The Obayashi Corporation aims to build a space elevator using a climbing vehicle to transport people and cargo along a tether to orbit and other planets.
The Japanese company, known for constructing the tallest structure in the world, the Tokyo Skytree, announced its plans for a space elevator back in 2012. The company intends to commence the $100 billion project in 2025, with operations potentially starting as early as 2050, according to Business Insider.
Simulation of a space elevator designed to transport people and cargo. (Photo: Science Photo Library).
The basic idea behind the space elevator is to use a long tether connecting Earth to space to launch people into orbit at a lower cost and travel to other planets at record speeds. Instead of taking 6 to 8 months to reach Mars, scientists estimate that the space elevator could reduce this time to just 3 to 4 months, or even as little as 40 days. While the concept of a space elevator is not new, the design and construction of such a structure are challenging due to numerous obstacles. According to Yoji Ishikawa, a representative in the company’s Future Technology Creative Department, although they cannot begin construction next year, they are currently in the research and development phase, working on preliminary designs, construction partnerships, and promotion.
Launching people and cargo into space is extremely expensive. For example, NASA estimates that each of the four Artemis missions will cost $4.1 billion per launch. Rocket launches require a significant amount of fuel to reach space, and due to the heavy nature of this fuel, the amount needed increases. The space elevator does not require rockets or fuel. According to some designs, the space elevator could transport cargo to orbit using electrically powered vehicles called climbers. These climbers can operate using remote power sources like solar or microwave energy, eliminating the need to carry fuel.
In a report for Obayashi Corporation, Ishikawa calculated that this type of space elevator could reduce the cost of transporting goods into space to $57 per 0.5 kg. Other estimates for the space elevator suggest costs of $227 per 0.5 kg. Even SpaceX’s Falcon 9 rocket, which has one of the lowest launch costs at $1,227 per kg, is still five times more expensive than the estimated cost for the space elevator. Additionally, the space elevator poses no risk of rocket explosions, and the climbers are expected to be non-polluting. Operating at a relatively comfortable speed of 200 km/h, Obayashi Corporation’s climbers will be slower than rockets but will produce less vibration, making them suitable for sensitive equipment.
According to Ishikawa, Obayashi Corporation views the space elevator as a public project that will benefit all of humanity. Currently, one of the biggest challenges in constructing the space elevator is selecting the materials for the tether. To withstand extreme tension, the tether needs to be exceptionally thick if made from conventional materials like steel, requiring more steel than what is available on Earth.
Ishikawa suggests that Obayashi Corporation utilize carbon nanotubes. A carbon nanotube is a rolled-up layer of graphite, which is significantly lighter and less likely to break under high tension compared to steel, allowing for a much smaller space elevator. Although carbon nanotubes are incredibly strong, they are extremely small, with diameters of just a few billionths of a meter. Researchers have yet to produce super long carbon nanotubes, with the longest existing sample measuring only about 0.6 meters. To achieve perfect balance and reach a geostationary orbit, the tether would need to be at least 35,406 meters long.
Instead, researchers may need to develop entirely new materials. However, there are many other challenges to overcome. For instance, the tether of the space elevator will experience such high tension that it is susceptible to breaking. A lightning strike could cause it to vaporize. Weather phenomena such as tornadoes, heavy rain, and storms could also threaten the space elevator system. Placing the base of the tether at the equator could reduce the likelihood of encountering storms. Moreover, the elevator system will need to operate numerous trips to offset the enormous construction costs.
Therefore, there are many obstacles to overcome before construction can begin in time for the 2050 operational target, especially as Ishikawa estimates that the project will take 25 years to complete.
