As the technology required to create a physical link between Earth and outer space becomes closer to a reality, discussions of next-generation space exploration have been given new life.
Japan announced recently that it was researching plans to build a space elevator – a link to space that could transport cargo and even tourists – for as little as 1 trillion yen ($11 billion).
"Just like travelling abroad, anyone will be able to ride the elevator into space," chairman of the Japan Space Elevator Association, Shuichi Ono, told The Times.
The news is believed to have shaken up scientists at NASA, who have traditionally focused on rockets to reach space but could now be considering following Japan's suit.
Australia too may play a part in the creation of a space elevator, with a region off the west coast identified as ideal for an Earth dock – the structure that would anchor the link.
Unlike some science-fiction depictions of a giant tower or elevator reaching into the stars, modern plans for a space elevator rely on a cable being stretched between a satellite and a platform on Earth along which vehicles could travel.
One location being considered by NASA for such a platform is off the coast of Perth, according to the West Australian co-author of the book Leaving The Earth By Space Elevator, Philip Ragan.
Mr Ragan, who wrote the book with former NASA scientist and space elevator expert Dr Bradley C. Edwards, said there were 12 criteria that had to be met when choosing a possible location for the Earth port including consideration of storms and lightning.
"We identified that the Indian Ocean, about 500km off of Perth, was a prime location to site the Earth end of the cable," Mr Ragan said.
"A second preferred location is about 2000 miles (3218km) south of Hawaii... (which would be) closer for Americans in air time but logistically more remote for servicing by shipping."
An Australian Senate report released last week backed up Mr Ragan's claims and said the West Australian oil industry's expertise in building offshore platforms could prove useful if the plans went ahead.
"The Indian Ocean off Western Australia has been identified as an ideal location for a space elevator – a thin carbon nanotube connecting a barge to a space station, along which supplies could be carried up," said the report.
Professor Lachlan Thompson, from RMIT's School of Aerospace, Mechanical and Manufacturing Engineering, said Australia would also be an ideal partner for space agencies because its land mass was not divided into different nations.
"Australia is an ideal place for suborbital and orbital tourism due to it being a large land mass not divided by countries," he said.
Technical challenges
Professor Thompson, who co-chaired the Space Elevator Technology Session at the 59th International Astronautical Congress in Scotland last month, said the creation of a space elevator, while not yet possible, was supported by theoretical evidence.
“Elevators to space can be made to work... eight papers presented (at the congress) supported strongly the idea is sound," he said.
If a space elevator was built, it would provide a method of transportation to a space platform floating about 36,000km or more above the Earth. But where to from there?
Many of the costs associated with space exploration stem from trying to get off Earth itself – by overcoming the planet's gravitational pull using extremely expensive rocket blasts.
Missions launched from a platform already outside of the Earth's atmosphere would be cheaper and more efficient, allowing for more exploration projects.
However plans for a space elevator rely on finding a material strong enough to form the cable, or "ribbon", stretched between Earth and space. Scientists say the ribbon would need to be 150 times stronger than steel to be stable.
"The stresses in the cable due to its own weight are partially relieved by the mass in space at the end of the cable, so that's not a problem," Professor Thompson said.
"But the loads are enormous and get dangerously high once the elevator starts oscillating as it moves along the cable.
"The first challenge is to develop fibres that have sufficient strength-to-weight ratio so that they will take the load without being so ridiculously large in diameter that it could never be deployed.
"The next is to work out how to make the cable, which is why everyone is looking at nanofibre technology."
Mr Ragan said it was likely that carbon nanofibre cables strong enough to sustain a space elevator would be produced within the next five years, and could be tested in space within a decade.
"If anyone can do it, the Japanese certainly can as they are currently the world's largest producer and user of carbon nanofibre at lower strengths," Mr Ragan said.
Mr Ragan said competition between space agencies would heat up in coming years as the technology to build a space elevator became available and the cost efficiency of launching missions from outside the Earth's gravitational pull became clear.
"When the appropriate strength carbon nanofibre is definitely in production, interest will intensify," he said.
"The first country to deploy a space elevator will have a 95 per cent cost advantage and could potentially control all space activities."
Posts
No comments:
Post a Comment