One problem with space travel is that humans aren’t very good at coping with reduced gravity - their bones and muscles deteriorate over time. But one company says they have an answer - a giant rotating space cylinder that can create artificial gravity. Scroll down for video . A Washington, DC-based company called United Space Structures wants to create a new space station. Their giant cylinder (shown, with the ISS and Space Shuttles illustrated) could apparently replace the ISS. It would rotate four times per minute to create artificial gravity, and would be 1,300ft (400 metres) long, cost £200 billion ($300 billion) and take 30 years to build . The ‘space mushroom’ was designed by Bill Kemp and Ted Maziejka from United Space Structures (USS), based in Washington, DC. The final design would be 330ft (100 metres) in diameter and 1,310ft (400 metres) long. • Orbiting Hotel/Casino/3D Sports Arena . • Orbiting space station - Planetary environmental monitoring/Research . • Solar system space vehicle . • Settlement cargo vehicle & construction platform . • Rescue vehicle . • Continuously looping space ferry system . • Mining vehicle/platform . • Manufacturing platform . • Bio-medical research/manufacturing . Artificial gravity is created by spinning the station 4.22 times per minute around its vertical axis, creating downward pressure via the centrifugal force to keep objects - including humans - on the floor. The force would be the same as the gravity experienced on Earth. Meanwhile on the ISS, the station is in constant freefall towards Earth as it orbits the planet - so the astronauts live in ‘zero-gravity’. While the main cylindrical body would spin in one direction, the top dome-shaped section would spin in the other direction. This would allow spacecraft to dock with the top of the station, which would appear stationary to them. The necessity for this dome gives the space station its mushroom-like appearance. The dome would house the command centre for the station, and also many of the supplies needed for the crew on board. ‘We believe artificial gravity is required to support long term living in space,’ Mr Kemp told MailOnline. To build the station, the team says they have ‘patents pending’ for six robotic systems that can manufacture and construct a variety of structures in space. While exact details aren’t known at the moment, another company - Tethers Unlimited -  has demonstrated how structures could be built in space with their SpiderFab proposal, a system of robo-spiders that would build parts of spacecraft in orbit, although Mr Kemp told MailOnline that the USS method would be 'different'. Mr Kemp added that, for this large structure, it would take about 30 years to build and cost close to £200 billion ($300 billion). For comparison, it took more than 10 years to build the ISS, at a cost of around £67 million ($100 billion) - although this new station has 2.89 million times more volume. And it would be ‘large enough to transport all the people and equipment required to set up a colony on Mars and would orbit Mars and provide a safe environment while the Mars base is being constructed.’ Artificial gravity has been considered many times before, most famously in the 'Stanford Torus' design (interior seen here). A rotating station would allow people to live as if they were walking on Earth, allowing them to stay in space for long periods of time . To build the station, something like SpiderFab (left) could be used, a proposed system of robo-spiders than can construct solar panels, trusses and other parts of spacecraft in orbit. On the right is an artificial gravity test Nasa performed in September 1966. The Gemini 11 spacecraft was attached to an Agena target vehicle and spun, with the astronauts reporting a small amount of artificial gravity in their spacecraft . On the ISS, the station is in constant freefall towards Earth as it orbits the planet - so the astronauts live in ‘zero-gravity’. However, they actually still experience about 90 per cent of Earth's gravity, but the constant falling makes them seem weightless . Inside, the structures would be spinning so anyone on the curved ‘floors’ around the edges would be pushed into the ground, simulating gravity on Earth. But Mr Kemp said they want to build a smaller structure first, to prove the design works. ‘Our first structure will be 30 metres [100ft] in diameter, it will create a 0.6 gravity environment and would house at least 30 people,’ he said. This smaller structure would cost between £3.5 and £7 billion ($5 and $10 billion), and could be built in the next 10 years. It would take just 12 to 18 months to build, according to Mr Kemp. ‘The International Space Station is estimated to be decommissioned around 2024,’ Mr Kemp noted. The team has yet to begin any serious construction or testing as of yet - so at the moment, the station remains somewhat of a pipe dream. Astronauts on the ISS (Terry Virts seen left, Scott Kelly on the right) live in a constant state of micro-gravity. Mr Kelly is spending a year on the ISS to see what effects such conditions have on the human body for a prolonged period of time . In the 1968 film 2001: A Space Odyssey, astronauts are shown running around a spacecraft that spins (shown) while on a mission to deep space, creating artificial gravity for them to operate in . Previous concepts for spacecraft include this 1969 station that would rotate on its central axis to produce artificial gravity. The majority of early space station concepts created artificial gravity one way or another in order to simulate a more natural or familiar environment for the health of the astronauts on board . However, space settlement expert Al Globus, who is also a contract scientist at Nasa's Ames research centre, told MailOnline that he thought the idea was somewhat sound - and artificial gravity was a necessity for prolonged stays in space. ‘Rotation to provide artificial gravity will counteract most, if not all, of the negative effects of micro-g,’ he said. And he says if we truly want to live in space, including raising children there, it will be necessary to create such a station. ‘There is no data on the effects of micro-g on kids, but it is safe to assume they will grow up very weak as muscles and bones develop in response to stress,’ he continued. ‘Thus, for settlement, there is simply no question that they must rotate and almost certainly need to provide 1g at least for the first few generations.’ But whether this station will be the answer remains to be seen. Several other proposals for a rotating space station have been drawn up - including a Nasa concept called Nautilus-X - but as of yet, there are no concrete plans by Nasa, Roscosmos (the Russian space agency) or any other nation on what to do after the ISS. Whether this station by United Space Structures or another concept will be built, remains to be seen. Nasa's Nautilus-X concept, shown, includes a doughtnut-shaped spinning section in the middle where astronauts can experience artificial gravity. The spacecraft is designed for long trips to the moon, Mars or beyond . While a spacecraft could be created with artificial gravity, astronauts will still have to contend with zero-gravity conditions if they ever venture outside into space. Shown are Nasa's Robert L. Curbeam, Jr. (left) and Esa's Christer Fuglesang above New Zealand in 2006 .
Washington, DC company United Space Structures wants to create a new space station .
It rotates four times a minute to create artificial gravity - with the 'stem' and 'dome spinning in opposite directions .
It would be 1,300ft (400 metres) long, cost £200 billion ($300 billion) and take 30 years to build .
‘We believe artificial gravity is required to support long term living in space,’ Bill Kemp from USS told MailOnline .