needs to be alive and complete at least one full orbit, second after:
What will be the next astronomical object a human orbits around?
see also:
What will be the next astronomical object a human lands on?
What will be the second next astronomical object a human lands on?
Does it have to be an actual, gravitationally bound orbit? Or just going around the object covering roughly 360 degrees?
@CodeandSolder It depends on where the object is and how big it is. My favorite scenario, where a relatively small asteroid is brought to lunar or Earth orbit robotically and the human astronauts land on it may rule out orbiting around it. What you need is that the Hill sphere of the object is not fully within the object.
Venus is like a third of the distance from Earth that Mars is. I don't know what the purpose of orbiting it in person would be though.
@cloudprism the linear distance is pretty much meaningless though, the Δv is nearly the same, the transfer time is significantly different but I'm not sure how much that matters at this scale.

@CodeandSolder Yeah, there's just very little reason to go there, until/unless we want to settle there. But that's two orders of magnitude harder than settling on Mars.
Other places we could go are also harder, like Titan for settlement purposes or Ceres because it would be cool. So my votes are on Mars, and after that Phobos or Deimos because they're somewhat easy if you're already on Mars.
We could slingshot around Venus on the way to Jupiter, but that's not an orbit, and I doubt it anyway because it makes the transit time too long.
Oh and it's very unlikely to be a moon of another planet, because nearly all trajectories put you in orbit around the planet before you get into orbit around the moon.
@CodeandSolder Just to make sure, "the sun" doesn't count as an astronomical object for this market right? 😅
@CodeandSolder Hmm, yeah usually you wouldn't go a full orbit around the sun... Is that a requirement for the other astronomical bodies though? Just "being in orbit" doesn't usually mean having to do a full orbit around, it just means that if you don't do anything else then you would eventually do an orbit around.
It's probably cleaner to just exclude the sun, it's not really what the market is about anyway. Otherwise you get edgecases like, what if you put a station at the L1 point between the earth and the sun? That's not in orbit around the Earth but also only sort of in orbit around the sun.