Birds use Dynamic Soaring to Pick Up Velocity. We Could Use a Similar Trick to Go Interstellar

The Solar Sail demonstration mission. Credit: NASA

To stand on a coastal shore and watch how eagles, ravens, seagulls, and crows take flight in high winds. it’s an inspiring sight, to be sure. Additionally, it illustrates an important concept in aerial mechanics, like how the proper angling of wings can allow birds to exploit differences in wind speed to hover in mid-air. Similarly, birds can use these same differences in wind speed to gain bursts of velocity to soar and dive. These same lessons can be applied to space, where spacecraft could perform special maneuvers to pick up bursts of speed from “space weather” (solar wind).

This was the subject of a recent study led by researchers from McGill University in Montreal, Quebec. By circling between regions of the heliosphere with different wind speeds, they state, a spacecraft would be capable of “dynamic soaring” the same way avian species are. Such a spacecraft would not require propellant (which makes up the biggest mass fraction of conventional missions) and would need only a minimal power supply. Their proposal is one of many concepts for low-mass, low-cost missions that could become interplanetary (or interstellar) explorers.

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What’s the Best Way to Sail From World to World? Electric Sails or Solar Sails?

Swarm of laser-sail spacecraft leaving the solar system. Credit: Adrian Mann

In the past decade, thousands of planets have been discovered beyond our Solar System. This has had the effect of renewing interest in space exploration, which includes the possibility of sending spacecraft to explore exoplanets. Given the challenges involved, a number of advanced concepts are currently being explored, like the time-honored concept of a light sail (as exemplified by Breakthrough Starshot and similar proposals).

However, in more recent years, scientists have proposed a potentially more-effective concept known as the electric sail, where a sail composed of wire mesh generates electrical charges to deflect solar wind particles, thus generating momentum. In a recent study, two Harvard scientists compared and contrasted these methods to determine which would be more advantageous for different types of missions.

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