In a rare video call to the International Space Station on Tuesday, RT asked Roscosmos cosmonaut Mikhail Korniyenko and NASA astronaut Scott Kelly questions from the channel's viewers. The crew opened up about the pros and cons of space life.

RT viewers grounded on Earth were understandably curious about life on the International Space Station (ISS), asking questions ranging from the coffee situation, to whether relations between the US and Russia affect the astronauts' relationship with one another.

Perhaps the most obvious hardship faced by the ISS residents is the fact that everyday earthly luxuries – such as hot showers and the ability to breathe fresh air – simply don't exist in space.

READ MORE: Russia-US crew dock at ISS for near year-long mission

Kelly said he misses the comforts of home, including “running water, the ability to go outside...air quality varies at times, but by and large it's pretty good.”

He added that there is simply no escaping work – because he can't go home at the end of the day.

“One thing that I find least appealing is that you're always at work. So imagine yourself, regardless of what kind of job you have, that you never leave. So it always feels like you're working, that you're always on. So over the long-term that can become fatiguing.”

READ MORE: NASA spaceman posts stunning pics on his 1yr ISS mission

But there is at least one luxury that will soon be enjoyed by Kelly and Korniyenko – coffee.

Referring to the espresso machine that was just delivered to the ISS, one RT viewer was curious if the astronauts had already brewed themselves a cup or two.

While Kelly said that he and Korniyenko “definitely look forward to the espresso machine,” he said they have not yet had a chance to enjoy it.

“We have a lot of activity going on right now with the dragon resupply ship that just brought the machine up to the station. So with that and all the other science going on, we still haven't had the opportunity to get into the espresso machine.”

But even once the machine is christened, the astronauts understand the need to use it sparingly – because they only have 15 servings.

“Unfortunately they use the single serving cartridges...I think we only have 15 of them now so we're not in any kind of rush to get through them and use them all up,” Kelly said.

And when the coffee runs out, the astronauts also won't be able to pop open a can of beer.

“It would be nice [if we had beer, but we don't]. One problem if any kind of carbonated beverage...when you open a beer or soda on Earth the carbonation will come to the top and out of the bottle...when we do that in space it would just stay in the liquid itself; it wouldn't rise to the top. So you'd be drinking a beverage that would have a lot of gas in it, so that's not ideal,” Kelly said.

Beer- and coffee-drinking aside, some of the questions posed by RT viewers were a bit more serious.

When asked whether tensions between the US and Russia have any impact aboard the ISS, Kelly responded with a concrete “no.”

“They don't. Up here on the space station we rely on each other, literally for our lives. We are great friends, professionals, colleagues, and it is not something that ever comes up in conversation, or should it...these are great guys and I wouldn't want to be flying with anyone else...what we're doing is very important and we'll leave those discussions to those that make that their job.”

Speaking of jobs, the two high-fliers have one that is envied by space enthusiasts and adrenaline junkies around the world...but one viewer was curious how Korniyenko came to enter this line of work.

“My father was a fighter pilot in the military. He welcomed the first cosmonauts back from space... At that time, space exploration was tremendously popular in the Soviet Union. I remember my father bringing souvenirs from the first landings...and that’s how I got the idea in the first place. And step after step, I went...through many hardships to this final goal, this ultimate goal in my life.”

But that doesn't mean the two men don't dream of life back on Earth from time to time.

“Before I got here, people asked me often about my last flight, what kind of dreams you have in space, and whether they're dreams that you're in space or on Earth...I remembered I dreamed in space, but not what [the dreams] were...so this time I made an effort that now when I wake up in the morning and remember what I've dreamt, I write it down...what I can tell you is they're sometimes about being on the space station with people who aren't even part of crew, and other times they're about being on Earth...when I sleep better and I'm more tired when I go to sleep, my dreams are about when I'm here.”