Everyone knows that solar energy is free and almost unlimited on Earth. The same applies to spacecraft operating in the inner solar system. But in space, the Sun can do more than provide electrical energy; it also emits an endless stream of solar wind.

Solar sails can use this wind and move the spacecraft. NASA is about to test a new solar sail design that could make solar sails even more efficient. Solar pressure permeates the entire solar system. It becomes weaker as you move away, but it is present. This affects all spacecraft, including satellites. This significantly affects long-duration space flights.

A spacecraft heading to Mars may deviate thousands of kilometers from its route due to solar pressure during its journey. Pressure also affects the orientation of the spacecraft, and they are designed to handle this. Although this is a hindrance, solar pressure can be used to our advantage.

Many solar sail spacecraft have been launched and tested, starting with the Japanese Ikaros spacecraft in 2010. Ikaros proved that radiation pressure in the form of photons from the Sun could be used to guide a spacecraft. The newest solar sail spacecraft is the Planetary Society’s LightSail 2, launched in 2019. LightSail 2 was a successful mission that lasted more than three years.

Solar sail spaceships have some advantages over other spacecraft. Their engines are extremely light and they never run out of fuel. Solar sail spaceships can perform missions more cheaply than other spacecraft and can last longer, although they have limitations.

The solar sail concept has now been proven to work, but the technology needs to evolve to be truly effective. An important part of the solar sail spacecraft is the jibs. The booms support the material of the sail; The lighter and stronger the spacecraft, the more efficient it will be. Although solar sails are much lighter than other spacecraft, the weight of enthusiasts is still an obstacle.

“Booms tended to be either heavy and metallic or made of a lightweight composite with a bulky design, neither of which are suitable for today’s small spacecraft.” Keats Wilkie, ACS3 Principal Investigator, NASA

NASA is about to release a new solar sail design with a better support structure. Called the Advanced Composite Solar Sail System (ACS3), it is stiffer and lighter than previous boom designs. It is made of carbon fiber and flexible polymers.

Although solar sails have many advantages, they also have a critical disadvantage. They work as small packages that need to be deployed before running. This operation can be challenging and stressful for the weak field team who must wait and see if it will be successful.

ACS3 will be launched using a twelve-unit (12U) CubeSat built by NanoAvionics. The main goal is to demonstrate the deployment of the burst, but the ACS3 team also hopes the mission will prove the solar sail spacecraft is operational.

The ship raises its sails to change direction. If the deployment of experts is successful, the ACS3 team hopes to perform some maneuvers with the spacecraft, tilting the sails and changing the spacecraft’s orbit. The goal is to build larger sails that can produce more thrust.

“We hope that the new technologies tested on this spacecraft will inspire others to use them in ways we haven’t considered.” Alan Rhodes, ACS3 Principal Systems Engineer, NASA Ames Research Center

The ACS3 rod design was designed to overcome the problem with rods: they are either heavy and thin or light and bulky.

“Boosters are typically either heavy and metallic or made of a lightweight composite with a bulky design, neither of which are suitable for today’s small spacecraft,” NASA’s Keats Wilkie said. said. Wilke is an ACS3 principal investigator at the Langley Research Center.

“Solar sails require very large, sturdy and lightweight arms that can be folded compactly. The gussets of this sail are tube-shaped and can be compressed like a tape measure and folded into a small package, offering all the benefits of composite materials, such as less bending and twisting during temperature changes.

ACS3 will be launched on an Electron rocket from Rocket Lab’s launch facility in New Zealand. It will enter a sun-synchronous orbit 1,000 km (600 miles) above Earth.

Once the spaceship arrives, it will unfurl its booms and unfurl its sail. It will take about 25 minutes for the sail to deploy with a photon collection area of ​​80 square metres, or about 860 square metres. This is much larger than the LightSail 2, which has a sail area of ​​32 square meters, or about 340 square meters.

Once opened, cameras on the spacecraft will observe the shape and symmetry. The data obtained as a result of the maneuvers will be used in future sail designs.

“The seven-foot deployable boom can be folded to fit your hand,” said Alan Rhodes, the mission’s principal systems engineer at NASA’s Ames Research Center. “We hope that the new technologies tested on this spacecraft will inspire others to use them in ways we haven’t considered.”

ACS3 is part of NASA’s Small Spacecraft Technologies program. The program aims to deploy small missions that quickly demonstrate unique capabilities.

With unique composite and carbon fiber booms, the ACS3 system has the potential to support sails up to 2,000 square meters, or approximately 21,500 square feet. This is about half the area of ​​a football field. (Or as our British friends mistakenly call it a football field.)

With larger sails the types of tasks they can perform vary. Although the solar sails are small demonstration models so far, the system could potentially power serious science missions.

“The Sun will burn for billions of years, so we have an unlimited supply of propulsion. Instead of throwing huge fuel tanks at future missions, we could sail bigger sails that use the “fuel” we already have, Rhodes said.

“We will demonstrate a system that uses this rich resource to take the next giant steps in discovery and science.” Solar sail spaceships do not have the instantaneous thrust that chemical or electrical propulsion systems have. But the thrust is steady and never wavers.

They can do things that are difficult for other spacecraft to do, such as occupy unique positions that allow them to study the Sun. They can serve as an early warning system for dangerous coronal mass ejections and solar storms.

The new composite booms have other uses, too. Because they are so light, strong and compact, they could serve as the structural framework for habitats on the Moon and Mars. They can also be used to support other structures such as communication systems. If the system works, who knows what other programs it could serve?

“This technology ignites imagination, redefines the entire idea of ​​sailing and applies it to space travel,” said Rudy Aquilina, NASA Ames Solar Sailing Mission Project Manager. “Demonstrating the capabilities of solar sails and lightweight composite booms is the next step in using this technology to inspire future missions.”