Electric sail

It creates a "virtual" sail by using small wires to form an electric field that deflects solar wind protons and extracts their momentum.

[1] The electric sail consists of a number of thin, long and conducting tethers which are kept in a high positive potential by an onboard electron gun.

In the E-sail, the part of the sail is played by straightened conducting tethers (made of wires) which are placed radially around the host ship.

By the time it reaches the ice giants, it may have accumulated as much as 20 km/s (45,000 mph; 72,000 km/h) velocity, which is on par with the New Horizons probe, but without gravity assists.

In subsequent ground-based testing, a likely reason for the failure was found in a slipring contact which was likely physically damaged by launch vibration.

An international research team that includes Janhunen received funding through a 2015 NIAC Phase II solicitation for further development at NASA's Marshall Space Flight Center.

In the HERTS concept, multiple, 20 kilometer or so long, 1 millimeter thin, positively charged wires would be extended from a rotating spacecraft.

A new satellite launched in June 2017,[15][16] the Finnish Aalto-1 nanosatellite, currently in orbit, will test the electric sail for deorbiting in 2019.

However, the electric sail cannot be used inside planetary magnetospheres because the solar wind does not penetrate them, allowing only slower plasma flows and magnetic fields.

The mission could reach its destination in about the same time that the earlier Galileo space probe required to arrive at Jupiter, just over one fourth as far away.

The proposed craft has three parts: the E-sail module with solar panels and reels to hold the wires; the main body, including chemical thrusters for adjusting trajectory en route and at destination and communications equipment; and a research module to enter Uranus's atmosphere and make measurements for relay to Earth via the main body.