Fitting rotational gravity segments on rockets?

[DominusNovus]

Rotating rings on a space station or vessel to produce gravity for astronauts is one of my favorite topics in this subject. There are obviously plenty of difficulties with the concept, of course. A particular question I have is how large does the difficulty of getting a ring of any sizable diameter onto a rocket loom in these considerations?

For example, fitting a ring space station with a diameter of 100 meters would be quite challenging, consider that the diameter of a Saturn V is only 10 meters. So, of course, it would have to be shipped up in segments, which is also difficult, since the segments would be, themselves curved. But, how important is this concern, when compared to other issues in creating such systems? Is it just a minor hiccup, fairly far down on the list of challenges, or is it a major roadblock?

[*Aqua*]

Curved segments are no problem. They just have to make sure the mass is (almost) centered and small enough to fit into the payload box.

The most difficult problem is the amount of work which has to be done on a space walk. On Earth building a 100 diameter ring made of high tech stuff already needs months of labor. In space they'll probably need years or decades.

Another problem would be the uneven distribution of mass in this ring. The astronauts will move around and cause oscillations every time they step on the "ground". I'm not sure how to avoid wobble and spinning the station out of control.

[Nuke]

just put a pipe in the deck and fill it half way with water. the water will auto-stabilize the ring for you. there was a whole thread about that a few weeks ago.

you can test what if scenarios about ring size with SpinCalc. its actually based on real science.

[DominusNovus]

Curved segments are no problem. They just have to make sure the mass is (almost) centered and small enough to fit into the payload box.

Given the limited dimensions in a typical payload fairing, wouldn't the curvature of any given segment of the station limit the effectiveness of being put in place as-is?

The most difficult problem is the amount of work which has to be done on a space walk. On Earth building a 100 diameter ring made of high tech stuff already needs months of labor. In space they'll probably need years or decades.

How is that any different from the ISS?

[DominusNovus]

just put a pipe in the deck and fill it half way with water. the water will auto-stabilize the ring for you. there was a whole thread about that a few weeks ago.

Mind if I ask you for a link? I imagined using water to stabilize oscillations, I'm glad to see that I was on the right track.

[Thiel]

How is that any different from the ISS?

It's a lot bigger.

[Winter Man]

You're best off going collapsible/inflatable for larger structures like that.

[DominusNovus]

It's a lot bigger.

The point of my comparison was that the ISS was also assembled piecemeal over years, and that wasn't seen as a problem.

[Thiel]

The ISS doesn't have to undergo any kind of meaningful levels of thrust, a spaceship is.

[DominusNovus]

The ISS doesn't have to undergo any kind of meaningful levels of thrust, a spaceship is.

Certainly. But my concern is just the construction of a rotational ring, regardless of whether it would be for a ship or a station. It would be likely, after all, that it would be tested in orbit, rather than on a voyage.

Here's my basic idea, for what its worth:

Picture a cylinder, cut into segments at alternating biases, so that each segment is a wedge (the larger the ring, the smaller the angle). After being placed into orbit, the individual segments would rotate along the biases so that the former cylinder is a portion (or, depending on its total length and the angle of the cuts, the entirety) of a ring.

Though its a two dimensional comparison, imagine a pizza cut into slices as the final product. While in transit, the slices would be alternating in their directions, laid out next to each other: the crust of one slice out on one side, the crust of the next on the opposite, so that they form one long line of slices, rather than a complete pie.

While I think this is a fairly elegant solution to storage, since storage and transportation is likely one of the smaller concerns, I doubt it would be much use overall. But, if I'm wrong and they are more significant concerns, then maybe it would be useful.

[Nibb31]

The whole assembled ring thing is a silly idea. You'd be better off with a giant inflatable or just rotate the entire spacecraft.

For all we know, artificial gravity isn't even necessary. You'd just be adding lots of complexity for very little gain.

[DominusNovus]

The whole assembled ring thing is a silly idea. You'd be better off with a giant inflatable or just rotate the entire spacecraft.

For all we know, artificial gravity isn't even necessary. You'd just be adding lots of complexity for very little gain.

Given the various health problems that continually are discovered due to a lack of gravity, I'd say that artificial gravity would be essential for any long term space habitation. Seeing as rotation is the only viable solution, other than constant acceleration, a ring or cylinder is the most efficient arrangement.

[CaptainKipard]

Hey guys and gals do you know about this website?

It has long articles about everything spaceship related including artificial gravity.

[DominusNovus]

Very familiar, myself, though it addresses primarily the issues in space, rather than getting them into space from the ground.

[Nuke]

thats easy, really really big rockets.

you can also break it up into modules and assemble it in space, but where is the fun in that.

[FREEFALL1984]

Why not just used the standard method of a cable and counterweight, that could all be lifted in a single launch and would serve the same purpose. Also the length of the cable could be several hundred meters meaning the coriolis effect would be minimized, if any maintenance works needed to take place which required the station to stop rotating you could simply wind in the cable until both segments docked and then kill the rotation.

[Nibb31]

Given the various health problems that continually are discovered due to a lack of gravity, I'd say that artificial gravity would be essential for any long term space habitation. Seeing as rotation is the only viable solution, other than constant acceleration, a ring or cylinder is the most efficient arrangement.

Many of those problems are currently alleviated through medication and or exercice. This currently allows long duration stays, without artificial gravity. Long-term studies on the ISS allow medical teams to improve those treatments on a regular basis. There is no reason that we couldn't envision 2 or 3 year missions in the near future based on those findings.

On the other hand, rotating rings might have negative effects due to the Coriolis force that is imparted on the inner ear and other body fluids. We simply don't know if those drawbacks exceed any potential benefits, and there will need to be many years of research before that question can be answered.

What we do know, however, is that building a rotating ring in space is excessively complex and expensive. If we really needed a centrifuge, which again, is not a certainty, there are much easier ways: either rotate the entire spacecraft or attach modules on a tether.

Edited April 26, 2014 by Nibb31