The Interstellar Engine We Could Build Today

Nuclear Salt Water Rockets move at a fraction of the speed of light

Uranium.

One element with two very different outcomes. In one scenario it could devastate our civilization, crumbling once great cities and natural vistas to an ashen and radioactive ruin. But in another it works to do just the opposite. Inside aerospace engineer Robert Zubrin’s Nuclear Salt Water Rocket (NSWR), uranium acts as the fuel which allows us to become an interstellar species. It’s a powerful concept, full of promise and potential, while remaining faithful to real-world science. It doesn’t require new physics nor exotic materials. Yet if someday realized the NSWR could propel us at a fraction of the speed of light. Of all the proposed methods for interstellar travel the NSWR is perhaps both the most accessible and the most extreme.

The rocket is based on a sustained nuclear reaction. Reactor grade uranium would be dissolved as a 2% uranium tetra-bromide mixture in water. The uranium in the mixture is enriched to about 20% U-235, giving it greater amounts of fissile material so that it can undergo nuclear reactions. This uranium salt — or in some cases, plutonium salt — is the “salt water” portion of the rocket.