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NASA's Working on a Nano-Starship That Travels at 1/5 The Speed of Light

But can it survive the 20-year trek to Alpha Centauri?

PETER DOCKRILL
9 DEC 2016
 

In April, a team of scientists including Stephen Hawking announced a mind-boggling new project to explore interstellar space, using lasers to propel a nano-spacecraft the size of a postage stamp to our nearest star system, Alpha Centauri.

If they could get their little 'StarChip' spacecraft to travel at 20 percent the speed of light, it could arrive in just 20 years. But how would the electronics on such a tiny, vulnerable spacecraft survive for 20 years in the hostility of space?

 

The problem for Hawking's Breakthrough Starshot project, say researchers at NASA and the Korea Institute of Science and Technology, is radiation.

Just like it does bad things to astronaut's bodies, the high-energy radiation in space would also cause serious defects in a nano-spacecraft chip's silicon dioxide layer, meaning the components would cease to be functional long before the 20-year voyage was up.

So what's the solution? As the team points out, you could get around the radiation problem by picking a route through space that minimises exposure to cosmic radiation.

But that could add serious length to the duration of a mission, and even a minimal amount of radiation could still inflict some serious damage on a tiny spacecraft.

Another option could be to add shielding to the electronics to reduce damage caused by cosmic rays – but again, by adding bulk and weight to the craft, you'd slow down the mission, as a larger vessel wouldn't be able to travel at equal speeds to the original StarChip specifications.

But there's a third way we could make the whole thing work, if we can devise a nano-spacecraft that's able to repair its radiation damage automatically en route to Alpha Centauri.

 

"On-chip healing has been around for many, many years," NASA researcher Jin-Woo Han told Richard Stevenson at IEEE Spectrum.

Using an experimental 'gate-all-around' nanowire transistor developed by researchers at KIST, the team says it would be possible to use electric current to heat the chip contained in a nano-spacecraft, in effect healing any damage incurred through exposure to radiation.

The idea is that the chip inside the craft would be powered down every few years during the journey, at which point the transistor heating would remedy any radiation-induced defects.

The chip could then power on again once it had healed sufficiently.

In the researchers' testing with the nanowire transistor in the lab, they say the heating process enables flash memory to be recovered up to around 10,000 times, and DRAM memory up to 1012 times.

While it's only a hypothetical solution at this point in terms of spacecraft applications – and the research hasn't yet been peer-reviewed by other scientists yet– the team says the technique would make lengthy interstellar space missions like Breakthrough Starshot technically feasible.

Of course, ensuring that the electronics stay functional is just one piece of the puzzle.

If a nano-spacecraft is going to make it all the way to Alpha Centauri intact, it'll also have to survive threats other than just radiation, such as cosmic collisions with gas and dust floating in space.

Earlier in the year, Breakthrough Starshot's scientific team began a series of experiments designed to assess these risks, and found that impacts with dust in particular could be catastrophic – which means at least some degree of extra shielding might have to be added to the craft.

There's a lot more research to be done before this amazing mission becomes a reality, as the science – like the little StarChip itself – still has a long way to go.

But that's fine with us, as we can't wait to see what the next development is for this crazy interstellar voyage.

The research was presented this week at the International Electron Devices Meeting in San Francisco.

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