# How is the height of a rocket measured?

How is the height of rockets measured? For example, the Saturn V is 363 feet tall, but is that 363 ft from the tip of the launch abort tower to the bottom of the engine bell or is it from the tip of the launch abort tower to the bottom of the rocket excluding the engines?

• There's no agreed-upon standard. This is a problem e.g. in aviation as well (does the pitot tube count or not). The only way to be sure is to find a dimensioned drawing. – Hobbes May 12 '19 at 19:05

363 feet is the height of the Saturn V/Apollo stack from tip of the launch escape tower to the bottom of the engine bells, according to the dimensioned drawing here.

Oddly, the "zero" vertical reference point on that drawing is not the bottom of the nozzle, but 115.36 inches above it; I'm not sure if that's the length of the F-1 nozzle extensions or something else, but at any rate, the total length is 363 feet and a fraction of an inch.

(As an aside, I note this drawing identifies the crew members as "command pilot", "senior pilot", and "pilot" rather than "commander", "command module pilot", and "lunar module pilot", and refers to the LM as "lunar excursion module". The word "excursion" was officially dropped in June 1966, but the date on this drawing is March 1967.)

In almost every case, I'd expect rocket height to refer to the total length from the bottom of engine nozzles to the top of a payload fairing. @Hobbes is correct, though, that for any purposes other than impressing tourists, you'll want to consult a dimensioned drawing to be sure of what's what.

• The zero reference is likely the MLP deck. – Organic Marble May 12 '19 at 20:35
• @MagicOctopusUrn The "0" reference is not the bottom of the rocket. On the left, the lowest point is BOTTOM OF F-1 ENGINE at -115.36 inches (-2.930m). – Turch May 13 '19 at 19:56
• @MagicOctopusUrn That's what the comments above are discussing, it's likely the Mobile Launch Platform deck. There's a picture too. (I had to figure out the negative thing myself while looking at that exact diagram when making a 3D-printed Staturn V model) – Turch May 13 '19 at 20:00
• @Turch sometimes my stupidity shouldn't be rewarded with further clarification heh, thanks for takking the time though. I missed that first comment, and definitely should not have. – Magic Octopus Urn May 13 '19 at 20:03
• @OrganicMarble: Notice how the gimbal plane is at a nice round 100 inches, exactly. That's because the origin of the Saturn I and IB structural reference frame was placed 100 inches below the gimbal plane. See Figures 8A and 8B of ibiblio.org/apollo/Documents/19700076120.pdf. – David Hammen May 13 '19 at 22:59