The transfer tunnel, known by the Russian acronym PrK, connects the Zvezda module with a docking port where Soyuz crew and Progress resupply spacecraft attach to the station.
Air has been leaking from the transfer tunnel since September 2019. On several occasions, Russian cosmonauts have repaired the cracks and temporarily reduced the leak rate. In February, the leak rate jumped up again to 2.4 pounds per day, then increased to 3.7 pounds per day in April.
“The Russian position is that the most probable cause of the PrK cracks is high cyclic fatigue caused by micro-vibrations,” Cabana said on November 13. “NASA believes the PrK cracks are likely multi-causal, including pressure and mechanical stress, residual stress, material properties, and environmental exposures.”
Crew members aboard the space station are keeping the hatch leading to the PrK closed when they don’t need to access the Progress cargo freighter docked at the other end of the transfer tunnel. Russian cosmonauts must open the hatch to unpack supplies from the Progress or load trash into the ship for disposal.
As a precaution, Barratt said space station crews are also closing the hatch separating the US and Russian sections of the space station when cosmonauts are working in the PrK.
The question is how much would it cost to build such? I believe the International Space Station itself cost like $100 billion to build, which is a lot of money. Now, maybe Space Station construction costs have dropped in the like 20 years, or something like that, since then.
$100 billion sounds a lot, but in comparison it’s miniscule. For that amount of money you can either run an international space station for 24 years or the US military for 1.3 months, or the russian military for one year. If we’d just start killing eachother a little less, we could easily save that much money.
I am all for killing less people and funding space stations. That’s for sure.
I would assume inflation made the number bigger today even if costs have dropped.
Well, apparently it cost a hundred billion to actually build the thing and that was in like dollars in 2000. So you’d have to hope that space station development went down faster than inflation went up. And if so, it might actually cost a little bit less to build it today.
Right now? Effectively infinity dollars. Or Euros. Or Dongs. Regardless of the currency used, really. The only operational launch vehicles that have the diameter and payload capabilities to put up modules of comparable size are the SLS and Vulcan Centaur. Everything else comes up short in size, payload, or both. But getting the modules up there is only step 1, they also need to be attached. For the ISS, the Shuttle’s Canadarm was used to actually assemble the station in its early stages. Nothing currently operational has that capability.
Of upcoming launch vehicles, New Glenn and Starship are both capable enough in both size and payload. But of all the options, only Starship could be equipped with something like Canadarm. Starship is an orbiter with a payload bay. Everything else’s second stage is just engines, tanks and a payload adapter for simply deploying something into orbit.
You might ask “Why not design the modules to dock and assemble the station autonomously?” It’s a valid question, but it comes down to two things: complexity and mass. Every module would need its own full suite of guidance and control systems. And they’d be used only when a module is maneuvering to meet with the rest of the station. That’s a lot of mass wasted on something that only gets used once, mass that could’ve been put into making the module itself bigger. There’s also the issue of any leftover propellants and their residues on the module exteriors. It’s practically inevitable that some residue from the thrusters will end up on the connecting surfaces of the modules. A lot of the common orbital maneuvering propellants are toxic as fyuck and you don’t want any of it near unprotected people. And any residue could interfere with getting a firm seal between modules.
Another thought is to put something like Canadarm on the first module, but that also wouldn’t really work. Soon as it tries to move a second module into position, the two nearly equivalent mass objects would start tumbling around the common center of gravity, putting the entire proto-station into an uncontrolled spin on several axes. Stopping it would require, once again, thrusters.
Yeah, you make a very good point, and at least to my knowledge, the private space stations that are being talked about are only one module. I think there was a proposal for a multiple module station. But it would suffer the same issues that you are talking about with having to have guidance on each module and possibly having propellant on the outer surface. As you mentioned above,