The US is currently, and for the foreseeable future, solely reliant upon Russia to get astronauts to & from LEO & the ISS. Frankly, I'm surprised Putin hasn't rattled that saber yet.
Edit: I'm rooting for Sabre & Skylon, myself. Perhaps not for big payloads but for 'naut travel, anyway.
Edit: I'm rooting for Sabre & Skylon, myself. Perhaps not for big payloads but for 'naut travel, anyway.
https://en.wikipedia.org/wiki/SABRE_%28rocket_engine%29
https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29