According to this Q & A, it's very likely that the Soyuz spacecraft's orbital module can be manually separated independent of other spacecraft operations.

On this CollectSpace page, there's an excellent photo of a bank of Soyuz control panel buttons with guards to protect against accidental activation of critical functions:

4 by 4 array of buttons, each row with a common metal guard plate, lifted up in the picture. Each button is labeled in abbreviated Cyrillic text.

I note that three of the buttons (#3, #12, #13) are labeled with "БO", the abbreviation for бытовой отсек (bytovoi otsek), or Orbital Module. I don't know any Russian, so I can't tell what the remainder of the labels say. It looks like buttons #12 and #13 are labeled very similarly if not identically.

Are any of these labels plausibly interpretable as "separate/jettison/disconnect orbital module"?

Any transliteration/translation/interpretation of the other controls is welcome in addition.

  • 12
    $\begingroup$ laughs question initiated by desperate astronaut on ISS $\endgroup$
    – anon
    Aug 30, 2018 at 22:31
  • 2
    $\begingroup$ Only one way to find out, press and see what happens. $\endgroup$
    – coredump
    Aug 31, 2018 at 8:33
  • 4
    $\begingroup$ @coredump: You really don't want to jettison the service module before you perform the reentry burn. $\endgroup$
    – SF.
    Aug 31, 2018 at 8:37

2 Answers 2


The 12th and 13th Critical Command Keys "ОТСТРЕЛ БО" are БО (Orbital Module) Jettison.

The БО separation (jettison) can be executed either automatically on the nominal separation schedule within the unified cyclogram or on the ОВК12 and ОВК 13 Critical Commands in case of the urgent descent before the СКД (Orbital Maneuver Engine) ignition for retrofire.

Perhaps you have to press them both simo? (Still checking on that.)

Source: Soyuz Crew Operations Manual.

This is all I can find from there on the Critical Command Keys.

enter image description here

  1. Descent Flag

  2. Separation Config (service module?)

  3. ?

  4. ?

  5. ?

  6. ?

  7. Ignite

  8. ?

  9. Separation (service module?)

  10. Contingency Power On

  11. ?

  12. Orbital Module Jettison

  13. Orbital Module Jettison

  14. ?

  15. ?

  16. Thermal Sensors Disconnect

  17. Configur Depressurize (sic) Arm the depress system?

  18. Depressurize

  • 1
    $\begingroup$ I wonder if any of the agencies considered pictographs/iconography for controls on international missions. $\endgroup$
    – anon
    Aug 30, 2018 at 22:33
  • $\begingroup$ Yeah. The official language of the ISS is English. But... $\endgroup$ Aug 30, 2018 at 22:39
  • $\begingroup$ I'm having trouble finding a good gloss; Google translate gives ОТСТРЕЛ -> "dismissed" for uppercase and отстрел -> "shooting" for lowercase. $\endgroup$ Aug 30, 2018 at 23:28
  • 1
    $\begingroup$ The duplication of the OM jett control is really interesting -- is it really the most drastic of these operations, that it requires the extra guard of simultaneous press? $\endgroup$ Aug 31, 2018 at 2:05
  • 1
    $\begingroup$ The depress has an arm/fire and is behind a screwed-down panel guard....maybe it's worse. $\endgroup$ Aug 31, 2018 at 2:05
  1. Descent/discharge mark (flag, warning, attribute)
  2. Preparation to separation
  3. Open KSD (pressure relief valve) of BO (orbital module)
  4. [explosive] separation of mechanical contacts
  5. Choice of DPO-B (Primary Berthing and Attitude Control Thrusters) for descent
  6. emergency detachment
  7. SKD (Orbital Maneuver Engine) on
  8. SKD (Orbital Maneuver Engine) off
  9. Separation
  10. Emergency supply on
  11. Connection of pressurized sections
  12. (explosive) detachment of BO (orbital module)
  13. (explosive) detachment of BO (orbital module)
  14. Conservation (Soyuz Crew Ops manual translates it literally as "Conservation, Pickling")
  15. thermal sensor on-line
  16. thermal sensor off-line
  17. prepare dehermetization
  18. dehermetization
  • $\begingroup$ Thanks for the translations -- unfortunately I can only accept one answer. $\endgroup$ Sep 25, 2018 at 19:43

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