Scenario Any way to Tether the Soyuz TMA to Final Stage - for Joe Carroll's Experiment?

[robertinventor]

Hi everyone, I've been using Orbiter to make screenshots and videos for an article on Joseph Carroll's ingenious artificial gravity experiment.

The way it works is that you tether the Soyuz TMA to its final stage - so after separation, then they remain attached.

So at this point they are still attached.

Then you do a series of boosts, always at the apogee in the southern hemisphere, to generate artificial gravity. Always do that when moving in the direction of the orbit in the tether spin.

This raises the perigee in the northern hemisphere - until eventually it becomes the new apogee. Finally you release the tether at the new apogee, when Soyuz is moving in direction of the orbit around the Cof g again.

This puts the final stage into an immediate re-entry into the Pacific, and sends the Soyuz on to the ISS with exactly the same boost it would have had if all that fuel was used just to go straight to the ISS. So almost no extra fuel is needed, you get a free experiment in artificial gravity lasting 2 days, and get a controlled targeted re-entry of the final stage into the Pacific.

Anyway - I've got some good images and video showing the Soyuz and the final stage. Most of the images come from Orbiter in fact.

But what would be really great would be if there was some way to attach the Soyuz to its final stage and get them spinning around each other within Orbiter.

I tried the TetherMFD but it didn't do anything, or maybe I don't know how to use it. I noticed though that someone says in a comment that it doesn't work on Orbiter 2010.

Can this be done?

It would be great just to create an orbiter video showing the Soyuz attached to its final stage over the Pacific, and both spinning about their common C of G.

Is this possible? Any ideas or thoughts?

Also, since it's such an intriguing mission, at least I think so, maybe others here will as well - I wonder if anyone else here is interested in working on this as a scenario to add to orbiter as a plugin, on top of the Soyuz TMA missions?

I'm very much a novice at Orbiter. Just about figured how to launch to orbit on manual but did those shots using it in automatic mode. It's a steep learning curve, the keyboard shortcuts take some learning and takes some searching to find out how to do things.

So, I'm not sure I'd be able to do it in the near future, the complete scenario. But imagine that some of you here might find it an interesting and not too challenging thing to do.

Here is my article, draft in progress:

JOSEPH CARROLL'S INGENIOUS ARTIFICIAL GRAVITY EXPERIMENT - SOYUZ IN TETHER SPIN - ALMOST NO EXTRA FUEL

Joe Carroll himself is going to talk about his ideas on the Space Show about a week from now.

Sunday, May 25, 1PM PDT, Webinar with Joe Carroll, Drs. Logan and Jurist on partial gravity and more. -Space show newsletter

And here's my original article on Science20 Ingenious Idea: Soyuz Crew in Tether Spin On Way to ISS - For Artificial Gravity - Almost No Extra Fuel

 

[Donamy]

I did this with a .dll from BrianJ

http://www.youtube.com/watch?feature=player_embedded&v=k7PjSDhjRxA

 

[robertinventor]

I did this with a .dll from BrianJ

http://www.youtube.com/watch?feature=player_embedded&v=k7PjSDhjRxA

Oh, that's just what I need!

What's the name of the dll, how can I find it? Just did a search in the forum for BrianJ + Tether, didn't turn up anything, and he has lots of posts here.

---------- Post added at 01:39 PM ---------- Previous post was at 01:36 PM ----------

For anyone who is interested BTW I published the article here:

Ingenious Idea: Soyuz Crew in Tether Spin On Way to ISS - For Artificial Gravity - Almost No Extra Fuel

It's like a blog post, I can continue to edit it, so will add the spinning video to it if I can figure a way to do it.

And as you'll see, Joe Carroll is going to talk about his ideas on the space show next Sunday.

 

[gattispilot]

Could you just make an attachment of each ship and attach?

 

[robertinventor]

Could you just make an attachment of each ship and attach?

Sorry I don't understand. I'm new to Orbiter, you need to say a bit more about what is involved.

What steps would you go through to attach the Soyuz final stage to the TMA so that they can spin around each other after separation?

 

[gattispilot]

First You would need to know where to place an attachment. You can use meshwizard and this to make the attachments.
[ame="http://www.orbithangar.com/searchid.php?ID=3058"]http://www.orbithangar.com/searchid.php?ID=3058[/ame]
[ame="http://www.orbithangar.com/searchid.php?ID=5849"]http://www.orbithangar.com/searchid.php?ID=5849[/ame]

 

[Castor]

What's the name of the dll, how can I find it? Just did a search in the forum for BrianJ + Tether, didn't turn up anything, and he has lots of posts here.

It would be best to send Brian a PM.

 

[robertinventor]

Thanks, just to say, Gattispilot has kindly said in a PM, he will attach the Soyuz to the final stage using attachment manager, and says he can attach them at 600 meters no problem.

So I've taken him up on the offer, hopefully that will sort it out.

Thanks for your help!

It would be best to send Brian a PM.

---------- Post added 05-22-14 at 02:09 AM ---------- Previous post was 05-21-14 at 06:11 PM ----------

Okay, got a video now thanks to Gattispilot. Will do fine and added it to the article.

Here is the video .

https://www.youtube.com/watch?v=FHLhIYKDOKg

Plus another with a slower spin. Both for 50 meter tether because at 600 meters then the spaceship and final stage were so small they were just a few pixels each.

https://www.youtube.com/watch?v=AYEyK1BBfnQ

And article - you need to scroll down a bit to find the second video, used the first one in the intor.

http://www.science20.com/robert_inv...first_human_test_of_artificial_gravity-136686

Also used it to do a screenshot over the S. Pacific of both craft for the article as well.

Really doesn't matter you can't see a tether I think. Pleased with it.

Thanks to everyone for your help!

 

[Castor]

Quite a good video there.

 

[robertinventor]

Great, glad you like it .

Done lots more videos now with help from Gattispilot - with a tether as well now, as you can see the results here - and if anyone is interested, Joe Carroll's space show webinar is tomorrow, Sunday 25th May. He'll be using the videos as resource material for the show.

Crew Tether Spin For Artificial Gravity On Way To ISS - Stunning New Videos - Space Show Webinar On Sunday

 

[robertinventor]

Here is the webinar with Joe Carroll talking about tether experiments and his ideas for an Artificial Gravity Lab - now archived as video on vimeo: [ame="http://vimeo.com/96541425"]Partial and Artificial Gravity for Human Spaceflight 5-25-14 on Vimeo[/ame]
and as audio here
http://thespaceshow.com/detail.asp?q=2249

- linking to my article as background material for the show

Thanks everyone for your help.

Some time I'd like to see if I can simulate the tether release - have it spinning in the final orbit just before it goes to the ISS, and then release the tether at the right moment and do a video of the final stage, probably time speeded up ten times - all the way to burn up in the pacific and the Soyuz going the other way to higher orbit.

Anyway that's for the future, probably needs another approach I imagine maybe the flexible tethers.

But was absolutely delighted to be able to do the videos for the article - it's great, I think without them then readers of the article wouldn't have nearly such a clear idea of how it works, a picture or video is worth hundreds of words, which nowadays many people haven't got time to read anyway most often.

 

[boogabooga]

Quick note to say that this looks more do-able now, thanks to the re-release of tether MFD for Orbiter 2010: [ame="http://www.orbithangar.com/searchid.php?ID=6697"]TetherMFD v1.0[/ame]

(I'm writing this as a courtesy to the thread starter, if he is still around, assuming he "watches" this thread. I hope this isn't considered a necropost.)

 

[robertinventor]

Thanks, yes that looks like what I'm looking for.

I'm just an occasional user of Orbiter and would need to get back into the way of it first to try it out. Last time was for an article I was writing for my Science20 blog and to help with background material for a webinar on the SpaceShow on the topic. That's all happened now of course.

So - most likely when I work on my next article on this topic, or when I get a bit of time.

Look forward to trying it out. The main issue I had before was that - though it worked really well and gave a good first impression of the idea, I could only attach the spacecraft together "eyeballs out" - so had to add a comment to the video explaining that this was done for technical reasons and not the way it would actually fly.

Presumably this tether would let me attach any part of the Soyuz to the final stage via a tether?

Also it would be great if I could also try releasing the tether and watch the final stage do its re-entry into the Pacific and the Soyuz boost to a higher orbit when that happens. Again sounds as if it could do this.

So anyway I look forward to giving this a go some time in the future. (Got rather a lot on right now.)

Thanks!

 

[boogabooga]

It isn't going to be very practical.

First of all, the tether is flexible so that the faster you rotate, the longer it gets. I'm not sure you were considering that before. So if you want a 150m tether, you need to set a shorter length.

Also, there is a lot of "tugging" when the tether isn't attached to the centers of gravity. What you might end up with is chaotic tumbling rather than smooth rotation. I wouldn't expect to control the rotation well enough to make precise maneuvers, as your article seems to suggest, if I were you.

 

[robertinventor]

It isn't going to be very practical.

First of all, the tether is flexible so that the faster you rotate, the longer it gets. I'm not sure you were considering that before. So if you want a 150m tether, you need to set a shorter length.

Also, there is a lot of "tugging" when the tether isn't attached to the centers of gravity. What you might end up with is chaotic tumbling rather than smooth rotation. I wouldn't expect to control the rotation well enough to make precise maneuvers, as your article seems to suggest, if I were you.

Oh, I see.

Well - for the first, seems there is an option to control the elasticity, so perhaps I could set that very low?

As far as this experiment is concerned, even a theoretical zero elasticity so it is in effect rigid would be okay, because I'm only interested in what happens when you release it, and all the rest of the time it might as well be a rigid body.

The experiment itself is actually practical in practice, because the author of the paper, Joe Carroll, is someone who works on space tethers as the main thing he does, and has been responsible for flights of tethered pairs of satellites before so knows what he is talking about (though never done for artificial gravity).

So, if the tether models good physics, then, if it is tethered in the right way and the separation is done carefully, and we use the right tether points, it should work.

What is needed is to set the assembly rotating with the plane of rotation within the plane of the orbit (axis of rotation perpendicular to it).

Apart from that no precision is needed. The precision comes in the timing of the separation which has to be done at apogee and also when the Soyuz is moving in the direction of the orbit and final stage moving in the opposite direction.

For first approximation, get a good enough idea if you just wait for the apogee and then as it slowly spins around its C of G, will be easy enough to choose a moment when the Soyuz is moving in the direction of its orbit to a good approximation, and you don't need much more than that to achieve what is expected. Like, get it right to within a few tens of seconds and should be fine, just by eyeball.

As for tether points, well I could tether to the CofG I suppose if you can do that - but that wouldn't set the orientation.

Better to tether to other points.

Doesn't matter if the final stage tumbles a bit. But the Soyuz obviously shouldn't. Maybe I can find a tether point somehow that is far enough away.

Anyway thanks, certainly seems more complex than I thought at first. I think just have to give it a go some time and see what happens. Any other thoughts do say!

 

[boogabooga]

Another problem that you will have in Orbter (and real life) is that the Soyuz upper stage performs an asymmetric LOX dump after cut of to intentionally set it spinning. You will have to kill rotation using the mission editor.

BTW, why Soyuz?
Could this not be done with say the Falcon9/Dragon?

 

[robertinventor]

Another problem that you will have in Orbter (and real life) is that the Soyuz upper stage performs an asymmetric LOX dump after cut of to intentionally set it spinning. You will have to kill rotation using the mission editor.

BTW, why Soyuz?
Could this not be done with say the Falcon9/Dragon?

Oh okay - I've noticed it did that, dumped fuel and started spinning, in Orbiter, and wondered why that was.

I've got an idea though about both of these. I have these scenarios already made, where the Soyuz and final stage are in orbit and joined together by a rigid element. And the whole thing is already rotating in the plane of the orbit also.

I wonder if I can somehow just remove the rigid element with the scene editor - and replace it by this flexible tether set to almost 0 elasticity - but attached to a different point on the Soyuz (for final stage, orientation doesn't matter)? Then just wait for the Soyuz to adjust around to its new orientation. So long as there is a bit of elasticity and give, and tether point is well chosen, I think that it would eventually settle down, if modeling the physical situation, especially since it is already rotating so forcing the tether to be under tension all the time.

Because - my aim is not to model the entire mission, just to simulate part of it. For the entire mission you'd have to stop it doing the LOX dump, yes, that wouldn't help. And somehow pre-attach the tether while the spacecraft is still on the launch platform - because that wouldn't be done in orbit in practice. It would be pre-attached and folded up in a way easy to unfold - and the whole thing lightly stitched - and the stitches then pulled apart as the Soyuz separates from the final stage (method used for previous space tethers). But that's too ambitious for me, and also - that part is well understood so, not really most important part to do a video about.

Yes you can use the Falcon9 / Dragon. Except - that it hasn't yet been flown or human rated. Just as a personal opinion, not saying this is right of course - I'm a little skeptical that it will be, in near future. I mean - probably they will fly it - but will they get it human rated in the near future?

Because - it is just too early. Soyuz has well over 100 flights to show it is reliable - how can we be as confident in the Falcon 9 / Dragon until it has had at least a few dozen flights and preferably more? Otherwise - what if there is some hidden Space Shuttle type issue that just hasn't turned up yet? I know they say that the rocket design is inherently simple and safe - but - there is always a gap between theory and practice you can only bridge with lots of tests.

For human missions that is. For unmanned flight not an issue except expense. Same perhaps for flights with test pilots - these are people who knowingly take risks with their lives that most people wouldn't, while at the same time of course doing everything they can to be safe.

But - a single accident with the Dragon with paying passengers rather than test pilots would be a human tragedy, and ground it right away. Same for the Virgin Galactica. I think that with more and more manned flight in the future - that accidents are almost inevitable and that the pioneers in this field aren't really prepared for that. They can get the humans to sign waivers - but - that does not really mean they understand on the human level that their lives really are at risk - or that their relatives do etc.

I think myself that flying into space, even on the Soyuz, is roughly as safe as, say, base jumping when done properly and carefully. And flying into space in a new rocket hardly yet tested, is far more dangerous than that. Not because of the technology, just because we can't currently test space flights as thoroughly as we can test cars, or planes, or submarines, helicopters etc because every test flight is so expensive. I mean who would drive a car that has only been test driven a little over 100 times and is the first ever car to feature its particular design? That's the Soyuz, safest of all our spaceships.

That's my personal view there of course. Obviously Elon Musk thinks they will get Dragon rated safe for humans. I'll believe it when he does it .

But whatever, yes could do that. But right now only prospect of it happening is on a Soyuz as far as I can see. So makes sense to do that. I could do an alternative with the Dragon - last time I tried but as a newbie had issues getting it into orbit. Now that I understand about the scene editor though probably I could just edit the scene and put a Dragon in place of the Soyuz in the orbiting assembly, same for its final stage.