Sending things into space is challenging. Rockets are our primary resource for doing so (in many cases, the only one), but they’re less efficient than we think. These vehicles require immense energy to cope with the planet’s gravity.
The fuel provides that energy but also has mass—mass that the vehicle must lift, requiring more fuel, and so on, until it reaches equilibrium. This is the best way to send objects into space, but it’s inefficient.
That’s why aerospace engineers are always looking for innovative solutions, from centrifugal “slingshots” to magnetic rails. And one design that occasionally catches the public's attention is the space elevator.
Several space elevator projects are in the initial stages of development. Japan’s Obayashi Corporation proposed one of them a decade ago. Although the company has made no further official announcements about its status, the project continues to catch media attention.
One of the media outlets that recently became interested in the Japanese project was Business Insider. Company sources told the outlet that the project didn’t appear to be on track to meet a timeline that called for construction of the elevator to begin in 2025.
The interest is not surprising. The project sounds like science fiction, but in an age where technology is catching up with many of our dreams, can this technology become a reality?
The concept of the space elevator is intuitive enough without having to explain it in detail. However, there are a few things to keep in mind. For example, due to the nature of orbital dynamics, this device has a significant limitation: It must have an “anchor” point in geostationary orbit.
The reason is that the speed at which an object orbits the Earth is proportional to its distance: The greater the distance, the slower the speed. Objects in low Earth orbit, such as the Hubble telescope or the International Space Station, orbit our planet more than once a day.
A Matter of Materials
On the other hand, geostationary orbit allows an object to orbit while remaining above the same point on the Earth’s surface. This is a necessary feature of the elevator. The distance to this orbit is over 22,000 miles, more than twice the diameter of the Earth itself.
Today, the project is still out of reach. A few years ago, University College London expert Kevin Fong told the BBC that we don’t even have the means to build it. Fong explained that we’d need a robust, flexible material with a specific mass and density.
Researchers have made great strides in this regard in recent years, but we still don’t have what we need to build this colossal structure. Peter Swan, president of the International Space Elevator Consortium, also interviewed by the BBC, pointed in the same direction: “Finding the material to make the rope is the main technological challenge.” The rest, he said, is a matter of incremental progress.
The rocket seems to be the space vehicle of choice, at least for the near future. Obayashi planned to begin construction in 2025 and have an operational elevator by 2050.
If we don’t develop a technology that makes orbital elevators obsolete before some company materializes them, we can expect them to remain a science fiction concept for many years. It wouldn’t be the first time.
Image | Obayashi Corporation | NASA
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