A space elevator is a proposed type of planet-to-space transportation system.
The main component would be a cable (also called a tether) anchored to the surface and extending into space.
The design would permit vehicles to travel along the cable from a planetary surface, such as the Earth’s, directly into space or orbit, without the use of large rockets.
An Earth-based space elevator would consist of a cable with one end attached to the surface near the equator and the other end in space beyond geostationary orbit (35,786 km altitude).
The competing forces of gravity, which is stronger at the lower end, and the outward/upward centrifugal force, which is stronger at the upper end, would result in the cable being held up, under tension, and stationary over a single position on Earth.
With the tether deployed, climbers could repeatedly climb the tether to space by mechanical means, releasing their cargo to orbit. Climbers could also descend the tether to return cargo to the surface from orbit.
The concept of a tower reaching geosynchronous orbit was first published in 1895 by Konstantin Tsiolkovsky. His proposal was for a free-standing tower reaching from the surface of Earth to the height of geostationary orbit.
A Japanese team has developed a “space elevator” and will conduct a first trial this month, blasting off a miniature version on satellites to test the technology.
The test equipment, produced by researchers at Shizuoka University, will hitch a ride on an H-2B rocket being launched by Japan’s space agency from southern island of Tanegashima next week.
The test involves a miniature elevator stand-in — a box just 6 cm long, 3 cm wide, and 3 cm high.
If all goes well, it will provide proof of concept by moving along a 10-metre cable suspended in space between two mini satellites that will keep it taut.
The mini-elevator will travel along the cable from a container in one of the satellites. “It’s going to be the world’s first experiment to test elevator movement in space,” a university spokesman said on Tuesday.
The movement of the motorised “elevator” box will be monitored with cameras in the satellites.
It is still a far cry from the ultimate beam-me-up goals of the project, which builds on a long history of “space elevator” dreams.
Japanese construction firm Obayashi, which is collaborating with the Shizuoka university project, is also exploring other ways to build its own space elevator to put tourists in space in 2050.
The company has said it could use carbon nanotube technology, which is more than 20 times stronger than steel, to build a lift shaft 96,000 kilometres (roughly 60,000 miles) above the Earth.
Carbon nanotubes (CNTs) are an allotrope of carbon. They take the form of cylindrical carbon molecules and have novel properties that make them potentially useful in a wide variety of applications in nanotechnology, electronics, optics and other fields of materials science.
They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat.
Carbon nanotubes, especially multi walled carbon nanotubes, are so strong because they are a single chain of unbroken covalent carbon-carbon bonds. More then that, they have many carbon-carbon bonds at each step, so breaking a carbon nanotube requires breaking many strong covalent bonds.
A diamond is so hard because it is a 3D matrix of carbon-carbon bonds, if it deforms in any way, bonds have to break.
Carbon nanotubes are made of a 2D matrix of carbon-carbon bonds formed into cylinders. This means they can bend and twist without breaking bonds, but they cannot stretch very far before bonds have to break.