Space Elevator

Race on to build world's first space elevator


By Andrew Ramadge and Kate Schneider November 17, 2008 11:45am

Space race ... artist's impression of the transport (left) and the Earth
dock (right) in a working space elevator / Supplied


(See attached file: ScreenShot001.gif)


AUSTRALIA could play a key role in the 21st century space race, with
competition heating up between Japan and the US to build the world's first
"space elevator".


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."

New super lubricant - BAM

http://www.newscientist.com/article/dn16102-material-slicker-than-teflon-discovered-by-accident.html

A superhard substance that is more slippery than Teflon could protect mechanical parts from wear and tear, and boost energy efficiency by reducing friction.

The "ceramic alloy" is created by combining a metal alloy of boron, aluminium and magnesium (AlMgB14) with titanium boride (TiB2). It is the hardest material after diamond and cubic boron nitride.

BAM, as the material is called, was discovered at the US Department of Energy Ames Laboratory in Iowa in 199, during attempts to develop a substance to generate electricity when heated.

Eternal lubricant

BAM didn't do that, but was found to have other desirable characteristics. "Its hardness was discovered by accident. We had a terrible time cutting it, grinding it, or polishing it," says Alan Russell, a materials scientist at Iowa State University in Ames.

Those chance findings have now developed into a $3-million programme at the Ames Lab to develop the BAM into a kind of eternal lubricant, a coating for moving parts to boost energy efficiency and longevity by reducing friction.

BAM is much slipperier than Teflon, with a coefficient of friction of .02 compared to .05. Lubricated steel has a friction coefficient of 0.16.

One way to exploit this slipperiness is to coat the rotor blades in everyday pumps used in everything from heating systems to aircraft, says Russel. A slick BAM coating of just 2 microns (see image, top right) could reduce friction between the blades and their housing, meaning less power is needed to produce the same pumping power.

Mystery material

Bruce Cook, lead investigator on the Ames Lab project, estimates that merely coating rotors with the material could save US industry alone 330 trillion kilojoules (9 billion kilowatt hours) every year by 2030 - about $179 million a year.

BAM is also potentially attractive as a hard coating for drill bits and other cutting tools. Diamond is commonly used for this, and is harder, but it reacts chemically with steel and so degrades relatively quickly when used to cut the metal.

By contrast, BAM is cheaper and does not degrade when used with steel.

The exact reason for the new material's characteristics is still unclear, Russell told New Scientist. Most superhard materials, such as diamond, have a simple, regular and symmetrical crystalline structure. But BAM is complex, unsymmetrical, and its lattice contains gaps, none of which would be expected in a hard material.

Its slipperiness is also not entirely understood. Although Russell says the best theory is that the boron interacts with oxygen to make tiny amounts of boron oxide on its surface. They would attract water molecules from the air, to make a slippery coating.

"It's almost as if it's a self-lubricating surface. You don't need to add oil or other lubricants. It's inherently slippery," he says.

Magnetic bubble to protect Mars explorers

Radiation in space is one of the greatest challenges facing a mission to the red planet (NASA)

Scientists believe they have found a way of protecting astronauts from a dangerous source of space radiation, clearing one of the hurdles towards sending humans to Mars.

The device has been developed by British and Portuguese scientists and appears in the journal Plasma Physics and Controlled Fusion.

Radiation is one of the greatest challenges facing a mission to the red planet, planned by the United States and Europe in the first half of this century.

The shortest round trip would take at least 18 months, and during this time, the crew would be exposed to sub-atomic particles that whizz through space. These particles are capable of slicing through DNA and boosting the risk of cancer and other disorders.

The peril has been known for nearly half a century, but has seemed difficult to solve because costs and technological difficulty.

Some experts have toyed with the idea of shielding the crew with lead or massive tanks of water, but the price of lifting this load into orbit from earth is high.

Another idea would be to swathe the spaceship with a replica of earth's own magnetic field, deflecting incoming cosmic rays.

According to previous calculations, the spacecraft would have to generate a magnetic field hundreds of kilometres across.

But such equipment would be huge and drain the ship's energy supply and its powerful field could well harm the crew.

Bubble protection

British and Portuguese scientists have taken a fresh look at this old concept and say the magnetic field does not, in fact, have to be huge - just a 'bubble' a few hundred metres across would suffice.

"The idea is really like in Star Trek, when Scottie turns on a shield to protect the starship Enterprise from proton beams - it's almost identical really," says Bob Bingham of the Rutherford Appleton Laboratory in the UK.

Their research uses numerical simulations also used by experts in nuclear fusion, in which hot plasma is kept in place by a powerful magnetic field.

This technology provides an accurate picture of how individual particles behave when they collide with a two-pole magnetic field.

As a result, the researchers have been able to devise a smarter, miniaturised model of magnetic protection.

Scaled test

Using a plasma lab at the Superior Technical Institute in Lisbon, the team tested a scaled down version of the device in a simulation of a solar storm of atomic particles.

Scaled up for a trip to Mars, the device would weigh around "several hundred kilos" and use only about a kilowatt of energy, or around one half to one third of the typical power consumption of today's communications satellites, says Bingham.

The force of the magnetic field would replicate the earth's, but to minimise any risk to crew close to its source, could be carried in spacecraft flying either side of the crewed ship.

Bingham says the "mini magnetosphere" is being pitched both to the European Space Agency and NASA.

It would scatter almost all particles dispatched in "solar storms" - protons belched out by the sun, he says.

It would not work against a somewhat less dangerous problem, of high-energy cosmic rays that fly across interstellar distances, but the ship could be swathed with material, like a Kevlar bulletproof waistcoat, to protect against that threat.

"It certainly will be the answer if we go to Mars, because going to Mars will take about 18 months and we need to protect the astronauts against these storms," says Bingham.

In 2001, a NASA study found that at least 39 former astronauts suffered cataracts after flying in space, 36 of whom had taken part in missions beyond earth's orbit.

The agency has tentatively estimated that a trip to Mars and back would give a 40-year-old non-smoking person a 40% chance of developing fatal cancer after they returned to earth, or twice the terrestrial risk.

http://www.abc.net.au/science/articles/2008/11/05/2411072.htm