Hyderabad: Obayashi Corporation, a Tokyo-based construction company, has announced plans to build a space elevator by 2050, with construction potentially starting by 2025. Obayashi Corporation is known for ambitious projects such as the world’s tallest TV tower Tokyo Skytree. The project announced by Obayashi Corporation aims to revolutionise space travel and cargo transportation.
A space elevator is a proposed structure that would link Earth to Space, allowing for cheaper and faster access to orbit and beyond. The Elevator would use electromagnetic vehicles called climbers to transport cargo, significantly reducing costs compared to rockets. The estimated cost of moving goods via a space elevator could be as low as $ 57 per pound, much cheaper than current rocket costs.
However, one major challenge is finding a suitable material for the tether, with carbon nanotubes being a potential but currently impractical option. There are more obstacles like tether's vulnerability and security threats, requiring extensive research and partnerships.
The project is seen as a transformative public works initiative that could benefit all of mankind. The Obayashi Corporation announced in 2012 that it would reach even loftier heights with its own space elevator. The company also said it would begin construction on the $100-billion project by 2025 and could start operations as early as 2050.
The concept was first envisioned by Russian rocket scientist Konstantin Tsiolkovsky in a 1895 book called "Dreams of Earth and Sky," in which he described an imaginary 22,000-mile tower. Russian engineer Yuri Artsutanov later expanded on the idea, describing a cable that connects the Earth's surface to a geosynchronous satellite.
What is a space elevator: The space elevator is an electric vehicle called a “climber” that drives up and down one thin tether between the ground and a satellite in stationary orbit, using another outside tether for balancing with centrifugal force. The total length of the tether extends to 100,000 kilometers.
Before 1991, a material strong enough for the tether’s construction didn’t exist outside of science fiction. Physicist Dr. Sumio Iijima discovered the mechanism of the carbon nanotube, a material light enough and with the theoretical strength to realise the tether.
The space elevator functions surprisingly similar to a regular one. It consists of tethers, a platform, a ballast, and a counterweight. An elevator works by letting a counterweight pull up a platform as it falls. Then, a motor adjusts the force applied to the counterweight so that the platform descends gently. The motor and counterweight also apply brakes in emergencies.
According to the Obayashi Corporation website, the space elevator journey starts at an Earth Port 10 km from another Earth Port at the shore. The Earth Port at sea has a ballast that will anchor the lift’s cable to the planet and adjust its tension. Moreover, it will transport people and cargo for the Geostationary Orbit Station construction.
The port will let everyone ascend to space and return to Earth once it is complete. The Geostationary Orbit Station will be 36,000 km above the planet. It will have a solar power system that will send energy to the Earth. It will also host visitors and allow them to enjoy space in zero gravity.
The space elevator also has a counterweight that will be 96,000 km away from the planet. As per the illustration by Obayashi Corporation, it will reach Jupiter and nearby asteroids. The counterweight will also send spacecraft to extract resources from planets and the other parts of the solar system.
The space elevator is designed to be built using a multi-stage process. Materials will be transported via rocket to low Earth orbit (LEO), where a spaceship will use electric propulsion to ascend to geostationary Earth orbit (GEO). At this point, the spaceship releases the CNT cable back to Earth, becoming a counterweight once reaching 96,000 km in altitude. The climber units will transport materials and eventually people, utilising the strength of CNT to withstand the necessary tension and environmental stressors.
The cost of construction will exceed 100 billion dollars, and the process itself will take more than two decades. Obayashi Corporation is actively looking for partners among corporations and scientific institutes to implement this large-scale project.
Spaceships require massive amounts of fuel to reach the stars. However, fuel is heavy, meaning you need more fuel for a successful launch. ScienceAlert says SpaceX’s Falcon 9 transports cargo at around $1,227 per pound. On the other hand, Obayashi Corporation Business Development Manager Yoji Ishikawa estimates the space elevator could drop that cost to $57.
It has no risk of explosion, as happens with rockets. The elevators themselves, which are electrically powered, have zero emissions at all. But a space elevator can be very slow, travelling at 200 km/h. It’s slower than rockets, but it reduces vibrations, which is very useful for putting sensitive equipment into orbit.
Shortage of Materials: Christian Johnson, who published a report on space elevators in the Journal of Science Policy & Governance noted flaws with the project. "If you try to build it out of steel, you would need more steel than exists on Earth," he asserted.
Another key obstacle to building a space elevator is the choice of material for the tether. The tether must be incredibly strong to withstand the tremendous strain. Steel is not suitable because there is not enough of it on Earth for such an ambitious project. Carbon nanotubes could be a potential solution, as they are much lighter and stronger than steel.
However, the current length of nanotubes is limited, the longest ones barely reaching a meter in length. But to build an elevator, the tether must be at least 40,000 kilometers long.
Ishikawa suggested the Japanese firm might use carbon nanotubes. They are lighter and tougher than steel, but the longest one ever made was only two feet long. Hence, Ishikawa said researchers might need to develop a new material.
Johnson also noted that thunderstorms and other extreme weather conditions may damage the facility. Moreover, the space elevator will need multiple trips to have a significant return on investment.
A space elevator tether would be under such incredible tension that it could easily break. Weather conditions such as tornadoes, monsoons and hurricanes are also worth considering. After all, a tether can be destroyed by a routine lightning strike.
