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Near-lightspeed nano spacecraft might be close

Thanks to research on nano-sized thrusters that act like portable particle accelerators, tiny spacecraft might be accelerated to near-lightspeed and sent to explore nearby stars — and all within our lifetimes.
Image: Nanosatellite
An artist's conception shows an 11-pound (5-kilogram) disk-shaped nanosatellite in space, with tiny microthrusters placed around the edge of the disk.NASA
/ Source: contributor

Massive particle accelerators are exploring the world of the very small, but similar technology may someday propel needle-sized spacecraft to distances on a scale so large as to be almost unimaginable — between star systems.

Thanks to research on nano-sized thrusters that act like portable particle accelerators, tiny spacecraft might be accelerated to near-lightspeed and sent to explore nearby stars — perhaps within our lifetimes.

The $10 billion Large Hadron Collider at Europe's CERN particle-physics lab was built with the goal of figuring out what exactly the universe is made of. The 17-mile-round machine can accelerate charged protons to nearly the speed of light. Once they reach top speed, the particles are smashed into targets, creating spectacular (and short-lived) collisions that spew out exotic forms of matter for scientists to study.

The principles behind atom smashing may one day show us more than what the rest of the universe is made of. They may actually take us there.

Since the late 1950s, humankind has sent a barrage of spacecraft to explore much of our solar system. We’ve launched probes toward every planet (including the iffy ones, like Pluto and Charon), as well as to the sun and a multitude of moons, asteroids and even comets. Rovers are currently trundling across Mars, and satellites are currently in orbit around Earth, the moon, Mars, Venus and Saturn. But only a handful of our probes have left the solar system, and they travel at a crawl. For example, the Voyager probes scoot at about 40,000 mph — only 0.00006 percent the speed of light.

We have never reached out beyond the vast interstellar void to explore our nearest star — Proxima Centauri.

Interstellar distances are incredible and disheartening. Space shuttles orbit the earth at about 250 miles up. The moon hovers a scant 250,000 miles away. Mars is about 140 million miles out from the sun, on average. Meanwhile, the nearest star is 4.2 light years away. This means that it takes a beam of light more than four years to travel the 24 trillion miles to reach the nearest star (and another four years to make it back). Visiting another star seems to be an impossible goal to complete within a human lifetime – unless a spacecraft travels at nearly the speed of light.

Turns out, that’s not quite as impossible as it sounds.

The solution to interstellar space exploration may lie in the use of micro or nano-sized spacecraft that can be accelerated to incredible speeds. Protons in a particle accelerator can reach near-lightspeed because they are so small and light. Similarly, very small unmanned space probes could be light enough to reach the speeds necessary for interstellar space exploration.

Researchers at the University of Michigan are creating the nano-sized engines that could someday drive a new wave of these mini-starships.

Funded by the Air Force, Brian Gilchrist and his colleagues are developing a new type of thruster that uses nanoparticles as propellant. Much of the engine is etched directly onto a wafer-thin piece of silicon via micro-electromechanical systems technologies, known as MEMS, that are more commonly used in the semiconductor industry. Measuring no thicker than a half-inch (1 centimeter, including the fuel) and with tens of thousands of accelerators able to fit on an area smaller than a postage stamp, these “stick-on” thrusters could power tiny spacecraft over vast distances.

The technology is called a “nano-particle field extraction thruster,” or nanoFET. The tiny thrusters that work much like miniaturized versions of massive particle accelerators. The device uses a series of stacked, micron-thick “gates” that alternate between conductive and insulating layers to create electric fields. These small but powerful electric fields charge and accelerate a reservoir of conductive nanoparticles, shooting them out into space and creating thrust.

“In that a particle accelerator uses an electrical field to propel charged particles to high speeds — that’s exactly what we’re doing,” Gilchrist said.

And since there is no friction in space, miniature starships could continue to accelerate for years at a time, approaching near-lightspeeds and carrying our scientific instruments to the stars.

For the time being, however, nanoparticle thrusters will stay within our solar system. According to Gilchrist, “there are lots of practical applications for this technology that are much closer to Earth.”

is an Oregon-based writer and the author of "."