A solar sail backed by NASA might take science to new worlds.

Sailing to the Stars

As NASA continues to push the frontiers of exploration, a new solar sail idea chosen for development as part of a demonstration mission might transport research to new worlds.

The NASA Innovative Advanced Concepts programme has chosen the Diffractive Solar Sailing project for Phase III investigation. Phase III strives to deliberately transfer NIAC ideas that have the greatest effect on NASA, other government agencies, or commercial partners.

Solar sails utilise the pressure generated by sunlight to move a vehicle across space, similar to how a sailboat uses the wind to span the ocean. Existing reflecting solar sail designs are often quite wide and thin, and they are constrained by the direction of the sun, requiring power-to-navigation compromises. Small gratings embedded in thin films would be used in diffractive lightsails to take advantage of diffraction, a feature of light that causes light to spread out as it passes through a tiny hole. This would enable the spaceship to utilise sunlight more efficiently while maintaining agility.

“Exploring the cosmos necessitates the development of new equipment, concepts, and methods of travel.” “at NASA Headquarters in Washington, said Jim Reuter, assistant administrator for NASA’s Space Technology Mission Directorate (STMD). “Our objective is to invest in such innovations over their whole lifespan in order to foster a healthy innovation environment.”

The new Phase III funding will provide the research team with $2 million over the next two years to continue technology development in anticipation of a future demonstration mission. Amber Dubill of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, is leading the study.

Diffractive lightsailing would expand the capabilities of solar sails beyond what is now achievable with missions under development. Amber Dubill of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, is leading the study. Dr. Grover Swartzlander of Rochester Institute of Technology in New York, who remains as a co-investigator on the project, led prior studies on the practicality of the idea under NIAC’s Phase I and Phase II contracts. Les Johnson, the project manager for two of NASA’s future solar sail missions based at the Marshall Space Flight Center in Huntsville, Alabama, is also a co-investigator. The team developed, produced, and tested several kinds of diffractive sail materials, performed tests, and devised novel navigation and control techniques for a possible diffractive lightsail mission circling the Sun’s poles as part of previous grants.

In support of this proposed solar mission, Phase III work will improve the sail material and conduct ground testing. Using traditional spacecraft propulsion, orbits travelling over the Sun’s north and south poles are difficult to accomplish. Lightweight diffractive lightsails pushed by sunlight’s steady pressure might be used to launch a constellation of research spacecraft into orbit around the Sun’s poles, advancing our knowledge of the Sun and improving our space weather forecasting skills.

“We’ll need creative, cutting-edge technology to propel our missions as we push farther out into the cosmos than ever before.” “NASA Administrator Bill Nelson told SFcrowsnest. “The NASA Innovative Advanced Concepts programme assists in unlocking and bringing visionary concepts closer to reality, such as innovative solar sails.”

The science behind the scifi

Solar sails, also known as light sails, are a propulsion technology that harnesses the energy from the sun to propel spacecraft through the vacuum of space. The idea of using solar sails for space exploration is not a new one, and scientists and engineers have studied and developed it for decades. Recently, however, there has been renewed interest in solar sails to enable deep space missions and opening up new possibilities for space exploration.

A solar sail works by reflecting sunlight off a large, reflective surface, creating a small amount of thrust that can propel a spacecraft. The concept is based on the fact that the sun emits a constant stream of photons, which have a tiny amount of momentum. When these photons hit a reflective surface, they transfer some of their momentum to the sail, creating a small but steady force. We know this force as radiation pressure, and it is the same force that causes comets to shed their tails.

One of the key advantages of solar sails is that they do not require any fuel to function, meaning they can operate indefinitely. Solar sails rely solely on the energy from the sun, which is abundant and available throughout the entire inner solar system. This makes them ideal for long-duration missions to deep space destinations, such as the outer planets or even the interstellar medium.

Another advantage of solar sails is their efficiency. Traditional rocket propulsion systems rely on the combustion of fuel to create thrust, which is an inefficient process. Solar sails, on the other hand, rely on the reflection of sunlight, which is a much more efficient means of propulsion. This means that solar sails could allow spacecraft to reach much higher speeds than traditional propulsion systems, and it also enables exploration of destinations that are farther away in a shorter time.

We have also proposed solar sails for several other applications, including to remove space debris from low Earth orbit, or to position large communication satellites.

In recent years, we have launched successfully several solar sail missions, such as JAXA’s IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) launched in 2010, and LightSail 2, developed by Planetary Society, in 2019. Both missions could successfully show the principles of solar sail propulsion.

Solar sails technology is still in development and further advancements in materials and design are being made to increase efficiency and durability of the sails, and make them more useful in a greater range of applications.

So, solar sails are a promising technology for space exploration, and can enable deep space missions, increasing efficiency and eliminating the need for fuel. Even though the technology is still in development, the success of recent solar sail missions, and the advantages they offer over traditional propulsion systems, suggest that solar sails will play an increasingly important role in the future of space exploration.