Which of these poles would be straighter and stronger then the others?

These are some poles that are compacted making them possible to send to space. Sending a single solid pole .5km long will not be possible.

  1. STEM ( Storable Tubular Extendible Member), a pre-stressed piece of thin metal that could be rolled up like a carpenters tape measure. On Alouette electric motors would roll out the thin pieces, which would form tubular semi-rigid antenna once they were deployed.

  2. Seamless gutter maker modified to make a round symmetrical pole.

  3. http://zippermast.com/

Each pole produced would have the same weight per measure.

What advantages and disadvantages does each pole made from these methods have?

Are there any other types of extendable poles I am missing that could be added to this list?

How would a long pole be transported to space?


1 Answer 1


I don't have direct experience with these types of contraptions (other than using a tape measure).


For something like this, straightness would seem to depend symmetry. Any imperfections in the pole could be amplified if they occur in the weak direction (seam) of the pole. In a symmetrical configuration, these would tend to cancel out.

Think about a tape measure. It can strongly support itself in one direction, but once it is flipped over, it bends easily. Also, if you have ever experienced a tape measure that has been bent out of shape, it never supports itself as well as before.

The third option is the only one with symmetry. It also does not have an open slot that would be a weak point.


We have no other information, so I am assuming that the individual size (width and thickness) of each tape is the same. In this case, the only difference between the options is the number of tapes used.

Once again, the third option is the best. It uses the most individual pieces.


In the end, if all you are going for is possible strength and straightness, the third option seems to be the best out of the three. There may be other reasons for choosing one over the other, but the third option seems pretty clever.

  • $\begingroup$ If you look at the first example at the interlocking by-stem that to me seems symmetrical? $\endgroup$
    – user4139
    Oct 13, 2018 at 18:55
  • 1
    $\begingroup$ @Muze It is hard to tell from those diagrams which ones have the seam in the same locations. It could be that there are options that are symmetrical. The strength point still stands though. $\endgroup$
    – hazzey
    Oct 14, 2018 at 0:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.