The best technology of the '70's. Again.
What? In this day and age no centrifugal section? Just give the money to SpaceX instead of these tired old retread companies.
NASA has splashed the cash on design contracts for space stations and a multibillion-dollar job for more Artemis boosters. With the days of the International Space Station (ISS) numbered, NASA is looking to maintain an uninterrupted US presence in low-Earth orbit. Although Axiom Space has plans to build from the ISS, the $415. …
I wonder if Musk would actually build an Arthur C. Clarke style "spinning wheel" space station on his own... (naw he'd probably ask for gummint money anyway, it's what he does, heh)
But chances are, a SpaceX space station would outperform at a lower cost. My $0.20 worth (was $0.10, formerly $0.02, but inflation again)
Maybe a tire company can build inflatable sections?
Maybe a tire company can build inflatable sections?
Dear god no Bob, we'd be launching perihelion and aphelion sets of inflatable sections. You *know* that the orbital traction at aphelion is lower and needs a different formulation of the material!
SpaceX's proposal didn't include a centrifugal section.
The real question is who is going to pay for a centrifugal section and why?
NASA wants the companies developing ISS replacements to fund at least 60% of development themselves. These companies aren't going to be doing this out of the goodness of their hearts. They are going to be looking to recoup their costs by leasing station space to non-NASA customers. Therefore we want to look at potential customers and figure out what they want and need.
Research done on ISS indicates there is a comparative advantage for manufacturing some products in microgravity. Drawing high quality fiber optic cable or growing replacement organs appear they will be highly profitable activities once the bugs are worked out of the production processes. In the case of drawing fiber optic cable vibrations from the centrifugal section are harmful to product quality so the companies attempting to bring this to market won't want a centrifugal section attached to their production facility. Manufacturers whose processes depend on gravity can get that for free here on Earth so we can't look to manufacturing to recoup the costs of developing a centrifugal section.
Another potential customer base is tourists. My informal survey suggests most tourists definitely want the chance to join the zero G club so a microgravity section is a must. Experiencing artificial gravity is something few are interested in. Having toilets and showers that function like those here on Earth would be nice but the costs would need to be tightly controlled. Developing and building a 100+ meter diameter centrifugal section isn't going to be cheap. Perhaps there might one day be enough demand to recoup the costs. For now all there is is speculation that does not justify the business case.
It wouldn't just be the showers and toilets though. The human body is "designed" with the expectation of Earth gravity. From the serious considerations like muscular atrophy to the merely convenient (your sinuses use gravity to drain mucous so being in zero-g for any length of time makes you feel stuffy like with a cold), artificial gravity is something we really ought to figure out before sending humans away on 2+ year journeys to other planets.
I agree that artificial gravity is something we should figure out before we undertake multiyear journeys. That is why my Ceres plans start with building a shipyard in LEO that builds a series of rotational gravity prototypes. Assuming I had an infinite supply of money the science and engineering needed for spaceships with artificial gravity could be done in as little as a decade.
The reality is no one who could conceivably afford to do so is currently planning on funding multiyear journeys. The closest is Musk's Mars plans, but the journey to Mars should take three to six months. The typical ISS mission last six months so we know it is possible to keep humans relatively healthy without needing to spend the time and money to develop artificial gravity ships for Mars.
The main reason is to let a human stay on-orbit much longer.
It's going to be necessary for any manned trips to Mars, for example.
However, tourists aren't going to stay up for more than a few days, and manufacturing needs a stable platform so...
The big problem with an AG station is docking. Anybody who ever played Elite with the auto-docking thing turned off will know what that's like when the hub is merely rotating. Add eccentric gyration because the station is a touch off-balance, and wa-hey! >CRUNCH!< "Sorree!".
I should patent my extending arm tubes so the hub can rebalance itself to dead centre.
If you go for a more sophisticated nonrotating airlock Arthur C Clark style, then you also have the scavenge pumps for the rotating seals to develop.
But I doubt NASA's quite ready to sponsor such niceties just yet.
That's the killer problem. I suspect that is going to be a much bigger engineering challenge than most might think. Movable joints in a spacesuit that gets used short term and doesn't rotate all that much or all that frequently is one thing. A rotating, air-tight joint moving constantly is a whole other mess of problems.
Solve in like a computer program by breaking the problem into parts that are easier to solve. Start with two hollow cylinders, one rotating and one stationary. Join the two cylinders with a coupling that allows rotation but is not air tight. Cap the the outside ends of the cylinders with docking ports to other modules. Cap the inner ends with docking ports leaving enough space between them for a small module. Now put a small module in the middle that can rotate independently of the two cylinders. Add a docking port at each end and two sets of brakes - one for each cylinder. Apply only one set of brakes at a time to match the rotation of the small module to either one of the cylinders. Connect only one docking port at a time - the port to the cylinder that the module is rotating with. The docking ports have to be air tight but do not have to handle rotation.
That sounds like it may, possibly work. On the other hand, it seems to have many more moving parts than I suspect most would have envisioned for a rotating airlock, not to mention all those potential failures. I'm sure that eventually there will be a space habitat that rotates and better minds than mine will find a way of docking with it. Maybe the first attempt will be simple. Two docking ports either side of the central axis, one for the "life boat", the other for visiting ships, which will simply match spin and dock, no moving parts required (other than opening doors and pumps)
Quite apart from marine mamals balancing on beachballs as they are spun around (I thangew, I thangew), this is an old and well engineered technology.
Any waferfab relies on high-vacuum pumps to suck out the air. All such pumps have (or did in my day) parts which slide or rotate across each other, with high vacuum on one side and atmospheric pressure on the other. Scavenging the air as it leaks through the high-pressure seal, but before it reaches the low-pressure seal, is a well-developed technique; cryo pumps even employ "the cold of outer space" to condense the air on a cold surface and catch the runoff. It just needs engineering in to the design. Which, for rotating space stations, is merely a matter of educating the designers in the need to go read a book on the subject.
Of course, what dot-com
waving willie ego will be seen dead acknowledging such a debt to the past? Maybe the lesser challenge will be to re-invent the wheel (sic) from the ground up (sic).
You do not need to build the whole wheel. Much cheaper would be something like a double headed hammer
A more efficient solution would be to spin up the sleeping pods.
Giving the astronauts 8 hours of gravity a day would probably be enough to maintain bone and muscle density.
Something like this would be essential for interplanetary craft if you don't want your astronauts to collapse under the gravity at their destination.
Why recreate gravity? Don't our bodies need gravity to do a bunch of our body-stuff?
And then you could have plumbing. And drink out of glasses. And not have your bones go all stretchy.
When did humans start to disparage gravity? What'd gravity ever do to us?
Gravity, I just want to apologize for human attitudes toward you. Maybe we got off on the wrong foot. Or botched our messaging. I think there's been a terrible misunderstanding between us and our space-faring ambitions. Just know, Gravity, we humans are ready to sit at the negotiating table and find a compromise that allows us to go and you to be provided for.
Looking forward to the upcoming summit renegotiating the light-speed limits.
A centrifugal/rotating section is an absolutely terrible idea which would only be suggested by science fiction writers. The problem is that it involves rotation (duh) which does horrible things to the human sense of balance. Sure, you get a pseudo-gravity effect but only at the everyone in it puking their guts out more-or-less continuously. The only and temporary way round it is to keep your head in a fixed orientation relative to the axis of rotation. All easily demonstrated in a turning airliner.
Centrifugal can work fine, but size matters. Fairground centrifuges are intentionally designed to make you queasy. By contrast, Spaceship Earth is a large enough spinning station for you to feel OK. There has to be a minimum size for a viable AG station; I'd hazard that it will be around the 20 m (65 ft) diameter mark. Also the level of AG needed to sustain good health might be less than one Earth normal, which complicates the numbers. Trained, fit and selected 'nauts will be able to cope with smaller size than turogs. One thing the Mars-in-their-eyes big dreamers and spenders absolutely need to get to grips with is a lengthy programme of playing with Earth-orbit AG stations to discover these minimum sizes and spin rates for their Mars ships. But there appears to be a severe lack of realism among them.
Update: Found a detailed research paper based on experiments in centrifuges. It suggests that a viable space habitat needs to be at least 60 metres (200 ft) across, with a radius of 30 metres (100 ft) and an overall circumference around the rim of 100 metres (300 ft). This reduces the variations (gravity gradient) to around five percent of gravity over the height of the human body.
The problem is that it involves rotation
Everything is whizzing along and rotating around a point which in turn is rotating around another point which in turn ... and so on and so on...
The factor you missed out is "frame of reference". Inside a suitably large station the rotation would be barely noticeable. Although they would need to be careful about where they put the windows, the view from a spinning platform could be a bit vertiginous.
Research suggests that most people can adapt to living and working in a centrifuge within about a week or so.
See part 3 in "HISTORY OF ARTIFICIAL GRAVITY" (it's a pdf so I couldn't link direct to the section I'm afraid, on the other hand, the entire paper is relevant).
No follow-up on the US space junk that the ISS had to dodge?
-This maneuver provided a healthy margin of separation from a fragment of Pegasus rocket debris (object 39915) that ballistics specialists have been tracking.-
No way to boost it. Plan is to let it come down.
Once the panels and truss break off it becomes a bit more brick like and slightly more predicatable.
There are motors on some core bits to do a bit of control, but not enough to give it anything like the precision you would want.
Also to allow the Russian launch site easy access it is in quite a high inclination, so can potentially hit a range of Northern (and Southern but who cares about them) latitudes.
edit: Inclination is 51.5 deg so all of USA, the habitable bits of Russia and Canada and most of continental Europe, but only the southern coast of Blighty, are in the touch down zone
Golgafrinchan Girl: When you've been in marketing as long as I have, you'll know that before any new product can be developed it has to be properly researched. We’ve got to find out what people want from fire, how they relate to it, what sort of image it has for them.
Ford Prefect: Go stick it up your nose.
Golgafrinchan Girl: Which is precisely the sort of thing we need to know. Do people want fire that can be fitted nasally?
You could design a small satellite to be simple and tough enough to survive launch or you could make something more complicated or cheaper and surround it in packing to reduce launch stresses. Once at the ISS an astronaut can unpack it, test it and if required, repair it before sending it out the equipment airlock in the Kibō module. This alternative way to reliably get small working small satellites into orbit has been so popular that Nanoracks funded their own equipment airlock module to increase throughput.
Except that keeping them in LEO whilst we learn what to and what not to do means that, when we do what we should not have done, we can bring the poor buggers back down and help them. Swapping them for more brave souls who now know not to do that thing.
But if we just send them direct to Mars without going through the LEO experience then they - and therefore the entire Mars mission - are well and truly shafted.
Hopefully the plan is to give the people the best chance we can of getting to Mars, surviving getting to Mars, doing some decent science there and maybe even making it all the way back again.
Biting the hand that feeds IT © 1998–2022