Comment by georgefrowny
6 days ago
4000 times purer seems a questionable claim to me. 4000 times purer then what? Current Earthbound state of the art? A guy in shed with a vacuum pump and a heater? On what axis: crystal defects or contamination?
High vacuums aren't at all impossible on Earth and silicon boules are already single crystals.
What exactly about their process permits such a huge quality improvement?
The best silicon single crystals still contain impurities at the 1E-11 level. This project is about doing crystal growing in low gravity (the ultra-high purity is only achieved due to the growth process). The vacuum of space is a lot worse than what can be achieved in the lab, especially in low orbits.
There have been experiments to create higher vacuums in space, which have been used to grow semiconductor crystals:
https://scfh.ru/en/papers/vacuum-in-the-wake/
https://en.wikipedia.org/wiki/Wake_Shield_Facility
I'm not saying it's practical, but it's pretty cool.
What I'm struggling with is the hard radiation, which causes defects and even impurities even if you start with isotopically pure feedstock
I had a similar thought regarding radiation - but also curious about cost to continuously launch materials and the overall reliability of recovery. Just seems like a lot of "what ifs" for the sake of finding funding.
What is the current defect rate preventing from happening? If you can lower it three orders of magnitude, what then becomes possible?
Earth's surface isn't a microgravity environment. The principle that you can get purer crystalline structures with less interference from the earth's gravitational pull has explored on space stations since the 1970s; that aspect and potential applications in higher performing semiconductors and drugs are fairly well understood
What hasn't been solved yet and Space Forge (and Varda et al for biotech) are hoping to solve are the unit economics of reentry vehicles to actually make it viable for manufacturing.