Commercial Space Station

fredymac

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Another new NASA project based on the NextSTEP program.

“NASA seeks to enable multiple privately owned and operated destinations in LEO that are commercially viable in the long term, providing services to the Government as one of many customers,” the draft solicitation states. “NASA seeks to potentially transition away from full reliance on the ISS and cost-effectively meet its long-term needs in LEO by purchasing services from commercially owned and operated destination(s) that offer a broad portfolio of products and services to both the commercial market and NASA.”

Story
https://spacenews.com/nasa-looks-to-support-development-of-commercial-space-stations/

Obviously Bigelow will make this a "must win" effort. Hopefully, someone will have an artificial G proposal. Or maybe Bigelow can steal an old design right up their alley.


Goodyear Inflatable Space Station.jpg
 
Bigelow already did present an idea: XBAse
(Bigelow B330 Commercial Space Station)

It starts attached to the ISS but eventually goes free-flyer and with the addition of a second module it becomes "Space Station Alpha"

To get an AG station you could assemble something like the 1962 "Olympus" single launch space station concept. Instead of having the arms already set up with modules, (wrong orientation to how it's designed since it's a horizontal instead of vertical like the original TransHab) you'd just have the access tubes to the central axis and dock a BA330 to the tubes (3 total to start) Then rotate the station for an initial couple of microgravities. Add tubes and docking systems and more modules and you'd eventually get something like the Von Braun Space Station concept:

That Gateway Foundation proposes.

Randy Project Olympus Space Station Concept 2View.jpg
 


 
Obviously Bigelow will make this a "must win" effort. Hopefully, someone will have an artificial G proposal. Or maybe Bigelow can steal an old design right up their alley.

View attachment 619812

This is surely the way ahead for long-term manned stations. It still has significant engineering challenges:

Do you de-spin the hub dock, or do you spin up the approaching shuttle? Spinning up the passengers in a zero-gee environment might have physiological kickback (think vomit comet), while having everything spinning on the station is a PITA for communications and survey, so my money is on attaching the lock to the de-spun stuff.

Given you have some zero-gee de-spun stuff, how do you vacuum seal the bearings? This is everyday engineering for the waferfab and cryopump industries, but scaling up to a bleedin' habitat will take some doing (think multiple bearings and scavenging pumps).

What is the structural lifetime of a plastic fabric under space radiation? Even light alloys are proving a challenge. How do you provide adequate insulation? My money is on a double-wall construction with structural inner, and an aerogel particle-shower catcher in between. The aerogel would be squooshed in post-inflation.

Seems to me this is a lot more plausible than hypothetical medical advances to induce long-term tolerance of low-gee einvironments.

Like the SSTO in the background, but don't believe it any more than the bioengineering.
 
This is surely the way ahead for long-term manned stations. It still has significant engineering challenges:
The main quiestion is - why exactly anyone would want artificial gravity, when zero-g is one of the most important keys for commercial space research & manufacturing? Its counter-productive. Most of space experiments on ISS are linked to zero-G (okay, actually freefall) conditions.
 
This is surely the way ahead for long-term manned stations. It still has significant engineering challenges:
The main quiestion is - why exactly anyone would want artificial gravity, when zero-g is one of the most important keys for commercial space research & manufacturing? Its counter-productive. Most of space experiments on ISS are linked to zero-G (okay, actually freefall) conditions.
The issue is specifically over the long-term habitability of a manned environment. We all know the muscular and skeletal deterioration encountered during prolonged low-gee exposure. Exercise, pills and springy clothing are only partial solutions. Less widely publicised is the brain damage. In everyday life, when we lie down and sleep our cerebrospinal fluid seeps up into the brain cavity, and during the day is gets pulled back down again by gravity. Take away the gravity and it builds up constantly; the internal pressure rises to painful and eventually damaging levels. As yet there is no route to prevention. Until these issues are solved, there can be no long-term habitation in space for anyone other than a few unlucky guinea-pigs. Artificial gravity solves them all at a stroke, and so is the only option for the foreseeable future. One might foresee a space station comprising both AG living quarters and zero/micro-gee manufacturing facility alongside. Another solution would be fully autonomous AI, with us wetware left in the queue at the spaceport for as long as it takes to reinvent our physiology.

And you know, why research high-gee processes in the ISS when you can already do so on Earth?
 
Do you de-spin the hub dock, or do you spin up the approaching shuttle? Spinning up the passengers in a zero-gee environment might have physiological kickback (think vomit comet), while having everything spinning on the station is a PITA for communications and survey, so my money is on attaching the lock to the de-spun stuff.

The probable solution may be tangential approach. I.e. shuttle would approach station on tangential course to its rotation. The station would release long truss/cable, that shuttle would catch & use to bend its trajectory into rotation around the station, synched with the station's own (since the truss/cable is long, the shuttle crew would not feel much discomfort). Then the shuttle would slowly drag itself down the truss/cable toward the station.
 
This is surely the way ahead for long-term manned stations. It still has significant engineering challenges:
The main quiestion is - why exactly anyone would want artificial gravity, when zero-g is one of the most important keys for commercial space research & manufacturing? Its counter-productive. Most of space experiments on ISS are linked to zero-G (okay, actually freefall) conditions.
The issue is specifically over the long-term habitability of a manned environment. We all know the muscular and skeletal deterioration encountered during prolonged low-gee exposure. Exercise, pills and springy clothing are only partial solutions. Less widely publicised is the brain damage. In everyday life, when we lie down and sleep our cerebrospinal fluid seeps up into the brain cavity, and during the day is gets pulled back down again by gravity. Take away the gravity and it builds up constantly; the internal pressure rises to painful and eventually damaging levels. As yet there is no route to prevention. Until these issues are solved, there can be no long-term habitation in space for anyone other than a few unlucky guinea-pigs. Artificial gravity solves them all at a stroke, and so is the only option for the foreseeable future. One might foresee a space station comprising both AG living quarters and zero/micro-gee manufacturing facility alongside. Another solution would be fully autonomous AI, with us wetware left in the queue at the spaceport for as long as it takes to reinvent our physiology.

And you know, why research high-gee processes in the ISS when you can already do so on Earth?

The solution is to rotate space workers, obviously, which is what literally every space agency does. Astronauts become oil rig workers who show up, do a job for 6 months, go home, repeat. It's a harsh environment and any advantages it has over Earth proper are somewhat inimical to the health of the occupants. No one wants to actually live in space lol it's not like you can raise five kids and a few chickens with your wife in a spent fuel tank. The benefits of zero gravity for manufacturing metals or growing crystals or something would vastly outweigh the relatively minuscule effects on the body of the workers.

Trying to replicate an Earth like environment on a space station is a good way to not have a reason to have space stations though.
 
Artificial gravity solves them all at a stroke, and so is the only option for the foreseeable future.
Of course, but near-Earth commercial space station is hardly a model of long-term habitat. Corporations would hardly pay for crew to stay longer than required for a specific set of experiments. And adding artificial-g to what essentially is a zero-g laboratory would create a lot of headache. Not only from engineering point of view; just the additional vibration and acceleration would seriously affect the zero-g experiments.
 
The solution is to rotate space workers
The whole thing about long-term habitats is that crew rotation is: a) ludicrously expensive, and b) by definition not long-term.

It's almost like there's no such thing as a long term habitat in space or something?

The only long term habitat for humans is Earth. Simple as.

Exporting steel refineries or something to space is beneficial for the environment since it removes the possibility of GHG emission and pollution and it would make metals and such stronger. This doesn't require any more a long term habitat than going to work requires you to sleep at your office...

There are no beneficial properties to having artificial gravity on a space station. It actually eliminates the beneficial aspects of the space station in the first place, so it would be a great way to dissuade people from investing in them if that's your goal, whereas most people prefer to have zero gravity for improved crystal growth and such. A steel refinery in space, by definition, would need to be zero gravity to have any benefit over Earth refineries or else it's pointless.

If that's going to hurt their DNA or make their bones weak until they start lifting weights again or whatever...so what? They're astronauts. They signed up for it. It's not like working in a refinery on Earth is good for your lungs either. Just find some other people to do the job. You don't need to be a PhD to work at a robotic refinery as a technician. It would be more akin to an underwater welder-technician. Highly paid, but still a trade that someone of more average intellect and demeanor can do, rather than a academic field that requires a literal one in a thousand combination of high IQ and cheerful personality.

It's not going to be hard to find those people, as they'd be working for a month and off for a month or two, much like a driller.

There are some beneficial properties to having artificial gravity on a Mars cycler space bus, and it would probably be highly desirable for anything beyond Martian orbit, as that would take the better part of a year to get anywhere even with a fairly robust starship.

It would absolutely be required for any sort of generational starship but you'd probably be exporting embryos and sperm tbh.
 
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The only long term habitat for humans is Earth. Simple as.
So you'd see projects like NASA's proposed manned Mars expedition as wholly unrealistic?

NASA expects people to raise families on Mars and establish self-sustaining multi-generational economies? I thought they were literally just going to collect some dirt and plant a flag lol. Perhaps you have a different definition of "long term" though?

Going to space for a year or whatever is not very important and probably wouldn't be advisable for any profitable venture that expects to reuse employees more than a couple times. This is fine for scientific and exploratory work because astronauts are literally paid to destroy their bodies so they can produce useful work. They have exceptional bodies to begin with so knocking them down to merely average, while a hefty amount of damage, is not going to terribly injure them unless you think average people are physically or mentally diseased I guess.

The only long term establishment in space is going to be establishing self-sustaining economies that can produce children indefinitely without importing goods from the rest of humanity. That's literally impossible at the moment, and will likely be impossible forever, without some rather dramatic shifts in macroeconomic outlooks at least.

However, space can be useful for producing things like steels, ceramics, and microelectronics (to name a few), and can potentially be a pathway to exporting most of our most environmentally deleterious industries off the only place where humans can naturally exist in the universe, helping us take care of a world that's been poisoned by pollution and industrial waste products. If you vent those into space they suddenly cease being issues for the world to deal with and become issues for the wider solar system. Not our problem.

Building a orbital ring that exports farming tractors or washing machines in reentry capsules to Earth's surface and eats asteroids to make such on-demand products is likely infinitely easier than making Mars habitable, as one we know is absolutely possible (it's simply a matter of scaling things, sufficiently automating production, etc.), and the other is so distant it's much easier to imagine than the former. The fact that a giant ring factory seems imposing, difficult, and frankly silly, is only because we are much closer to knowing the actual difficulties in producing one than the difficulties of making human reproduction work in microgravity, or even reduced gravity like Mars, or whatever.
 
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So you'd see projects like NASA's proposed manned Mars expedition as wholly unrealistic?
NASA expects people to raise families on Mars and establish self-sustaining multi-generational economies? I thought they were literally just going to collect some dirt and plant a flag lol. Perhaps you have a different definition of "long term" though?

According to NASA here, "On Mars, astronauts would need to live and work in three-eighths of Earth’s gravitational pull for up to two years. Additionally, on the six-month trek between the planets, explorers will experience total weightlessness."
When NASA first mooted this Mars mission, they admitted that AG might prove essential and studied a minimal-toroid AG solution. It was a flawed design and very expensive, so they shied off it. Now, "Research is being conducted to ensure that astronauts stay healthy before, during and after their mission. NASA is identifying how current and future, FDA-approved osteoporosis treatments, and the optimal timing for such therapies could be employed to mitigate the risk for astronauts developing premature osteoporosis. Adaptability training programs and improving the ability to detect relevant sensory input are being investigated to mitigate balance control issues. Research is ongoing to characterize optimal exercise prescriptions for individual astronauts," I am struck by the way the ISS has singularly failed to deliver such basic answers as yet, and NASA's masterplan similarly fails to mention the issue of cerebrospinal fluid accumulation. See for example here (enjoy the brain scans).

How do we define "long-term"? For me it is simply, too long for zero-gee palliative technologies. For the ISS, this seems to hover around the 1-year mark. NASA are still hoping they can squeeze the biotech out to three-plus years.

So forgive me for questioning their abandonment of AG just because their first shot was badly conceived, without bottoming-out that medical research first. Why are they not bottoming-out those AG design flaws, too? I suspect the answer to that is that they reckon it looks cheaper, and hence politically more realistic, to stripe the medical research budget across other institutions' funding programmes, and to drip-feed the costs as and when "new" issues needing medical intervention are discovered. Call me an old cynic, but that is my view. With luck, we shall one day know who is right.
 
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With the current state of technology - slow spacecraft, no AG, inadequate radiation shielding - you'd have to be deluded/ignorant/stupid/suicidal/desperate/all of the above to put up your hand for a manned mission to Mars.
 
With the current state of technology - slow spacecraft, no AG, inadequate radiation shielding - you'd have to be deluded/ignorant/stupid/suicidal/desperate/all of the above to put up your hand for a manned mission to Mars.
Yes, but some wag suggested that you recruit smokers and then not give them any cigarettes for their expedition. Their life expectancies would actually increase.
 
With the current state of technology - slow spacecraft, no AG, inadequate radiation shielding - you'd have to be deluded/ignorant/stupid/suicidal/desperate/all of the above to put up your hand for a manned mission to Mars.

You'd be surprised at how much motivation you can squeeze out of a man when you promise him a pension, a few medals, and a place in history. NASA's manned Mars mission, which is likely going to go ahead in the 2040's assuming nothing silly happens, will probably physically destroy any astronauts who go there, but they'd be remembered forever. It's a decent trade for adventurous types.

A PI Orion and a DST bus isn't going to offer that much radiation protection or artificial gravity beyond what the ISS has anyway, both because they more or less already exist, and because the rockets that go into them won't allow it. Maybe a storm shelter for the four to six man crew will be included that is just a closet with sleeping bags and some waterbed-esque lining? That's about all you can really budget for mass wise I'd think.

Without more funding and a better developed world space industry, both of which is impossible at the moment, there's no other serious options besides extrapolating ISS stuff out another 20 years with some modern enhancements. Which is why DSH and DST both start with ISS-style capsules because that's the space operating standard. Perhaps the PRC will be able to push new standards, perhaps not, since they're the only other serious player that isn't the US in space.

Once the orbital mission finishes in the 2040's I'm sure NASA will start prepping for a manned landing in the 2070's. They might be able to start looking at more significant departures from the ISS standards then, since they would be almost 100 years old at that point.

I suspect the answer to that is that they reckon it looks cheaper, and hence politically more realistic, to stripe the medical research budget across other institutions' funding programmes, and to drip-feed the costs as and when "new" issues needing medical intervention are discovered. Call me an old cynic, but that is my view. With luck, we shall one day know who is right.

You're right, that's not cynical though, that's smart.

We literally don't know what health hazards might occur in a mission to Mars, so how can we budget for proper safety equipment? You cannot overbuild a spacecraft because you're working with extremely strict mass and budget margins. Which means extremely simple solutions reign supreme and overly complicated ones die out. It's why America went to the Moon in a tin can with a RCS bus instead of a direct ascent nuclear rocket with centrifugal gravity launched from a mercury solar powered rotating space station.

You kind of have to expose people to extreme dangers to find out what they need to survive there in the first place, too. Sure, that means breaking some eggs to make an omelette, but there are plenty of good eggs who are willing to do that, and it's very likely that the first Mars mission astronauts will come back with some big health problems. That can be fixed for the next Mars mission. And so on. And so on. It could very well turn out that artificial gravity was a blind alley all along.

Do we actually need artificial gravity on Mars? Can we design exercise equipment to mitigate the bone loss of astronauts over a two year mission to Mars sufficiently that they don't die on landing back in Earth gravity? If we can do that, we certainly won't need artificial gravity, because the point of AG isn't to eliminate bone or muscle loss, it's to allow astronauts to return to Earth without dying and be able to recover their lost bone and muscle in a gym like normal people. That's just going to happen no matter what you do. It's something that comes with the territory.

It could also turn out that Mars missions are infeasible without further industrial development of the Earth-Moon system to produce larger spacecraft that can be functional centrifuges or haul large artificial gravity bowl structures to Mars. Perhaps the 2001 starship will look as quaint as a Flash Gordon rocket if we ever start going past Mars due to its limited and lackluster emphasis on engineering in favor of Hollywood styling. No one knows, because no one has done it before, so it's still an iterative process.

You can certainly point to the accumulated data that are there and say "well there's this much radiation" or "ISS astronauts had this much bone loss over a year" but that's not really taking into account that a Mars mission has to operate within a budget determined by legislatures. If you had infinite resources it would be trivial to design a safe and effective spacecraft to Mars, but no one does, which is why engineering this thing is going to be quite hard.

There will be tradeoffs, and it's more than likely the tradeoff will be astronaut health, because the human body is the most effective self-healing machine anyone has ever seen. It's also free, excluding the cost of gym membership and cancer screening every 9 to 18 months, so it's not going to cost the Congress a cent.

Of course, if someone is overly concerned about musculo-skeletal health then being an astronaut probably isn't for them.
 
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Maybe, just maybe, sustained long term spaceflight will eventually turn the more adventurous among us inevitably into blobs...
 
OK, now if we can now breed an intelligent strain of Deinococcus radiodurans and make it possible legally adopt them...
 
According to NASA here, "On Mars, astronauts would need to live and work in three-eighths of Earth’s gravitational pull for up to two years. Additionally, on the six-month trek between the planets, explorers will experience total weightlessness."
During the trek, why not use the onboard engine to accelerate the ship and thus produce some gravity?

Not necessarily 1G, maybe only 3/8 like on Mars, and maybe not all the time to preserve fuel.
On the last part of the trip, just turn the nozzles (or the spaceship itself) to reduce the built-up speed.
On the return home, brake increasingly strong to progressively re-train them to Earth's 1G.

If fuel turns out to be an issue (haven't done the math), just have 2 spaceships: a minimal one with humans, lotsa fuel and almost nothing else, and a second one with cargo-only which doesn't have to create AG onboard and can take its sweet time to get there.

Any obvious showstoppers?
 
According to NASA here, "On Mars, astronauts would need to live and work in three-eighths of Earth’s gravitational pull for up to two years. Additionally, on the six-month trek between the planets, explorers will experience total weightlessness."
During the trek, why not use the onboard engine to accelerate the ship and thus produce some gravity?

Not necessarily 1G, maybe only 3/8 like on Mars, and maybe not all the time to preserve fuel.
On the last part of the trip, just turn the nozzles (or the spaceship itself) to reduce the built-up speed.
On the return home, brake increasingly strong to progressively re-train them to Earth's 1G.

If fuel turns out to be an issue (haven't done the math), just have 2 spaceships: a minimal one with humans, lotsa fuel and almost nothing else, and a second one with cargo-only which doesn't have to create AG onboard and can take its sweet time to get there.

Any obvious showstoppers?
Because of launch mass/performance constraints, you'll only use rocket propulsion as sparingly as possible to meet celestial mechanics requirements in strategic boosts for any spacecraft, crewed or uncrewed, at least as long as we're confined to chemical rocket propulsion.
 
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The showstopper, if you're using chemical rockets, is you will need to accelerate not only the payload, but also the mass of fuel to power the acceleration throughout the entire flight. That adds up very quickly indeed.

You could resort to a laser propelled sail
- but acceleration would be minimal AND
- you'd need whacking great lasers at both ends of the trajectory

 
Maybe, just maybe, sustained long term spaceflight will eventually turn the more adventurous among us inevitably into blobs...

Here's hoping they have kids beforehand to continue the trend.

Of course if Valeri Polyakov can walk out of his capsule to a lawn chair, then I don't see why a NASA astronaut can't do the same, unless NASA's astronaut corps is just lazier than Russian cosmonauts. They'll probably have better exercise equipment than an elliptical.

A Mars mission won't turn astronauts into blobs, but it might turn 40-somethings into 80-somethings, I guess.

The showstopper, if you're using chemical rockets, is you will need to accelerate not only the payload, but also the mass of fuel to power the acceleration throughout the entire flight. That adds up very quickly indeed.

You could resort to a laser propelled sail
- but acceleration would be minimal AND
- you'd need whacking great lasers at both ends of the trajectory


I'd think building high energy propulsive lasers is a bit beyond the scope for a fuel/exploration staging depot in Lunar orbit, which is the only feasible and realistic manned Mars mission that has any chance of succeeding, tbh.

It's relatively trivial to have a chemical rocket that can take you to Mars. Just lift the stages with a heavy lifter like SLS. It's much harder to establish the manned human presence on the Moon that allows for construction of powerful propulsion lasers for a solar sail ship that pulls people around. Maybe such lasers will be used for communications on a potential manned Jupiter mission, but that's a few centuries out, at least at the rate of historic space programs.

Nuclear rockets are more promising, and if the Gateway proves itself viable as a staging ground (i.e. it doesn't explode or something on launch and makes it to orbit with no problems), they will probably unironically come back.

Lifting an atomic core and sufficient water to propel it to Mars, faster than a chemical rocket, is quite a bit easier than any other alternative. Perhaps the DST, since no one knows if it's actually using LH2/LOX, methane, or nuclear thermal power, might end up having a super evolved form of NERVA. That would require DOE approval to manufacture but it wouldn't exactly tax America's nuclear industry either. DOE is already pretty interested in very smol nuclear powerplants and has a few funded after all.

Building the ISS in Lunar orbit is something we can just barely do with existing technology i.e. SLS and the Orion capsule. Add on a nuclear thermal rocket and you're pushing the state-of-the-art quite a bit both in terms of lift requirements and reliability concerns. Anything more complex than this is probably a non-starter because it would require too many launches or be too unreliable.
 
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During the trek, why not use the onboard engine to accelerate the ship and thus produce some gravity?

Not necessarily 1G, maybe only 3/8 like on Mars, and maybe not all the time to preserve fuel.
On the last part of the trip, just turn the nozzles (or the spaceship itself) to reduce the built-up speed.
On the return home, brake increasingly strong to progressively re-train them to Earth's 1G.

If fuel turns out to be an issue (haven't done the math), just have 2 spaceships: a minimal one with humans, lotsa fuel and almost nothing else, and a second one with cargo-only which doesn't have to create AG onboard and can take its sweet time to get there.

Any obvious showstoppers?
Because of launch mass/performance constraints, you'll only use rocket propulsion as sparingly as possible to meet celestial mechanics requirements in strategic boosts for any spacecraft, crewed or uncrewed, at least as long as we're confined to chemical rocket propulsion.

Absolutely. Fuel is the biggest single cost factor. Anything at all which impacts total fuel usage costs massively, and the further along in the mission it occurs the more humungous sums you have to spend to get the wasted fuel that far. The mas of fuel needed to generate AG for even an hour or two is way higher than the mass of a hollow doughnut.

In-flight refuelling also costs more than double; not only must you develop two different payload craft, but you must also develop, prove and launch to Mars the docking and fuel transfer systems. Cheaper and quicker to just strap the two together at launch time, as one mega-rocket.
 
Fuel is literally why NASA is considering the DST to have a nuclear thermal rocket? This reduces the SLS launches from something like 50 to about 5 with assembly and refueling done at the Gateway.

There's no point to have in flight refueling for the Orion-DST transfer vehicle. The delta-v saved by launching from the Moon and not LEO is literally why it's being built in Lunar orbit and not on the ISS, after all.
 

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