Are astronauts stuck on the ISS?

Do Alexander Gerst and the crew of the ISS have enough food?

Yes. They have plenty of food. They will not starve. And it is good food.

Can they still get home?

Yes. There's a Soyuz spacecraft attached to the ISS that's just begging to take them all back to Earth. And they can go whenever they'd like. Yes, yes, yes, this is the same spacecraft that once had a two-millimeter hole in it.

But that hole was in a section that has no relevance whatsoever to the crew's re-entry. It'd be like discovering a hole at the airport near your gate, then boarding your perfectly safe airplane and leaving that hole far behind. 

So what's the big deal then?

Right now there is no operational rocket on Earth that can bring people to the ISS. That's just... spooky, isn't it? There's no way to get up there. It just feels like we've lost an important lifeline, even if temporarily. That's how dependent we were on the Soyuz, which remains the world's most "robust, reliable and sound" manned rocket, as Thomas Reiter, the German astronaut who advises ESA's director general, told DW after the failed launch. In the tweet below, the head of Roscosmos (pictured center) loosely identifies "spring" as the time the Russian space agency hopes to fly the two crewmembers to the ISS. That's... quite a while.

That said, the "freight trains" of space, aka unmanned rockets, can still bring supplies up there. SpaceX, Boeing, and Japan's JAXA space agency all have rockets capable of doing this. So we can send stuff up there. Just not people.

OK, so we just send them supplies and they can stay up there.

No, they can't. Remember that Soyuz capsule? The one with the hole in it? It's got a battery life of 210 days (plus a "buffer," according to Reiter). So based on its arrival in August, it has to leave the ISS, with the crew inside, at some point near January 2019.

That's well before "spring."

And also, even if they could stay up there longer, would you want them to? Long-term spaceflight is hard on the human body, with radiation, bone loss, elevated core temperatures, and some weird eye/brain morphings being just a few of the known medical issues. Microgravity hurts astronauts - and in ways we're not quite sure of yet. It's best to take a teaspoon of it, not gulp down a ladleful.

So the question is really just whether the three crewmembers up there — Commander Alexander Gerst of Germany, Serena Aunon-Chancellor from the US and Russia's Sergey Prokopiev — will be back on Earth before, or shortly after, Three Kings' Day on January 6.

Great!

Not really. In the short term, imagine having to keep a cafeteria running, but instead of having five people to cook, clean and fix that finnicky oven, you just had three. Would you cook less food? Clean fewer dishes? Or work longer hours? Similar questions now face the ISS planners. They've planned for this contingency, of course, but repairs will now have to be re-prioritized based on the fewer hands available. It'd stand to reason that some science will get lost as a result, and that's a pity. The ISS will be emptier, and for the worse.

Then, come January (roughly), the ISS might be TOTALLY empty. And nobody wants that.

To understand why, let's say you were renting a large cabin way out in the forest. There'd be a big difference between handing the keys over to the next round of friendly, smiling guests versus locking it down for winter. The lockdown scenario would involve draining the outdoor water lines, closing the chimney chute, battening down the shutters, etc.

And then, once you leave, you'd have to wait three months to get back inside if you realized you'd left a burner on. 

There are probably a million other issues that would or could crop up in microgravity, some of them foreseeable, some of them not. But none of the space agencies involved in ISS operations want to see it, 400 kilometers (250 miles) above our heads, passing over us every 90 minutes like an abandoned, billion-dollar ghost ship.

Is there a solution?

Not yet. According to Reiter, SpaceX will do an unmanned test flight this year. Boeing will follow suit at the beginning of 2019. Then, after that, a first manned mission is expected to happen.

"You have to assume that, at the very latest, one of the two companies will be involved in the first quarter of next year ... to take astronauts to the ISS," Reiter said. He then clarified that he'd meant SpaceX, and that, shortly thereafter, Boeing would likely follow with its Starliner.

That would allow astronauts to reach the ISS once more between January and late March of next year.

The question is — will it be empty when they get there?