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For the sake of the question, let's assume the STS-107 crew realizes in orbit that the heat shield is too damaged for reentry, but they realize it too late for shuttle Atlantis to rescue them in time. As reentry would most certainly mean death to the crew, the U.S. government asks Russia to send spacecraft into Columbia's orbit to save the crew. The Soyuz can fly unmanned controlled remotely as Soyuz 2 did, right?

So here go(es) my question(s):

  • Could a Soyuz have reached Columbia's orbit (having an inclination of 39°) without wasting too much fuel in the first place? If the answer to this question is no, let's assume the Soyuz launched from Kourou, even though they didn't at that time.
  • Once the Soyuz reaches the Columbia, would it be possible for the crew to open the Soyuz reentry module's hatch in their EVA suits? If not, could they possibly have been able to enter through the docking hatch of the orbital module?
  • If only one Soyuz spacecraft was launched, three astronauts would have seats in the Soyuz' reentry module. What would the other four astronauts do when the Soyuz is about to reenter, experiencing up to 5g? Could they have fastened themselves somewhere in the capsule? If not, could they lie down or kneel and hold onto something?
  • Would seven astronauts even fit into the reentry module? (even if they're quite squeezed together, since staying in the Columbia would mean death) And could more seats be possibly built into a Soyuz?
  • Baikonur has at least one other launch pad used for Soyuz launches, and Kourou has multiple launch pads. So if Russia sent two Soyuz spacecraft instead of one, six astronauts would have seats. As for the seventh astronaut, the same questions as above apply, except that he/she would certainly fit with the other three into a Soyuz reentry module. What could he/she have done while the Soyuz is about to reenter at up to 5g?
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    $\begingroup$ The first issue is that preparing a Soyuz launch takes months. It would take a very lucky coincidence to have one, much less two on the launchpad almost ready to launch at the right moment. $\endgroup$
    – SF.
    Feb 28 at 11:06
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    $\begingroup$ There's no way all 7 would fit in one Soyuz capsule. Maybe 4, unlikely 5. Also, Russians would need to fly some Orlans up, which someone would need retrieve through EVA, 'cause 3 EVA suits on the Shuttle is def not enough, and moving into Soyuz in IVA suits (tethered to the shuttle by oxygen hose, which must then be crimped and cut when closing the hatch, astronauts passing out on oxygen remaining in the suit as Soyuz slowly re-pressurizes) is a little too sketchy to my liking. re: Reentry. Unbalanced like that it would need 6g+ ballistic reentry. Injuries guaranteed, lives saved. $\endgroup$
    – SF.
    Feb 28 at 11:09
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    $\begingroup$ @OldManJohn Maybe doable, although the problem is the EVA suit operate at 0.3bar, Soyuz and STS operate at 1bar, the process of adapting to the pressure change is lengthy. The whole operation would take ages and lots of air with the orbital module serving as an airlock, while people without suits are crammed like sardines in the reentry module. Unless there's a way to temporarily pump down Soyuz to 0.3 bar and re-pressurize it slowly with everyone inside. $\endgroup$
    – SF.
    Feb 28 at 13:18
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    $\begingroup$ Soyuz nominal reentry is about 4-5 g. With astronauts piled on top of each other things would not go well for the astronauts on the bottom. Besides their own body weighing 800 pounds they would have an 800 pound astronaut lying on top of them, which would lead to suffocation. Some type of support structure would need to be installed. $\endgroup$ Feb 28 at 13:36
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    $\begingroup$ One important lesson that the results of the Columbia investigation made clear is that a rescue mission (by any spacecraft) has to be planned and ready prior to the launch of the operational mission. "Could they have saved Columbia if..." is pretty much a beaten down question by now. I think a more interesting question would be what modifications would be needed to make Soyuz a (planned) rescue vehicle for a seven person Shuttle crew. For example are two Soyuz sufficient or would it require three Soyuz. $\endgroup$ Feb 28 at 13:45

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Unless you allow the possibility of launching from a launchpad that didn't exist at the time (and the Soyuz pad in South America never had the infrastructure for crew launches anyway) - placing your question into "completely hypothetical" mode - the answer is no, as stated in the CAIB report. They didn't even consider rescue by expendable vehicle anyway, just launch of supplies.

There has been some discussion regarding the possibility of sending supplies to Columbia using an expendable launch vehicle – to lengthen the amount of time available to execute a rescue mission. Because of Columbiaʼs 39-degree orbital inclination, an expendable launch from a launch site with a latitude greater than 39 degrees would not be able to reach Columbia. This rules out a Soyuz/Progress launch. There was an Ariane 4 in French Guiana that successfully launched an Intelsat satellite on February 15. The challenge with developing a supply kit, building an appropriate housing and separation system, and reprogramming the Ariane seems very difficult in three weeks, although this option is still in work.

CAIB report Volume 2 Appendix D.13

It would also have been impossible for Soyuzes from the ISS to reach Columbia. The inclination difference between the ISS and Columbia's orbits was about 12 degrees. At that altitude 1 degree of plane change takes about 120 m/s delta-v and a Soyuz-TMA is capable of a total of about 390 m/s delta-v.

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    $\begingroup$ @OldManJohn: Yes, inclination changes are expensive. Changing the inclination of a circular orbit by $\theta$ requires delta-v equal to $2\sin(\frac12\theta)$ times the orbital velocity. For $\theta = 7°$ that's about 12% of the total orbital velocity. $\endgroup$ Feb 28 at 20:08
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    $\begingroup$ (For inclination changes of about 49° of more, it's actually more efficient to boost to a highly eccentric orbit, do the inclination change at apogee where velocity is negligible, and then circularize again at the new inclination. If you can aerobrake to circularize, the threshold drops to about 24°.) $\endgroup$ Feb 28 at 20:21
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    $\begingroup$ For 10 degrees it's seems like it might be better to launch at a very steep south angle and correct after traveling 10 degrees south at a much lower velocity. It's still a boatload of fuel that a Soyuz doesn't have. $\endgroup$
    – Joshua
    Feb 28 at 21:21
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    $\begingroup$ @Joshua, an extreme dogleg like that is still a very expensive maneuver. You need to get up to a substantial fraction of orbital velocity just to get the 10-degree range. $\endgroup$
    – Mark
    Feb 28 at 21:45
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    $\begingroup$ If the goal is to abandon the shuttle anyway and not a resupply as in the report, you could try to meet half way and add whatever delta-v is left in the shuttle, e.g. whatever fuel is reserved for the deorbit burn. If you are willing to litter the orbit even further you could even think about dismantling the shuttle to decrease weight. Realistically this might still not be enough, but a group of astronauts in partially improvised space suits, strapped to a crudely detached aft part of the shuttle would definitely make an interesting scene for a science fiction movie. $\endgroup$
    – mlk
    Feb 29 at 9:16

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