This is Part Two of our three-part series on space-based manufacturing and logistics. In Part One, we discussed why space-based manufacturing may be on the verge of becoming a reality now. Here in Part Two, we look at some specific examples of manufacturing applications that are already being tested and pursued.
Manufacturing ZBLAN Fibers in Space
Several companies have been exploring the manufacturing of extremely high-quality ZBLAN optical fibers in space. These are potentially valuable for creating higher-bandwidth terrestrial fiber optic networks. ZBLAN glass fibers manufactured in zero-gravity have far fewer crystallization imperfections than those made on Earth. This reduction in imperfections results in much lower attenuation (signal loss) and much wider wavelength (higher bandwidth) than fibers manufactured on Earth.1 There are at least seven companies already doing or planning optical fiber manufacturing experiments in space, with plans or aspirations for the eventual commercialization of production.2 Data published by Factories in Space indicates that the fiber produced from space-based ZLAN would sell in the range of $600K/kg to $3M/kg, representing a premium of between $300K/kg to $2M+/kg compared to prices for ZBLAN produced by Earth-based manufacturing. Thus, transport costs of $1K/kg to $10K/kg are far outweighed by the premium achieved through space-based manufacturing. It is important to note, however, that research3 has demonstrated some techniques for creating high-quality ZBLAN on Earth, by combining rapid cooling with a vertical magnetic field. So, there is a risk that Earth-based manufacturing of similar quality may become feasible, which could inhibit this space-based manufacturing opportunity.
Biomanufacturing in Space
There are potential opportunities for disease modeling, stem-cell-derived products, and biofabrication in space.
The 2020 Biomanufacturing in Space Symposium explored some of these areas and laid out a roadmap to a sustainable market for regenerative medicine biomanufacturing in space.
Regarding disease modeling, humans in sustained weightlessness experience accelerated loss of skeletal muscle; acute changes in cardiac physiology, structure, and function; accelerated bone loss; and acceleration of other aging-related changes such as immune dysfunction. Thus, microgravity can be used to study and improve the understanding of aging and related disease processes. It can also be used for research into biofouling and anti-fouling4 of medical devices, since the formation of microbial communities (biofilms) in zero-gravity is also accelerated.
There are several areas of promise regarding stem-cell-derived products. Cardiac progenitor cells show promise in regenerating cardiac (heart) tissue after injury, such as a heart attack. Cardiac progenitor cells5 cultured in the weightlessness of space grow more quickly and have increased migratory potential.6 Mesenchymal stem cells7 (see illustration), which have potential use as therapeutic agents, have shown improved immunosuppressive capabilities and therapeutic potential in a traumatic brain injury model when grown in microgravity. Finally, there may be some advantages in creating induced pluripotent stem cells (iPSCs)8 in a weightless environment, though further study is needed. Pluripotent stem cells show tremendous promise for various therapies.
Constructing Large Structures in Space
Man-made structures launched into space are subject to high acceleration forces during launch, and their size is constrained by the maximum payload dimensions that the launch vehicle can accommodate. The James Webb Space Telescope (JWST) had to be engineered to unfold and self-assemble in space (as described in part one of this series) because it wouldn’t fit on any launch vehicle in its fully deployed size. That constraint added significant cost, engineering effort, and risk to the project. By constructing structures in space, they can be made much larger and lighter/weaker (requiring less material) compared to structures that need to withstand the forces and constraints of being launched from Earth. Advocates of in-orbit fabrication expect it to bring order-of-magnitude improvements in packing efficiency and system mass, dramatically lower launch costs, and/or enable the construction of much larger structures. We can see this already in the proposals for space-based manufacturing of the enormous lens needed for the next generation of space-based telescopes after JWST.
As part of the Artemis program,10 NASA awarded a $74M contract (OSAM-2)11 to Made in Space to demonstrate space-based construction of an operational solar array, using 3D printing and autonomous robotic assembly from a small spacecraft about the size of a refrigerator. The solar array will extend about 33 feet from each side of the spacecraft.
Examples of other structures considered for space-based construction include very long booms and shields, antennas, reflectors, radars, telescopes, and entire space stations. Orbital Assembly was founded to build and operate space structures that have artificial gravity (created by centrifugal force). They are aiming (rather ambitiously) for the first one to be in orbit by 2025. Some other companies pursuing in-orbit construction include Redwire, Magna Parva, Skycorp, Tethers Unlimited, United Space Structures, and Gateway Spaceport.
For more on this topic, see Large Space Structures.
Other Examples of Potential Space-Based Manufacturing
Examples of some other areas of space-based manufacturing that companies and/or governments are experimenting with include:
- Extraterrestrial Agricultural — Both space-based and Moon-/Mars-based agriculture will be required. Bases on the Moon and Mars will require food to be grown, not only for long-term nutritional needs, but also for conditioning the habitats’ atmosphere (e.g., converting CO2 to oxygen and providing moisture), and providing the psychological support of greenery and fresh food to inhabitants. Farming on spacecraft may be required or desired for the long trips to Mars, or desired by space tourists. NASA is already funding various research. There is also some thinking that microgravity can be used to enhance genetic engineering for Earth-based agriculture. Some companies involved in extraterrestrial agriculture include Eden Grow Systems, Zero G Kitchen, CemVita Factory, Aleph Farms, and Orbital Farm.
- Medicine and Drugs — Space-based production of medicines holds the promise of creating higher purity and more efficient drugs, better microencapsulation of drugs, and superior crystals, including well-ordered, high-resolution insulin crystals and high-quality interferon crystals. In addition, there will eventually be a need to manufacture drugs on the Moon and Mars as increasing numbers of permanent or long-term residents start residing there. Some organizations involved in these areas include Angiex, Zaiput, Merck, Confocal Science, and BSGN’s Life Sciences Industry Accelerator.
- Microfabrication — Producing Gallium nitride (used in making LEDs) in microgravity should decrease the number of defects and may benefit from in-space production. The vacuum of space is also a natural clean room. Existing Earth-based chip manufacturing processes require tremendous amounts of water, power, and air pressure. To make chip manufacturing in space feasible, new microfabrication processes are being developed that don’t require enormous amounts of those resources. Semiconductor fabrication in space may become financially superior to Earth-based production as launch costs fall further. NASA awarded a grant in 2020 to Made In Space to develop a space-based autonomous, high-throughput semiconductor manufacturing capability. University Wafer is also working on space-based chip fabrication.
- Carbon Nanotubes — Carbon nanotubes are one of the strongest materials currently known to mankind. They also have very high electrical and thermal conductivity, making them potentially very valuable in commercial applications such as electronics, communications, composite materials, nanotechnology, and many other applications. However, carbon nanotubes are notoriously difficult to make. The longest individual nanotube produced so far is about 0.5 meters and typically they are much shorter (around 0.03 meters). Weightlessness eliminates convection and in theory could help increase purity to create much longer carbon nanotubes, as some scientists have proposed. NASA has funded research into this area in the past, but we couldn’t find examples of recent investments in space-based carbon nanotube production.12
- Perfect Spheres — There is a market for nearly perfect spheres, though that market is relatively small. Nearly perfect spheres can be produced in microgravity. The market includes applications such as reference size spheres for microscopes and instrument calibration, near-perfect ball bearings, and hollow ball bearings.
Segmenting Space-based Manufacturing Markets by Destination of Goods
One way to segment space-based manufacturing markets is based on where the goods will ultimately be consumed or used:
- On Earth
- On the Moon or Mars
- In Space
The big differences between these segments are A) the types of goods needed and B) the criteria used in deciding which products to manufacture in space vs. manufacturing on Earth. For products that will be consumed on Earth, a key question for each potential product or material is whether the advantages of space-based production, compared to Earth-based production, are large enough to justify the high cost of transporting to/from and manufacturing in space. Until now, the answer has been “no” for virtually everything, since launch costs were so high. As launch costs continue to fall, there will start to be some high-value goods that do make sense to manufacture in space. We have touched on some candidate products above.
For products and materials that will be needed on the Moon or Mars, the equation is very different. The launch and delivery costs go up tremendously. For that reason, there is a strong incentive to build infrastructure to do the manufacturing and farming and mining on the Moon and (especially) on Mars, rather than trying to continuously supply from Earth everything those colonies need. Thus, for the Moon and especially for Mars, there will be a lot of extraterrestrial production that is not space-based, but rather is done on the surface of those planets. Agriculture will be especially important. Extraction of local resources will also be key, such as mining for water, as well as mining of regolith to make concrete-like building materials, silicon dioxide for glass, and various metals.
For products and supplies to be consumed in low earth orbit (LEO) stations and ships — such as the International Space Station and potentially other research stations, space hotels, and waystations/staging/resupply stations for missions to the Moon and Mars — most of their food, infrastructure, and supplies will originate on Earth. However, there is a strong case for being able to 3D-print some replacement parts for service and repair purposes on LEO stations. For spacecraft that are much further from earth, such as Mars mission spacecraft, the ability to do on-ship agriculture and to produce the full range of replacement parts that may be needed becomes vital. There may also be a case for space-based manufacturing of many of the structures in space, as discussed above in Constructing Large Structures in Space.
In the third and final installment of this series, we discuss the current status and future potential of space-based mining as well as the logistics required to support the ever-growing space-based economy and its supply chains.
1 Lower attenuation reduces the need for repeaters, which reduces network latency and security risks. A wider wavelength allows the use of many more frequencies of lasers, thereby increasing the bandwidth achieved through a single cable. As the total bandwidth needs of the world continue to increase and the cost of laying cable remains constant, having higher bandwidth per cable becomes highly desirable. — Return to article text above
2 This page discusses plans for space-based fiber manufacturing by Apsidal, Flawless Photonics, Physical Optics Corp., G-Space, Made in Space, ACME Advanced Materials, and FOMS (Fiber Optic Manufacturing in Space). — Return to article text above
3 See Eliminating Crystals in Non-Oxide Optical Fiber Preforms and Optical Fibers for a review of some of the research on improving fiber optic production. — Return to article text above
4 Biofouling is when unwanted microorganisms, plants, and algae accumulate on the surface of machines and devices. Anti-fouling is the use of techniques and technologies to prevent or remove biofouling. — Return to article text above
5 For more, see Cardiac progenitor cells application in cardiovascular disease. — Return to article text above
6 Migratory potential is the ability for stem cells to migrate (change their location) enabling the creation of structures such as organs or blood vessels. — Return to article text above
7 Mesenchymal stem cells are a type of stem cell that can differentiate into bone, cartilage, muscle, or fat cells. — Return to article text above
8 Induced pluripotent stem cells (iPSCs) are somatic cells (e.g., skin, bones, blood, connective tissue) that have been transformed back into pluripotent stem cells. Pluripotency is the ability of a cell to differentiate into many different types of cells. iPSCs are potentially very important, since embryonic stem cells are rare and ethically controversial, whereas skin and blood cells are abundant and relatively easy to obtain. — Return to article text above
9 Mechanotransduction is various mechanisms by which cells convert mechanical stimulus into electrochemical activity. Mechanotransduction effects are influenced by gravity. — Return to article text above
10 The Artemis program is a series of missions to land astronauts on the moon and start to build up a lunar outpost over the next ten years with increasing amounts of infrastructure, including habitats, rovers, refueling systems, scientific instruments, and resource extraction equipment. — Return to article text above
11 OSAM-2 is short for On-Orbit Servicing, Assembly, and Manufacturing-2. — Return to article text above
12 Carbon nanotubes have been cited as a potential technology to make space elevators viable. Functioning space elevators would further lower launch costs, enabling an even broader set of space-based manufacturing applications to become economically feasible. — Return to article text above
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