This past summer, a plane went into a stomach-churning ascent and plunge 30,000 feet over the Gulf of Mexico. The goal was not thrill-seeking, but something more genuinely daring: for about 25 seconds at a time, the parabolic flight lifted the occupants into a state of simulated weightlessness, allowing a high-tech printer to spit out cardiac stem cells into a two-chambered, simplified structure of an infant’s heart.
Impressive though this may be, it’s just a brick in the road toward an even bolder goal. Executives at nScrypt (the makers of the stem cell printer), Bioficial Organs (the ink provider), and Techshot (who thought up the heart experiment) are planning to print beating heart patches aboard the International Space Station by 2019. The printer will fly up on a commercial rocket.
Private spaceflight companies like Blue Origin and SpaceX have been criticized as vanity projects for plutocrats surfing on taxpayer investments. But the emergence of these companies has led to nose-diving prices for sending goods and equipment into space. Today it costs roughly $5,000 to launch one kilogram of stuff, compared to $30,000 during the space shuttle era. So a growing number of entrepreneurs and researchers are looking to use this relatively cheap access to harness the unique qualities of low Earth orbit—including its vacuum, microgravity, unlimited solar power, and extreme temperatures—for manufacturing. Their experiments are already spurring innovations in medicine, technology, and materials science. Eventually, if it takes off, orbital fabrication could revolutionize the way we make things.
A LIGHTER HEART
A heart transplant patient can spend months waiting for a new ticker. After he gets one, he’ll need to take immunosuppressants for the rest of his life, so that his body won’t reject the foreign organ. A heart printed from the patient’s own stem cells could get to him faster, with a lower chance of immune rejection. It could also be perfectly tailored to fit the dimensions of his original heart.
But it turns out that gravity is a real problem when it comes to printing hearts on Earth. For printable bioinks to grow, the broth of stem cells and nutrients needs to have a watery consistency to ensure the cells are mobile enough to knit together into healthy heart tissue. Because of this watery consistency, to grow a heart on Earth, you need a support structure.
“If you think about the heart, you’re really talking about four big open voids wrapped in muscle,” says Eugene Boland, chief scientist at Techshot. Unfortunately, scientists haven’t devised a scaffold for growing stem cells that can later be removed or dissolved without damaging the nascent organ.
By printing organs in space instead, Techshot thinks it can grow whole hearts without the use of a scaffold.
“If we try to do it on Earth, it would look pretty for about a second and then just kind of melt all over the table,” says Boland. “It would look like you just poured a Jell-O mold and then tried to immediately serve it—it would glob on your plate into this gelatinous mess.”
But microgravity helps the heart maintain shape without a scaffold. That’s partly because low gravity makes printing 3D shapes more direct. On Earth, complex 3D objects such as a model heart need to be printed as 2D layers that are overlaid on top of one another in a time-consuming process. nScrypt CEO Kenneth Church calls this “2-and-a-half-D.” Printing in microgravity allows the object to be spit out in genuine 3D, improving speed by up to 100 times.
During the parabolic flight in July, the first heart structure that nScrypt and Techshot printed lost about half its height in just the first minute after printing, once gravity was re-established on the plane. The weightlessness aboard the International Space Station should let the stem cells maintain shape as they grow together into the tissue of a functioning heart. Boland estimates the space-made organs could be ready to return to Earth about 45 days after the culturing process begins.
Church sees the project as a way of getting beyond the hype and disappointment of 3D printing. “People are getting tired of seeing Yoda figures being printed,” he says. “They’re saying ‘You promised me a heart. Where is it?’ And what I’m going to tell you is, ‘It’s in space.’”
NOT YOUR AVERAGE CABLE COMPANY
Ioana Cozmuta, a physicist in NASA’s Space Portal Office, has reviewed hundreds of space-related technologies. Her role is to look for and vet potential partners who want to do business in space. “My goal is to create success stories for commercial space,” she says. “But I’m struggling with hype.”
Part of Cozmuta’s job is to worry about the dangers of disappointment inherent to such a glamorous but risky field. Numerous explosions show that even the black swan entrepreneur Elon Musk is not immune to costly errors that emerge from the hideous complexities of rocket science. Or consider Richard Branson’s 2008 prediction that space tourism operations would commence by mid-2010. And then Christmas of 2013. Then Christmas of 2014, a deadline that was torpedoed by a fatal accident during a test flight. Space is hard, even for the smartest, wealthiest businesspeople on the planet. Having assessed hundreds of companies for the NASA space portal, Cozmuta has to watch out for executives claiming to have nailed down an exciting space business idea even though the plan is full of holes.
FOMS is a Southern California company that has won funding to begin making stuff on the ISS next year—and the company did so in part by keeping the project on a solid economic footing. Dmitry Starodubov, FOMS’ chief scientist, decided to pass on the idea of space mining rare metals such as platinum, which currently sells for around $30,000 per kilogram. In his view, that’s still not enough to make space mining profitable. “Even if our moon were made out of pure platinum, our model shows that it’s not commercially feasible to mine platinum on [the] moon and bring [it] back to Earth,” he says.
Instead, FOMS set its sights on something both lighter and even more valuable per pound: exotic fiber optic cable. Typical fiber optic cable, of the type that likely helped bring these words to your screen, sells for between $3,000 and $5,000 per kilogram. But exotic fiber optic cable capable of transmitting more data, or making data transmission cheaper because it requires less power? The priciest type can cost up to a few million dollars per kilo. That’s the type of value-to-weight ratio that can justify the costs and risks of making things in space.
Exotic fiber optics, such as a type that goes by the initials ZBLAN, can be made on Earth, but it’s not easy. The normal process of making ZBLAN involves heating a blob, or “preform,” of this special glass to hotter than 300 degrees Celsius, and then pulling it down, like a long string of chewing gum, from a drop tower typically between 10 and 20 meters tall. But the size of the white-hot blob limits how long the resulting cable can be—fibers max out at about 700 meters in length. Ideally, companies want longer segments, because connection points lead to signal loss. Plus, gravity causes sedimentation in the crystal structure of the ZBLAN, creating defects that result in a weaker signal.
That’s why Starodubov has his sights set on pulling ZBLAN and other composites on the ISS, with a product of far greater quality and quantity than is possible on Earth. He’s helped create a prototype that uses a luggage-sized equivalent of a drop tower that spools fiber optic cable like garden hose. “It can theoretically pull hundreds of kilometers in 24 hours,” says Cozmuta. And without gravity, there is no troublesome crystallization.
Though ZBLAN is hard to make on Earth, researchers are intrigued by the stuff because it can transmit a much broader spectrum of light than silica, including ultra-violet and deep-infrared. This could be useful for creating futuristic tech like ultraviolet surgical lasers, eye-safe infrared manufacturing tools, and better countermeasures against heat-seeking missiles. And it could also make our broadband pipes “fatter”; Cozmuta estimates that, compared to existing silica-based fiber optic cable, space-made ZBLAN would result in about 100 times less loss of signal intensity as it moves down the pipe. Alternately, it could help make the process of sending data cheaper, since the same amount of data can be sent over a longer distance, using less power, and requiring less expensive transmission equipment.
As for how the cable spools would get back to Earth? “You can bring them back on SpaceX,” Cozmuta says.
THE BRIGHTER SIDE OF ARSENIC
Some space-made materials won’t need to come back to Earth to help us out. Consider a compound called gallium-arsenide, which costs about $5000 per 8-inch wafer and results in lots of toxic byproducts when manufactured (hello arsenic!). But it makes for great solar panels, converting about 40 percent of the light that hits it into energy, versus the 15 to 20 percent efficiency of the silicon-based panels that are commonly installed here on Earth.
University of Houston materials scientist Alex Ignatiev first manufactured a gallium-arsenide semiconductor in the vacuum of space in the 1990s, onboard a NASA craft called the Wake-Shield Facility. The space-made semiconductor was 10,000 times better in quality than the ones made on Earth. That’s because atomic oxygen and the quality of vacuum in space allows the compound to be neatly grown in layers one atom high, piled on top of each other in hundreds or a few thousand layers, without any distortions. The absence of these distortions increases its solar efficiency; in theory, defect-free gallium-arsenide could produce solar power with as high as 60 percent efficiency.
Ignatiev envisions kilometer-wide gallium-arsenide panel arrays in orbit, collecting the sun’s energy and beaming it back to Earth via microwaves, similar to the solar farms Japan proposed and started to demo in 2015. Rather than creating the fragile panels on Earth and blasting them up in multiple trips, Ignatiev wants to assemble the solar cells in space, as a way to significantly reduce costs.
“When you’re in space, you can go into geosynchronous orbit so you’re always pointing at the sun, and then beam down to a place on Earth,” he says. Mesh-like receivers on Earth would receive the microwave signals, which would be diffuse enough to avoid harm to planes, birds, crops, or livestock.
No one wants to see low Earth orbit turn into a floating toxic waste dump. Fortunately, space has unique abilities to break down noxious residue. Outside the protection of our planet’s atmosphere, ultraviolet radiation from the sun breaks apart dangerous molecules, and the components disperse harmlessly. “Our planet is a closed system, whereas space is an open environment that is very caustic for most molecules,” says Ignatiev. “They will either break apart or evaporate by the vacuum environment of space.”
This idea of moving toxic production off the planet echoes the somewhat cryptic comments from Amazon.com and Blue Origin founder Jeff Bezos in June and then September. “You go to space to save Earth,” he said. He added that, for environmental reasons, we need to build “gigantic chip factories in space,” where the dirty business of making things like semiconductors would be moved off the planet entirely.
And in spite of the gleaming beauty of our electronic gadgets, making computer chips is dirty indeed. According to Cozmuta’s calculations, making a single 12-inch integrated circuit requires 2,200 gallons of water, used to clean and cool the chip—and, in 2015, we made 900 billion such circuits. Despite wastewater treatment efforts, U.S. semiconductor companies were cited for 10,000 environmental violations between 2003 and 2013. But who needs water if you use the freezing vacuum of space as a coolant?
MADE IN SPACE
However alluring the prospects, off-world production will take immense amounts of money and tolerance of risk. Loss of life and huge costs are pretty much guaranteed. But that doesn’t mean it can’t work. After the successful cardiac printing in weightlessness, Techshot’s Boland took time to celebrate the milestone. “We were surprised. I can tell you the guys up there were doing backflips, probably literally.”
And nScrypt’s Church is thinking far beyond printing hearts on the ISS. Assuming they can increase the production speed significantly, the advantages of printing in true 3D versus the “2-and-a-half-D” layer-by-layer approach will allow space printing to compete even with massive terrestrial manufacturers. Ignatiev’s idea of kilometer-wide, space-made gallium-arsenide solar panels offer one example, but the same principle applies for satellites and even spacecraft. “I want to print everything in space,” Church says. “I want to print a rocket in space.”
Source in Flipboard