Shuttle to reel out satellite on 12-mile line

AT THE turn of the century, Konstantin Tsiolkovsky, a Russian schoolteacher and space pioneer, proposed a 'cosmic railway' built from tethering a ring of unbelievably high towers - anchored to the ground - together in space.

The first real practical test of his ideas will come later this month, when one of the most dangerous experiments in space begins with the launch of a space shuttle that will reel out a satellite on a thin line 12 1/2 miles long.

The experiment will test the feasibility of using extremely long tethers in space, but scientists at the US National Aeronautical and Space Administration are nervous about what may happen if the satellite and line start swinging out of control.

The science fiction author Arthur C Clarke, writing 70 years after Tsiolkovsky, suggested that space tethers could be used to form a ring of satellites around the planet, with 'space elevators' taking people for rides in space. 'The distinction between Earth and space would be abolished, though the advantages of either could still be retained,' he wrote.

But it was an Italian space engineer, Giuseppe Colombo, who gave the ideas of tethered objects in space a firm practical basis. Colombo, who died in 1984, moved from Padua University in the late 1970s to Nasa's Goddard Institute in New York, where he proposed that tethers could be used to build giant structures, such as space stations, in orbit.

It is largely Colombo's ideas that have led Nasa, in conjunction with the Italian space agency, to test its first tethered satellite system, TSS-1, to be launched on 31 July on board the shuttle Atlantis.

The seven-strong crew will reel out the tethered satellite into a higher orbit - considered safer than lowering it into the rarefied atmosphere of Earth below.

Explosive bolts and other safety measures are ready to jettison the tethered satellite should the 'skip-rope effect' become uncontrollable. 'It's a squishy subject,' said Dave Bowlan, a Nasa scientist. 'We don't really know what will happen until we try.'

Nasa's tether, a mixture of copper wire, nylon and carbon fibres, is only a tenth of an inch in diameter but it can support 400lb. Even so, in the near weightlessness of the shuttle's orbit it is expected to experience a tension of no more than 15lb, despite being connected to a 100-ton shuttle and its one-ton satellite.

Nevertheless, there are plans for a second TSS mission, which involves lowering a tethered satellite below a shuttle to sample the upper regions of Earth's atmosphere. At this altitude the air is extremely rarefied, and as a result is much too high for the air- breathing engines of conventional aircraft. However, because there is enough air to cause quite severe aerodynamic drag, it is too low for a satellite to keep orbiting.

Scientists envisage testing the aerodynamics of future space planes by towing models from a shuttle overhead.

Even further into the future, there are tentative proposals to tether large landing platforms - 'shuttle ports' - to space stations orbiting high above. Space elevators would take crew and cargo from one to the other, cutting down on fuel.

If the tether is spring-loaded, it would absorb the shock of shuttles landing and taking off from the platform and prevent the space station from being disturbed too much.

Tethers from the space station, or other shuttles, could also take communications satellites or weather satellites into very high orbits at a fraction of the cost of getting them there using rockets.

Fuel depots tethered high overhead could be refuelled from below with the fuel taken up via the elevators. Nasa also envisages that two tethered objects could be spun around 'much like a set of bolas' to create artificial gravity - another fantasy of science fiction writers.

A further reason for using tethers is that they can be used as giant antennas to transmit radio signals around the globe. The mission later this month will use its tether as a rudimentary radio transmitter to test the idea.

Perhaps the most interesting phenomenon the TSS-1 experiment will test is whether it is possible to generate electricity as the tethered satellite and shuttle move through the Earth's magnetic field at 17,000mph.

Just as a dynamo generates electricity by the movement of wires in a magnetic field, so the tether - with its copper wire - is expected to produce up to 4 kilowatts of power as it hurtles through the Earth's field.

The generation of electricity also means that electrons will flow from the satellite on the end of the 12-mile line down the tether and on to the shuttle, causing it to become negatively charged. An unanswered question is whether enough electrons will jump off the shuttle to return to the positively charged satellite through the charged ionosphere of space.

Electron guns, which fire negative charge from the shuttle and the tether into the ionosphere, are ready to help complete the electric circuit and prevent a build-up of static electricity on the shuttle. If the experiment proves successful, scientists believe it may be possible to use tethers as the electrical generators of future space missions.

Suggested Topics
Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: IT Support Technician

£20000 - £22000 per annum: Recruitment Genius: This is an intermediate help de...

Recruitment Genius: Personal Injury Fee Earners

£15000 - £25000 per annum: Recruitment Genius: This specialist personal injury...

Recruitment Genius: New Business Sales Executive / Business Development

£20000 - £30000 per annum: Recruitment Genius: Join a fast growing, UK based I...

Recruitment Genius: Tennant Liaison Officer

Negotiable: Recruitment Genius: An experienced TLO is required to manage, deli...

Day In a Page

Turkey-Kurdish conflict: Obama's deal with Ankara is a betrayal of Syrian Kurds and may not even weaken Isis

US betrayal of old ally brings limited reward

Since the accord, the Turks have only waged war on Kurds while no US bomber has used Incirlik airbase, says Patrick Cockburn
VIPs gather for opening of second Suez Canal - but doubts linger over security

'A gift from Egypt to the rest of the world'

VIPs gather for opening of second Suez Canal - but is it really needed?
Jeremy Corbyn dresses abysmally. That's a great thing because it's genuine

Jeremy Corbyn dresses abysmally. That's a great thing because it's genuine

Fashion editor, Alexander Fury, applauds a man who clearly has more important things on his mind
The male menopause and intimations of mortality

Aches, pains and an inkling of mortality

So the male menopause is real, they say, but what would the Victorians, 'old' at 30, think of that, asks DJ Taylor
Man Booker Prize 2015: Anna Smaill - How can I possibly be on the list with these writers I have idolised?

'How can I possibly be on the list with these writers I have idolised?'

Man Booker Prize nominee Anna Smaill on the rise of Kiwi lit
Bettany Hughes interview: The historian on how Socrates would have solved Greece's problems

Bettany Hughes interview

The historian on how Socrates would have solved Greece's problems
Art of the state: Pyongyang propaganda posters to be exhibited in China

Art of the state

Pyongyang propaganda posters to be exhibited in China
Mildreds and Vanilla Black have given vegetarian food a makeover in new cookbooks

Vegetarian food gets a makeover

Long-time vegetarian Holly Williams tries to recreate some of the inventive recipes in Mildreds and Vanilla Black's new cookbooks
The haunting of Shirley Jackson: Was the gothic author's life really as bleak as her fiction?

The haunting of Shirley Jackson

Was the gothic author's life really as bleak as her fiction?
Bill Granger recipes: Heading off on holiday? Try out our chef's seaside-inspired dishes...

Bill Granger's seaside-inspired recipes

These dishes are so easy to make, our chef is almost embarrassed to call them recipes
Ashes 2015: Tourists are limp, leaderless and distinctly UnAustralian

Tourists are limp, leaderless and distinctly UnAustralian

A woefully out-of-form Michael Clarke embodies his team's fragile Ashes campaign, says Michael Calvin
Blairites be warned, this could be the moment Labour turns into Syriza

Andrew Grice: Inside Westminster

Blairites be warned, this could be the moment Labour turns into Syriza
HMS Victory: The mystery of Britain's worst naval disaster is finally solved - 271 years later

The mystery of Britain's worst naval disaster is finally solved - 271 years later

Exclusive: David Keys reveals the research that finally explains why HMS Victory went down with the loss of 1,100 lives
Survivors of the Nagasaki atomic bomb attack: Japan must not abandon its post-war pacifism

'I saw people so injured you couldn't tell if they were dead or alive'

Nagasaki survivors on why Japan must not abandon its post-war pacifism
Jon Stewart: The voice of Democrats who felt Obama had failed to deliver on his 'Yes We Can' slogan, and the voter he tried hardest to keep onside

The voter Obama tried hardest to keep onside

Outgoing The Daily Show host, Jon Stewart, became the voice of Democrats who felt the President had failed to deliver on his ‘Yes We Can’ slogan. Tim Walker charts the ups and downs of their 10-year relationship on screen