Can a long pole or a set of poles be strapped to the out side of a rocket (like a bottle rocket)or on the nose as an external payload without interfering with the aerodynamics of the rocket? How would a very long thin pole .5 km or longer be transported to orbit normally?

This link is why I ask. Can a satellite utilize gravity gradient stabilization and solar stabilization together?

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    On Earth we would transport a 500 m long pole in parts of about 50 m and assemble them where the pole is needed. Why should we transport the long pole in one piece to orbit? – Uwe Sep 28 at 9:23
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    @Uwe - Off the top of my head, perhaps because it was a single long crystal that couldn't be sub-divided? – Richard Sep 28 at 11:16
  • If the pole is stiff enough, why can't you attach some stabilizing fins and an engine onto it. When it's high enough, jettison the fins and engine. The pole would effectively be a solid body rocket. – B540Glenn Sep 28 at 13:48
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    An important thing missing from the question is the set of fundamental requirements on the pole. What will it be used for? What mechanical requirements result from that use? Those requirements, along with characteristics of candidate materials, will determine specs like pole diameter and wall thickness, and those will affect the choice of implementation method. When designing space hardware in a cost-constrained environment (and what real mission other than JWST isn't cost-constrained?) it is crucial to define the objectives first, then design the hardware. – Tom Spilker Sep 28 at 18:01
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    This gets into the difference between a mission objective and a technological capability. Building a gravity-gradient stabilized spacecraft isn't a mission objective, unless the objective is just to demonstrate that gravity-gradient stabilization actually works as theorized. A mission objective would be something like "Image Earth's surface at 10-m resolution", or "Receive the sun's low-frequency radio emissions". Those objectives and their implementations will determine how much perturbing torque must be countered, and thus the design of the "pole". – Tom Spilker Sep 28 at 22:04
up vote 23 down vote accepted

Long rigid structure can be transported as raw material for fabrication in space, in the same way that continuous rain gutters are made.

In the pictures below, you can see a machine that creates the rigid rain gutter from a compact roll of sheet metal.

The method is provides for compact transportation, only limited by the compacted size and weight of the material required to make the structure. The machine itself is small enough to be carried by any spacecraft that would be involved in deploying something the size of what you described.

enter image description here enter image description here


The Canadian Alouette satellites used this technique 56 years ago to deploy 45 metre antennae from a 1 metre diameter satellite.

  • This, and the additive manufacturing approach @qq jkzdt suggested, are probably the only truly practical approaches to this task. – Tom Spilker Sep 28 at 18:12
  • @TomSpilker a good answer. – Muze Sep 28 at 21:09
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    The Canadian Alouette satellites used this technique 56 years ago to deploy 45 metre antennae from a 1 metre diameter satellite... spacenet.on.ca/data/pages/canada-in-space/alouette.html – DJohnM Sep 30 at 6:44
  • The difference between the 2 is that the lower picture is a memory metal that returns to its initial form to make a pole also retractable where machine used to make the storm gutters permanently mold the metal. Which of the 2 devices produce a sturdier pole? – Muze Sep 30 at 22:19
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    @Muze That's a new question. – called2voyage Oct 6 at 17:24

The ISS solar array masts are launched collapsed in canisters, and run through a deployer mechanism to erect them as a long straight object. I see no technical reason why a much longer mast couldn't use this system.

For details see this question and answer: How do the booms on ISS (and other spacecraft) extend and retract?

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    Obviously not to be a noodle this would need a significantly higher diameter... This would be a payload for Falcon Heavy or Arianne, not a common small launch. – SF. Sep 28 at 8:06
  • @SF.: Why? The OP just says "thin", not how thin. – jamesqf Sep 28 at 16:24
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    @SF.: Obviously, the "pole" is made of a high-strength epoxy (or similar). The two components are carried to orbit wound on a spool. Once there, the spool is unwound, the components mix and harden, and you have your long straight pole :-) – jamesqf Sep 29 at 4:38
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    @jamesqf: That's actually a very good, practically doable idea. Would still require some very tricky engineering (a pressurized chamber so the epoxy doesn't boil off, with a sealed hole to push the pole off through as it hardens) but possibly gives best length and strength to weight ratio of all. (although likely not very long-lived... UV degradation.) – SF. Sep 29 at 10:54
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    @SF.: To deal with UV degradation, the components can be contained in a thin coating of metal foil (like a Mylar balloon). I'll leave it to the chemists to figure out an epoxy-like material that hardens in vacuum. Or perhaps it could be a metal shape-memory alloy: en.wikipedia.org/wiki/Shape-memory_alloy – jamesqf Sep 30 at 4:12

Best way to do this could be to research, develop and send a "3D tube printer satellite" to low Earth orbit, and feed it with whatever material in liquid, powder or filament form, which will not require any special attachement or design modification to existing rockets, since it can fill any shape of a given volume.

For instance one 0.5 km long tube, 10 cm in diameter and 1 mm of wall thickness is only about 0.155 cubic meter of raw material. Which means the 3D printer satellite and the required raw materials could fit in one single launch.

Of course all of this highly depends on the mechanical strains you expect this tube to withstand.

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    I agree that fabrication in orbit is the only practical way to do this. An additive manufacturing ("3D printer") device in orbit is a viable approach, and a capacity we're going to need eventually. Another approach is similar to the gutter-extruder (See @Jim's answer), one that takes in a sheet of material (from a roll), bends it into a tube, and welds the seam. The weld could be viewed as a limited type of additive manufacturing. – Tom Spilker Sep 28 at 17:50

A thin pole .5 km long is easier said than done. A scaffolding pole (4 m long, 4 cm diameter) may seem rigid, but link a few end-to-end and the resulting pole will be flexible. If you attach it to the outside of a rocket, it'll start wobbling under the aerodynamic loads.

You can combat this by making the diameter larger, but to support a pole 500 m long you'll need a diameter larger than the rocket itself, and the pole will be too heavy.

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    This is an important point, you can't hold such a long and narrow pole vertically stable on earth, it doesn't matter whether there is a rocket underneath it or not. – jpa Sep 28 at 10:09
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    Hell, I'd say it would start to wobble to the point of collapse long before launch! I don't know what material you would make the pole out of to even achieve such length without lateral stiffening! – KlaymenDK Sep 28 at 11:00
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    This isn't my field of expertise, so a potentially stupid question: What if you pulled the pole behind the rocket? Digging a half-kilo silo for it under the launch platform, surrounding the pole with some sort of shield to protect it from the rocket's exhaust. Since, as you describe, any 500m long material is essentially a rope. Is that what you all are picturing? I'd imagine the collection of forces may even help keep it straight. – HammerN'Songs Sep 28 at 13:11
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    That's a non-starter because the pole will be blasted by the exhaust, and because you need to drop the first stage at some point without losing the pole. – Hobbes Sep 28 at 14:48
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    I was going to dispute the existence of 0.5km ropes, but the Golden Gate bridge has a longest span of 1.3km - and that's a load-bearing cable. – John Dvorak Sep 29 at 18:03

A 500m pole would have a very significant effect on the rocket aerodynamics because it will disturb the airflow above the rocket; increasing the drag. Especially once supersonic.

The drag would be monstrous, and it would need to survive the strong forces of Max Q, and the high Gs of launch.

This leaves us with a somewhat inextricable problem, and out good old friend: the tyranny of the rocket equation:

  • To survive Max G/Q it need to be reinforced => It need to be made heavier => It need a bigger rocket.

OR

  • To survive Max G/Q it need to be launched more slowly => It need a bigger rocket

However; a foldable/telescopic 500m pole should be plausible.

I have created this answer for comments that have been left that could have been an answer. If it is your comment I will delete that part out of this answer when you make an answer out of it. Feel free to use the illustrations TKS

From comments:

Zippermast enter image description here enter image description here

2) You could send a Polish person named Haf Keelometer Orlonger to have a Haf Keelometer Orlonger Pole in orbit.

3)

enter image description here enter image description here

(from a comment)

  • @altendky feel free to use this. – Muze Sep 30 at 18:12
  • @Keeta I have seen comical answers do well if you get a down vote just delete it. I think it would we worth it. – Muze Sep 30 at 19:52
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    Thanks. I wondered how many upvotes it would get as a comment before someone super-serious came along and deleted it. I saw it as 20 upvotes on Friday. – Keeta Oct 1 at 18:31

This answer is different from the answer I made out of the comments for it is my own. One long pole is quite impossible but maybe a bundle of poles on the sides of a rocket like a bottle rocket could achieve orbit. Sure there would be some modification needed but could work?

enter image description here

I think the best way would be to have the "rocket" at the top & pull the pole, but not directly behind - rather have 3+ rockets in a ring configuration, spaced laterally far enough apart & angled such that the engines exhaust won't melt the tube, with a stiff mechanism at the top/nose to maintain the distance - this assumes the tube is stiff enough to support its own weight through the acceleration, but the bending loads won't be as bad as if it were to be pushed from underneath, as the aerodynamics are now working to help keep it (mostly) straight

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    Sadly, the aerodynamics will do nothing of the sort, and almost certainly will cause destructive sympathetic vibrational frequencies – Carl Witthoft Sep 28 at 14:21
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    Before the launch, the pole should be placed vertically within a 500 m high launch base tower or within a 500 m deep hole below the launch pad? Placing the pole horizontally before launch might break the pole during the turn to vertical orientation. If the pole does not break during the turn, its pendulum movement after full lift from ground will be difficult to control by the rockets attitude control. – Uwe Sep 28 at 14:44
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    Unfortunately a pendulum will only swing faster under the influence of the acceleration. – Uwe Sep 28 at 15:06
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    @user2813274 I had had the same idea. Simplify it though to a weight hanging from the rocket, and assume the rocket goes into orbit by following a simple quarter-circle arc, at constant speed. Net force is clearly then always perpendicular to the rocket. If the rocket accelerates along its arc, then that perpendicular force will only increase. That centripetal acceleration is normally provided by the rocket's fins and possibly a gimbaled motor. The pole will need that same acceleration (towards the center of the arc, not towards the rocket) in order to not become a pendulum. – HammerN'Songs Sep 28 at 15:51
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