$4m spacecraft launched to journey to the stars on sunbeam

From: habshi (habshi_at_anony.com)
Date: 02/27/05 

Date: Sun, 27 Feb 2005 10:23:45 GMT

        Could these mirrors not reflect sunlight back to earth ?

Space yacht rides to stars on rays of sunlight

Robin McKie and Nick Paton Walsh in Moscow
Sunday February 27, 2005
The Observer

A spacecraft that flies on sunbeams is about to begin its travels
across the solar system. A group of American and Russian scientists
are preparing to launch a probe with giant, wafer-thin plastic sails
that can catch sunlight just as a yacht's sails fill with wind.
Cosmos-1 has been designed to tack across space without using rockets
and could form the forerunner of a network of solar observatories that
would hover over the sun to provide early warnings of disruptive
magnetic storms, or deliver instruments to remote space stations and
planetary exploration teams.

The probe, to be launched from a Russian nuclear missile submarine, is
made up of a fan of eight 15-metre sails, each thinner than a dustbin
bag but stiffened and coated with mirror material.

The technology is the product of years of collaboration by the US
Planetary Society, a group of private space enthusiasts; the Russian
Academy of Sciences; and Moscow space industry designers Lavochkin.

'Cosmos-1 will be blasted into space by conventional rocket technology
but once in orbit above earth, solar sail technology will take over,'
said Susan Lendroth of the Planetary Society. 'We will be able to move
each one of Cosmos-1's sails individually and so direct the craft in
whatever direction we wish. The aim will be to get it to higher and
higher orbits.'

Solar sail technology exploits the fact that photons have momentum and
apply pressure to surfaces. A comet's tail is the result of solar
photons battering its surface, for example. But this pressure is still
relatively meagre and only recently - with the development of
micro-electronic circuits that allow tiny spacecraft to be constructed
- has it become possible to consider powering craft with solar sails.
However, to date, test flights have gone badly.

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 Several years ago, Russian cosmonauts tried to unfurl a small solar
sail while in orbit. One panel had been painted with a sponsor's name
and stuck together so the full sail could not unfold. In 2001 a test
version of Cosmos-1, with only two sail blades, was lost when its
launch vehicle malfunctioned.

'We could have launched another test flight but have decided to press
ahead with a full mission,' said Lendroth. This will involve a
three-stage missile being blasted into space from a submarine in
April. 'It's cheaper to launch below the surface because you don't
have to clean up the submarine afterwards,' she added.

The mission has cost a mere $4 million, raised by the Planetary
Society. Cosmos-1 weighs only 50kg and contains only sails and
electronic systems for guiding its panels. 'It is a technology test,
no more than that,' said Lendroth. 'Once we have shown what can be
done with solar sails, we hope all sorts of other agencies will
follow.'

Both Nasa and the European Space Agency say they are interested. One
mission they are eyeing is for a full solar sail mission to place a
probe in Mercury's orbit. Mercury whirls round the sun every 88 days,
and a traditionally powered spacecraft would need to gain enormous
energy to manoeuvre above the planet. A solar sail ship could spiral
in towards Mercury and slip into orbit without any fuel.

In short, sunbeams could be the transport system of the 21st century.