Most noodle-like (highest aspect ratio) orbital launch vehicle ever?

Question

are well and good, but after seeing the Scout D-1 in the excellent Curious Droid video Black Arrow : The Lipstick Rocket - A Very British Space Program at around 09:33 (screen shot below) where it looks as thin and tall as the metal towers holding the lightning wires around the launch site I wondered if this is in fact the highest aspect ratio (height/width) or most "noodle-like" orbital launch vehicle ever.

Question: What is/was the most noodle-like orbital launch vehicle ever? Which one has/had the highest aspect ratio? Don't including fins, strap-ons or fairings, just the rocket body diameter. If it's modulated along the length, feel free to take some length-averaged mean diameter if necessary.

From If not constrained by underpasses, etc., would Falcon 9 have been less of a flying noodle? illustrating that rockets can be so long and narrow that they can bend and flex in the wind!

@DrSheldon I've asked for the highest aspect ratio, right there in the title. How would you define it for those geometries? — uhoh, May 29 '21 at 05:29

score 8 · Accepted Answer · answered Jun 01 '21 at 17:41

For simplicity, I will go with the ratio of height to largest cylindrical diameter. That should be an okay definition of "noodly".

This is the result of going through all the all-solid orbital launchers I could find, since none of the liquid ones were even close.

To start out, let's check your Scout-D.1 suspicion:
Scout D-1: 25m : 1.14m = 21.93, as a starting point.

But there were many versions of the Scout, and going through all of them, the following ones were more "noodly" than the D-1:

Blue Scout II: 24m : 1.02m = 23.52
Scout B: 25m: 1.01m = 24.75
Scout X-1: 25m: 1.01m = 24.75
Scout X-2: 25m: 1.01m = 24.75
Scout X-3: 24m : 1.02m = 23.76
Scout X-4: 25m: 1.01m = 24.75

I couldn't find anything better, but here's a selection of others:

Even with their noodly reputation, none of the Falcons are above 20:1

SLV is pretty noodly, but 22m : 1m = 22 isn't good enough to beat the scouts.
ASLV: 23.5 m : 1m = 23.5, but that may or may not count as it had boosters.

Lambda 3 17.4m : 0.74m = 23.51, very close.

Scout X-2

Excellent! fyi I've just asked Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios? and cited your answer as "Evidence of solid rocket launch vehicle 'noodlicity'". — uhoh, Jun 02 '21 at 01:55
In mid-May, LandSpace showed pictures of the rocket’s 3,700-kilometer journey through China to the pad. This transport is also why the common diameter of Chinese rockets, including ZhuQue-2, is about 3.5 meters. Anything bigger than that would limit the rocket’s ability to be transported on roads and trains. While also limited in diameter by domestic transportation realities, at about 14 it's not very noodly at all. — uhoh, Jul 11 '23 at 21:55

Most noodle-like (highest aspect ratio) orbital launch vehicle ever?

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