In April this year, a group of businessmen and scientists, including Stephen Hawking, announced an ambitious project to explore interstellar space using a compact, postage stamp-sized nanosatellite powered by laser propulsion. Objective: to get to the nearest neighbor of the solar system - Alpha Centauri.
If this tiny spacecraft manages to accelerate to almost the planned 1/5 the speed of light, then the ship will be able to reach its destination in just 20 years. But can the electronics of such a tiny and fragile device work for 20 years in the harsh space?
The biggest problem that Hawking's Breakthrough Starshot project will have to face, according to researchers from NASA and the Korea Institute of Science and Technology, is space radiation.
As in the case of astronauts, the spacecraft will have to experience the colossal impact of highly charged particles every second, which can cause serious damage to the layer of silicon dioxide that will cover the spacecraft. In this situation, all the internal components of the device will fail long before the end of the 20-year space journey.
How do you solve this problem? One of the options, according to scientists from NASA, may be laying a route around the most dangerous areas, where the background radiation concentration is much higher than usual. However, in this case, the duration of the mission can increase many times. In addition, even minimal exposure to radiation is bound to result in some serious damage to the spacecraft over time.
Another, more practical option may be to shield the probe and its electronics in the hope of reducing the impact of the harmful cosmic background radiation. However, again, adding extra weight to the spacecraft will slow down the speed of the mission, as the larger spacecraft will not be able to accelerate to the desired speeds.
However, there is a third way that could work if we can build a nanoship capable of self-healing from cosmic radiation on its way to Alpha Centauri.
"In fact, the technology of self-healing chips has been around for years," says NASA researcher Jin-Woo Han.
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Experimental GAA FET (gate-all-around) transistors developed by an international team of scientists can solve the problem. Their peculiarity lies in the fact that chips based on these transistors can recover under the influence of heat. Heat, in turn, can be generated using electric current. The main idea is that such a chip inside the spacecraft will turn off during a long space trip every few years. At the time of such "reboots", the effect of heat will restore it from the effects of radiation. After recovery, the chip will re-enable and continue to do its job.
In laboratory tests of these transistors, scientists have made sure that flash memory based on them when heated can be restored up to 10,000 times, and DRAM memory - up to 1012 times. Of course, from the point of view of the prospects for use in spacecraft at the moment, these transistors are still a hypothetical solution. As mentioned above, transistors are experimental. A fresh and outside perspective on their effectiveness is needed. However, the team that created them believes that their use in space missions like Breakthrough Starshot is indeed possible.
Of course, solving the problem of how electronics works in challenging environments is only part of a larger puzzle. If the tiny spacecraft does go to meet Alpha Centauri, it will have to fight more than just radiation. Collisions with cosmic gas and dust will be just as dangerous on this journey.
Earlier this year, the Breakthrough Starshot research team began a series of risk-based experiments and found that a collision of such a tiny ship with even particles of cosmic dust would be catastrophic. This means that it is necessary to return again to the issue of protective shielding of the device.
Before the project becomes a reality, it will take a tremendous amount of work. And not only engineering, but also scientific. Ultimately, however, all efforts may not be in vain. The idea itself, rather not even an idea, but a very real desire - to reach a star outside the solar system in 20 years - should not only amaze, but also incredibly motivate. Fortunately, modern science has both the first and the second in abundance.
NIKOLAY KHIZHNYAK