Androgynous vs Probe-and-drogue docking interface.

[CaptainKipard]

Since the non-androgynous (probe and drogue) interfaces were developed first, I'm curious what makes them the obvious first choice, and what benefit they have over androgynous ones.

Edited January 11, 2015 by Cpt. Kipard

[Bill Phil]

Technically, all docking ports are non-androgynous, it's just that the androgynous ones can switch from "Active" and "Passive."

It's easier to develop a docking port that doesn't switch between two modes.

[CaptainKipard]

I meant the probe and drogue systems, like on the Apollo and Soyuz.

edit

Title edited.

Edited January 11, 2015 by Cpt. Kipard

[Bill Phil]

What I said still applies, in fact, that's what I was thinking about.

And maybe no one had the idea.

[Kryten]

Probe-and-drogue requires less force to properly latch than APAS, and allows for fuel transfer.

[xenomorph555]

Probe-and-drogue requires less force to properly latch than APAS, and allows for fuel transfer.

To go further, the Chinese used APAS for Shenzhou and T-1 but may switch due to the larger force required that could damage station modules.

[CaptainKipard]

Probe-and-drogue requires less force to properly latch than APAS, and allows for fuel transfer.

Why wont APAS allow fuel transfer? And conversely how/why do probe and drogue systems allow it?

[Kryten]

It's simply that probe-and-drogue includes plumbing for fuel connections in the design, while APAS doesn't.

[Bill Phil]

Kryten, are you sure you didn't mix those up? Probe and drogue a la Apollo was a connection latch, then the crew had to basically pull the latch out. That isn't the case with APAS.

[Kryten]

I'm talking about russian probe-and-drogue.

[Bill Phil]

That explains then. You learn something every day...

EDIT:

Wasn't the shuttle docking port basically an APAS copy? From ASTP hardware?

[TheShadow1138]

Wasn't the shuttle docking port basically an APAS copy? From ASTP hardware?

The Shuttle docking port, I'm fairly certain, was essentially the APAS system that had been developed for use with Buran. This port was mounted onto a bracket that had been originally intended for use with the U.S. space station Freedom.

[Nibb31]

That explains then. You learn something every day...

EDIT:

Wasn't the shuttle docking port basically an APAS copy? From ASTP hardware?

The Shuttle used the Russian APAS system, because it had been contributed by the Russians for the Shuttle-Mir program as a leftover from Buran. Instead of refitting the Shuttle fleet, NASA continued to use APAS on the ISS.

Note that Columbia never received a docking port, therefore even if she hadn't been destroyed, she couldn't have been used for ISS operations.

[CaptainKipard]

Does anyone know where the fuel pipes are on the Suyuz docking port?

[Nibb31]

Does anyone know where the fuel pipes are on the Suyuz docking port?

The power, data, and fluid transfer connectors are on the outer ring of the docking port.

[CaptainKipard]

Are those the ones? And I assume the data connectors are the four big ones with pins. Which are the power ones?

Is there any place which describes this port in detail like that?

[CaptainKipard]

I found out that it's actually Progress, not Soyuz, that has fuel transfer capability. Their docking ports are different in that respect. I still don't know what's where. Anyone?

[Nibb31]

I found out that it's actually Progress, not Soyuz, that has fuel transfer capability. Their docking ports are different in that respect. I still don't know what's where. Anyone?

This is a picture of the Progress docking port.

So if you are correct about Progress having fuel transfer capability and not Soyuz, then the difference between the two seems to be the two silver valves just above the two grey locating pins that are replaced by blanking plates on your Soyuz picture.

The ATV also had fuel transfer capability, and it also had those valves, with red covers on this picture. So I guess those are what you're looking for.

Edited January 14, 2015 by Nibb31

[CaptainKipard]

Cool. Any idea what the circled things are?

[Nibb31]

Cool. Any idea what the circled things are?

Not really. They might be for water or some sort of coolant loop... There doesn't seem to be any documentation on the Internet about the implementation details of the docking interface.

[Sampa]

The Shuttle used the Russian APAS system, because it had been contributed by the Russians for the Shuttle-Mir program as a leftover from Buran. Instead of refitting the Shuttle fleet, NASA continued to use APAS on the ISS.

Note that Columbia never received a docking port, therefore even if she hadn't been destroyed, she couldn't have been used for ISS operations.

Actually, that is not entirely correct... There were plans for the Columbia to visit the ISS at least once before retirement if she hadn't been destroyed.