Rotating space station
They’re a staple of science fiction, but a Californian company is planning to finally make them a reality
They’re a staple of science fiction, but a Californian company is planning to finally make them a reality
As we edge closer to sending humans to Mars, one of the great uncertainties is how our biology will cope with long exposure to little or no gravity. Crews will spend months in microgravity getting to the Red Planet, then potentially spend years in one-third Earth gravity on the surface. Microgravity causes all manner of physical problems, from muscle and bone weakening to changes in blood flow.
While microgravity is hugely useful for science in space, the ideal situation for humans working in space would be to create a significant gravity field to live in. We can’t yet build gravity generators, but there is a technique we can use. First proposed by Konstantin Tsiolkovsky in 1903, spin gravity can make a gravity-like effect using a rotating structure. This uses the same effect as the perceived force we feel when a car goes around a corner or we spin on a roundabout: centrifugal force.
The bigger the structure of the spacecraft, the slower it spins to create effective gravity, so its less dizzying to the occupants. This could be accomplished by creating a large cylindrical structure, spinning on its long axis, with crew members living and working on the inside.
The classic spin gravity space station is a spoked wheel with a docking port in the middle to receive spacecraft and a toroidal living space around the outside. But a key problem with these concepts is the size of structure needed to make it work comfortably. The bigger the wheel, the slower it can spin, and therefore less difference in the ‘gravity’ experienced by your head and your feet, producing a more comfortable environment.
This is where Californian start-up Orbital Assembly comes in, working on the machines to build this huge Earth-orbiting outpost. Although Orbital Assembly ultimately aims to create a full station, the company has started with creating the tools to assemble it in space. The Structure Truss Assembly Robot (STAR) and Gateway Segment Assembly Line (GSAL) are free-flying robots which will take stock metal tubes and weld them into trusses in space. Orbital has also designed space drones specifically to catch tools or parts that might drift off in the construction process in an attempt to minimise space debris.
Given these tools, Orbital is thinking big, with a 200-metre (656-foot) wheel called Voyager Station planned. This will consist of a huge, circular truss with 24 inflatable modules arrayed around it to create living space for up to 440 people, and spaced in between will be 44 lifeboat spacecraft. Spinning less than once per minute, it will generate one-sixth Earth’s gravity like that felt on the Moon. Orbital Assembly hopes to have Voyager completed by 2027.
1 Central hub
Orbital Assembly’s robots will start by constructing a small ringshaped truss to form the hub of the space station.
2 Outer truss
The main structure of the ring will be a circular truss nearly 200 metres (656 feet) in diameter, assembled in orbit.
3 Living space
Orbital Assembly hopes to complete the Voyager Station in 2027. When complete it will be able to support up to 440 people.
4 Escape pods
Arrayed around the station will be 44 escape spacecraft to enable all on board to safely return to Earth if something happens to the station.
5 Inflatable structures
The living pods will be inflatable structures, making it much easier to launch them into space.
6 Tension spokes
The main ring will be braced to the central hub by tension cables, like the spokes on a bicycle wheel.
7 Starship
SpaceX’s new Starship is planned to be a foundation of the project, providing cheap launches for all the components – and visitors in future.
8 Low-Earth orbit
Voyager Station will be placed in an inclined low-Earth orbit, providing changing views of the Earth and making it accessible from many launch sites.
“free-flying robots will take stock metal tubes and weld them into trusses in space”