China's New Space Station Will Be Powered by Ion Propulsion System

This decades-old technology could slash journey times to Mars from eight months to 39 days.
Derya Ozdemir
NASA's ion propulsion system

China's upcoming Tiangong space station's first module will be equipped with an ion propulsion system which will greatly improve energy efficiency and could slash journey times to Mars, the South China Morning Post (SCMP) reports.  

Such thrusters have been used since the 1970s; however, the Tiangong's core module is set to become the first crewed spaceship propelled by ion drives. China is betting big on ion thrusters and intends to develop them on a far greater scale for its deep-space missions.

The space station’s core Tianhe module, which will welcome its first astronauts later this month if all goes to plan, is propelled by four ion thrusters, which utilize electricity to accelerate ions as a type of propulsion.

When compared to chemical propulsion, which keeps the International Space Station (ISS) in orbit, ion drives are much more efficient. According to the Chinese Academy of Sciences, the ISS's thrusters require four tons of rocket fuel to keep it afloat for a year, whereas ion thrusters would require only 882 pounds (400kg) to do the same.

Today's rocket technology would take a crew aboard a spaceship large enough to carry fuel and other supplies to Mars in more than eight months. However, according to some calculations by researchers, a vehicle powered by a 200-megawatt ion drive array may reduce the journey time to 39 days, allowing the mission to employ smaller vessels or carry more supplies.

It sounds good on paper, but its implementation hasn't been the best due to the thrust created not being significant enough. Most ion thrusters deployed in space, mostly in satellites, generate roughly 1 kilowatt of power, SCMP writes, but China's goal is much more ambitious. 

How does an ion thruster work?

An ion thruster generates thrust by accelerating ions using electricity: It ionizes a neutral gas by removing some electrons from atoms, creating a cloud of positive ions. When fired up, the ion drive emits blue fumes that are created by incredibly hot, electrically charged particles leaving the engine at speeds exceeding 30 times the speed of sound.

These charged particles can degrade engine components, reducing satellite longevity and possibly putting astronauts at risk. Moreover, the thrust is usually fairly low. However, the Chinese Academy of Sciences says they found a way to make it work.

The Chinese scientists put the thrusters through rigorous testing to make sure the engines could resist the damage caused by the particles. By putting a magnetic field over the engine's inner wall to repel damaging particles, they were able to protect the engine from erosion. They also developed a unique ceramic material designed to withstand severe heat or radiation for an extended period of time.m adoption has been hampered by the fact that the thrust produced isn’t very significant.

Their ion thruster has reportedly run non-stop for more than 11 months without a hitch.