Author Topic: Apollo docking mechanism.  (Read 8694 times)

Offline Flookie

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Apollo docking mechanism.
« on: February 20, 2016, 08:43:39 PM »
I came across this in a newspaper forum and I have no idea how the docking mechanism did work much less what he means by "3' ringed-circles" (the hatches between the two modules?). I couldn't find information online that I could properly comprehend.

"Try using your brain and explaining how the LEM and control module managed to reconnect two 3' ringed-circles in a frictionless environment with only four directional thrusters and a computer that wasn't fast enough to help. They didn't even use a cone-type receiver like a jet would to re-fuel."

In terms of "using your brain" it seem a good idea to ask the people who would know  :)

Offline ka9q

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Re: Apollo docking mechanism.
« Reply #1 on: February 20, 2016, 08:47:35 PM »
Actually, they did use a "cone-type receiver like a jet would use to refuel". It's on the LM side, and was called the "drogue".

Check this page. Note links to illustrations.

http://www.apollosaturn.com/asnr/docking.htm
« Last Edit: February 20, 2016, 08:54:18 PM by ka9q »

Offline raven

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Re: Apollo docking mechanism.
« Reply #2 on: February 20, 2016, 08:50:10 PM »
This should give you all the information you need.

Offline DD Brock

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Re: Apollo docking mechanism.
« Reply #3 on: February 20, 2016, 10:16:27 PM »
This should give you all the information you need.

Hey, thank you very much for posting that. I've always wondered just how the hell the docking mechanism actually worked, beyond the bare-bones basics of it that is. I haven't read through it yet, but I already understand it better from just perusing the diagrams.

Offline bknight

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Re: Apollo docking mechanism.
« Reply #4 on: February 20, 2016, 10:43:19 PM »
This should give you all the information you need.

This question is for Jay, but anyone may answer of course.  During A14 when the CSM had difficulty docking, Jay indicated it was most likely ice in the ? Probe or docking ring assemblies?
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Offline onebigmonkey

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Re: Apollo docking mechanism.
« Reply #5 on: February 21, 2016, 02:31:14 AM »
Am I right in thinking that modern docking mechanisms aren't that much different - other than the computer control?

Offline gwiz

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Re: Apollo docking mechanism.
« Reply #6 on: February 21, 2016, 05:40:39 AM »
This should give you all the information you need.
This question is for Jay, but anyone may answer of course.  During A14 when the CSM had difficulty docking, Jay indicated it was most likely ice in the ? Probe or docking ring assemblies?
The theory was ice in the capture latches on the probe, however I believe the investigation came down in favour of contamination in the latch mechanism.
Multiple exclamation marks are a sure sign of a diseased mind - Terry Pratchett
...the ascent module ... took off like a rocket - Moon Man

Offline Flookie

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Re: Apollo docking mechanism.
« Reply #7 on: February 21, 2016, 12:40:20 PM »
Thanks guys. I think I can grasp the engineering  :D  I'm still wondering how they did the maneuvering precisely enough to get the right attitude to line up with the CM & drogue?

Offline Allan F

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Re: Apollo docking mechanism.
« Reply #8 on: February 21, 2016, 02:24:42 PM »
Thanks guys. I think I can grasp the engineering  :D  I'm still wondering how they did the maneuvering precisely enough to get the right attitude to line up with the CM & drogue?

They had aimpoints on the target vehicle and sights on their own vehicle.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline VQ

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Re: Apollo docking mechanism.
« Reply #9 on: February 21, 2016, 03:19:19 PM »
Thanks guys. I think I can grasp the engineering  :D  I'm still wondering how they did the maneuvering precisely enough to get the right attitude to line up with the CM & drogue?

They had aimpoints on the target vehicle and sights on their own vehicle.

Not to mention lots and lots of practice ahead of time. I would think that docking two spacecraft once rendezvous is complete is objectively easier than aerial refueling.
« Last Edit: February 21, 2016, 05:18:09 PM by VQ »

Offline bknight

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Re: Apollo docking mechanism.
« Reply #10 on: February 21, 2016, 04:14:25 PM »
Thanks guys. I think I can grasp the engineering  :D  I'm still wondering how they did the maneuvering precisely enough to get the right attitude to line up with the CM & drogue?

They had aimpoints on the target vehicle and sights on their own vehicle.

No to mention lots and lots of practice ahead of time. I would think that docking two spacecraft once rendezvous is complete is objectively easier than aerial refueling.
For sure about that one, it would have been a rather dark day if you were orbiting the moon in the LM and unable to rendezvous and dock with your ride home.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
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Offline Allan F

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Re: Apollo docking mechanism.
« Reply #11 on: February 21, 2016, 04:19:41 PM »
That is why they kept the OPS so that they could transfer via spacewalk if the docking failed.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline Flookie

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Re: Apollo docking mechanism.
« Reply #12 on: February 21, 2016, 06:35:14 PM »
Thanks guys. I think I can grasp the engineering  :D  I'm still wondering how they did the maneuvering precisely enough to get the right attitude to line up with the CM & drogue?

They had aimpoints on the target vehicle and sights on their own vehicle.

I should have been clearer. How did they achieve the accuracy of entering the same orbit as the CM so that they were within close proximity? I'm thinking back to the original quote from someone who didn't think it could be done. I'm assuming a combination of what computing power they had, backed up by NASA's transmissions and the thrusters had sufficient finesse.

Offline Allan F

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Re: Apollo docking mechanism.
« Reply #13 on: February 21, 2016, 06:45:19 PM »
Most of the ascent and closing with the CSM was done by a pre-programmed set of maneuvers. First, the ascent stage acheived orbit, then that orbit was matched with the CSM over several hours. They KNEW where the ascent stage and the CSM were, what their respective velocity and position were, and the radar/transponder confirmed the distance between them. Just like the supply craft which dock with ISS. It's not a one-shot deal. It's not like hitting a bullet with a bullet. It's more like two airplanes flying in formation - just without the problems caused by air. Once the vehicles were close, the rest was done by vision and manual inputs on the hand controllers.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline raven

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Re: Apollo docking mechanism.
« Reply #14 on: February 21, 2016, 06:51:27 PM »
Am I right in thinking that modern docking mechanisms aren't that much different - other than the computer control?
Here's an overview of various docking systems both past and in use. Many modern systems seem to be androgynous, unlike the probe and drogue systems like Apollo.