Spacelog Apollo 13

Okay. Roger that, Jim. I want to verify a couple of things I'm not sure I heard you read back. The first one was Zebra Libra (laughter) that's Sigma Libra. The set stars 31 and 23. Did you get that? Over.

Okay. No, I had 31 and 33, and I got Sigma Libra now, and it'll be 31 and 23 for the set stars.

Okay. And your GDC pitch aline, I wasn't sure whether that was—whether you read back 245 or 045. The correct number is 245. Over.

Good show, because I have 045 down. 245.

Okay. And the Moon check here, unlike the horizon check, is on the 36-degree window mark all the way. Just wanted to repeat that.

Moon check on 30-degree window mark.

That's 36-degree window mark, Jim.

Three six. Roger.

Okay. Readback correct. And, Aquarius; Houston. If you want me to read you the landing area summary, I'll do that.

Sounds good.

Okay. In the mid-Pacific landing area, the weather is good. The cloud cover is 2000, scattered; visibility, 10; winds 060 at 10; wave heights are 4 feet, and the altimeter 2986, if you care. Scattered showers less than 10 percent of the area. Recovery forces are as follows: the Iwo Jima will be at the touchdown point, the aircraft call sign will be Recovery 1, on station with swimmers on board. The—we have the constant g backup reentry area covered with the USS Hall, the Good Liberty Ship, and the other recovery aircraft whose call signs you may hear are Samoa Rescue C-130s.

Okay, fine. We have the Iwo Jima as the prime recovery ship.

That's correct.

Joe, Jack tells me he is still having trouble looking through the optics. I'm just going to pitch up a little bit more here to see if he can get into the dark spot.

And are you tracking us, and do you have any results on that last midcourse?

Stand by. It looks good. I'll try and get you numbers.

It feels nice to use the hand controller again.

Go ahead, Aquarius.

I just said, Joe, it feels nice to use the hand controller again.

Oh. Roger that. FIDO says he's got you nailed within a half a foot per second; the midcourse looked real good.

Okay.

And I've got two things we'd like Jack to do in the command module to ease the load on MAIN A. One of them is to verify or turn the CM/RCS HEATER switch to OFF. We're done with that, and even though the circuit breakers are pulled, the switches might be drawing a little current. And the second one is, we'd like him to turn SCS LOGIC POWER 2/3 to OFF; we don't need it now. It's called up in the checklist at the appropriate time, and we'd like him to turn that off. Over.

Okay. I'll tell Jack to check that the CM/RCS HEATER switch is off, and, if not, we'll turn it off; and also to turn off the SCS LOGIC POWER 2/3 switch, OFF, since it comes up later in the checklist.

That's correct.

Houston, Aquarius. We're recording MAIN A voltage up to 31.0.

Houston, Aquarius.

Go, Aquarius.

Okay. How about if I hold a pitch attitude of about 115 instead of about 91. I think Jack can use the optics a little bit better at that angle.

Jim, that's perfectly okay with us, if it looks good for stars.

He just looked at them briefly; I'll go down and look at them a little bit better here.

Aquarius, Houston.

Go ahead.

Okay, Jim. We—We've been talking about your going to a different attitude than the pad attitude for better star field vision out the command module, and what we'd like to have you do is this. If you can predict now or sometime soon, what attitude it is that you would like to hold at that time, and go to that attitude now, we'd like to be able to compute the coarse aline gimbal angles for the CSM, and we can do that if you go to the selected attitude, hold it, call up a VERB 06 NOUN 20, and read us your LM gimbal angles, we can take those and compute CSM coarse aline gimbal angles on the assumption that, when we get back into the CSM coarse aline, you will return to that selected attitude. Does that sound okay? Over.

Yes. I'll try to hold the attitude we select directly, while you're giving us the coarse aline attitude. We're not too sure what—what's the best attitude. I'm going to ask Jack again if 115 is sufficient for him.

Okay. You can take some time figuring out the best attitude, and then you won't have to hold it all the way from now until then, if you just get back to it.

Houston, Jack would like to know what constellations are in his sextant, or scanning telescope, field of view at an attitude of about 105 pitch, zero roll, zero yaw. Can you give that to us?

Okay. We'll sure give it a go. As I said, we—We have some stars. They're not—They're not centered with the shaft and trunnion zero. Let us take a quick look at 105 pitch, shaft and trunnion zero, and see if we can get you an answer.

Aquarius, Houston.

Go ahead.

Roger. These—None of these stars will be exactly centered, but, at a pitch attitude of 115, we had computed that Vega, Altair, Rasalhague, and Deneb would all be in the telescope field of view, and the first three were also in view at the 91-degree pitch, so he should be able to see one or more of those four stars. Over.

Okay. Thank you, very much.

Okay. And, Jim, I can give shaft and trunnions if—if he's interested.

Okay. Why don't you give us the shaft and trunnion for—say, Altair at 115, and I'll go up there, and I'll see if he can pick it up.

I'll verify it, Jim. I'm sure it's okay.

Okay, Aquarius; Houston. With the present amount of power you've got in the LM, which is over 500 amp-hours, and the rate you're using them, we figure you've got almost 12 hours of power left.

Twelve hours, huh? We could reenter with it.

That's affirm.

That's enough for two touch-and-goes and a full stop, Jim.

That's right, Joe; if you could dig a crater like Cone Crater, I could might hit it.

(Laughter) Okay.

Jack reports that he thinks he can see Altair.

Very good.

He says, he thinks he can see Altair.

Houston, Aquarius.

Aquarius, Houston. Go.

I ran back there to take a look and see what I could see in the—in the scanning telescope. It looks pretty grim back there right now. It might be that we have to go with the coarse aline, and maybe computation of some fine aline docking angles, if we have time.

Okay. We'd like to do that, too. Wait a minute; stand by, Jim.

Aquarius, Houston. How do you read?

I read you loud and clear.

Okay. What we'd like to do, Jim, is—We'll go ahead and get the coarse aline to the gimbal angles that—that you're going to be holding for us; and we'll get the platform up, and then when you call P52 and you use PICAPAR, it probably won't be close enough to put the star in the sextant, but if you can see any kind of a bright star in the general vicinity,—and like general vicinity, I mean 2 to 3 degrees from the center of the telescope, so that you have some clue as to which way to go, then the identification problem shouldn't present much of a—of a difficulty. And once you get the thing in the sextant, then you can go ahead and treat it like any other PICAPAR.

That sounds great, Ken. One little problem: there's all sorts of bright objects floating around us, and also that just staring at part of Aquarius; it's just reflecting light like mad. We can give it a try. There's no problem there; if we can see it, we'll get it.

Okay. And in—in the event that that doesn't work, we're standing by with the original scheme, a set of LM FDAI angles to fly to that'll point the command module optics at the Moon and the Sun; so we can always go back to that.

Okay.

And, Aquarius, Houston. We'd like you to verify the SUIT RELIEF valve to closed. Over.

Stand by. It's closed.

Okay, Houston; Aquarius.

Aquarius, Houston. Go.

We'll go with your original 91-degree angle, if you have the stars figured out, and the coarse aline angle for it.

Okay. Roger that, Jim. Then at—at your convenience here, we'd like you to go to that attitude, as close as you can get, and call up a NOUN 20 for us.

Okay. In work now.

Houston, Aquarius.

Go ahead, Aquarius.

Okay. I take it that, if—if Jack cannot see stars at this attitude after you give him the coarse aline angles, we're just not going to read down to you our gimbal angles and have you figure out a target angle for Jack, but you want him to do sighting on the Moon and the Sun. Is that correct?

That's roughly correct, Jim. Jack will coarse aline at that attitude. This is what we're having you maneuver to the—to that attitude for. We're going to compute coarse aline gimbal angles and pass them up to him, and the first thing he'll do when he gets there, per his checklist, is to coarse aline his platform. Then he'll go into the P52, and, if he can't see stars, we will quickly pass up to you the—your FDAI angles to put him in the Moon-view attitude, and he'll do his P52 on the Moon, and then have you maneuver on the Sun and complete the P52 of the Sun.

Okay. But I'm going to have to maneuver to the Moon to help him out.

Oh. That's—That's affirmative. If he can't see stars at the—at the SEP attitude that—that you'll be holding, you'll have to maneuver to the Moon attitude and then to the Sun attitude for him.

Aquarius, Houston.

Go ahead.

Just like to mention that, even if, for some reason, we run out of time or something and don't complete the Moon-Sun P52, Jack will have a platform coarse aline to the entry REFSMMAT, which we feel will be plenty good enough.

Roger. That's my feelings, too.

Aquarius, Houston.

Hello there, Houston.

Hi! Jim, we—We've gone ahead and computed the CSM coarse aline gimbal angles based on your being at the service module SEP attitude at the time that Jack cranks up the computer and—and coarse alines the IMU. That is, we assume that you're going to be at roll, 0; pitch, 091; yaw, 0; and, if you concur on that, I'd like to pass up the angles for—for Jack to have.

Okay. I'll be there to the best of my ability.