Welsh-based Space Forge has achieved important breakthroughs in semiconductor manufacturing, deploying an orbital furnace on-board its ForgeStar-1 satellite. This innovative project aims to produce seed crystals for gallium and aluminum nitride or silicon carbide substrates, which are essential for high-performance power devices. The furnace produces extremely hot plasma with incredible accuracy. This discovery marks a new milestone in the search for more effective materials for use in electronics.
The satellite operates in low Earth orbit (LEO). It harnesses the unique properties of microgravity to improve the quality of crystal growth. Space-grown crystals have huge potential. Through this improved electron mobility, they have been able to get 20 to 40 percent more switching efficiency than crystals grown on Earth. The combined impacts of these breakthroughs have the potential to create massive benefits across untold electronic applications.
Space Forge’s mission is particularly well-timed, as demand for advanced materials continues to grow. The market for in-orbit manufacturing is poised to take off. It is projected to reach $28.19 billion by 2034, highlighting the tremendous economic opportunities this technology has to offer. The company has announced plans to return this first batch of space-grown crystals back to Earth on a follow-up mission next year. Their goal is to demonstrate the feasibility of manufacturing in space.
The Science Behind Space-Grown Crystals
Between 1973 and 2016, only about 160 semiconductor crystals were ever successfully grown in microgravity aboard spacecraft. The Discovery channel reports that 86 percent of these space-grown crystals grew larger and showed more uniformity. They even did better than their Earth-grown counterparts. The microgravity environment offers more homogeneous conditions in which the crystals can grow which is decisive to reach high-quality materials.
On Earth, the effects of gravity create challenges for the crystal growth process, frequently resulting in non-uniform development inside reactors. Crystals may break or grow unevenly across the inner interior surfaces as opposed to evenly and symmetrically throughout the entire growth medium. In space, the unique conditions just provide crystals a “better head start.” That’s because the artificial environment enables them to grow more uniformly and efficiently.
“For example, if you’re worried about nitrogen interfering with your growth process, on Earth nitrogen might be present at concentration of around 10 to the -11,” – Joshua Western
In outer space, above 500 kilometers altitude, nitrogen is virtually non-existent. This concentration is about 10 to the power of -22. This dramatic difference further purifies the semiconductor growth environment, increasing the likelihood of higher-quality semiconductor materials.
Economic Viability and Future Prospects
The economic prospects of crystals grown in space has become more pressing as launch costs to reach low-Earth orbit continue to drop. SpaceX’s Falcon 9 provides launch services for less than $1,500/kg. This cost-effectiveness has opened the door for companies like Space Forge to realize their manufacturing operations in space.
Yet even with this advancement, experts are warning that the costs of developing manufacturing capabilities in space still needs to decrease. Matt Francis emphasizes the huge decrease in expense too, going from $20,000 per wafer only a few generations ago to hundreds of dollars today in volume markets. He notes that these reductions still fall short of the declining production costs for wafers on Earth.
“While I remember paying $20k a wafer in the early days, we are down in the hundreds of dollars range in volume markets like power,” – Matt Francis
There’s some hope in thinking about more niche applications where space-grown materials could offer significant cost advantages. As Lehigh engineering professor E. Steve Putna notes, using a space-grown substrate might improve the yield of a cutting-edge AI processor from 50 percent to 90 percent. More importantly, it would let quantum computers operate at or near room temperature rather than near absolute zero, which would make launch costs a tiny fraction of the overall value produced.
Challenges and Considerations
Even with such a promising outlook for space-grown crystals, challenges still exist. According to lead researcher Anne Wilson, microgravity is not the ideal environment for bulk materials manufacturing. While this is true, the impact on specialized applications has tremendous benefits and thus space manufacturing is an investment worth making.
“I don’t think that microgravity is going to be ideal for the manufacture of bulk materials,” – Anne Wilson
This is because degradation could potentially happen over time and through generations of crystal growth, notes Joshua Western. This degradation can reduce long-term performance. Environmental conditions, which must be accounted in the design, underscore the importance and necessity for continued rigorous research and development applying crystal science and engineering principles.
Space Forge is currently preparing for their next de-orbit later this year. To keep its returning satellite safe, the company will attempt to use an experimental heat shield to protect its satellite as it re-enters. This maneuver is intended to exercise ForgeStar-1’s ability to repeatedly build the optimal manufacturing environment. Further, it’s essential for the effective growing of superconductor crystals.