Reaching for the stars: the top ideas in space travel

A starship drive, a vacuum airship, solar surfing. NASA has awarded funding to 22 new projects as part of the NASA Innovative Advanced Concepts (NIAC) program. This is where the organisation awards the most innovative, and sometimes wacky, ideas for new technologies aiding humanity’s future exploration of space

The newly published description of far-out projects reads like the contents of a sci-fi anthology. 

The grants program has two tiers: Phase I for initial concepts; and Phase II for graduating the most promising ideas from previous Phase I grants. “All of the final candidates were outstanding,” says Jason Derleth, NIAC program executive. “We look forward to seeing how each new study will expand how we explore the universe.”

Here is a round-up of some of the most exciting projects.

Phase I

First the Phase I projects. These each receive about $125,000, for nine months, to help define and analyse their concepts.

Mach effect to travel to the stars

This project proposes to develop a futuristic thruster, based on the so-called Mach effect, that could be capable of sending a spacecraft to an exoplanet 5 light years away in as little as 20 years. 

The thruster is based on the ideas of James Woodward, who hypothesised the new kind of propulsion system in 1990.

The core of the device is a huge capacitor moving up and down on a piston, being continually charged and discharged as it moves. Woodward hypothesised the simultaneous change in energy and acceleration, would cause the capacitor’s mass to briefly change – raising the possibility it could “push” and “pull” a craft through space.

It would be a bit like standing on an ice rink with a bowling ball in your hands, and pushing the ball back and forth to shuffle yourself along. 

Like the electromagnetic (EM) drive is claimed to do, the Mach Effect Thruster (MET) is predicted to produce thrust without ejecting any propellant. In fact, some physicists are trying to explain the EM drive by applying the physics of the Mach effect.

The project is led by Heidi Fearn at the Space Studies Institute, a non-profit based in California. Using the grant, she plans to improve lab prototypes of the device, and figure out what it would take to send a 1.2 tonne spacecraft a distance of 8 light years. 

The physics community has always been highly sceptical of Woodward’s idea, since it seems to violate Newton’s third law of motion, but if it works we’d enter a new era of space exploration. So NASA obviously reckon it’s worth a shot.

Laser powered spacecraft

Another breakthrough propulsion project is based on the relatively conventional idea of using a laser to remotely power a spacecraft. Rather than using the light’s momentum to push the craft, as with solar sail technology and Breakthrough Starshot, the idea here is to remotely send electrical energy that can then power a thruster.

John Brophy at the NASA Jet Propulsion Laboratory plans to use laser beams generated by a 10-km diameter array of satellites to power a spacecraft equipped with giant solar panels. The panels would convert the laser beam energy to electricity, which would in turn be used to accelerate lithium ions through a thruster. Brophy estimates the project could deliver a drive system 20 times as powerful as the current state-of-the-art ion drive on the Dawn space probe orbiting Ceres.

Vacuum airship

A balloon or airship works by filling a huge bag with very light air (helium, hot air, or, in the case of the ill-fated Hindenburg, hydrogen). An airship filled with nothing (i.e. a vacuum) would theoretically provide even greater lift. On Earth such a design could never work with currently known materials, as atmospheric pressure would crush the ship. But Mars is a different story. Its lower gravity and sparser atmosphere mean a vacuum airship just might work. This project, by John Paul Clarke at Georgia Institute of Technology, aims to nut out the details.

Solar surfing

Robert Youngquist at NASA’s Kennedy Space Center plans to develop a coating that could reflect 99.9% of sunlight, making it 80 times more reflective than current materials. A bit like in the 2007 movie Sunshine, such a reflector would allow probes to get much closer to the Sun than currently possible – as close as one solar radius to the Sun, Youngquist thinks. That’s less than 1 million kilometres. (For comparison, on its closest approach Mercury is still 57 times further away from the Sun.)

Other Phase I projects include a mission to use the Sun’s gravity as a lens to directly image an exoplanet with megapixel resolution, a ‘turbolift’ artificial gravity device for deep space missions, and a project to render Martian soil useful for agriculture with synthetic biology.

Phase II projects

The Phase II program awards up to $500,000 for the most promising projects from the Phase I program.

Probing asteroids with lasers from afar

Gary Hughes and California Polytechnic State University plan to reveal what asteroids are made of by blasting them with a laser (from Earth orbit) and detecting the light given off by the atoms discharged. Since each element has a unique spectral fingerprint, this light can be used to identify the atomic makeup of the asteroid – and perhaps figure out which ones could be worth mining.

Optical mining 

This advanced asteroid mining project is based on using focused sunlight as a mining drill. Joel Sercel at TransAstra Corp is leading this project, which envisions a huge solar reflector to direct sunlight onto an asteroid. The oxygen, water vapour and other materials given off would then be captured and stored to fuel other missions exploring the solar system.

Other Phase II projects include developing a new way to identify exoplanets by detecting starlight reflected from distant worlds, and a fusion-powered probe for visiting Pluto.

NASA cautions that all projects are still in the early stages of development, most requiring more than a decade of before they’ll ever see use on a NASA mission. Still, Derleth is upbeat: 

“Hopefully, they will all go on to do what NIAC does best – change the possible.”