What is required to get us to other planets? A lot of things but mainly energy. Our current rockets simply can't produce enough energy to get us that far.
American aerospace engineer, author, and advocate for human exploration of Mars Robert Zubrin has one idea for getting us to space and it's a rather interesting one. It's called Nuclear Salt Water Rocket (NSWR) and it replaces traditional chemical propellant with salts of plutonium or 20 percent enriched uranium.
The end result would be an engine that is both highly efficient and delivers great amounts of thrust, according to Medium. If Zubrin's plans could work, it would allow the NSWR to reach a power output of about 700 Gigawatts.
The NSWR would make it possible to reach planets in the outer Solar System in just a few months while traditional rockets need at least a few years to reach Saturn. And that's just getting there. Getting back would take just as long.
The NSWR has an exhaust velocity of 60,000 m/s versus just 4,500 m/s for today's common rockets. This is good but still not enough to reach other galaxies.
For that to happen, the NSWR would have to travel at a fraction of the speed of light. This can work if we replace the reactor grade uranium for weapons grade uranium which has been enriched to 90% U-235 concentrations, according to NPL. This is complicated but not impossible.
It seems that all of Zubrin's plans can be executed with today's scientific knowledge and materials. There is one catch, however. The technique could not be used in the initial launch from Earth as its radioactive exhaust would contaminate our precious planet. Once in deeper space, the radioactive material would be easily diluted reducing its negative effects but getting there would require another form of propulsion.
Zubrin's plans remain one of the most viable and intelligent solutions for space travel but one aspect is still unanswered. Since the engine is used for acceleration how would it decelerate in space? Perhaps once we answer this dilemma we might see the NSWR propel us to new and exciting destinations, nuking our way to the stars.