A group of scientists has simulated a journey to Mars and interstellar space using a solar sail made of aerographite, yielding impressive results.
Simulation of the solar sail of the LightSail 2 spacecraft. Photo: Planetary Society
A group of scientists explores the potential use of aerographite material for a solar sail 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 non-profit organization Planetary Society, which successfully raised the orbit of a small CubeSat satellite by 3.2 km using only the thrust of photons or sunlight from the Sun. The research, published in the Acta Astronautica journal, describes in detail how scientists simulated a journey to Mars and interstellar space using a solar sail made of aerographite.
In the study, the expert team behind the project simulated the speed of a solar sail spacecraft made of aerographite. They modeled a one-kilogram solar sail spacecraft, including 720 grams of aerographite, with a surface area of 104 square meters. They measured the speed at which the solar sail could travel to Mars and interstellar space, also known as the heliopause, the point where the influence of the solar wind is no longer felt. The researchers simulated two different routes for each journey from Earth, known as direct outward transfer and inward transfer methods.
The direct outward transfer method for the journey to Mars and the heliopause involves deploying the solar sail and launching from a polar orbit around Earth. In the inward transfer method, the solar sail spacecraft would be transported by conventional rockets to a point 0.6 astronomical units (AU) from the Sun. The solar sail would then be deployed, commencing the journey to Mars or the interstellar boundary.
The research team found that the direct outward transfer method allowed the solar sail spacecraft to reach Mars in 26 days. The solar sail spacecraft using the inward transfer method would reach the red planet in 126 days. For a journey to the heliopause, the inward transfer method took 5.3 years, while the direct outward transfer method took 4.2 years. The direct outward transfer method required 103 days of travel before deployment but reached the heliopause faster due to the solar sail achieving maximum speed within 300 days. Using the inward transfer method, it took two years to reach maximum speed.
The primary reason the simulated solar sail made of aerographite could reach distant locations at high speeds is due to its low-density material. Julius Karlapp, the research assistant at Dresden University of Technology and the team lead, stated that with a density of 0.18 kg/m3, aerographite outperforms all conventional solar sail materials.
“For example, compared to Mylar, it is much less dense. The thrust of the solar sail is directly dependent on the sail’s mass, resulting in significantly higher thrust. Besides the advantage of acceleration, the mechanical properties of aerographite are very interesting,” Karlapp said.
Despite achieving extremely high speeds, a solar sail can only carry a very small payload to Mars or deep space. For example, the Breakthrough Starshot mission hopes to send a lightweight camera to the nearest star system, Alpha Centauri, within the next 20 years.