There's a long chain of influences across the border in winged spacecraft development. Dyna-Soar (https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar https://en

There's a long chain of influences across the border in winged spacecraft development. Dyna-Soar (https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar https://en.wikipedia.org/wiki/Boeing_X-20_Dyna-Soar) project in USA pushed works on Spiral' project in USSR, and BORs are a part of that. It arguably provides a link from HL-10 via USSR projects to HL-20, among other things.