Normally during the Progress or ATV hatch opening procedure the crew inside the ISS turn a handle to unseal the SSVP drogue cover which they then pull inward, revealing the Progress docking probe and hatch.

How is the Progress or ATV hatch opened from outside the spacecraft?
Is it remotely controlled from within the station, on the ground or is there a mechanical linkage?

In addition, is it possible for the station crew to open the hatch of a soyuz from outside the spacecraft in the event the soyuz crew is incapacitated or an empty soyuz were launched to the station for some reason?

Edit: After looking at a lot of nasa images I noticed this hex key hole, could this be an actuation mechanism?

soyuz SSVP probe and hatch closeup


2 Answers 2


After doing some further research in the NASA photo archives I discovered the hatch actuator is actually a round socket containing a square peg mounted near the collar of the docking mechanism. This correlates with the location of the interior hatch actuator handle being on the body of the spacecraft and not built into the hatch itself.

It can be seen in this photograph of Progress 55 (mechanism at the 1 o'clock position just inside the double o-ring seal:

And in this photograph from expedition 26 showing how it appears to the crew onboard the station (mechanism at the 5 o'clock position):

Also visible in the above picture are two holes in the drogue cover (AKA the 'passive docking unit cone') which supports a 'hatch tool extension'.

The hatch opening procedure is described on page 39, section 5.2 of the Russian Segment Operations 2A.2B Flight document (PDF) posted on spaceref.com:


Hatch tool→РАБОЧЕЕ ПОЛОЖЕНИЕ (Working Position)
Fully insert hatch tool extension into socket ГЕРМЕТИЗАЦИЯ КРЫШКИ (hatch actuator)
Secure hatch tool extension on SM passive docking unit cone
Fully insert hatch tool into socket on hatch tool extension
Rotate hatch tool in the direction of arrow ОТКРЫТИЕ (Open) until it clicks (6-7 turns)
Stow hatch tool and hatch tool extension into СтА accessories kit 11Ф732.Г4000А1-30
Open hatch and secure it in open position
Report to MCC. MCC-H⇒MCC-M

This photograph from expedition 40 shows Alexander Skvortsov actuating the hatch opening mechanism of ATV Georges Lemaitre. The hatch tool extension is similar to a ratchet extension bar and is held in place by the two holes in the drogue cover. The hatch tool attaches to the end of the extension and is rotated clockwise to retract the hatch latches. Pen marks are visible on the inside of the drogue cover which say "open" and "close" in russian. ISS040-E-091940

There is also a silent video from expedition 26 showing the opening procedure of the hatch of AVT Johannes Kepler:

Soyuz capsules have this actuation mechanism as well, so it is possible to open the hatch from within the station without the assistance of any crew aboard the spacecraft.

  • $\begingroup$ But before the opening of the hatch the pressures on both sides should be equalized. Is there an extra valve for equalization? $\endgroup$
    – Uwe
    Commented Oct 10, 2018 at 9:19
  • $\begingroup$ Nice answer! And thanks for the link to a site with Russian segment procedures, I was unaware of that, and I'm sure it will be a useful reference for me in the future. $\endgroup$ Commented Oct 10, 2018 at 12:38
  • $\begingroup$ @Uwe in the procedures document linked in the answer, pressure equalization is called out before hatch opening. $\endgroup$ Commented Oct 10, 2018 at 12:44
  • $\begingroup$ @OrganicMarble congratulations on your dupe hammer super power! (wielded here) It seems sufficiently answered here and a good closing, I suppose I can re-ask the "When did it arrive to the ISS?" part separately if it seems interesting as it's a history question rather than a "how does this work" or identify-this-object question. $\endgroup$
    – uhoh
    Commented Aug 5, 2021 at 0:03
  • 1
    $\begingroup$ I was surprised when it closed instantly, I actually don;t care for that here - I'm ok w/it on scifi. Forgot I had ISS gold badge. $\endgroup$ Commented Aug 5, 2021 at 0:06

Partial answer to a different but very related question:

(What exactly is this device? What is it's function, how does it work? Is it basically the keys to Nauka's front door? When did it get to the ISS? from @uhoh)

From the same link in the answer above i got most of the answers below:

What is it's function,

allows you to unlock, open and then remove the hatch.

how does it work?

Lots of gears. Not found a technical description or pictures. (if i find it i'll update this..)

Is it basically the keys to Nauka's front door?

Also keys to Progress, Soyuz, FGB, SM and PMA-1 doors...

When did it get to the ISS?

It is part of a docking accessories kit that includes wipes, extension tool and hatch cover. One kit went up on 2 November 2000 with first crew, unsure if it returned on the decent module though.

It would have been required then to open the hatch to enter Zvezda SM, Zarya FGB and their side of PMA-1.

After all the hatch openings it was returned to a docking accessories kit which was stored inside Soyuz. So, my understanding is that each Soyuz has one, as they refer to a 'nominal position' it is kept in.

The others were launched with each module:

An identical kit is in a storage position on the axial transfer section on Zvezda.

(https://blogs.nasa.gov/stationreport/2020/11/20/iss-daily-summary-report-11-20-2020/ says: "Checking Docking Assembly (СтА) accessories kit stowage in SM ПрК" which is Zvezda's rear transfer tunnel)

Another kit is in storage location on panel 230 in FGB.

And another kit was tethered.to PMA-1 hatch handle, and later got moved to Unity module.

Nauka MLM probably has one so they do not need to keep going into the other modules to get parts from those kit bags.


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