Iodine-powered spacecraft built – What the first test showed

Researchers in France have successfully tested for the first time in the world a space propulsion system that uses iodine instead of xenon.

It is the first time that iodine has been confirmed as a viable alternative to the widely used xenon hitherto, which is more expensive and more difficult to store. The breakthrough, described as “historic”, could lead to new, more efficient, electric iodine-based spacecraft propulsion systems as an alternative “fuel”.

The researchers, led by Dmitry Rafalski of the French company ThrustMe, who published the article in the journal “Nature”, announced that they had successfully carried out a test with a small CubeSat satellite weighing 20 kg in orbit, which was equipped with a system based on iodine, which allowed him to make various maneuvers in space.

Propulsion is an important subsystem that many satellites need to perform maneuvers in space, such as avoiding collisions or “derailing” them at the end of their lives. Electric propulsion uses electricity to generate propulsion from a propellant.

Electric propulsion systems, such as ion motors, are an attractive choice due to their high fuel efficiency. Such systems typically use a propellant that maximizes their efficiency. This so far is almost exclusively the noble xenon gas and to a much lesser extent krypton.

But xenon is rare (less than one part per 10 million in the atmosphere), it is expensive (it costs about $ 3,000 per kilo), it requires high pressure storage and its commercial production for space is limited, as xenon also needs in other applications (medicine, lighting, semiconductors, etc.).

Thus, the space industry is looking for an alternative, which is cheaper, more abundant and can be stored without pressure in solid form instead of gases. Iodine is now being touted as a possible alternative, as, in addition to its other benefits, it provides higher efficiencies than xenon, as tests have shown.

It is estimated that more than 24,000 satellites will be launched within the next decade and most will need electrical propulsion systems. It is assumed that the demand for propellant fuels from the space industry will exceed supply in the coming years, so it is considered vital to find a suitable fuel for mass use. Iodine has been studied by universities, companies and space agencies for at least 20 years, but so far no iodine propulsion system has been tested in space.

Researchers believe that iodine should be introduced more widely in the space industry and used in a wide range of space missions. Among other things, it allows for a significant reduction in size and simplification of propulsion systems, which is especially useful for satellites.

“ThrustMe has developed a revolutionary propulsion system with an ion and iodine engine, the NPT30-I2, which includes all the necessary subsystems,” said Rafalski, chief technology officer and co-founder of the company, which was founded in 2017 near Paris. and fits in a space of about 10 cubic centimeters “. Comparison with xenon shows that iodine gives an efficiency increase of almost 50% in terms of propulsion / fuel ratio.

This prototype system was integrated into Spacety’s Beihangkongshi-1 satellite, which was launched into space with the Chinese Long March 6 rocket a year ago. Since then ThrustMe has carefully analyzed the operation of the iodine propulsion system, confirming its great effectiveness.