How can our products be used in space applications?
Ionic liquids possess combinations of properties that make them attractive for space applications, for example:
- because they have virtually no vapor pressure,
- because they are flame-retardant,
- and because they remain liquid even at high temperatures
(up to 200°C).
This opens up several potential areas of application:
1. Propellants – hypergolic liquids
There are ionic liquids that are hypergolic—meaning they react spontaneously with strong oxidizers when mixed with them. The gases released can be used to generate the desired thrust in a controlled manner by regulating the supply of the oxidizer.
Since they hardly evaporate at all due to their extremely low (virtually unmeasurable) vapor pressure, complex pressure vessels are not required (resulting in mass savings).
Another advantage is easier handling compared to conventional hypergolic liquids such as hydrazine; hydrazine not only has an unpleasant odor but is also classified as a CMR substance (carcinogenic, mutagenic, or toxic to reproduction).
2. Propellants for electric propulsion systems
Ionic liquids can serve as propellants for ion beam or electrospray thrusters. In this propulsion method, ions are accelerated in an electric field and then ejected as a beam after neutralization. The resulting momentum provides the necessary thrust.
Here, too, they offer the advantage of negligible evaporation in a vacuum; furthermore, due to their low vapor pressure, they do not produce unpleasant odors and cannot be absorbed through inhalation.
3. Heat transfer fluids
Due to their low vapor pressure and relatively high heat storage density in particular, they can be used as heat transfer fluids in the cooling systems of satellites or space probes.
Thanks to their high thermal stability, they function effectively even under extreme conditions.
4. Lubricants
Conventional oils evaporate in space. Ionic liquids, by contrast, have a very low vapor pressure and can lubricate moving parts such as bearings or gears.
As pure substances, they can also be used under extreme pressures.
5. Batteries and energy storage systems
They are suitable for use as electrolytes in batteries or supercapacitors.
This allows energy storage systems to operate more safely and across a wider temperature range.
6. In-space material production
Since ionic liquids can dissolve substances such as cellulose or certain polymers, they could potentially be used for the production or recycling of materials on space stations or lunar bases.