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The June 25, 1997, collision with the unmanned Progress supply vehicle knocked the Mir space station into a slow spin. In his Oral History, U.S. Mir astronaut Michael Foale discusses the situation.
He relates, ". . . after the collision, we were spinning at about one degree a second, and the call came up on the ground . . . 'Guys, what's the spin rate? . . . We've got to know how fast it's spinning.'
Foale moved quickly to a window. "[I] put my thumb against the window, looked at the stars, and was able to tell the ground what the spin rate was.
"I called it down. . . . This was the first time I had made an operational call on the state of the Mir to the ground . . . They had no other choice but to accept my word for it, because at that point Sasha [Aleksandr Lazutkin] says, "Well, yes . . . Mike's right." So that went down to the ground as well.
"So [ground control] said, 'Okay,' and they then took that information and fired the engines in a blind mode to stop the spin."
The maneuver worked. Then, ground control told the Mir crew that they would need to "spin the station," using the Soyuz vehicle's thrusters.
Foale continues. "And then we went out of contact with the ground. [And] we then lost all power . . ."
Neither Vasily Tsibliev nor Aleksandr Lazutkin had been trained how to spin the station, but Foale says that that at point he had some ideas. Furthermore, he'd gained confidence when he'd reckoned the spin rate correctly.
He goes on. " Because I was puffed up that they'd accepted my measurement on the rotation rate . . . I thought, 'Well, now is the time to tell these guys how I think they can spin the station.'"
As a physicist, Foale understood rotation dynamics of irregular objects like Mir. He says that he said to his crewmates, " You know we need to use the Soyuz to fire the engines in a translation mode, not in a rotation mode."
Foale relates that Tsibliev at that point ". . . was thinking to use the Soyuz like an airplane. [He was thinking, for example, that] if he turns the Soyuz this way, he's going to turn the station. [But] I said, 'No, that's not the way you want to do this, Vasily. You need to approach it where you actually fly the Soyuz to the left or to the right, and then that effect has an effect on the station's rotation.'
"So we discussed this at some length. I was not totally sure of myself. . . . My biggest fear . . ., was that I would give them instructions that they -- just in their desperation -- would act on, but would use up fuel excessively out of the Soyuz," which would then ruin the Soyuz as an escape vehicle.
Foale continues, "So the whole concern in my mind was, 'They're starting to listen to you. There's a real danger here, because you may not know enough.'
"So I spent a lot of time [explaining this], and we had a lot of time to talk [because] there was nothing to do. There was no sound. There were no fans. [Also,] at that point we were very afraid [that] the carbon dioxide building up around us would poison us, so we were keen to be with each other, [and we kept] waving paper like this, to keep the air moving around us, to keep the CO2 from puddling around us." [Editor's note: In microgravity, there are no naturally occurring convection air currents to keep mixing the air, therefore harmful gasses can "puddle" in places and pose a danger.]
The crew discussed how to reorient Mir.
Foale says, "At that time after the collision, I had no clue, really, about the moments of inertia at the station, and ... I didn't know which axis would be different from which. That's not something anyone in the [Russian Cosmonaut] corps is taught. They just don't know it. In fact, I'm not totally sure the ground knows it. They could sort of calculate it and think about it, but based on where you've put payloads and food boxes in the Mir, it changes what I call these moments of inertia properties in the station. . .
". . . So we worked out a scheme whereby, in the Soyuz, Vasily would fire a thruster or a jet and try and see what effect it had on the station. It was horribly complicated... And Sasha and I were both confused for at least an hour as to quite how the axes of the Soyuz lined up with the rest of the station. We had no clear picture. There was no picture in our flight files. The model wasn't correct."
Foale describes the labyrinthine lay-out of Mir. "As you fly through the base block into the Soyuz . . ., you have to do a twist around the hatches, and that twist totally throws off your orientation. . . . So we had a running argument as to what that orientation difference was. We knew it was 45 degrees out; we didn't know which way."
Regardless, Foale said to his crewmates, "'Okay, let's just try it.'"
However, the durations of the thrust impulses were a problem, too, because, according to Foale, Tsibliev was "terribly worried about wasting fuel..."
Then, Foale says, he, ". . . looked out the window and nothing had happened. I said, 'Vasily, did you do it for real?' He said, 'No, no, I didn't. I just did a blip.' [And] I said, 'Vasily, we can't do this. We can't measure this thing, the effect of what your impulse is, unless you do it for the time you say . . .
" After back-and-forth discussions along fifty feet of Mir corridors, and after about three hours of work, the crew finally got the station into a better orientation. Foale says, ". . . we were basically upside down and spinning and charging again at about the rate that we set up.
"Over that period of time we slowly got the base block systems back on line -- the CO2 scrubbers especially, which was very important -- and [we] were able to let Vasily sleep. They actually had me sleep for six hours before the other two did. It was just too much. They had to be on watch."
Profile: Michael Foale
Michael Foale Oral History (PDF)
Foale on the Collision
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