Satellites, the eyes and ears of our modern world, are designed for communication and weather forecasting services in the vacuum of space. But they have a fantastic limitation: in most cases, they will work for years — most probably not that long — just within the amount of fuel in their tanks, and after that, the satellites have to de-orbit and end their mission way too soon. But what if these satellites could start using the very atmosphere they are turning into circles as a source of propellant?
Dr. Mansur Tisaev, a postgraduate researcher at the University of Surrey, is at the forefront of developing a groundbreaking technology that could revolutionize satellite propulsion and extend mission lifespans indefinitely. His work focuses on air-breathing ion engines, a concept that promises to transform how satellites operate in very low Earth orbit (VLEO).
The principle behind air-breathing ion engines is elegantly simple yet technologically complex. As Tisaev explained during a recent interview: “You wouldn’t need to take any propellant or any fuel with you. You’re basically flying through the propellant you’re using.” This innovative approach involves satellites orbiting at extremely low altitudes, around 200 kilometers, where they can collect residual atmospheric particles to use as propellant.
Drag at these altitudes is so high that satellites usually de-orbit at an expeditious pace. However, this is the very problem the air-breathing ion engine concept seeks to leverage for an advantage. In this way, these engines could produce sufficient thrust to resist the drag, which, in all other cases, constantly drains one’s satellite to allow that satellite to forever remain in orbit.
The potential upsides of this technology are far-reaching.
“The life of your spacecraft, you know how long you’re able to use your engine for, isn’t limited by propellant from Earth,” Tisaev pointed out, adding that: “Being able to produce thrust to counteract the drag would mean that you can stay in these orbits without basically re-entering.”
This could lead to dramatically extended mission durations and reduced launch costs, as satellites would no longer need to carry massive amounts of propellant. Besides, the technology offers one solution to another problem growing in space: debris. Satellites with air-breathing ion engines that fail, for example, by definition, will naturally de-orbit in weeks, making it less likely they’ll add to a growing junkyard in orbit.
However, the development of air-breathing ion engines is not without its challenges. The technology requires a delicate balance between thrust generation and drag management. Tisaev described it as “a little bit on a knife edge,” stressing the need for highly efficient propulsion systems and carefully designed spacecraft configurations.
One of the key areas of focus in Tisaev’s research is optimizing the ionization and acceleration of atmospheric particles, which differ significantly from the noble gases typically used in conventional ion engines.
“There’s a big jump or step to kind of now really optimize thrusters for other propellants such as air,” he explained, highlighting the need for innovative approaches to plasma physics and materials science.
Possible uses for air-breathing ion engines would expand even beyond Earth’s orbit. Tisaev and his coworkers are looking into using this technology within the atmospheres of other planets, such as Mars and Titan. This would open new avenues in planetary exploration and long-duration missions around different parts of the solar system.
We are probably standing on the threshold of a new era in satellite technology as progress in this field is being made. The vision of satellites that will indefinitely maintain their orbits while “flowing through the propellant” they use represents a quantum leap in space exploration and utilization. Although it is yet to come, the vision laid out by Tisaev and colleagues may describe a view of the future: a world in which satellites are not limited to the fuel they carry in their tanks.
As the technology matures, it might reform how we perceive space missions, environmental monitoring, and global communications with an epoch of sustainable space operations. This will enable air-breathing ion engines to revolutionize satellite technology. Many eyes may see in the sky, not long afterward, the new-generation satellites with their inbuilt device for harnessing the very atmosphere they orbit — an approach to breaching the impossible in space exploration and utilization.
Featured image: Credit: Fraser Cain
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