Space - Ernst Stuhlinger's Sun Ship or Cosmic Butterfly

[Starbase1]

Thought I'd gather up the final shots of this one.

It's a serious design for a 1950's ion engine spacecraft. For more info see the very short documentary I made, full HD with soundtrack, titles, the works:



Rigel has already pointed out I don't really leave enough time to read the text. Right now I;m unsure of the best way to handle this - still frames that hold for a long time are boiring, maybe it would be better to break it into more frames, Better still to find something to animate near the text...

The central ship was not specified in the original work, so I went for something reminiscent of the "Colliers" ships, (ES was pone of the Werher von Braun team).

Nick

[Rigel]

Another well executed project, Nick. Congratulations.

[Eden]

Very nicely done….already commented about the animation in the wip thread

[vitruvian]

Originally Posted by Rigel

Another well executed project, Nick. Congratulations.

yeah !

[Starbase1]

Thanks Guys - I want to step back a bit before doing anything different to it - not least because rebuilding the audio will be a major job, so I want to get everything perfect next time. Eden has already suggested a wireframe which is good.

I'm still wondering about the best way to handle text without extended still images though - I don't think my voice sounds good enough for a voiceover...

[lonewriter]

Very nice animation, I'm going to make a render of it this week, thanks for the great mesh.

[Starbase1]

Here's my recreation of the Frank Tinsley picture which inspired the work in the first place!

I had to make changes to the lighting - in the original the sun appeared to be shining down on the north pole, so I rotated Earth and moon 90 degrees.

Nick

[lonewriter]

I like it but you stole my idea now I have to come up with something new. Nice job.

[Starbase1]

Originally Posted by lonewriter

I like it but you stole my idea now I have to come up with something new. Nice job.

Sorry about that!

I keep thinking there should be some very dramatic options for an image near Mars (and there are two versions of a Mars I made in resource). Either having Mars reflected in the boiler mirrors, or providing a warm indirect light to the rear of the ship...

But I'm struggling to come up with something more specific...

[Rigel]

Originally Posted by Starbase1

Sorry about that!

I keep thinking there should be some very dramatic options for an image near Mars (and there are two versions of a Mars I made in resource). Either having Mars reflected in the boiler mirrors, or providing a warm indirect light to the rear of the ship...

But I'm struggling to come up with something more specific...

It would look pretty awesome seeing Mars reflected in the mirrors. But that would mean either a) they are aiming the mirrors away from the sun because they don't need to generate power at the moment or b) they are beyond Mars and heading further out. But, logic be damned, it would make a nice picture!

[Starbase1]

Originally Posted by Rigel

It would look pretty awesome seeing Mars reflected in the mirrors. But that would mean either a) they are aiming the mirrors away from the sun because they don't need to generate power at the moment or b) they are beyond Mars and heading further out. But, logic be damned, it would make a nice picture!

Well, not quite...

Consider it as it goes past Mars - looking across the mirrors from just in front, with a half Mars beyond it and just above the front of the mirrors. Or with the ship just past Mars, looking at the mirrors from the sunward side, with a crescent Mars reflected in the mirror..

twitch.

twitch.

Argh!

[Treybor]

That looks awesome! One quick physics question, with all the dishes rotating in the same direction, would that cause problems maintaining a stright course? I've seen some suggestions thate each side should be counter-rotating. (1/2 clockwise adn 1/2 counter clockwise - or is that another urban science myth for the mythbusters....?)

[Starbase1]

Originally Posted by Treybor

That looks awesome! One quick physics question, with all the dishes rotating in the same direction, would that cause problems maintaining a stright course? I've seen some suggestions thate each side should be counter-rotating. (1/2 clockwise adn 1/2 counter clockwise - or is that another urban science myth for the mythbusters....?)

Thanks Treybor!

Can I ask where you saw these suggestions?

I see what you are getting at, but I'm out of my depth on how important the effect is. Part of me says you are right, and that reversing one side would be simple (in the real world!), and should neutralise any overall twisting.

The other part of me says that its a low proportion of the weight that would actually spin, (the mirrors could be foil in the notes I saw). Particularly if I had stuck to the illustration more rigorously, where the cooling vanes did not spin, and the rods above the mirror went up through the centre rather than leaning in from the rim. These changes would reduce the angular momentum considerably.

(I really liked the idea of the spin being obvious for animations).

Hmmm...

Nick

[Rigel]

I could see that being a problem only with a helicopter. I'm not a physicist either, but, for the spinning dish to counter-spin the vehicle I believe it needs to be on the centre line, much like helicopter rotor blades are.

Also, the spinning section of the ship in Space Odyssey did not seem to cause counter-rotation problems, so I'm sure it could be worked out.

[Starbase1]

That makes me think - if you consider it as a set of gyroscopes, they would resist turning. So in that case it would make sense to point it the right way, (the mirrors towards the sun), spin up the boilers, and the effect would be to keep them pointing in the correct direction, yes?

If for any reason you wanted to point them away from the sun, they wouldn't be working anyway, so you could spin them down.

The attitude jets could rotate the ship within the plane of the mirrors, to direct the thrust of the central ship.

(though is that's all they do, these ones are over sized I think).

Keeping a helicopter always facing the same direction is not a good idea, but for this craft it seems to make sense.

Or am I adjusting physics to match my version of the craft?
Nick

[Treybor]

I'm not sure. I'm not a physists so I don't know for sure.
But these types of mechanical engineering ideas vs. Zero-g physics have always interested me.

Egad! I had a heck of a time finding the old forum links
http://www.physicsforums.com/showthread.php?t=128897
There was a discussion about a spindle like craft, with counter rotating rings, and whether or not it was necessary to provide stability along the axis of the spindle.

There was anotehr discussion in the same forum about a rotating space station like you'd see on 2001. The rings both rotate in the same direction to preserve angular momentum, and provide artificial gravity.

But in a spaceship like yours I'm not sure the rotating dishes provide enough inertia\resistance to impact the momentum of the ship moving forward. I supposed it depends on the central mass of the ship and the speed it's traveling.

Gotta stop now... smoke coming out of my ears....

[Shrubery]

Had a big long reply with the force equations and everything... click the wrong button... <sigh> short version, yes spinning all the dishes in the same direction would cause rotation of the whole structure around a common center of mass. But usually only a problem during spin up.

After that, there shouldn't be too much transfer of momentum to the host system, and what transfer there is would be manageable.

[Starbase1]

Originally Posted by Shrubery

Had a big long reply with the force equations and everything... click the wrong button... <sigh> short version, yes spinning all the dishes in the same direction would cause rotation of the whole structure around a common center of mass. But usually only a problem during spin up.

After that, there shouldn't be too much transfer of momentum to the host system, and what transfer there is would be manageable.

Thanks Shrubery - sorry you lost the detail, but that sounds good enough to me, I'll leave it as it is.

[Marty Miller]

Nicely done mate. Congratulations

[Treybor]

Originally Posted by Shrubery

Had a big long reply with the force equations and everything... click the wrong button... <sigh> short version, yes spinning all the dishes in the same direction would cause rotation of the whole structure around a common center of mass. But usually only a problem during spin up.

After that, there shouldn't be too much transfer of momentum to the host system, and what transfer there is would be manageable.

Awesome. Thanks for anwering the question.

[Shrubery]

Wish I could figure out how to do this so that it shows up all fancy like....

T= 2pi x sqrt of (r + R)3 / G(M + m)

That would get you the period of rotation for any 2 opposing dishes. Doing it for ALL of the dishes in unison is a bit more complicated, but the above is the gist of it.

[Rigel]

Originally Posted by Shrubery

Wish I could figure out how to do this so that it shows up all fancy like....

T= 2pi x sqrt of (r + R)3 / G(M + m)

That would get you the period of rotation for any 2 opposing dishes. Doing it for ALL of the dishes in unison is a bit more complicated, but the above is the gist of it.

Do it as an image.

[3D_CG]

so all the dishes you want them to rotate, but have every other dish rotate the opposite direction so they would cancel each other out, correct...??? for inertia dampening kinda thing ??

Interesting....
I thought I would go into the graph editor and do a couple of tests
and rotated a ring in one direction..
secound ring i rotated in the opposite direction, then I just cloned them..

[Shrubery]

Is it sad that I can teach this in a 3 or 400 level course, but it never dawned on me to copy and paste an image of the formulas from mathmatica or wolfram...

Anyway, still a cool series of renders.

[Starbase1]

Originally Posted by Shrubery

Is it sad that I can teach this in a 3 or 400 level course, but it never dawned on me to copy and paste an image of the formulas from mathmatica or wolfram...

Anyway, still a cool series of renders.

Thank you all - and I really enjoyed the discussion too!

[Rigel]

Originally Posted by Shrubery

Is it sad that I can teach this in a 3 or 400 level course, but it never dawned on me to copy and paste an image of the formulas from mathmatica or wolfram...

Anyway, still a cool series of renders.

It's always the little things that catch us.