Imagine a long cable connecting Earth to space that could launch us into orbit at very low cost and launch us to other worlds at record speeds. This is the basic idea of ​​the space elevator. Instead of taking six to eight months to reach Mars, scientists estimate that a space elevator could get us there in three to four months, or even 40 days.

The space elevator concept is not new, but developing such a structure will not be easy and there are many problems other than technology. Therefore, the passion to seriously build it appeared relatively recently. The Japanese company Obayashi Corporation believes that it has relevant experience.

Obayashi Corporation, known for building the world’s tallest tower, Tokyo Skytree, announced that it will reach even higher heights with its own space elevator in 2012. In a report published the same year, the company said the $100 billion project would begin construction by 2025 and could become operational as early as 2050.

To find out how the 2025 project is progressing, we sat down with Yohji Ishikawa, who wrote the report and is part of the company’s future technology creation department. While Ishikawa said the company probably won’t start construction until next year, he told Business Insider that it’s currently “busy with research and development, black design, partnering, and promotion.” Some doubt that such a structure is even possible.

“It was a bit of a crazy idea,” said Christian Johnson, who published a report on space elevators in the peer-reviewed journal last year. Journal of Science Policy and Governance. “But there are real scientist people who really support this and really want to do it,” Johnson said.

A cheaper way to go to space

Launching people and objects into space on rockets is extremely expensive. For example, NASA estimated that four missions to the moon Artemis would cost $4.1 billion per launch. This is due to the so-called rocket equation. Going into space requires a lot of fuel, but it is heavy, which increases the amount of fuel needed. “So you see a vicious cycle,” Johnson said.

With a space elevator, you don’t need a rocket or fuel.

According to some designs, space elevators will carry payloads into orbit with electromagnetic vehicles called climbers. These climbers can be powered remotely, for example by solar power or microwaves, eliminating the need for fuel.

In a report for the Obayashi Corporation, Ishikawa wrote that this type of space elevator could help reduce the cost of transporting goods into space to $57 per pound. Other estimates put space elevators at a total of $227 per pound.

Even SpaceX’s Falcon 9, at about $1,227 a pound, is one of the cheapest rockets to launch and still costs about five times more than the highest cost estimates for space elevators.

There are other benefits besides cost.

According to Johnson, there is no danger of the rocket exploding and the climbers could be zero-emission vehicles. At a relatively slow 194 miles per hour, Obayashi Corporation climbers will move slower than rockets and with less vibration, which is a good thing for sensitive equipment. Ishikawa said Obayashi Corporation sees the space elevator as a new kind of public project that will benefit all humanity.

There isn’t enough steel on Earth to build a space elevator

One of the biggest hurdles to building a space elevator right now is what the cable or pipe will be made of. The pipe, if made of typical materials such as steel, would need to be very thick to withstand the tremendous stress it would be subjected to. But “if you try to make it out of steel, you’re going to need more steel than there is on Earth,” Johnson said.

Ishikawa’s report suggests that Obayashi Corporation may be using carbon nanotubes. A nanotube is a wrapped sheet of graphite, the material used in pencils. It’s much lighter than steel and less likely to break under stress, so a space elevator could be much smaller, Johnson said. But there is a problem.

Although nanotubes are very strong, their diameters are only a billionth of a meter. And researchers didn’t do these for very long. The longest is only 2 feet. According to Ishikawa’s report, the cable would need to be at least 22,000 miles long to balance properly but still achieve a geosynchronous orbit, where objects synchronize with the Earth’s rotation.

“So we’re not there,” Johnson said of the nanotube’s length. — But that doesn’t mean it’s impossible.

Instead, researchers may need to develop an entirely new material, Ishikawa said.

Other obstacles

Whatever the material, other problems remain. A space elevator cable, for example, would be under incredible tension and prone to breakage, Johnson said. A lightning strike could vaporize it. There are other weather conditions to consider, such as hurricanes, monsoons, and tornadoes.

Johnson said placing the anchor base on the equator would reduce the likelihood of hurricanes, but it still needed to be in the open ocean to make it harder for terrorists to target. Plus, a lot of traveling would be required to make up for that huge construction price tag.

This is only a superficial problem. Not all of these can be solved by a single company, Ishikawa said. “We need partnerships,” he said. “We need different sectors”

“Of course,” Ishikawa said, “fundraising is very important.”

There are many hurdles to overcome before construction can begin in 2050, especially since Ishikawa estimates that construction will take 25 years. He noted that predictions up to 2050 are always accompanied by warnings about the advancement of technology. “That’s not our goal or our promise,” he said, but the company is still targeting that date.

“I think these time estimates are optimistic,” Johnson said, “even if we assume there will be an improvement tomorrow.”