Spacelog Apollo 13

Okay, copy that, Jim.

I might mention that the noise level during the first stage was not sufficient to be uncomfortable at all.

Roger. And I assume COMM was okay.

That's affirm. COMM was very good all during—throughout the entire flight. Much better than I expected.

Okay.

Now, in answer to Question 2, there was, of course, a vibration transient in the second stage that—due to the number 5 engine going out—which occurred shortly before the engine went out, and slightly after that then the S-II stage was very smooth.

Okay, Jim. I guess the significant point there is that you didn't notice the vibration before you saw the engine light.

That's right. We—we noticed the vibration but it wasn't such that we thought something catastrophic was going to happen; it just started vibration and then the EN light came on, and then the vibration went away and the stage itself was smooth.

Okay, copy that.

Yes, and that—it was all pretty—pretty short in span—just a second or so before and like a second afterwards, Joe.

Oh. Roger.

And on the S-IVB, the vibration of the vehicle itself wasn't what … second … powered flight—a very-high-frequency vibration.

That was—was that during—just during TLI, or did you notice that at insertion?

Well, it was a high-frequency viola—vibration but more noticeable during the TLI burn than it was during the … flight.

Okay, I—understand.

I guess the S-IVB vibration during TLI was there all the time although it seemed to—to grow to us as the burn progressed, although that may have been just due to the boost weight decrease.

Okay, you called this about 3-1/2 minutes, but I guess the thing was slowly building up throughout the whole burn. Right?

That's right.

Okay, was it uncomfortable or did it cause your vision to degrade or anything like that?

No, it—it was not uncomfortable at all but I was recalling the ride on 8, and the S-IVB was more—much more smooth than even it was on 13.

Copy that.

Okay, now, in answer to number 3, we did not experience any unexpected transients except that all of us noticed the PU shift. We thought it was more pronounced than we had expected it to be.

Okay. Understand.

Joe, on that. I guess most of every time that PU shift occurred we all—almost all of us glanced at the engine light. We could feel definite acceleration change.

Roger. Understand, Jack.

And, during the high-Q portion of the flight, the Alfa meter, to my knowledge, nearly went above 25 percent.

Okay.

In answer to number 4, we got a pretty good look at the thermal shroud and the IU after taking the LM away, and from our viewpoint, the shroud was completely intact. I saw no loose particles or parts of it floating at all.

Okay, Jim. Understand.

And, I guess we answered number 5. I don't think at any time did we have any communication problem during powered flight.

Roger.

In answer to number 6, the answer is essentially no. We saw no venting or suspected leak on the LM or the CSM …

Okay, Jim. I guess you described to us the non-propulsive venting on the S-IVB after the APS maneuver and we copied that at the time.

Okay. Fred saw the S-IVB venting.

Yes, we had already talked about that, Joe. And that was also visible when it—of course, when it did its evasive maneuver when we were looking at it right close up.

Roger.

Okay, Joe. The last time we saw the S-IVB positively was when Fred saw it venting at about—at about 5 hours. We think we might have picked it up later on. We saw a particle or something out there that was tumbling which might have been the booster or one of the SLA panels.

And when was that, Jim?

We're—we're debating. It was somewhere between—say 7:30 and 9 hours.

Okay.

But, Joe, assuming the S-IVB is still stable. The object I was looking at was definitely tumbling.

Okay, Fred. As I recall, it was stable then, although it's tumbling now.

Okay. It probably was the SLA panel I picked up.

Right. Incidentally, I guess the guys in building 6 —

Oh and I think we -

Go ahead, Jim.

I—I think we answer to number 9. We—at around 5:32, I think, was when we think the number 5 light came on in the S-II, and a definite vibration which was more than just a high-frequency vibration we got with the normal S-IV burn, and then the light came on. I called ECO thinking from the training that it was 7:42 and looked up at the time and realized it was early. And then, soon after the light came on, the vibration stopped and the engine or the booster smoothed down. It was very smooth from there on.

Okay. This may be a stupid question, but do you have any idea what the frequency of it was?

Only to say that it was much higher—I couldn't really guess now. It was rather a rapid longitudinal vibration.

Okay, Jim. Stand by now for a minute, we're going to switch OMNI.

Houston, 13, …

13, Houston. I read you. We still have quite a bit of noise on the loop.

I'll stand by. Roger.

Okay, Jim. It should be pretty good now. We copied you answering question number 9.

Do you want any more comments on the S-IVB vibrations?

I don't think so. When you get all done, I'll—I'll make a quick check to see if the booster people have any—any additional questions. You skipped number 8, Jim; could you go back to that for a second?

Okay, stand by.

Our only comment there, Joe, was that the burn on TLI, to our knowledge, was about 3-3/4 second longer than had been predicted and that was the only thing that we really noticed; otherwise, looked like PI [?] was nominal at cut-off.

Okay, understand.

Okay, on comparing the flight of 13 to Apollo 8, lift-off was about the same amount of vibration as I noticed on 8, but at the beginning of the flight, there was less of the sideways motion than we experienced on Apollo 8. The S-IC separation felt more violent on 13 than it did on 8, maybe that's because I was in a different seat, I don't know. But there was about three sharp transients of the cut-off and a couple of big bangs where we were thrown backwards longitudinally on our straps before the S-II went off. And the S-II was, of course, just as smooth on 13 as 8 except for the number 5 engine. And we did not experience the vibration that we experienced on 8 towards the end of the S-II burn. And the S-IVB was—had more vibration than we had on 8.

Okay, Jim, got all that.

The up—the update on the ORDEAL ball was a good one. At the burn, we were about—just about 8 degrees. We had to pitch down. The yaw was right on all the way through the entire burn, and just towards the end of the burn, the ball started going black in pitch a little bit.

Okay, sounds good, we'll give Mike Wash a gold star on that one. Okay, Jim, stand by 1 while I see if we have any extra questions.

Jim, while we're waiting to see if they have any more questions, I'd like to read you the booster people's preliminary analysis on the—the S-II cut-off. Over.

That would be very interesting. Go ahead.

Okay, preliminary analysis of the data indicates that the center S-II engine vibrated at a somewhat higher amplitude than we've seen on previous flights, and it started at about 160 seconds into the S-II burn. As a result of these vibrations, the engine chamber pressure decreased to the level where the two low-level thrust sensors, the thrust-okay sensors, initiated center engine cut-off. Early evaluation of data indicates that no damage occurred to the engine, and the cause of the increased vibration amplitude is still under investigation. Over.

I thought it was the center engine.

Yes, right.

Joe, do you have any word on what marks we had for TLI?

At the time of TLI, as I recall, you had 6 seconds longer than the nominal burn which was 3 seconds longer than the B-sigma low burn, and you were also GO for a second-opportunity TLI if we had required one.

Okay, we were just wondering because it appeared to us that we had a longer TLI burn than had been predicted.

Yes, you did. We confirmed that—that—that cut-off time just about as you saw it, and I don't have an explanation for it, but it was within the B-sigma margin.

13, Houston.

Go ahead.

Roger, we have no further questions. All the answers were clear and satisfactory, and we thank you very much. You can press on with the rest of your busy day.