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News | Electric sail invention approaches implementation
Electric sail invention approaches implementation
15.4.2008
The electric solar wind sail developed at the Finnish Meteorological
Institute has moved rapidly from invention towards implementation.
Electric sail propulsion might have a large impact on space research
and moving in space in general.
The electric solar wind sail developed by Dr. Pekka Janhunen at the
Finnish Meteorological Institute might revolutionise travelling in deep
space. The electric sail is a Finnish invention which uses the solar
wind as its thrust source and therefore needs no fuel or propellant.
The solar wind is a continuous plasma stream emanating from the Sun.
Changes in the properties of the solar wind cause auroral brightening
and magnetic storms, among other things.
Progress without problems
Over its two-year history, the electric sail has developed rapidly from
invention towards implementation and has aroused much international
interest. The main components of the device are long metallic tethers
and a solar-powered electron gun which keeps the tethers positively
charged. The solar wind exerts a small but continuous thrust on the
tethers and the spacecraft. The electric sail and its applications have
been developed mainly at the Finnish Meteorological Institute, but
component work is also carried out at the University of Helsinki and in
Germany, Sweden, Russia and Italy.
"We haven't encountered major problems in any of the technical fields
thus far. This has already enabled us to start planning the first test
mission," says Dr. Pekka Janhunen. An important subgoal was reached
when the Electronics Research Laboratory of the University of Helsinki
managed to develop a method for constructing a multiline
micrometeoroid-resistant tether out of very thin metal wires using
ultrasonic welding. The newly developed technique allows the bonding
together of thin metal wires in any geometry; thus, the method might
also have spinoff applications outside the electric sail.
Potential important applications of the electric sail
If and when realised, the electric sail could enable faster and cheaper
Solar System science and exploration. It might also enable economic
utilisation of asteroid resources for, e.g. producing rocket fuel in
orbit.
"The electric sail might lower the cost of all space activities and
thereby, for example, help making large solar power satellites a viable
option for clean electricity production. Solar power satellites
orbiting in the permanent sunshine of space could transmit electric
power to Earth by microwaves without interruptions. Continuous power
would be a major benefit compared to, e.g. ground-based solar power
where storing the energy over night, cloudy weather and winter are
tricky issues especially here in the far North", says Dr. Pekka
Janhunen.
The electric sail was invented as a by-product of basic research done
at the Finnish Meteorological Institute on the interaction of the solar
wind with planets and their atmospheres. Work on the electric sail in
Finland is currently funded by the Academy of Finland and private
foundations.
More information:
Dr. Pekka Janhunen, Academy Research Fellow, +358 9 1929 4635,
pekka.janhunen@fmi.fi
Read more about electric sail
The first international electric sail meeting will be arranged at ESA ESTEC in Noordwijk, The Netherlands on May 19, 2008.
More information about ESTEC-meeting 19.5.2008
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