NASA's Solar Sail Mission will harness sunlight for space exploration

Engineers at NASA’s Langley Research Center test deployment of the Advanced Composite Solar Sail System’s solar sail. (Image credit: NASA)

NASA is set for a groundbreaking leap in space exploration with the upcoming deployment of its Advanced Composite Solar Sail System (ACS3). Scheduled for launch in April aboard Rocket Lab’s Electron rocket from New Zealand, this innovative mission aims to tap into the power of sunlight for propulsion.

Solar Sails: Using sunlight for propulsion

Similar to the way a sailboat harnesses the wind to move on water, solar sails utilise sunlight for propulsion. By reflecting sunlight, these sails generate thrust for the spacecraft, enabling longer and more cost-effective missions without the need for heavy propulsion systems. This abundant resource holds the potential to revolutionise space exploration by offering a sustainable and efficient means of propulsion.

Applications of Solar Sail Technology

As per NASA, solar sail technology can be used for studying space weather, advanced studies of the Sun's poles, and enhancing missions to Venus or Mercury due to their proximity to the Sun.

Advantages of Solar Sails for space exploration

According to the American Space Agency, one of the key advantages of solar sails lies in their high propulsive efficiency and low mass, making them ideal for deep space missions. The technology could advance future space travel and expand our understanding of our Sun and solar system.

Specifications of Solar Sails

As outlined on NASA's website, after reaching a Sun-synchronous orbit, approximately 600 miles above Earth, the spacecraft will deploy its composite booms, spanning the diagonals of the polymer sail. The solar sail will fully deploy within approximately 25 minutes, measuring about 860 square feet. The complete sail will measure 17,780 square feet when fully deployed, with a thickness less than a human hair at 2 and a half microns. It is made of a polymer material coated with aluminum. Once fully expanded, the reflective material of the sail will be as bright as Sirius, the brightest star in the night sky.

Keats Wilkie, principal investigator at NASA Langley, highlights the need for lightweight, stable booms for solar sails. “Booms have tended to be either heavy and metallic or made of lightweight composite with a bulky design – neither of which work well for today’s small spacecraft. Solar sails need very large, stable, and lightweight booms that can fold down compactly,” said Keats Wilkie, the mission’s principal investigator at NASA’s Langley Research Center in Hampton, Virginia. “This sail’s booms are tube-shaped and can be squashed flat and rolled like a tape measure into a small package while offering all the advantages of composite materials, like less bending and flexing during temperature changes.”

Alan Rhodes, lead systems engineer at NASA Ames, emphasizes the innovative potential of the new technologies.

“Seven meters of the deployable booms can roll up into a shape that fits in your hand,” said Alan Rhodes, the mission’s lead systems engineer at NASA’s Ames Research Center in California’s Silicon Valley. “The hope is that the new technologies verified on this spacecraft will inspire others to use them in ways we haven’t even considered.”

Rhodes underscores the limitless propulsion potential of solar sails, leveraging the Sun's energy for exploration.

“The Sun will continue burning for billions of years, so we have a limitless source of propulsion. Instead of launching massive fuel tanks for future missions, we can launch larger sails that use “fuel” already available,” said Rhodes. “We will demonstrate a system that uses this abundant resource to take those next giant steps in exploration and science.”

Rudy Aquilina, project manager at NASA Ames, sees solar sail technology as transformative for future missions. “This technology sparks the imagination, reimagining the whole idea of sailing and applying it to space travel,” said Rudy Aquilina, project manager of the solar sail mission at NASA Ames. “Demonstrating the abilities of solar sails and lightweight, composite booms is the next step in using this technology to inspire future missions.”