Alex Tolley has written up an analysis of an improved plasma magnet sail concept called Wind Rider. Centauri Dreams covered the work.
Nextbigfuture notes that the design looks very simple and achievable. If it works then by 2030s we would be able to mass produce probes by the thousands to explore the solar system and sending out telescopes to the gravitational lens point would give direct high-resolution imaging of exoplanets in thousands of solar systems.
The Plasma Magnet [PM] required relatively little energy and yet was capable of propelling a much larger mass at a velocity exceeding any current propulsion system, including advanced solar sails.
The Plasma Magnet was proposed by Slough. It arranges coils to use solar wind ions to induce a very large magnetosphere that is propelled by the solar wind. Unlike earlier proposals for magnetic sails that required a large electric coil kilometers in diameter to create the magnetic field, the induction of the solar wind ions to create the field meant that the structure was both low mass and that the size of the resulting magnetic field increased as the surrounding particle density declined. This allowed for a constant acceleration as the PM was propelled away from the sun, very different from solar sails and even magsails with fixed collecting areas.
The Wind Rider improves magsails by using superconducting coils. This allows the craft to maintain the magnetic field without requiring constant power to maintain the electric current, reducing the required power source. Because the superconducting coils would quickly heat up in the inner system and lose their superconductivity, a gold foil reflective sun shield is deployed to shield the coils from the sun’s radiation.
Calculations show that it will accelerate very rapidly and reach the velocity of the solar wind, about 400 km/s. This has implications for the flight trajectory of the vehicle and the mission time.
The sail is powered by 4 solar panels that also double as struts to support the sun shield and generate about 1300 W at 1 AU and fall to about 50W at Jupiter.
The flight trajectory is effectively a beeline directly to Jupiter, starting the flight almost at opposition. No gravity assists from Earth or Venus are required, nor a long arcing trajectory to intercept Jupiter.
The New Horizons mission to Pluto — which reached 45 km/s as it left Earth but slowed to 14 km/s as it flew by Pluto. It took 1 year to reach Jupiter to get a gravity assist for its 9 year mission to Pluto. The maximum average velocity of 19 km/s between Earth and Jupiter. The Wind Rider can be about 20 times faster.
The Wind Rider can fly by Jupiter in 3 weeks, Saturn in 6 weeks, and Neptune in 18 weeks. Voyager 2 probe took 4 years to reach Jupiter and 12 years to reach Saturn. Pluto could be reached by Wind Rider in just 6 months.
The Wind Rider could reach the solar gravity focal line around 550 AU from the sun in less than 7 years. Putting telecopes at the gravitational lens lines would let us look at the continents and islands on exoplanets in other solar systems. We would be able use the sun to focus light with a billion times gain in resolution. The nearly one million mile diameter of the sun would focus light onto our telescopes.
Wind Rider might be able ride the gusts of higher solar wind velocities and reach 550 km/s.
The craft could steer up to 12 degrees away from the solar wind direction. The coil therefore acts like a weather vane, always trying to align itself with the solar wind. This makes steering difficult. Reaction wheels like those on the Kepler telescope could only act in a transient manner and shifting center of gravity might be another solution. This would add mass and complexity. Jeff Greason has an upcoming paper that is expected in 2022 on theoretical navigation with possible ranges of steering capability.
Trajectory simulation results estimate the trip time from 1 to 542 AU near the plane of the ecliptic takes 6.9 years. Adding a compact imaging instrument enables the probe to sample data from the vantage point of the Trappist-1 SGL, as well as PickUp Ions (PUI) for a 1 year science campaign. Total pathfinder mission time after launch is less than 8 years. A set of policy-making recommendations for enabling such small precursor-type missions is provided in the conclusions, as well as ways to extend the mission to communicate from 1,000 AU to 1,800 AU. Alternatively, a method to gradually decelerate to a near stop at the end of the mission, using the Wind Rider to drag against the interstellar plasma, is also included.
SOURCES- Centauri Dreams, Jupiter Observing Velocity Experiment (JOVE), Introduction to Wind Rider Solar Electric Propulsion Demonstrator and Science Objective, Wind Rider Pathfinder Mission to Trappist-1 Solar Gravitational Lens Focal Region in 8 Years
Written by Brian Wang, Nextbigfuture.com
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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