2
$\begingroup$

xkcd 2125 titled "Luna 2" refers to the object shown below. All faces seem to be pentagons. (found in this question.)

xkcd.com/2125/ Soviet pennant Luna 2

Soviet pennant Luna 2

Copy of the Soviet pennant sent on the Luna 2 probe to the moon, at the Kansas Cosmosphere, Source


Question: What is the name of the polyhedral shape of the Soviet pennant on the Luna 2 spacecraft?

note: This question is about the shape without the spherical caps, the way that the underlying shape of a football is a truncated icosahedron. In this case though I am not sure if this shape will be a polyhedron or not as the five vertices of the pentagonal faces may not lay in a plane.

enter image description here

"Comparison of a truncated icosahedron with the typical appearance of a football/soccer ball." Source

$\endgroup$
3
$\begingroup$

as a 72 faced object, it's a canonical pentagonal heptacontakaidihedron or dokaiheptacontaheron

In Conway terms, it's a spherical quinto dodecahedron 'C969qD' spherical quinto dodecahedron play with it here

However, I've not seen much about quinto outside the wikidpedia page and that viewer, so I'm no longer so sure about it. Another Conway recipe, 't5oD' is very similar.

| cite | improve this answer | |
$\endgroup$
2
$\begingroup$

Ball.

In the collection of our museum there are two unique samples that were delivered to the moon in the area of ​​the Sea of ​​Rains near Aristill, Archimedes and Autolycus. These two balls consisted of pentagonal steel segments. A larger ball (150 mm) was installed on the third stage, a smaller ball (90 mm) - on a container with equipment. For each ball there were 72 pentagons of two types - regular (12 pcs.) And irregularly shaped (60 pcs.). Inside the hollow balls housed explosives. There was a shock fuse that caused luck on the land of the moon. With the explosion of the pennants scattered in all directions, like shards. Falling speed, and they should remain on the surface. All space pennants were minted at the Leningrad Mint.

From http://www.kosmo-museum.ru/news/lunnye-vympely-sssr

enter image description here

| cite | improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ Uhoh, I believe that @A.Rumlin gave interesting information that was lacking in your original post: the ball has 12 regular pentagons and 60 irregular pentagons. (I have no idea if that shape has a name.) $\endgroup$ – Ertxiem - reinstate Monica Mar 20 '19 at 11:57
  • $\begingroup$ @Ertxiem Oh, I understand what you mean; yes that's very useful. Thanks! $\endgroup$ – uhoh Mar 20 '19 at 12:04
  • 1
    $\begingroup$ @uhoh The Humanity Star surface consists of several flat triangles. In case of Luna-2 - These plates have a convex shape - like spherical cap. $\endgroup$ – A. Rumlin Mar 20 '19 at 12:12
  • $\begingroup$ I see what you mean now. I've made an adjustment to the question loosening it up a bit by using the analogy of a football versus a truncated icosahedron. Yes the football is a "ball" but we can understand that it is vertex-by-vertex linked to a truncated icosahedron. This was my intention and I should have understood it wasn't clear without stating explicitly. The information in your answer is very helpful, thanks! $\endgroup$ – uhoh Mar 20 '19 at 13:13
  • 1
    $\begingroup$ This image is in very high resolution. I do not know whether the image will be automatically reduced to an acceptable size on this page . $\endgroup$ – A. Rumlin Mar 21 '19 at 7:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.