Can you honestly write you believe there are astronauts on the ISS?
If yes, why?
Yes. As for why...
Because you can see the ISS from the ground. It's definitely up there. There are websites where you can find out when and where to see it.
I've even see a video from a flat earther (Jeranism, possibly?) showing the ISS doing a transit of the moon. Even he conceded it was up there.
I've seen a Shuttle launch so I know that the Space Shuttle was a thing. No, I didn't see it go all the way into space but neither did I see it land anywhere.
I've not seen a scrap of evidence that the shuttle secretly landed anywhere. I have no reason to think that the Shuttle didn't operate exactly as NASA claimed. Hundreds of people have been to space. Am I to believe they are all lying? 7 of those were "space tourists" who paid a huge sum to spend time on the ISS. Are they lying too or have they been fooled somehow? In the space race in the 60s Russia got many of the initial "firsts" then the US started pumping huge amounts of money into it and managed to overhaul them. Neither site ever called the other out as faking anything. Why wouldn't they?
Jodrell Bank in the UK was tracking the Apollo 11 mission and Luna 15, a Russian unmanned probe that crashed on to the moon not long before the Eagle landed.
https://www.jodrellbank.net/20-july-1969-lovell-telescope-tracked-eagle-lander-onto-surface-moon/https://www.bbc.co.uk/news/uk-england-manchester-49001181Are these guys lying too?
My Satellite dish is pointing at something in the sky. I know this because a neighbour did some work on his house and the scaffolding blocked the signal, he had to move the dish for me so my TV worked again. My GPS works, I have no reason to think it works in any other way than the way I've been told.
Do you believe have the ability to discern the difference between the videos presented as originating from the ISS and those of the movie Gravity
I don't. But do you? All the "evidence" I've seen claiming that the footage is faked is from people who are clearly not experts in the field. Vague assertions from people with an agenda isn't strong evidence of fakery.
Further, even camera shots from the ISS have been shown to present way more curve than would be mathematically expected.
So what's your claim here? Someone else has explained to you about different lenses and the effects of them.
Are you claiming that NASA are smart enough to fake footage from space well enough to fool most people in the world but also dumb enough to get the curve wrong? Or did they deliberately put a fish-eye effect on their CGI to help out the conspiracy theorists? Why on earth would they do that?
Bottom line: I can't go to space right now. I can't go to Antarctica. I could go to Australia, but it's a long way. My beliefs about anything I can't directly experience have to be based on other people's accounts, as do yours. I know you're all about what you personally witness but that isn't always possible. Do you have an opinion about the Kennedy Assassination? Unless you were there, your opinion has to be based on things you've read and seen as does mine. Unless we witness an event, that's all we have. We have to look at evidence and balance of probabilities. What is your evidence that makes you think space travel isn't a thing and is all a big hoax? Powerful rockets demonstrably exist so why is it so hard to believe?