in GSO is still well beyond our current capabilities. In addition, Keith Henson, who’s a technologist, engineer, and the co-founder of the National Space Society (NSS), argues that carbon nanotubes simply don’t have the necessary strength to endure the kinds of stresses involved. To this, engineers have proposed using other materials, like diamond nanofilament, but production of this material on the scale required is also beyond our current capabilities.
There are other challenges as well, which include how to avoid space debris and meteorites from colliding with the space elevator, how to transmit electricity from Earth to space, which could perhaps be overcome by using geostationary solar arrays like this one that was proposed a while ago, and ensuring that the tether is resistant to high-energy cosmic rays which could whether it. But if and when a space elevator could be constructed, it would have immense payoffs, not the least of which would be the ability to transport crews and cargo to space for far less money.
In 2000, prior to the development of SpaceX’s reusable rockets, the cost to place payloads into geostationary orbit using conventional rockets was about US $25,000 per kilogram ($11,000 per pound). However, according to estimates compiled by the Spaceward Foundation, it is possible that using a space elevator payloads could be transferred to GSO for as little as $220 per kg ($100 per pound).
In addition, the elevator could be used to deploy next-generation satellites, such as space-based solar arrays like the one I mentioned before. Unlike ground based solar arrays, which are subject to the day-night cycle and changing weather conditions, these arrays would be able to collect power 24 hours a day, 7 days a week, 365 days a year. This power could then be beamed from the satellites using microwave emitters to receiver stations on the ground.
Spaceships, like SpaceX’s BFR rocket which will take people to Mars, could also be assembled in orbit, another cost cutting measure. Currently, spacecraft either need to be fully-assembled here on Earth and launched into space, or to have individual components launched into orbit and then assembled in space. Either way, it’s an expensive process that requires heavy launchers and tons of fuel. But with a space elevator, components could be lifted to orbit for a fraction of the cost. Even better, autonomous factories could be placed in orbit that would be capable of both building the necessary components and assembling spacecraft.
Little wonder then why multiple companies and organisations are hoping to find ways to overcome the technical and engineering challenges such a structure would entail. On the one hand, you have the International Space Elevator Consortium (ISEC), an affiliate of the National Space Society which was formed in 2008 to promote the development, construction, and operation of a space elevator.
Then there is the Obayashi Corporation, which is working with Shizuoka University to create a space elevator by the year 2050. According to their plan, the elevator’s cable would be composed of a 96,000km (59,650 mi) carbon nanotube cable capable of carrying 100 ton climbers, or “elevator cars.” It will also consist of a 400m (1,312 ft) diameter floating Earth Port and a 12,500 ton (13,780 US ton) counter weight.
As Professor Yoshio Aoki of the Nihon University College of Science and Technology, who supervises Obayashi’s space elevator project, said: “[A space elevator] is essential for industries, educational institutions and the government to join hands together for technological development.”
Granted, the cost of building a space elevator would be enormous and would likely require a concerted international and multi-generational effort. And significant challenges remain that will require significant technological developments. But for this one time expenditure, plus the cost of maintenance, humanity would have unfettered access to space for the foreseeable future, and at significantly reduced costs. And if this experiment proves successful, it will provide essential data that could someday be used to create the space elevator of every sci-fi nerds’ dreams.