For the first time in three decades, scientists have figured out a way to enrich plutonium-238 at Oak Ridge National Labs to help NASA go into deep space.

The reality is that solar power doesn’t work efficiently once you get too far away fromt he sun — say, beyond Jupiter. That’s why modern day spacecraft rely on an internal nuclear power source, but the lack of plutonium-238 that has fueled Cassini, New Horizons, and Voyager has proved a problem — until now, according to a Popular Mechanics report.

The Oak Ridge National Labs has just produced 50 grams of the precious power source. Scientists will still need to verify that it’s an efficient way to create plutonium-238, but if it works out, it could help the space program hugely: it doesn’t have much radiation that could harm handlers, it can produce plenty of heat that would allow instruments to stay at an optimum temperature, and it has a half life of 87.7 years that can allow spacecraft to be powered for a long time without also provided long-lasting damage if there were to be an accident.

This is good news, because NASA is running out of plutonium for its missions. The agency only has about two or three missions left worth of plutonium, and a lot of missions it needs to conduct.

The reason why NASA is running low on plutonium-238 is because of the nuclear disarmament movement in 1988, even though plutonium-238 is not a suitable source of fuel for nuclear weapons. If NASA could go back to producing it again, it could have huge implications for future space missions.