NASA has joined hands with Stephen Hawking for his Breakthrough Starshot project with the goal of flying a nano-spacecraft to Alpha Centauri in less than 20 years and the key according to the US space agency is self-healing chips.
Hawking announced his revolutionary project recently and ever since has garnered a lot of attention for various reasons. While we will not go into those aspects, the primary goal is to start exploring interstellar space and to reach some of the nearest stars in a fraction of the time – just tens of years instead of hundreds of thousands of years and possibly misions.
The celebrity physicists is already working with Korea Institute of Science and Technology and now NASA has joined the bandwagon to propose solutions for some of the technical issues that Hawking and team are facing.
NASA is helping Hawking and team to find out solution to one of the major problems to interstellar space travel – radiation. Just like humans, electronic devices are also incapable of withstanding long-term exposure to radiation. While electronic devices on spacecrafts will be able to handle the radiation for a much longer time if it comes to interstellar travel spanning tens of years they too won’t be able to complete their journey and die out well before they reach their destination.
This is particularly true if we want to travel to Alpha Centauri in search for a habitable planet. Alpha Centauri is located 4.37 light-years or over 25 trillion miles from us. To travel to the star system it would need Hawking’s “StarChip” spacecraft at least 20 years at a speed that is one-fifth the speed of light. Even for relatively such a short duration, the spacecraft’s electronics will not be able to survive and that’s where NASA’s expertise comes in.
NASA scientists have proposed a number of solutions including shielding the spacecraft with material that will be able to prevent the radiation from harming the electronics. But this solution increases the overall weight of the spacecraft making it a rather not-so-optimum solution. The next option is to adjust the route of spacecraft such that it doesn’t pass through regions known to be high-radiation areas. This option is not suitable considering that it will add to the overall flight time and will not be able to avoid all the high-radiation areas anyways.
The best solution as of now, thought theoretical, is to use silicon chip that would automatically repair itself. “On-chip healing has been around for many, many years,” NASA team member Jin-Woo Han said recently at a presentation at International Electron Devices Meeting in San Francisco. Han pointed out that there have been many advances in this field and one of the most important ones being ability to heal chips through heating.
Han pointed out a study by researchers at KAIST wherein they have developed an experimental “gate-all-around” nanowire transistor. The major different between gate-all-around nanowire transistors and today’s chips is that the former uses nanoscale wires as the transistor channel instead of today’s fin-shaped channels. The gate, the electrode that turns on or off the flow of charge through the channel, completely surrounds the nanowire. Adding an extra contact to the gate allows you to pass current through it. That current heats the gate and the channel it surrounds, fixing any radiation-induced defects.
Nanowire transistors are ideal for space, according to KAIST, because they have a relatively high degree of immunity to cosmic rays and because they are very small, with dimensions in the tens of nanometers. The technology has already been used to form three key building blocks for a single-chip spacecraft: a microprocessor, a DRAM memory for supporting this, and a flash memory that can serve as a hard disk and studies have shown that repairs to radiation-induced damage can be made many times, with experiments showing that flash memory can be recovered up to around 10,000 times and DRAM returned to its pristine state 1012 times.
With logic devices, an even higher figure is expected. These results indicate that a lengthy interstellar space mission could take place, with the chip powered down every few years, heated internally to recover its performance, and then brought back to life.