After reading up on the matter I noticed that there currently are only two options to remain in space for longer than a few hours:
- International Space Station (US and Russia) assembled in orbit: altitude 409 kilometers (221 nautical miles), 51.65° inclination
- Tiangong-2 (Chinese): altitude 392 kilometers (212 nautical miles); crews transported by Shenzhou spacecraft
(Source: Wikipedia on human spaceflight)
And two upcoming commercial alternatives that provide a longer stay in space (24+ hours):
Which provide hope as steppingstones for human space exploration. Especially since Bigelow Aerospace has already been testing their inflatable module on the ISS!
Though the initial press message of Orbital stated it would be available in 2016, which it was not. On top of that the website of Orbital Technologies had its most recent messages in 2011.
So Orbital Technologies' prospects don't look too promising anymore, which led me to question:
Are there any other commercial competitors which intend to provide long (24h+) space stay?