A team of researchers may have found an elusive component to make electric propulsion more widespread in the near future. Interestingly, the component is not some rare earth mineral, but a simple food supplement, iodine. According to this document, a small satellite was launched into orbit last year using iodine as fuel published in Nature today.
Chemicals have traditionally been used as propellants for space vehicles. According to European Space Agency, an electric drive, in which electricity is used to accelerate fuel, is a much more efficient way to drive because it uses less mass of fuel and can eject it up to twenty times faster. This could drastically reduce the mass of spacecraft with fuel for orbiting and other similar maneuvers, further reducing the cost of launching these vehicles.
This method of propulsion is widely used for satellites used for applications such as Earth observation, navigation and telecommunications. However, the current fuel of choice is xenon, an inert gas found in traces of the planet. Sometimes, Krypton is also used.
Michael Tate, co-founder and chief operating officer of Infinite Composites, a company that makes pressure vessels for storing propellants, said: “Krypton and xenon have a very high density. Their pressure usually varies from 3000 psi (200 bar) to 5000 psi (350 bar), which is ideal for electric propulsion systems, as it’s all about “throwing” as much mass as possible behind. “
However, in addition to being rare, commercial fuel production is expensive and unsustainable in the long run. A collaborative team of researchers consisting of the French space company ThrustMe and technical experts from Instead, Nanyang University of Technology in Singapore uses iodine.
According to the ThrustMe website, iodine can be stored as a solid fuel inside a spacecraft, unlike xenon, which must be pressurized. When a moderate temperature is applied, the halogen element sublimes – it turns into its gaseous form, completely passing the liquid phase. This makes it ideal for applications where pressurized gases are required.
On November 6, 2020, ThrustMe used iodine as a CubeSat propellant weighing 44 pounds (20 kg) and maneuvered to place it in its orbit. The Nature document not only confirms the use of iodine as a propellant, but also claims that it has a higher ionizing efficiency.
“The effectiveness of ionization refers to how efficiently the power can be used to ionize propellants in the plasma, which will eventually be ejected from the spacecraft,” said Dr. Natalia Bailey. co – founder of Accion Systems, which provides movement powered by electricity satellite systems using patented ion electrospray boosters.
Istvan Lorinz, president and co-founder of Morpheus Space, which provides satellite propulsion systems powered by artificial intelligence, adds: “The higher this efficiency, the less fuel and electricity are needed to operate the propulsion systems, which leads to to smaller tanks, solar panels, and batteries, leading to cheaper satellites and cheaper rocket launches“
This is also the claim that the authors make in the article that the use of iodine as a propellant can make satellite systems smaller, simpler, easier to deploy, and be discarded after their lifetime. Iodine is much cheaper to produce and is more abundant than xenon on Earth. However, there are some disadvantages.
As Dr. Bailey points out, “Propellants like iodine need to be heated before use, which leads to periods of heating and cooling. At a higher level, electric propulsion systems are energy-intensive, preventing satellites from pushing and using their main payloads. This leads to a significant downtime when satellites are unable to fulfill their destination. “