Scientific breakthrough will allow us to fly to Alpha Centauri

Scientists have created a revolutionary light sail that is cheaper and faster to produce. It could reach the nearest stars in decades, not millennia, reports SciTechDaily.

Since its launch in 1977, the Voyager 1 space probe has traveled 24.9 billion km from Earth. While that’s an impressive figure, it’s only 1% of the distance to Alpha Centauri, the closest star to the Sun. To reach the closest stars, humanity will have to build a ship that can travel faster than anything built to date.

A promising solution to this problem is a “light sail” – a thin reflective plate that uses light pressure to propel itself, much like the wind pushes a sailboat.

Compared to conventional propulsion systems, light sails could dramatically reduce the time it takes to travel to nearby stars, potentially cutting it from thousands of years to just a few decades.

Recently, scientists from Brown University and Delft University of Technology (TU Delft) have created a new method for designing and building ultra-thin, highly reflective light sail membranes.

The prototype is 60 millimeters across but only 200 nanometers thick — thousands of times thinner than a human hair. The surface of the craft is covered with billions of tiny holes at the nanoscale, reducing weight and increasing reflectivity, making it more efficient for acceleration by light.

“The team’s experimental breakthrough proves that their fabrication process is scalable to the sizes needed for interstellar travel and can be done in a cost-effective manner,” said study leader Miguel Bessa from the Brown School of Engineering.

The breakthrough could be a significant step toward projects like Starshot Breakthrough, which aims to use ground-based lasers to power hundreds of meter-long light sails carrying microchip-sized spacecraft. The researchers say this new light sail design could be scaled up to the meter scale fairly easily, and at a reasonable cost.

To create the design, the scientists used single-layer silicon nitride, a lightweight and highly durable material that was perfect for a light sail. The scientists then focused on increasing its reflectivity while reducing the sail’s weight.

The optimization process involved designing a pattern of nanoscale holes — billions of them on the surface of the material with diameters smaller than the wavelength of light. The team used a new artificial intelligence method they developed to optimize the shape and placement of the holes to increase reflectivity and reduce weight.

It would normally take up to 15 years to make such a sail, but the new method allowed scientists to create a prototype in just a day and at a cost of thousands of times less.