Wikipedia's Docking and berthing of spacecraft says that

The first spacecraft docking was performed between Gemini 8 and an uncrewed Agena Target Vehicle on March 16, 1966.

Were multi-pin electrical connections made as part of that docking maneuver? If not, when was this first done?

Connectors are never-ending source of trouble both on Earth and beyond, but in spaceflight:

  • in vacuum there are things like cold welding which could make disconnecting again problematic.
  • getting connectors to line up and engage can demand some mechanical precision and would have been a challenge during docking or using an EVA-gloved hand.

Question: What was the first multi-pin electrical connection made in vacuum in space? Was it part of a docking maneuver? Were precautions against cold welding taken?

Cold welding in spaceflight:


1 Answer 1


For Gemini/Agena dockings it appears the answer is No, with only a single pin connecting between the two vehicles when docked, included here as an answer to avoid others chasing down the same information.

Agena had three interfaces to Gemini, described in this document. The control drawing is at 3.4-14 and shows the UHF link to ground, L-band link to Gemini and the 'hard line'. The Hard line is elsewhere described as a direct connection between the two control systems that bypasses the radio. Separately there was a control panel and the Agena that aligned with the windows of the Gemini that showed additional status information including burn time to remaining (figure 3.4-10).

The actual connector is shown at figure 3.4-7 as 'umbilical connector' and unfortunately shows it as cross section only but from this and the hard line description it appears this is just a single pin (no front view or description to confirm this). It is possible the lack of detail on the hardline connection is because it was so basic and therefore more description was seen as unnecessary. The description implies it just connected the two control systems together bypassing the RF part of the radios but after the PCM encoding step, hence being able to operate across a single connection.


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