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IrishRage42 t1_jc75lg9 wrote

Reply to comment by SlavaUkrainiFTW in NASA wants new 'deorbit tug' to bring space station down in 2030 by DevilsRefugee

Are there no parts of the ISS they could use with a new station? Or is it's orbit too far off from where they want to build a new one? Or it's more cost effective to launch all new equipment?

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PandaKing185 t1_jc78hje wrote

Just a hypothesis, but the core technology on the ISS is over 20 years old at this point, and I'm sure we have learned a lot ways in which we can improve upon the basic design and systems. There are standards used in the ISS design that any incremental update (think replacing one module at a time) would have to be backwards compatible with as it transitions, thus limiting any major overhauls. I imagine it would be more cost effective and allow for more improvements to just start from scratch using everything we've learned and create new standards

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LukeNukeEm243 t1_jc7oitd wrote

Axiom is planning to use the ISS as a starting point for their new space station. Axiom's first module is planned to launch in late 2025 and will dock to the forward port of the Harmony module of the ISS. The second, third, and fourth modules are planned to launch in 2026, 2027 and 2028 respectively. Then the Axiom segment will separate from the ISS and become its own modular space station.

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cowboycoco t1_jc78l2m wrote

It's too far off. The ISS orbits at about a 51.6 degree inclination to make it easier for Russia to get there. The moon orbits at about 28 degrees.

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Raspberry-Famous t1_jc7gpe9 wrote

Stuff wears out over time. Even something as simple as the shutters on the cupola windows have through hull connections that have o-rings to make them air tight.

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Northwindlowlander t1_jc8a6oc wrote

For quite a while it was assumed that using the old ISS as the building site for a new one was the best way to do it- without the shuttle, assembling was going to be harder. But the chinese station pretty much shows that time's past, especially considering that you don't necessarily want the new station in the same orbit

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thegoodtimelord t1_jc8m17h wrote

So looking purely at the physics and safety rather than the dollar cost, what is the current consensus among us Reddit armchair experts about the best location for a replacement international off world station, moving forward?

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Northwindlowlander t1_jc91tct wrote

Safety isn't that much of a concern, it's a simplification but all of the places we're likely to put an orbiting station for the forseeable future are in the same ballbark of risk in terms of ease of access and return, obstacles, etc.

You can't separate physics and dollar cost since dollar cost is directly related to payload, quite simply delta v costs money.

Launches play a big part... Like, the ISS is low enough that it suffers a lot from atmospheric drag and its orbit needs frequent boosts (and that'll get worse as the atmosphere warms). But obviously higher up = harder to get to. So that's just a plain old compromise, but it's ultimately one that can be handled within a really wide range- raising it occasionally is just a question of fuel, so that's meant that the low-ish orbit has worked well and that's probably still true.

The other being the orbital path of course, since you have to have the launches intersect with the orbit. And that's simple phyics really but not simple human-stuff. Where will we be launching from in 2040, and how will we be launching? Will we have equatorial stations, or more mobile floating launchers? Will be still be using chemical rockets for everything with no other options in sight, or will we be kettling stuff up, or have a big railgun up an equatorial mountain, or be launching payloads from the moon, or getting close to any of those? It all gets insanely complicated, right down to "which US politicians want to keep launching from their state" or "which countries will be friendly and stable enough to invest this stuff in"

An ISS replacement in the short to medium term, I bet 20 scottish pence would end up at a similar orbital height, but with a different track to suit current US launch sites and less or no thought to Russian cosmodromes. In the longer term I'd expect payload delivery to get easier and therefore a higher altitude to become more desirable, especially with a warming atmosphere, but for now it's almost certainly still better to be lower and to get mass there easier

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