‘Dynamic Soaring’ trick could accelerate spacecraft through interstellar space: ScienceAlert
Sailing for the stars on the scale of human lives can be a matter of choosing the right kind of wind.
Researchers from McGill University in Canada and the Tau Zero Foundation in the US have proposed a new way to span the extraordinary distances of interstellar space, using a whole lot of nothingness and a hint of seabird inspiration.
To date, one of the most promising solutions for space travel uses the spectrum of starlight emanating from the sun. Although the impact is small, the sheer numbers and high speeds make photons an intriguing powerhouse for building the high speed needed to traverse light years of emptiness in a short time.
While functional, shade sails all have one drawback in common: the sail itself. Shade sails must be meters wide to capture the photons needed to propel a craft.
They also need the right shape and material to convert each photon’s tiny bit of momentum into motion. And they have to give off good enough heat not to deform and break.
This isn’t just a headache in materials science; all these requirements add mass. Even if we use the lightest materials known, we could reach the fastest speeds with the radiation from our sun just over 2 percent the speed of light, meaning a journey to the nearest star would take another few centuries.
Needless to say, sailing to the stars would be a lot easier if we could ditch the sailing part.
Fortunately, another kind of storm is blowing from the solar surface, not made of photons but a plasma of ions that crackles and creaks of the sun’s magnetic fields.
Although there are much slower electrons and protons emanating from the sun than photons, their charged masses have a greater impact.
Such particles would normally be a problem for typical sails, as they transfer their charge to the material surface, such as static on a wool sweater in winter, creating drag and changing the shape of the sail.
But as anyone who has ever tried to push the poles of magnets together knows all too well, an electromagnetic field can resist without requiring a large, solid surface.
And so it’s goodbye shiny material, and hello superconductor. A cable just a few feet long could theoretically produce a field wide enough to deflect the charged wind away from the sun on a scale of tens to hundreds of miles.
The system would work more like a magnetic parachute, one dragged along by a stream of particles moving at speeds close to 700 kilometers (about 430 miles) per second, or just under a quarter of a percent of the speed of light.
This isn’t bad but as birds like the albatrosses knowthe wind doesn’t set the speed limits when it comes to flying high.
By looping in and out of air masses moving at different speeds, seabirds can pick up on the energy of headwinds, using what’s known as rise dynamically to gain speed before returning to their original trajectory.
Using a similar trick in the ‘headwind’ of the termination shock – a turbulent area of contrasting stellar winds used by astronomers to define the edge of our solar system – a magnetic sail could exceed the speeds of the solar wind, potentially putting it within the range of solar sails based on radiation alone.
While the technology may not seem much faster than the “traditional” solar sail method at first, other forms of turbulence at the edges of interstellar space could provide a bigger boost.
Even without a gentle nudge from dynamic hovering, viable plasma-based technology could send cube satellites around Jupiter within months instead of years.
Like the age of the sail of old, there are plenty of ways we can take advantage of the currents that wash through the vastness of space.
And yet the seabirds show us the way.
This research was published in Frontiers in space technologies.
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