Promising space manufacturing in the foreground

  Due to the rapid development of private space companies, the price of goods and equipment used to transport commercial rockets to space has been greatly reduced. More and more entrepreneurs and researchers are able to use the unique conditions of low-Earth orbit to conduct manufacturing research, including vacuum, microgravity, pure solar energy and extreme temperatures. The new experimental environment has spurred innovation in modern medicine, technology, and materials science, and it is foreseeable that space manufacturing will dramatically change the way we make things.
  ”Easy” Print artificial heart
  at the end of 2016, there is an airplane over the Gulf of Mexico somersault, it suddenly risen sharply, then dash down. This is not to experience excitement or filming, but to simulate a weightless environment where high-tech printers can print heart stem cells into simple baby heart tissue.
  This crazy experiment is an important step in the 3D printing heart project. After the experiment is successful, the participating companies are expected to send high-tech printers to the International Space Station through commercial rockets before 2019, and print a beating heart patch on it. .
  Traditional heart transplantation can really help patients, except that patients need to take immunosuppressive drugs for life, so as to avoid transplant rejection, and a series of “can do” or “can’t do” rule taboos. If we can develop a heart from the patient’s own stem cells, this not only reduces the risk of rejection, but the patient does not have to wait for the right donor to appear.
  Why do you have to print your heart in space? It turned out that scientists found that printing organs is a big problem in a gravity environment.
  The ideal experiment planned by scientists is this: the printer initially prints the heart stem cells, and the newly printed tissue can’t be used immediately. It takes a while to develop; then the scientist will put the tissue into a viscous liquid culture. In the base and nutrient solution, let it continue to grow for a while. It should be noted that we can’t print a whole heart at a time, only print and nurture each part of the heart, and finally let them grow together. This is because at present our 3D printing technology can’t build 3D “hands-on”, we need to print out the 2D layer, and then stack these plane layers to become 3D.
  The crux of the problem is the gravity on the earth. It not only limits the 3D printing technology, but also causes the newly printed tissue to collapse and deform in a few seconds, unable to maintain a perfect finished state. In order for the tissue to maintain its structure and grow smoothly, we need to build a scaffold that can support the growing stem cells and be removed or melted without damaging the organ tissue after the cultivation is completed. Unfortunately, scientists have so far failed to design such an ideal stent.
  It is difficult to print organs on the earth, and scientists can’t help but look into space. In the virtual “zero gravity” environment of low Earth orbit, there is no longer a need to consider gravity interference, and researchers can develop a whole heart without using a bracket.
  This is because the 3D shape can be printed directly in a low-gravity environment, and the complete structure and shape can be maintained at all times, allowing researchers to put the printed product into the incubator. After about 45 days, the finished product will grow. Into a fully functional heart tissue, at that time, it can be shipped back to Earth for use.
  More efficient space optical
  fibers are widely used in light-conducting means, multi-transport material is used for communications. There are many types of optical fibers, one of which is a fluoride fiber, which is made of fluoride glass. It is considered to have ultra-low loss characteristics and can transmit a wider spectrum. It is a good choice for long-distance communication.
  Unfortunately, it is difficult to produce fluoride fibers on the earth, and the finished product is not ideal. In the production of such an optical fiber, it is necessary to first heat the glass raw material to 300 ° C, and then stretch downward from a height of 10 to 20 m, and pull the softened glass into a strip to become a fiber. Due to space and gravity limitations, the length of the fiber may only be pulled up to 700 meters, and the glass will crystallize or precipitate under gravity. Although we can connect multiple fibers to increase the distance, the signal will be lost at the connection. The precipitation and crystallization in the fiber will weaken the signal strength, and the final communication effect will be greatly reduced. This fiber is also expensive because of its high cost, its material is “fragile”, and its effect is still unsatisfactory. It has not yet been put into the commercial market.
  Later, researchers discovered that the manufacture of fluoride fibers in a zero-gravity environment can avoid these problems. In a vast space, you can use a larger glass block to easily pull a few kilometers of fiber; on the other hand, without the influence of gravity, precipitation or crystallization is no longer easy in the fiber. From the finished product, the fiber made in space is longer and the interior is clearer. This means that there is less signal loss during transmission and the signal delay is greatly improved.
  At present, a US company has already launched materials and equipment for the production of fluoride fiber to the International Space Station. After arriving at the space station, the production device will start to manufacture the space fiber, and when it is completed, it will return to Earth with the returning space capsule. If the subsequent tests are in good condition, the fiber may be put into production and sold in the short term.
  The relocation of polluting industries earth
  to 3D printing with a low-gravity environment or the manufacture of high-quality fiber, are just one of the benefits of manufacturing space. Another very obvious benefit of space manufacturing is that it protects the planet from the toxic waste generated in the production chain.
  Gallium arsenide is currently the material of choice for making good solar panels. It converts 40% of light into energy, which is twice the conversion rate of mainstream silicon-based photovoltaic panels. But when producing gallium arsenide, many toxic compounds are left behind.
  In the 1990s, the material scientist at the University of Houston, Alex Ignatiev, first produced a gallium arsenide semiconductor in a space vacuum environment. It was evaluated that the quality of semiconductors manufactured in space is better than that of the earth. It’s 10,000 times better. This is because atomic oxygen (generally oxygen has two oxygen atoms, while oxygen in the near-Earth orbit is in the form of a single oxygen atom, the chemical properties are very active) and the vacuum environment allows the compound to be neatly arranged at one atom. The layers are stacked on top of each other and will not be distorted and distorted in the middle.
  No deformation distortion is an important condition for the production of high quality gallium arsenide. Theoretically, a defect-free GaAs solar panel can achieve 60% energy conversion.
  Ignatiev envisions producing high-quality solar panels directly in space, and then arranging several kilometers of GaAs solar panels in orbit to collect the energy of the sun and then use microwaves to The energy is emitted back to Earth for us to use. However, when GaAs is produced, it will produce a lot of toxic substances. People are worried that the space factory will pollute the space, and then the space orbit will be filled with space garbage or toxic waste.
  Fortunately, space has a unique ability to break down harmful residues. In addition to the protection of the Earth’s atmosphere, ultraviolet radiation in the sun can help break down dangerous molecules and disperse these components harmlessly. Although our planet is a closed system, space is an open environment that is highly corrosive to most molecules. In a vacuum environment, these molecules either split or evaporate.
  Based on this situation, scientists have the idea of ​​transferring toxic production from the Earth to space. They believe that for environmental protection, we can build a “megachip factory” in space to make heavy-duty products like semiconductors, when pollution production can completely disappear from the earth.