The stars are no limit with a Mega drive

Want to be cheered up at the end of this benighted year? Okay, how’s this? It’s starting to look like interstellar travel may be possible in a time frame that would be manageable for human beings.

No, it’s not a cure for cancer. But we know we are bound to find that eventually, so long as our civilisation is not destroyed by war or global warming. Until recently, our understanding of science told us that travel even to the nearest stars would never be possible.

That may still be true, for the answers are not yet all in. But last April, the US National Aeronautics and Space Administration (Nasa) gave James Woodward and the Space Studies Institute a phase 2 grant under the Nasa Innovative Advanced Concepts programme.

They got a phase 1 grant in 2017 to work on their proposed space drive. They have now been funded to test new designs that increase the thrust produced by their Mach effect gravity assist (Mega) drive. If that scales up satisfactorily, we will one day be able to build spaceships that go to the stars.

I must admit I really enjoyed writing that last line, for all my life I have been told that interstellar travel is science fiction. Real space flight is ruled by Russian scientist Konstantin Tsiolkovsky’s classic rocket equation of 1903, which says a rocket can get into space by expelling enough of its mass (fuel) at high velocity, but also says the payload and/or speed is limited.

More payload or more speed is possible, but only by burning more fuel. You must carry that fuel all the way from launch, which makes the vehicle heavier, which requires more fuel.

The “tyranny of the rocket equation” is what makes space flight so expensive – and interstellar travel by rocket impossible. For a manned spaceship to reach the nearest star (Proxima Centauri, 4.2 light years), slow down again when it gets there, and do it all within one human lifetime, it would have to burn an amount of fuel roughly equal to the total mass of the sun.

All recent proposals for interstellar flight have therefore abandoned rocketry and assumed ultra-light vehicles that carry large sails and are pushed by Earth-based lasers or the solar wind. Two problems: the push dies before they have travelled even one light-year and they have no way of stopping at their destination.

So, along comes Dr James Woodward, who published his first peer-reviewed article on the Mach effect in 1990, and Dr Heidi Fearn, his colleague at California State University, Fullerton. They worked on the theoretical physics of the Mach effect, they built miniature models of a space drive that doesn’t need to burn a propellant and tested them and, gradually, the space community began to take them seriously.

Nasa is certainly taking them seriously now.

Suffice to say their Mega drive uses electricity to produce mass fluctuations within a block of metal which, in turn, propels the drive forward without burning fuel. What is it pushing against? All the rest of the mass in the universe.

There is still controversy over whether the “push” is real, or just an electrical or magnetic effect that creates a false positive. But Nasa is willing to spend money on it. It would open the doors to the rest of the universe for us.

How’s that for (potentially) good news?

Gwynne Dyer.

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