Ultra-thin lightsails with billions of tiny holes to enable high-speed space travel
TU Delft and Brown University researchers have engineered scalable lightsails, ultra-thin reflectors propelled by laser radiation pressure for high-speed travel.
Lightsails represent a unique approach to nanotechnology, focusing on extreme thinness at a nanoscale level (1/1000th the thickness of a human hair) while simultaneously achieving large-scale sheet dimensions.
The 200 nanometer-thin prototype is a 60mm by 60mm square with billions of tiny holes. If scaled, this lightsail would be incredibly large (equivalent to seven football fields) while remaining extremely thin (just one millimeter).
“This is not just another step in making things smaller; it’s an entirely new way of thinking about nanotechnology. We’re creating high-aspect-ratio devices that are thinner than anything previously engineered but span dimensions akin to massive structures,” said Richard Norte, associate professor at TU Delft.
Harnesses the power of laser
What makes this lightsail special is the simultaneous combination of large-scale and nanoscale precision, making it both lightweight and highly reflective.
They utilized a neural topology optimization technique to generate optimal structural designs for the sails.
Moreover, a novel gas-based etching process was created to selectively remove material beneath the sail structure, leaving behind only the desired ultra-thin membrane.
“We have developed a new gas-based etch that allows us to delicately remove the material under the sails, leaving only the sail. If the sails break, it’s most likely during manufacturing. Once the sails are suspended, they are actually quite robust. These techniques have been uniquely developed at TU Delft,” added Norte.
These newly developed lightsails are designed to harness the power of laser-driven radiation pressure to achieve incredibly high speeds.
This method of propulsion offers the potential for faster space travel compared to standard chemical rockets.
To illustrate this potential, the researchers suggest that probes equipped with these lightsails could, in principle, reach Mars in a timeframe comparable to the delivery time of international mail.
Moreover, current rocket technology would take 10,000 years to reach the nearest star, but the lightsail tech could drastically reduce that to 20 years.
Lightsail tech could benefit physics also
Although interstellar travel with lightsails is a future aspiration, current research shows they can be propelled over tiny picometer distances.
Norte’s team is now working on experiments to demonstrate movement over centimeter distances against Earth’s gravity.
“It might not sound like a lot, but this would be 10 billion times farther than anything pushed with lasers so far,” Norte added.
The lightsail technology could also help create new avenues for physics experiments. For instance, it could be used to study light-matter interactions and relativistic physics in ways previously impossible.
“In some ways, I think it might be just as exciting as missions beyond the solar system. What is remarkable to me is that creating these thin optical materials can open a window into fundamental questions such as; how fast can we actually accelerate an object. The nanotechnology behind this question is certain to open new avenues of interesting research,” said Notre in the press release.
Source: Interesting Engineering
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Ultra-thin lightsails with billions of tiny holes to enable high-speed space travel