Spacelog Apollo 13

Yes, everybody wondered if you would remember that; by golly, you did.

Hey, Jim, I got a little bit more information—maneuver pad, I got LAT/LONG range to go, VERB 10 and GET; if you got a place to copy that down, I'll give it to you for EMS.

Okay. Stand by.

Go ahead.

Okay, Jim. I just have the last three blocks. NOUN 61: latitude, minus 021.62; longitude, minus 265.37; range to go, 2162.9; VERB 10:36291: GET of .05g is 142:41:30; read back.

I didn't get the latitude, but the longitude is minus 165.67; range to go, 11629; velocity 36291; 142:41:30.

Okay, Jim. The latitude is minus 021.62; I have a correction on the longitude—minus 165.37. Go ahead.

Roger, Jack. The latitude is minus 21.62; longitude is minus 165.37, and this goes in conjunction with that midcourse 7 pad you gave us.

That's affirmative. That means no maneuvers between now and midcourse 7. And this is a horizontal in-plane burn, plus X, toward the Sun, 19.3 feet per second.

Roger. …

And, Jim, on the—Setting up the AGS, right after you do the 400 plus 5, you should do a 400 plus all balls. And one other point we want to clarify is that we know that you're sure that this burn will be made with the plus X-axis pointing at the Sun to make the entry angle steeper. You got it?

That's right, Jack. What I'm going to do is—We'll stop with the Earth in the commander's window, the COAS down, and then I'm going to maneuver the spacecraft so that I have the lighted portion of the Earth at the top of the window; that is, the COAS will be along the plus-Y of the spacecraft and the top of the window—of the rendezvous window, I should be looking into the Sun. That means I'll be burning towards the Sun and steepening the angle.

That's affirm, Jim. I—You got the attitude right, and did you copy about doing a 400 plus all balls after—you do the 400 plus 5? That is, a 400 plus 5 and a 400 plus all zeros back to back.

Roger. I have copied that.

Jack—this is Aquarius. I'm not too sure how long or with what force the venting is going to do to our trajectory. However, you might keep a check on that. It may have been going on for some time.

Roger, Jim. We've been taking a look at it. We haven't been able to detect it on the Doppler, however.

Roger.

And, Houston, Aquarius.

Go ahead, Aquarius.

Jack, would you give me a time hack on an even GET so I can start my watch.

Okay. Coming up on 87 hours and 35 minutes, we will be there in 30 seconds. Set it for 87.35.

Just give me a hack at 88 hours.

Okay. I'll give you a hack at 88 hours. That'll be another 25 minutes.

Houston, Aquarius.

Go ahead, Aquarius.

Okay, Jack. Let's just talk over how I'm going to get to the attitude and then do the burn. What I'm talking about is the control techniques. The way it looks now I'll try to stop the spacecraft in yaw with the Earth out my window, then we'll be in GUIDANCE or we'll be AGS CONTROL; we'll be in—yaw will be in MODE CONTROL. Then we'll be using the TTCAs to control the pitch and then control the roll. I don't see another way we can control the combination that we have here without using the TTCAs. Then we will also use the TTCA during engine burn. Do you people concur with that technique?

Jim, that sounds like the one that is best to use to me. Let me talk it over with the rest of the guys here, and we'll advise you.

Jim, in that control mode, that sounds like the best way to go. The only thing you'll have to do is to get ATTITUDE HOLD in the AGS, and so before you start to maneuver, you'll have to bring the AGS up, and get a 400 plus all zeros in there, and then AGS will respond in yaw when you go to MODE CONTROL. That is, AGS will control your yaw in MODE CONTROL and your pitch and roll can be taken care of in PULSE with a TTCA. After you get in attitude, then, you'll have to re-do an AGS body axis aline which is 400 plus 5, then go back to 400 plus all zeros again.

Right, Jack. That was my next question. I don't want to aline the AGS ball 000 until I am in position, so we use that as a primary attitude burn monitor device.

And, Jim, you can do a 400 plus all zeros any time you want to; that just tells the AGS that you want it to control your attitude should you go to ATTITUDE HOLD in MODE CONTROL.

Roger. I understand, but after we get to the attitude, we'll do a 400 plus 5 to get the AGS aline ball, and then we'll do a 400 plus zero.

Affirmative.

Another thing, Jim, is while you're maneuvering to that attitude using AGS to control your yaw, if you find out enroute to that attitude that you didn't quite have the yaw where you wanted it to be, you can use your ACA and tweak up the yaw, and your AGS needles go right back to zero because you zero the attitude errors.

Roger. Sounds good.

Jim, you'll be splashing down about 560 miles southeast of Samoa at about 0800 local time. The weather forecast for the area is good; 1500, scattered, high broken, 10-mile visibility. The seas will be 5-foot waves, 15 knots, and you'll be going to Samoa by boat and/or aircraft. You'll spend either the night on the boat or in Samoa and return to Ellington by 141 on Saturday, the following day.

Roger. Would you tell the people of the LRL to turn it off.

Oh, no. We're going to do the whole bit.

And don't forget my hack at 88 hours, Jack.

Say again, please, Aquarius.

I want to get my time hack at 88 hours.

Roger. That will be in about 6-1/2 more minutes.

Say again, Jim.