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A one-kilometre-long electric sail tether was produced
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The electric sail (ESAIL), invented by Dr. Pekka Janhunen at the Finnish Kumpula Space Centre in 2006, produces propulsion power for a spacecraft by utilizing the solar wind. The sail features electrically charged long and thin metal tethers that interact with the solar wind. Using ultrasonic welding, the Electronics Research Laboratory at the University of Helsinki successfully produced a 1 km long ESAIL tether. Four years ago, global experts in ultrasonic welding considered it impossible to weld together such thin wires. The produced tether proves that manufacturing full size ESAIL tethers is possible. The theoretically predicted electric sail force will be measured in space during 2013.
An electric solar wind sail, a.k.a electric sail, consists of long, thin (25?50 micron) electrically conductive tethers manufactured from aluminium wires. A full-scale sail can include up to 100 tethers, each 20 kilometres long. In addition, the craft will contain a high-voltage source and an electron gun that creates a positive charge in the tethers. The electric field of the charged tethers will extend approximately 100 metres into the surrounding solar wind plasma. Charged particles from the solar wind crash into this field, creating an interaction that transfers momentum from the
solar wind to the spacecraft. Compared with other methods, such as ion engines, the electric sail produces a large amount of propulsion considering its mass and power requirement. Since the sail consumes no propellant, it has in principle an unlimited operating time.
The electric sail is raising a lot of interest in space circles, but until now it has been unclear whether its most important parts, i.e. the long, thin metal tethers, can be produced.
The planned space missions and funded projects for the esail are:
ESAIL EU FP7 project
The ESAIL EU FP7 project (2011-2013) develops laboratory prototypes (TRL 4-5) of the key components of the E-sail. The project involves five countries, nine institutes and has a budget of about 1.7 million Euros.
* Deploy and confirm the deployment of a 10 m conductive Hoytether from a 1U CubeSat
* Test of a 100 m tether deployment on Aalto-1 3U CubeSat (2014)
Solar Wind Electric Sail Test (SWEST)
SWEST (Solar Wind Electric Sail Test) is a proposal to the EU whose purpose is to build a flight-ready 60 kg satellite which is able to measure the E-sail effect in the solar wind with four 1 km long tethers. The satellite is mainly built by the Alta space company in Italy.
See more and subscribe to NextBigFuture at 2013-01-08 15:15:48 Source: http://nextbigfuture.com/2013/01/a-one-kilometre-long-electric-sail.html
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