Why were there missing rungs on the Lunar Lander’s Ladder?

Something about the Apollo missions always confused me, sure, the step off of the lunar lander’s 91 cm footpad was a small step, but the step just before that was actually enormous!

I’m talking about this, the huge gap between the last rung on the ladder and the ground. Why on the Moon is that gap so huge?! Isn’t it dangerous to require an astronaut to jump down onto the surface and jump back up?

The lunar lander’s ladder had nine rungs all spaced 22.8 cm (9”) apart, but the gap between the last rung and the ground was about three times that at a whopping 76 cm (30”)! So really, the ladder wasn’t missing one rung, it was missing two!

I mean sure, the gravity’s only 1/6th that of Earth’s, but wouldn’t it have been so much safer if there was even one more rung to close that gap up a little?

So today we’re going to look into why NASA and the Lunar Lander’s manufacturer Grumman, chose a ladder of this length, we’ll talk about design considerations of the hardware, the unknown conditions of the lunar surface, and the astronauts who were basically too smooth of pilots to get the ladder’s last rung any closer to the surface of the moon.

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[WhereisRoadster]

"Woopie! That may have been a small one for Neil, but that's a long one for me"- Pete Conrad's first words walking on the Moon, Apollo 12.

[andii]

Only you can make a 15min discussion about ladders so interesting. ..

[herbertkeithmiller]

Ah yes those famous first words spoken from the surface of the Moon . . . " Okay. Engine stop. ACA - Out of detent."

[Derek_Read]

Given the detail in this video I'm a bit surprised the maker is not mentioned. Héroux Machine Parts (in Quebec) won the contract to make the landing gear in 1965 (beating out 15 other companies). In total Héroux delivered 17 sets of 4 legs used for the Apollo program, including those used on the Eagle.

[AB-fkgw]

12:30 is now my favourite moment in space history "whoopie! that may have been a small one for Neil, but that's a big one for me"

[cyborg]

I remember laughing hysterically at the time when Pete Conrad said "that may have been a small step for Neil but it was a large one for me". Thanks for looking up that footage and include get in this video. It clearly qualifies as the greatest joke ever made on the surface of the moon. In some ways for me that line was more memorable than Armstrong's original.

[michaeldomansky]

They didn’t want moon raccoons climbing up the ladder.

[EDKguy]

They should have brought one small step ladder for a man

[ibahalii]

You: "Let me know if i answered all the questions you had about the lander ladder."

Me: "I did not even knew there where so many questions to be asked/explained about a ladder."

[jackdaniels]

Helps to keep moon rats from climbing up into the cabin of the lunar module. 😊

[jasongannon]

When I was a small child in the 70s after seeing the video of the first step my first question was over this subject. Finally someone answered my first question asked about space travel. Thanks

[pspicer]

Not only did you answer the question, but provided excellent context as to the decision making and concerns of the time. This is a great video.

[VisualSOLUTIONSMedia]

Though any discussion of ladders is bound to have its... ups and downs, you wrung out all relevant info... Great explanation, I've been wondering since '69!

[rogerkearns]

So, one flies most of the way to the moon, but still has to jump the last bit.
Mind the gap?

[ernestosaboia]

Hi Tim, me again, can you do a video on the Dragon Capsule's parachutes? How do they work? Why are they attached on one side of the capsule and not on both sides? How do they open slowly? And the history behind of capsule parachutes...And so on...

[worldmenders]

A co-worker met one of the landing leg engineers at a party in the 80s. He was really, really freaked out when Armstrong had to jump so far to the pad.

[zapfanzapfan]

Ok, I thought they removed two rungs to compensate for the weight of the flag and flagpole. Glad there was a better explanation :-)

[astroZ]

Great video, Tim, very informative and entertaining. Have you considered making one to explain how the latter Apollo mission astronauts removed and assembled the rover? It looks really big raising questions of where it was stowed, how they got it out and unfolded or assembled it. I’m really curious! Thanks!

[PhilipChou]

Fascinating video. The check by the first astronaut out of the LM to see if they could climb back up. Just shows the level of detail that the engineers a looked into regarding every bit of the landing. I"m sure the folding vs straight ladder came up around for many debates (weight, reliability, etc.)

[caseygecko]

"crushcore" sounds like some obscure metal genre lmao