Space Manufacturing: Microgravity and Industrializing Space

Credits: Space Odyssey 2001

Becoming a spacefaring civilization is both inspiring and necessary to preserve consciousness in case of existential threats that may end civilizations on Earth. Humans are explorers by nature. Early humans stepped foot out of Africa about 2 million years ago. However, it was only homo sapiens who moved out 60,000 years ago that seem to have become the forebearers that populated the rest of the world. If humans had never taken the risk or found the necessity to venture out of Africa, it is possible that human civilization would have perished or at the very least the progress we have made thus far would have been unlikely.

We built technologies to adapt to harsh conditions that were different from early Africa. Our forefathers and foremothers gave us agriculture, roads, democracy and trade. However, it was only after the Enlightenment-era did we start seeing rapid progress in making the world a better place.

Advances in science and technology - steam engine, air travel, computers, medicine etc - have tremendously shaped the modern world we are in today. The arrival of the space race in the 1950s and 60s helped us reach for the final frontier. We put a man in space in 1958 and sent a manned mission to Moon and brought them back in 1969.

Although interest in outer space gradually started to cool down, the knock-on effects from space technology enabled us to build satellite-based communication, positioning services, earth observation and spin-off technologies that could be used on Earth. With SpaceX, it's brainchild Starlink, newspace companies such as Planet and Relativity Space, we see a renewed interest in Space. Building and deploying constellations of internet satellites will enable connectivity for the remotest of areas. 3D printing rockets and satellites will enable faster and more launches. Mapping the entire world through Earth observation satellites will help us better understand the world and the role of climate change.

But what about space manufacturing and why is it necessary?

Historically, new cities were built alongside ports where trade and economy flourished. In the modern era, cities have thrived on industrialization. Most cities across the world became modern industrial capitals by building factories and supply chains. The same applies to Space. To accelerate humanity's path out to the stars and colonize other planets, we need to industrialize space and build a space economy.

If the first big step towards becoming a space-faring civilization is building reusable rockets. The second is industrializing space.

The good thing about industrializing space is, besides the necessity to create a space supply chain, space through micro-gravity, or low gravity, offers enormous potential in radically shifting manufacturing capabilities for certain products required here on Earth.

Chemistry, the underlying science, is not exempt from the effects of gravity, a fundamental force on Earth that influences all systems at a molecular level. From proteins to semiconductors, everything is made of molecules and compounds. Certain earthbound limitations conjure upon how molecules behave due to gravity.

However, microgravity is free from forces affected by gravity such as:

• Sedimentation, the process of deposition of solid material from a state of suspension or solution in a fluid (usually air or water). The absence of sedimentation in microgravity enables the combination of any number of substances that would normally be extremely challenging or impossible to mix evenly on Earth.

• Buoyancy forces that generate convection - the transfer of heat due to the bulk movement of molecules within fluids due to temperature gradients and density differences - is absent in microgravity.

• Hydrostatic Pressure: In presence of gravity, the weight of the fluid on top pushes down on the fluid below it, resulting in hydrostatic pressure gradients. This pressure can be almost completely eliminated in microgravity which then allows other forces such as surface tension - the property of the surface of a liquid that allows it to resist an external force - and diffusion - the mixing of particles of liquids or gases so that they move from a region of high concentration to one of lower concentration - to dominate. These forces fundamentally transform the behaviour of fluids.

• Shear stress, created by reaction forces on fluid container walls, is absent in microgravity affecting the way proteins and fluids respond.

• There are no directions in microgravity since a spacecraft in free fall results in weightlessness. Additionally, weightlessness allows materials to levitate and thus removing the need for containers which drastically makes it easy to manufacture materials in a contaminant-free environment.

The forces mentioned above affect how molecules crystallize. All crystals (diamonds, salts, proteins etc.) are made of constituents (atoms/molecules/ions) that are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. Eg: Take salt(NaCl), the crystals are made up of Sodium/Na ions and Chlorine/Cl ions and they form a repetitive structure. Take Diamond and Graphite - they are both made of carbon but differ only in their crystal structures giving them completely different properties.

The reduction or absence of gravity-driven forces allows for a slower and more orderly arrangement of molecules into the crystal lattice. This enables researchers to better determine the structures that offer high performance.

Microgravity applications span across:

a. Drug Research: The same principle of crystal structure applies to one of the key constituents of life that are vital to the proper functioning of tissues and organs in our bodies: Proteins. Each Protein - molecules made of a particular sequence of amino acids - has a unique 3D folded crystal structure that determines its function. Studying the structure enables one to better understand the protein's function and design drugs to work with the proteins and treat diseases.

b. Thin Film Manufacturing: Many products such as photovoltaic cells, chemical sensors, and optical fibres are multilayered thin films. Manufacturing these products in microgravity offers homogeneity, precise orientation, and stability of multi-layered thin films that increase the performance of these products at least by a factor of 10. Undersea silica fiber optic cables have repeaters that cost 1 Million $ every 50 miles and are subject to excess crystallization. However, ZBLAN cables made in microgravity have 2 orders of less attenuation and require less than 15 times fewer repeaters compared to these silica fiber optic cables.

c. Vaccine development: Microgravity experiments can help identify the components of the organisms(bacteria/virus) that facilitate increased virulence in space, and then applies that information to pinpoint targets for anti-microbial therapeutics, including vaccines.

d. 3D Bioprinting tissue organs: An organ contains multiple tissues made of different layers of cells. Let's suppose there are 3 different layers each with different types of cells - Layer 1 above which is Layer 2 and Layer 3 the topmost. When these layers are printed on Earth, due to the kind of materials and gravity, the layers may end up combining. To combat the effects of gravity, researchers use scaffold structures to support these layers. This limits the types of materials used and the types of cells that thrive in these environments. However, in micro-gravity, the mixing wouldn't happen due to the absence of forces such as gravity and the tissues can develop into complex three-dimensional structures.

e. Carbon Nanotubes: One of the strongest materials that is both lightweight and conductive known to science is Carbon Nanotubes - sheets of graphene. They are extremely difficult to produce on Earth due to convection but microgravity may offer a solution to manufacture them in a robust and scalable process that is commercially viable.

There are companies working towards enabling in-space manufacturing but understanding the capabilities of different materials in microgravity, preserving the material manufactured for long duration before bringing these materials back to Earth and building an economically viable supply chain system are the challenges that need to be overcome before space manufacturing becomes the norm.

Technical Landscape:

Research in microgravity has been around for 20-25 years. But the viability of commercializing the applications boils down to the economics of orbital manufacturing. At a top-level, there are 3 stages involved here:

• Launching the required materials at an affordable price

• A standardized autonomous space manufacturing unit/spacecraft

• Safe return of the manufactured product back here on Earth

Until the era of SpaceX, the cost of launching anything into space was prohibitively expensive. But the launch costs have drastically dropped from 50,000$/kg in the 1980s to 5,000$ per kg today. With new smallsat rocket launchers cropping up everywhere, this trend will continue to go further down to at least 3000 $/kg or optimistically less than 1000 $/kg by end of this decade.

Microgravity experiments have taken place so far in parabolic flights or on the ISS. However, they come with their own set of challenges. Parabolic flights last for a very short duration. While they can be ideal for testing the hardware and conducting research, manufacturing is not an option. The International Space Station (ISS) has been the host for both research experiments and manufacturing activities to date and has propelled the possibilities of in-space manufacturing. However, it has two major concerns:

a) ISS is part of a research community including NASA, ESA etc and not a commercial entity. Hence, a need for a new commercial equation that enables an in-space manufacturing economy.

b) The presence of humans/astronauts demand an extremely cautious approach towards manufacturing or conducting research in microgravity, increasing both complexity and cost. Additionally, the presence of humans demands air to be circulated which will hamper the effect of microgravity.

The current exorbitant costs of sending and bringing back a human from space also demand completely autonomous manufacturing units in space which is definitely not easy either. Building an autonomous manufacturing space unit that can be launched and returned to Earth is much more economically feasible because it will not require docking mechanisms or the environmental control systems like capsules designed to carry people.

In other words, a free-flying spacecraft that can be sent into low Earth Orbit with robotic systems onboard to manufacture high-value products. Different materials require different manufacturing units with different functionalities. Manufacturing protein crystals in space require different capabilities as compared to manufacturing optical fibres. Therefore, it is necessary to standardize spacecrafts based on manufacturing requirements.

Additionally, they must also support themselves with solar panels to power themselves throughout the journey, primary batteries to store and distribute power to perform manufacturing activities, propellants to change orbits or descend and other components to ensure automated, free-flying capabilities.

The third but most important segment is bringing the spacecraft safely back to earth from orbit. While gravity can assist in helping the spacecraft re-enter, the spacecraft has to tackle the atmosphere and the speed of re-entry(which increases as it gets closer to Earth). Air is made up of molecules, anything that passes through air should push through these molecules and at the high speed at which spacecrafts re-enter Earth(thanks to gravity), they heat up the air molecules. The heat then breaks the chemical bonds in these air molecules resulting in the electrically charged plasma surrounding the spacecraft. To prevent the spacecraft from burning, a thermal heat shield is required.

Additionally, for controlled descent, it is likely that the spacecrafts will carry parachutes to splashdown on water. (Although retro-propulsive thrusters that directly land the spacecraft could be an option in the future if we make advances in technology for landing small spacecrafts, miniaturize the technology and make it fail-proof.)

If the economics of orbital manufacturing - launch costs, re-usable spacecrafts and safe return - turn out to be comparable to manufacturing on Earth, there will be an increase in volume for the launch market, opening doors to industrializing space. And the returns will be enormous which is why so many companies are venturing towards industrializing space.

Market Landscape:

In-space Manufacturing as a commercial opportunity has been explored for at least almost a decade now. Made In Space, a company recently acquired by Redwire Space, has been one of the biggest players in space manufacturing. They have sent successful missions with facilities that leverage additive manufacturing to produce new materials at the ISS National Lab.

Space Tango builds research and manufacturing systems into compact smart containers, called CubeLabs focused on biotech and biomedical applications in microgravity. They also unveiled plans for a fully autonomous robotic orbital platform called ST-42 designed specifically for manufacturing in space.

Varda Space is the most recent startup to create buzz in this 'space'. The company raised 9 Million$ to create a scalable and economically viable system to manufacture products in space that are extremely important on Earth. With a vision to industrialize space, Varda Space aims to start with profitable unmanned in-space factories manufacturing product.

Space Cargo Unlimited is a European company that plans to leverage the advantages of a microgravity environment on manufacturing and production. The startup has formed a subsidiary dedicated to in-space biotech specifically called Space Biology Unlimited.

Space Forge Ltd is a UK start-up that is looking to lead the clean industrial revolution by harnessing space and raised 600K $ in seed funding in June 2020. They are developing fully reusable satellites that are designed for manufacturing next generation super materials in space for return to Earth to be used to help move to low carbon technologies.

There are a bunch of startups such as Yuri, Luna and Researchsat that provide services to research institutions to run their microgravity experiments in space. Techshot Inc., a commercial operator of microgravity research and manufacturing equipment, developed and sent a 3D BioFabrication Facility (BFF) aboard the ISS that bioprinted human tissues and intends to commercialize 3D bioprinting in space. Aleph Farms, an Israeli startup growing meat directly from non-GMO animal cells, launched its ‘Aleph Zero’ program focused on cultivating meat for space exploration. The company believes this will enable human life to become multiplanetary and build resilience for food security by producing meat in harsh as well as remote conditions on Earth and beyond.

SpacePharma is a company that aims to leverage the miniaturized microgravity lab technology through the end-to-end miniaturized lab systems developed in-house with sensors and readers, enabling unprecedented possibilities to develop new drugs in Space.

Tethers Unlimited Inc. is a company that develops robotic arms and manufacturing technologies to be deployed aboard the ISS in-space manufacturing to support long duration manned missions. Axiom Space which recently raised 130 Million $ is building the world's first commercial space station to provide Microgravity-as-a-Platform that will enable microgravity research and product development.

GITAI is a space robotics startup developing robots that can conduct tasks in all realms of space development, some of which will include space manufacturing but mostly focused space operations for building Lunar and Martian bases. They build general purpose robots, task-specific robots and remote tele-operable robots.

Astrogenetix, a subsidiary of Astrotech, is a biotechnology company developing and commercializing novel therapeutic products in microgravity in space.

Resources:

Factories in Space offers the best resources on startups working towards accelerating the space economy

A video by Bloomberg covering Made in Space on how space manufacturing could change everything we make.