ISS astronauts are building impossible objects on Earth

Until now, virtually everything the human race has built, from rudimentary tools to one-story houses to the tallest skyscrapers, has had one key constraint: Earth’s gravity. However, if some scientists have their way, that could change soon.

On board the International Space Station (ISS) right now is a metal box, about the size of a desktop PC tower. Inside, a nozzle is helping to build small test pieces that are not possible to do on Earth. If engineers tried to make these structures on Earth, they would fail under Earth’s gravity.

“These are going to be our first results for a really novel process in microgravity,” he says. Ariel Ekblawa space architect who founded MIT’s Space Exploration Initiative and one of the researchers (on Earth) behind the project.

The MIT group’s process involves taking a flexible silicone skin, shaped like the part it will eventually create, and filling it with a liquid resin. “You can think of them as balloons,” he says. Martin Nisser, an MIT engineer, and another of the researchers behind the project. “Instead of injecting them with air, inject them with resin.” Both the skin and the resin are commercially available products.

The resin is sensitive to ultraviolet light. When the balloons experience an ultraviolet flash, the light filters through the skin and bathes the resin. It cures and hardens, hardening into a solid structure. Once it heals, astronauts can cut through the skin to reveal the inside.

All this happens inside the box that was launched on November 23 and is scheduled to remain on board the ISS for 45 days. If all is successful, the ISS will send some experimental pieces back to Earth for MIT researchers to test. MIT researchers have to ensure that the parts they have made are structurally sound. After that, more tests. “The second step would probably be to repeat the experiment inside the International Space Station,” Ekblaw says, “and maybe try slightly more complicated shapes, or tweak a resin formulation.” After that, they would want to try making parts outside, in the vacuum of space itself.

The benefit of building parts like this in orbit is that Earth’s most fundamental stressor, the planet’s gravity, is no longer a limiting factor. Let’s say you tried to make particularly long beams with this method. “Gravity would make them sink,” says Ekblaw.

[Related: The ISS gets an extension to 2030 to wrap up unfinished business]

In the microgravity of the ISS? Not so much. If the experiment is successful, its box could produce test pieces that are too long to manufacture on Earth.

The researchers envision a near future in which, if an astronaut needed to replace a mass-produced part, say a nut or bolt, they wouldn’t need to send one back from Earth. Instead, they could place a nut or bolt-shaped skin in a box like this and fill it with resin.

But researchers are also thinking long term. They think that if they can make very long pieces in space, those pieces could speed up large construction projects, like structures for space habitats. They can also be used to form the structural frames for solar panels that power a habitat or radiators that keep the habitat from getting too hot.

ISS astronauts are building objects that could not exist on Earth
A silicone skin to be filled in to make a truss. fast liquid printing

Building things in space also has some key advantages. If you’ve ever seen a rocket in person, you’ll know that as impressive as they are, they’re not particularly wide. It is one of the reasons why large structures like the ISS or China tiangong working your way up little by little, assembling one module at a time over the years.

Today’s mission planners often have to go to great lengths trying to cram telescopes and other spacecraft into that small cargo space. The James Webb Space Telescope, for example, has a sprawling telescope the size of a tennis court. parasol. To fit it onto their rocket, engineers had to delicately fold it and plan an elaborate deployment process once the JWST reached its destination. Every solar panel you can assemble in Earth orbit is one less solar panel you have to put on a rocket.

[Related: Have we been measuring gravity wrong this whole time?]

Another key advantage is cost. The cost of space launches, adjusted for inflation, has fallen more than 20 times since the first space shuttle rose in 1981, but every pound of cargo can still cost over $1,000 to put into the space. Space is now within reach of small businesses and modest academic research groups, but every last ounce makes a significant price difference.

When it comes to other worlds like the Moon and Mars, thinkers and planners have long thought to use material that already exists: lunar regolith either martian soil, not to mention the water that is frozen in both worlds. In Earth orbit, that’s not so simple. (Architects cannot exactly convert the Van Allen radiation belts in construction material.)

That’s where Ekblaw, Nisser and their colleagues hope their resin-blasting approach can excel. It won’t create intricate components or complex circuitry in space, but every little part is one less astronauts have to take on.

“Ultimately, the purpose of this is to make this manufacturing process available and accessible to other researchers,” says Nisser.

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