This is my first time on Space Exploration SE, although I have participated quite a bit over on Worldbuilding. Anyway, as an avid sci-fi reader, I have been wondering if sending a Soyuz interplanetary (with a sufficiently heavy service module) would actually be feasible from a technical point of view. Especially after seeing this used in both Critical Mass (Suarez, 2023) to go to a near Earth asteroid and For All Mankind season 3 (2022), I am curious as to if this is merely a plot device or if it could actually work.


  1. The Soyuz spacecraft itself must remained unchanged from its most modernized version, the Soyuz-MS.

  2. An auxiliary service module with consumables is allowed for interplanetary travel, but arrival at the target must be completed with only the Soyuz's life support/power/propulsion systems. EDIT: The consumables may include propellant mass approximately equal to the Block DM upper stage used on Proton/Proton-M today.

  3. The resulting vehicle must be able to launch on current Russian launch vehicles (man-rating is preferred but not required).

Following these guidelines, is there any way a one-way or even roundtrip interplanetary mission could be mounted, and if so, where?

Thank you very much for your time and feedback.

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    $\begingroup$ The Soyuz can provide ~400 m/s delta-v (not counting pushing your bigger hab module). astronautix.com/s/soyuztma.html Check the map here and see where that gets you. i.sstatic.net/ndRXj.png $\endgroup$ Mar 5, 2023 at 20:16
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    $\begingroup$ Soyuz have solar panels so as long as you aren't going to go past Mars for power you are okay. If you are limiting the mission to only the available life support and propulsion on the spacecraft then there's not going to be enough of either, you'd have to augment them. $\endgroup$
    – GdD
    Mar 5, 2023 at 20:27
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    $\begingroup$ Can the "auxiliary service module" include additional propulsion? If so, then for a one-way mission, you're mainly limited by what you mean by "arrival at the target must be completed" with the Soyuz. If the service module can do most of the orbital insertion burn before being discarded, then the Soyuz could complete it. As Organic Marble notes, the Soyuz doesn't have the delta-V to get back from anywhere interesting. You also wouldn't be able to do it on any current Russian launchers. $\endgroup$ Mar 5, 2023 at 20:30
  • $\begingroup$ @RussellBorogove Alright, just clarified that the service module can include a reasonable amount of propellant and capabilities similar to common upper stages. Thank you for the input. $\endgroup$
    – Lelu
    Mar 5, 2023 at 22:49
  • $\begingroup$ The Soyuz 7K-LOK was designed to be the lunar orbital module of the Soviet moonshot in the 1960s and flew uncrewed. Over the years there have been suggestions and proposals to create a Soyuz spacecraft for lunar space tourism: smithsonianmag.com/air-space-magazine/… and smithsonianmag.com/air-space-magazine/lunar-clipper-21290187 $\endgroup$ Mar 15, 2023 at 11:58

1 Answer 1


While the stock Soyuz capsule has a huge range of issues with long range use (life support, power, radiation shielding, communications etc) a clear cut issue with:

The Soyuz spacecraft itself must remained unchanged from its most modernized version, the Soyuz-MS.

Is the limitation of the Hydrogen Peroxide RCS system of around six months storage life. This would be fine for things like a moon mission but interplanetary would need a system with a lifetime in years which Peroxide is probably not a good choice for.

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    $\begingroup$ Transfer to Mars only takes 7 to 9 months. So it might just be possible if you exceed the specs slightly. $\endgroup$
    – Michael
    Mar 6, 2023 at 9:22

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