A team of scientists has simulated a journey to Mars and interstellar space using a solar sail made from aerographite, yielding impressive results.
A group of researchers is exploring the potential of using aerographite material for solar sails that could travel to Mars and beyond, as reported by Interesting Engineering on September 27. The solar sail was first tested in space during the LightSail 2 mission by the nonprofit organization Planetary Society, which helped raise the orbit of a small CubeSat satellite by 3.2 kilometers, solely using the thrust from photons or sunlight. The study published in the journal Acta Astronautica details how scientists simulated a flight to Mars and interstellar space using a solar sail made from aerographite.
Simulation of the solar sail from the LightSail 2 spacecraft. (Image: Planetary Society).
In the study, the team of experts simulated the speed of the solar sail made from aerographite. They modeled a solar sail spacecraft with a mass of one kilogram, consisting of 720 grams of aerographite, and a cross-sectional area of 104 m². They measured the speed at which the solar sail could reach Mars and interstellar space, also known as the heliopause, the point at which the influence of solar wind is no longer felt. The researchers simulated two different trajectories from Earth known as direct outward transfer and inward transfer for each flight.
The direct outward transfer method for the journey to Mars and the heliopause involves deploying the solar sail and departing from a polar orbit around Earth. For the inward transfer method, the solar sail spacecraft would be launched using a conventional rocket to a location 0.6 astronomical units (AU) from the Sun. Afterward, the solar sail would unfurl and begin its journey to Mars or the interstellar boundary.
The research team found that the direct outward transfer method allows the solar sail spacecraft to reach Mars in 26 days. The spacecraft using the inward transfer method would arrive at the Red Planet in 126 days. For the journey to the heliopause, the inward transfer method takes 5.3 years, while the outward transfer method takes 4.2 years. The outward transfer method requires 103 days of travel before deployment but reaches the heliopause faster since the solar sail achieves maximum speed in 300 days. Using the outward transfer method, it takes two years to reach maximum speed.
The key reason the solar sail in the scientists’ simulation can reach distant locations at high speeds is due to the aerographite material. Team leader Julius Karlapp, a research assistant at the Dresden University of Technology, stated that with a low density of 0.18 kg/m³, aerographite outperforms all conventional solar sail materials.
“For example, compared to Mylar, the density is significantly lower. Assuming that the thrust of the solar sail depends directly on the mass of the sail, the result is much higher thrust. In addition to the acceleration advantage, the mechanical properties of aerographite are quite fascinating,” Karlapp noted.
Despite its extremely high speeds, the solar sail can only carry a very small payload to Mars or deep space. For instance, the Breakthrough Starshot mission hopes to send an ultra-light camera to the nearest star system, Alpha Centauri, within the next 20 years.
