nasa e-sail
E-Sail design incorporates 10 to 20 aluminium wires that carry an electrical charge.Extending nearly 20 km, the wires will repel the protons and electrons coming from the sun to propel itself forward.NASA/MFSC

When the Voyager 1 crossed the Heliopshere in 2012 after flying over 18 billion km for 35 years, it had reported reaching its imaginary boundary, the Heliopause. The National Aeronautics and Space Administration (NASA) says with their new technology, the distance can be covered in 10 years.

The Heliopshere is the region in space that's dominated by the sun, and marked by the extent of the reach of solar winds (the charged particles emitted by the sun). The area where the solar winds are stopped by the charged particles that are emitted by the stars in the rest of the universe is considered the Heliopause. This lies well beyond Pluto.

While the Voyager 1 was powered by a radioisotope thermoelectric generator, NASA's plans don't involve any fuel at all. Instead, it wants to use solar winds to propel their future spacecraft. NASA calls this technology Heliopause Electrostatic Rapid Transit System (HERTS) and is testing the HERTS E-Sail at its Marshall Space Flight Center in Huntsville, Alabama, USA.

"The sun releases protons and electrons into the solar wind at very high speeds — 400 to 750 kilometers per second," said Bruce Wiegmann, the principal investigator for the HERTS E-Sail, in a statement. "The E-Sail would use these protons to propel the spacecraft."

Resembling an umbrella frame (and not the sails that one typically imagines), the E-Sail design incorporates 10 to 20 aluminium wires that carry an electrical charge. The wires will be about 1mm thick and extend nearly 20 km, according to NASA. The positive charge in the wires will repel the protons, and as a result, propel it forward.

Compared to the Solar Sail, a similar propulsion system that uses photons or light to propel it, the E-Sail can cover a distance that's up to three times more. It intends to do this by increasing the surface area covered by its sails in conjunction with the difference in behaviour between solar winds and photons. This will allow the E-Sail-powered spacecraft to accelerate over a greater distance. While Solar Sails can accelerate up to five astronomical units (AU) or five times the distance between the earth and the sun (1 AU is about 150 million km), the E-Sail can accelerate for up to 16-20 AU, says Wiegmann.

"Our investigation has shown that an interstellar probe mission propelled by an E-Sail could travel to the heliopause in just under 10 years," he said. "This could revolutionize the scientific returns of these types of missions."

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