Space Hotel With Artificial Gravity by 2025

[ukimalefu]

https://gizmodo.com/orbital-assembly-sp ... 1848855049

Orbital Assembly Corporation announced plans to develop a space business park, complete with artificial gravity, that’s designed to accommodate 28 guests in five modules built around a rotating gravity ring.

The California startup is aiming to make its first Pioneer-class space station operational by 2025, in what is an ambitious and likely unrealistic timeline. That said, Orbital Assembly is intent on making this the first commercial, hybrid space station that can be leveraged for both research and leisure.

Private space company Axiom Space is also planning to build its own commercial space station, one designed to house future visitors and host scientific research. Axiom is hoping to launch the first section of the station to low Earth orbit in 2024.

*checks date, not aprils 1st, not dec 28*

wait... they're not kidding?

[maurvir]

We have known how to simulate gravity in space for a while, though if (and that's a big if) these guys pull it off, they will have accomplished a true first. Most science in space is done in space precisely because of microgravity, so simulating gravity sort of defeats the purpose, but for tourists? Yeah, that would be a big deal, as it would mean less time to acclimatize.

The real problem isn't gravity, though. It's the fact that space is freaking dangerous. Between radiation, micrometeorites, space junk, and the extreme distance from medical assistance, it's definitely going to be "adventure tourism".

[DEyncourt]

B-b-but:

Docking bays on the ring?

Even at 1/6th Earth gravity (perhaps to help people to get used to the gravity on the Moon?), docks in the rotating ring would be very risky: collisions between the spacecraft with any part of the space station, the imbalance in gravity when a spacecraft is docked (which might be offset by a PAIR of spacecraft docking simultaneously though that would increase the launch costs and increase the complexities in docking).

Arthur C. Clarke and Stanley Kubrick got it right in 1968:

[ukimalefu]

you're missing the main thing

"operational by 2025"

they won't even have one piece up so soon

and whoever made that crude mockup could have added windows, all space tourist so far have been able to look out of windows, kind of a big part of why they pay for the trip

Spinning gravity? yeah... I guess... technically possible...

Basically that thing, in space, in orbit, with docking bays

And it's not going to be like 2001 because that's science-FICTION

[maurvir]

Modern computers would have zero problem lining up a shuttle to dock like that, and not having it in the middle dramatically simplifies the whole operation. Otherwise, you have to find a clean way to transition from microgravity to partial gravity.

Interestingly, Kubrick also depicted both of these in 2001 - note the pilots aren't touching squat while the computer calculates the terminal phase of the flight. Later, and not in that clip, you see the transition from the hub to the ring.

Still, it's pretty clearly vaporware, because there is no way they are going to get all that built in time even if approvals weren't a thing.

As an aside, while the ring shown on the space station is realistic, the one shown on the ship would be cutting it close. Both the US and USSR studied this, and at small radii, the rotational (angular) speed required to simulate gravity is high enough to cause inner ear issues, and perhaps worse, there is enough of a difference in forces between the head and feet to cause disorientation. You really need a pretty good size ring to simulate gravity without making humans sick.

[DEyncourt]

The drawing was from Orbital Assembly Corporation, not one made up by some artist at Gizmodo.

What Clarke and Kubrick could NOT have known was that--even now (21 years too late)--we would STILL not have any materials with which that space station with close to Earth gravity at the ring level could have been constructed. It was an overly optimistic view.

I agree: their proposed space station should have obvious windows, though lining the sides of pods. Any on the OUT sides of the pods would be on their floors.

[maurvir]

[maurvir]

The reference frame for the occupants would have the outer circumference as the "floor", so the windows would be on the sides. However, these look eerily similar to a bunch of those Bigelow inflatable space station pods, and I don't believe those had windows. Perhaps they intend to use counterweight areas across from the docking rings for a viewing area?

Which, as it occurs to me, is the problem with that picture. While the navigation wouldn't be a problem, the proposal as shown would throw the balance of the system off.

[DEyncourt]

Now imagine that tilt-a-whirl getting a mass of several tons attached to its outside--imagine the resulting mess. Yes, in orbit spacecraft are WEIGHTless but they are not MASSless. Even at 1/6th Earth gravity the imbalance created by adding a spacecraft to only one side might be enough to worry about sheering the connections between the modules. It would be enough that anyone onboard would no longer have "straight down to the outside" being downward except at the exact opposite point of this station.

Having a central docking port means that docking would be so simple that even a human could do it--almost. Matching the rotation is still difficult.

[DEyncourt]

they will have accomplished a true first

Well, not quite.

There is a centrifuge aboard the ISS. While not big enough to accommodate a human, it has been used to simulate the Moon's gravity to check how dependent plants are to gravity (short answer: not all of them are, but those which are dependent, the Moon's gravity is not enough). This centrifuge also can create the Earth's gravity for growing plants in order to make certain that something else on the ISS may be causing problems ("Huh...these plants stopped growing a week or so after planting. <snap> Hey! Just how efficient are the CO2 scrubbers?").

[jkahless]

Looks like they're only planning on launching an 11kg ring into space on the first go. That part sounds doable.

[DEyncourt]

While the navigation wouldn't be a problem, the proposal as shown would throw the balance of the system off.

I commented on this in my first post:

the imbalance in gravity when a spacecraft is docked (which might be offset by a PAIR of spacecraft docking simultaneously though that would increase the launch costs and increase the complexities in docking).

[DEyncourt]

you have to find a clean way to transition from microgravity to partial gravity.

Um, you do realize that any visiting astronauts will be doing THAT when docking their spacecraft to this space station, yes?

--

Let's look again at that drawing from Orbital Assembly Corp (OAC):

I have no idea what the OAC illustrator was thinking about with that sort of a mini-shuttle near the bottom center, especially considering that somehow it is being docked via what has been the engines in most shuttle designs, plus it is very small, so let's ignore that.

Instead consider the more conventional capsule in the lower right corner. Maybe that OAC illustrator had no idea what they were drawing, but let us assume the dimensions for the next generation Orion capsule. Unlike the capsule above (which has a height-to-width ratio closer to those of the Gemini capsules), Orion will be about 3 meters tall and 5 meters wide. Let's use that 5 meters to guesstimate the other dimensions for the OAC Pioneer space station.

The presumed four living pods appear to be about 10 meters in width and about 25 meters in length. A guesstimate for the ring forming Pioneer appears to be about twice that length, so call the general radius of Pioneer 50 meters.

This page allows one to enter 2 of the values in order to determine the other two values. So, let R=50 meters and A=0.1666 G (the Moon's gravity), then the angular velocity is about 1.72 rotations per minute and a tangential velocity of a bit over 9 meters per second.

So the approaching spacecraft must hit a target which will be traveling relative to the "motionless" center of Pioneer at about 32 km per hour or about 20 miles per hour.

At least the design of Pioneer appears to be such that if an approaching spacecraft misses, then that craft will not tear into the side of one of the living pods. On the other hand there must be a ladders that are extendable from the docking bays for any of the astronauts to get in. Moving any cargo from the spacecraft becomes much more of a problem than doing the same on the ISS.

[Pariah]

I don't see anyway that docking on the outside of the spinning ring would work.
I think that until we invent gravity plating ala Star Trek our space stations will have to be ring and hub. Not just because lining up on a target that is speeding past laterally would be hard but even if it could be done it would take a more fuel than lining up with a hub would. It would be costly accelerating the craft sideways like that.

[DEyncourt]

Well, I can be persuaded that docking with a port on the ring is possible though like Pariah suggested it would likely be rather expensive in fuel (probably requiring the use of a spacecraft's main rear engines), but I do have another serious objection.

My guess is that OAC is imagining that their Pioneer space station will be constructed using very lightweight, easily compressible materials. Its construction will be done completely in orbit (though, of course, individual parts like those ring struts will be made on the ground).

But compare that to a typical capsule+service module spacecraft. That set must be built to withstand the launch through the atmosphere and--for the capsule--re-entry into the atmosphere, so that spacecraft must be rather heavily constructed. So much so that chances are that this spacecraft could easily outweigh the entire Pioneer space station.

So after docking the spin rotation of Pioneer plus that spacecraft is now centered close to the nose of the spacecraft. If you happened to be in one of the pods closest to the dock being used, your gravity sense of down is no longer towards the "outside" of the ring but almost toward the next pod along. Which is not to say that people in the opposite pair of pods will be feeling comfortable. This design will require a generous number of air sickness bags EVERYWHERE, and--the station's crew having become used to 1/6th gravity--there will be a lot of messes as things go flying or sliding about due to changes in directions of gravity. Those changes then go away once the spacecraft is undocked. The only benefit is that the spacecraft wouldn't have to fire anything to get away from Pioneer, though the crew/Mission Control will have to be aware of where the detacted spacecraft is now heading.

All those problems could be avoided by having two docks--one on each side at the center of Pioneer.

[Ribtor]

This project seems like an investor scam.

[DEyncourt]

BTW: using that SpinCalc site for an Orion capsule (radius 2.5 meters) docked at Pioneer's center, the g force on the outside edge of the capsule as it rotates with Pioneer will be about 0.008333 g. So not zero or technically micro-gravity...could it be called milli-gravity?

[Pariah]

Docking on the ring in synchronized pairs is an absurd idea and single docking would throw off the center of mass which would make the spin go all out of kilter.
The more I think about it the less workable ring docking seems.