Thanks to Albert Einstein, we know that there is energy stored in mass itself. Using his famous E = mc² equation, we know that exhaust speeds up to the speed of light are achievable, and way more than necessary to escape Earth’s gravity.
A sustainable exhaust speed of 1,000 km/s, less than 1 percent of the speed of light, would pretty much enable our dream ship. Its fuel-to-mass ratio would be about the same as that of your typical car.
The next question is: how do we get access to the energy stored in the mass (fuel and propellant) sufficient to achieve those speeds? The answer lies in nuclear reactions or, better yet, matter-antimatter reactions. In short, we need to put a mass reactor, nuclear or matter-antimatter, on board our ship. Think of the Enterprise’s “warp core,” for all those Star Trek fans out there.
Nuclear rockets may seem farfetched, but various versions have already been proposed and prototypes have even been built. The Nuclear Engine for Rocket Vehicle Application (NERVA) project, a joint NASA-Atomic Energy Commission program, developed a flight-certified nuclear-based rocket engine that meets all the requirements for a manned mission to Mars.
What is interesting, and perhaps a little sad, is that this was done in 1968, over four decades ago! The NERVA engine achieved exhaust velocities pretty close to Earth’s escape velocity, around 10 km/s. The program was tied to NASA’s manned Mars exploration program and, since it was unable to justify the expense of going to Mars, was scrapped in 1972.
More recently, NASA has been developing electric propulsion systems that can generate large effective exhaust velocities that are limited only through the strength of the electric field. Effective exhaust velocities of 90 km/s are already achievable. But this is just the propulsion part. The solar panels, batteries or fuel cells that are currently used as power sources for these engines limit their usefulness. Electricity generated from nuclear power could solve this problem.
Back to the future
With the renewed interest in space exploration and innovation, we challenge inventors and entrepreneurs to consider looking at advanced nuclear/antimatter-powered rocket systems. This could enable us to achieve the dream of a space car in our garages in half a century.
The key to all the recent advances in space exploration technology has been combining older proven technologies with modern computing capabilities, materials and fabrication processes. NASA’s push to get technologies into private hands will accelerate this process.
Back in 1972, we were at 1 percent of the needed exhaust speed. It’s not too much of a stretch to propose that, after 40 years of advances, we need only revisit the designs with fresh and entrepreneurial eyes to make it possible for a Han Solo – or, to be more contemporary, Rey Skywalker – to jump into the Falcon and speed off to somewhere far, far away.
Fredrick Jenet, Associate Professor, University of Texas Rio Grande Valley and Volker Quetschke, Associate Professor, University of Texas Rio Grande Valley
This article was originally published on The Conversation. Read the original article.
Feature Image Credit: Tom Simpson/Flickr, CC BY