The Gemini 8 Flight Journal
Gemini 8
Part 5: Orbit height adjustment
Corrected Transcript and Commentary Copyright © 2025 by Tracy L. Scott and W. David Woods. All rights reserved.
Last updated 2025-09-09
This is Gemini Control, Houston, We'd like to review some of the maneuvers coming up. These values may change, but probably only slightly. Presently the spacecraft is over Hawaii. They are in conversation now, but first we will cover this maneuver information. At 1 hour, 34 minutes and 37 seconds into the flight, they are to perform a slight height change. This will come south of New Orleans several hundred miles out over the Gulf, on this pass on and below the U.S. The delta-V is now to be a -2.9 or retrograde maneuver. This will leave the spacecraft with an estimated 722 pounds of usable fuel onboard. At 2 hours and 18 minutes and 25 seconds into the flight, the spacecraft is to perform a phasing maneuver which will require a delta-V or a delta velocity of 51.2 feet per second. At 2 hours and 45 minutes, 31 seconds into the flight, the spacecraft will perform a plane change or maneuver calculated to get rid of a very slight wedge angle in the two orbits. This angle is presently estimated at .05 degrees. The spacecraft will be oriented with the blunt end north and will burn toward the south. It will burn 25.7 feet per second and this will leave the spacecraft with some 643 pounds of fuel remaining. We will be along 3 hours and 47 minutes and 36 seconds into the flight, the spacecraft will perform its coelliptic burn, or circularization burn. This is one of the larger burns, 59.2 feet per second and it will leave the spacecraft with 583 pounds. At 5 hours and 4 minutes into the flight the spacecraft will initiate its terminal phase maneuver. And at 5 hours and 36 minutes into the flight, they will perform a maneuver which will require a 43.6 feet per second. This will be the terminal phase final. Now, as we have been talking, we have been hearing in our other ear that Wally Schirra and Frank Borman, who are returning from their far eastern tour, we believe they're in Hawaii and we understand they are trying to contact the spacecraft. They haven’t put out a call for several minutes but Neil Armstrong and Dave Scott are aware that they're being paged and the Schirra advised that their call sign is Gemini 76. At 1 hour and 20 minutes into the flight, this is Gemini Control, Houston.
001:20:03 Scott: Okay. Let's see how we get the IVI's. What do you say?
001:20:08 Armstrong: Okay. Catch-up and we'll see what happens.
001:20:10 Scott: You will?
001:20:20 Armstrong: [Garble] Prelaunch [garble].
001:20:25 Scott: [Garble] this [garble]. Forward firing thrusters, Retrograde burn at 1:34:37.
001:20:36 Armstrong: [Garble] that's 14 minutes fram now.
001:20:38 Scott: Okay. Now we want to do a Platform Align before that.
001:20:42 Armstrong: It's really not required - for 3 feet per second, I don't think.
001:20:44 Scott: Does that concur with [garble]?
001:20:46 Armstrong: What does it say in the Flight Manual?
001:20:56 Scott: [Garble.]
001:21:01 Hawaii CC: Gemini, this is Hawaii. We have nothing further for you. Standing by.
001:21:06 Scott: Okay. All good and well up here.
This is Gemini Control, Houston. We've just been handed the final computer runouts on the initial orbit for the Gemini 8 spacecraft. It goes like this - these are conditions at second stage cut-off plus 20 seconds. In other words, that time when the spacecraft would have parted from the second stage. The insertion velocity at SECO plus 20 seconds was - the actual was 25,737 feet per second. This against a planned value of 25,730 feet per second. The perigee presently shows 86.2 actual, 86.2 nautical miles, as against the planned value of 86.8 nautical miles. The apogee, actual, 146.2 versus a planned apogee of 146.0 [nautical miles]. We have conversation between the ground and the spacecraft from Hawaii and here it is.
001:21:09 Scott: Yes. You want to align it as good as you can. It says 15 minutes prior [garble] allow Platform Mode to align platform.
001:21:18 Armstrong: 1:34:37 is start time. [Garble].
001:21:27 Scott: You understand [garble] Platform. You can see out the window that it's - no, that it's 90 degrees, anyway.
001:21:42 Armstrong: [Garble.]
001:21:43 Scott: If you align it, it takes the [garble].
001:21:44 Armstrong: I agree.
001:21:46 Armstrong: If you align it in a 3-feet-per-second burn, if you are 10 degrees off on the Platform, it'd be hard for us to see it, as far as the Delta-V operation is. So why don't we - as we come upon the stage we'll put it in SEF [Sharp End Forward] for a little while. Well, 5 minutes before you're supposed to go to Orbit Rate. Okay. I'll just put it in SEF Comp right now. Kind of fun.
001:22:28 Scott: It really kicks it around there, doesn't it?
001:22:31 Armstrong: Yes. It's winding right up.
001:22:41 Scott: Wonder where we'll be at 1:34. Oh, I know! It's on the - on the - we'll be right over Houston on this pass.
001:22:58 Armstrong: [Garble]. Try and get that camera.
001:23:13 Scott: 1:34 [garble].
001:23:18 Armstrong: [Garble]. Hang on.
001:23:25 Armstrong: No, I'm sorry - Yes. l:34.
001:23:26 Scott: Okay. All right, All right. Just a minute.
001:23:34 Armstrong: [Garble.]
001:24:20 Scott: We'll have to ask Houston, won't we?
001:24:22 Armstrong: Think we're going to have to.
001:24:24 Scott: Think we ought to.
001:24:25 Armstrong: Think we ought to [garble].
001:25:00 Scott: Oh! Look at that one!
001:25:51 Armstrong: What was that time? 1:34 what?
001:26:01 Scott: 1:34:37.
001:26:26 Scott: You got your...
001:27:05 Armstrong: What's the matter?
001:27:08 Scott: The thermometer is [garble].
001:27:10 Armstrong: Yes. The thermometer's always a nuisance.
001:27:12 Armstrong: I'm not sick! Tell them I'm not sick!
001:27:34 Armstrong: 1:27:33. Right?
001:27:39 Scott: Well, I would say maybe we'd better do [garble].
Guaymas CC: Flight, Guaymas. We have both birds 630. Gemini 8's still in mode one.
Houston Flight: Roger.
Guaymas CC: He's barely readable on my UHF here, Flight.
Houston Flight: Okay.
Houston Flight: Hawaii, Houston Flight.
Hawaii CC: Hawaii, go ahead.
Houston Flight: Did the crew confirm that they got that maneuver update okay?
Hawaii CC: Rog. Affirmative.
Houston Flight: Roger.
Hawaii CC: He's got the catchup now, Flight.
Houston Flight: Okay.
This is Gemini Control, Houston. A little additional information on the inclination of these two vehicles - the Agena achieved a 28.86-degree orbit - that is the degree that it is running north and south of the equator. The planned value for the Agena was 28.87 degrees - off by .01 degrees. Meanwhile the Gemini 8 achieved a 28.91-degree inclination - the planned value there was 28.86. So on our one plane change maneuver we will burn off that .05-degree difference in order to make the two inclinations match. The Guaymas station acquired Gemini 8 only a minute or so ago. Let's tune in on that conversation live.
001:27:42 Guaymas CC: Gemini VIII, Guaymas CapCom.
001:27:44 Armstrong: Roger.
001:27:48 Scott: Station calling Gemini VIII, say again.
001:27:49 Scott: Station calling Gemini VIII, say again.
001:27:51 Guaymas CC: Gemini VIII, this is Guaymas. I have a load update...
001:27:56 Scott: Stand by. He has an update. What kind of update do you have, Guaymas?
001:28:05 Guaymas CC: It's a Map update.
001:28:06 Scott: Okay. Stand by.
001:28:08 Guaymas CC: Roger.
001:28:20 Guaymas CC: Okay?
001:28:22 Scott: Okay. Go ahead.
001:28:27 Guaymas CC: Time on load...
001:28:28 Scott: Beautiful!
001:28:29 Guaymas CC: Time: 01:07:13; Rev 1, 159.1 degrees east; 16 plus 00, right ascension.
001:28:47 Scott: Right. Got you. Node: 01:07:13; Rev 1, 159.1; 16 plus 00, right ascension.
001:28:58 Guaymas CC: That's affirmative. We have you Go on the ground.
001:29:03 Scott: We're going over Baja California now. Can you see it?
001:29:08 Armstrong: Oh! Look at all those ships!
001:29:10 Scott: [Garble.]
001:29:27 Armstrong: Okay. I've got to go into a - Orb Rate here.
001:29:29 Scott: Also Attitude Control, Rate Command.
001:29:35 Armstrong: Platform, Orb Rate.
001:29:37 Armstrong: Computer, Catch-Up.
001:29:38 Armstrong: Computer looks good.
001:29:42 Armstrong: FDR, Comp.
001:29:44 Scott: FDR, Comp.
001:29:51 Armstrong: Maneuver Controller, unstow.
001:29:52 Scott: That's good.
001:29:53 Scott: Maneuver Controller, On.
001:29:56 Armstrong: Okay. On.
001:30:05 Armstrong: 1:34:37. How's that?
001:30:13 Scott: 1:34:37. We want to have a 5-second burn and forward firing thrusters will give us a Retrograde Maneuver.
001:30:20 Armstrong: Okay. I think I'll burn it back.
001:30:24 Armstrong: All right.
001:30:28 Scott: Sort of like to know how it works.
001:30:30 Armstrong: Yes, I think we ought to take a picture.
001:30:49 Armstrong: Would be nice, but I - nice [garble].
This is Gemini Control, Houston, here. In just four minutes the spacecraft will perform their first maneuver and as we’ve been talking the Texas station assumed control. Let’s go back live.
001:31:04 Scott: Nice cloud formations!
001:31:08 Scott: Beautiful! Just spectacular!
001:31:13 Scott: Hope you remember to look up when we start going after the Agena.
Houston Flight: Guaymas, Flight. We have it now.
Guaymas CC: Roger.
001:31:20 Lovell: Gemini VIII, this is Houston CapCom. We're standing by for your burn.
001:31:28 SC: Roger. Got 3 minutes to go.
This is Gemini Control, Houston. We're about one minute away from the burn. Mark one minute.
001:31:44 Armstrong: Pressure coming up [garble] approach.
001:31:51 Scott: We cross Houston at the burn; it's between Houston and - the Cape.
001:31:56 Armstrong: Okay. 0, 0, 0, Platform.
001:32:01 Scott: Okay. Orb Rate and we're Catch-Up.
001:32:03 Armstrong: Standing by to hear [garble].
001:32:08 Armstrong: [Garble] the Controller is off and on. Start Comp [garble].
001:32:22 Scott: I have a shoreline in sight here. I really don't have Houston picked out though.
001:32:30 Armstrong: [Garble.]
001:32:46 Scott: We are coming up on 32.42 [garble] Houston [garble].
001:32:49 Armstrong: I've got it.
001:32:53 Scott: I'm going to push your Start Comp 1:33. Right?
001:32:56 Armstrong: 1:33 Start Comp.
001:32:59 Scott: Now you're going to go back. Right?
001:33:03 Armstrong: Aft. I'm going to pull aft.
001:33:25 Scott: Save that gas.
001:33:30 Armstrong: Coming up on 1:33:37.
001:33:34 Scott: Okay. We're 1 minute to burn, going right over the coastline now...
001:33:39 Lovell: Roger, VIII. Stand by for a 30-second Mark to your burn.
001:34:08 Lovell: Mark. 30 seconds to burn.
001:34:30 Armstrong: Keep an eye out the window and see what it looks like with this forward firing.
001:34:35 Armstrong: Mark.
001:34:36 Armstrong: Burn.
Lovell: Burning, Flight.
Houston Flight: Roger.
001:34:42 Armstrong: Purging.
001:34:43 Armstrong: Mark.
001:34:44 Armstrong: 2, 1, burn.
001:34:47 Armstrong: Fine. Burn end.
001:34:48 Armstrong: Mark.
001:34:51 Scott: What number?
001:34:53 Armstrong: Minus 0001.
001:34:0540 Scott: I got that.
001:34:55 Scott: 2. Okay. 82. That's...
001:35:08 Lovell: Gemini VIII, this is Houston. We're placing your T/M switch to Real Time/Delay Time.
001:35:10 Armstrong: Okay.
001:35:13 Armstrong: Yes. A real good idea.
001:35:15 Scott: Okay. Let's try it.
001:35:21 Armstrong: Wrong way.
001:35:25 Scott: Address 82 is not the [garble].
001:35:27 Scott: Address 82 is minus, so we want to go...
001:35:28 Armstrong: Let's try it again.
001:35:33 Lovell: Gemini VIII, this is Houston requesting your Tape Playback switch to Continuous.
001:35:37 Armstrong: Oh, shoot! Stand by.
001:35:39 Scott: Stand by, Houston.
001:35:40 Lovell: Roger. Will do.
001:35:42 Armstrong: Let's try Address 81 again and see what it is.
001:36:00 Armstrong: It's building up now.
001:36:10 Scott: Fine. Okay. Now to put - now you're 82 [garble] 80, 81, 82 is down. You should go. Yes. I guess you're right. It should go.
001:36:14 Armstrong: I think I was.
001:36:15 Scott: Okay. I understand.
001:36:22 Lovell: Gemini VIII. This is Houston. You don't have to answer. We'd like to have your computer in Prelaunch when you can.
001:36:55 Armstrong: [Garble.]
001:37:03 Armstrong: That's almost a foot per second.
001:37:11 Scott: Computer's in Prelaunch. We're putting Tape Playback to Continuous.
001:37:14 Lovell: Roger. Thank you. Understand you were to take out residuals. How did it go?
001:37:24 Armstrong: Yes, we took out the residuals, but they seem to be building up on us with time.
001:37:31 Lovell: Roger. That is part of your accelerometer bias.
001:37:36 Armstrong: Yes, I think that's right. Are you going to update that bias?
001:37:43 Lovell: Whenever you're ready, we're going to send you an accelerometer update.
001:37:46 Armstrong: Okay. I think we're probably - stand by a minute.
001:37:50 Lovell: Roger. We're standing by.
001:37:57 Scott: What was the last number?
001:37:58 Armstrong: 81 was a 3.
001:38:00 Armstrong: 80 was a zero.
001:38:07 Armstrong: Okay. Tell them to go ahead.
001:38:10 Scott: Okay. Go ahead and send the new bias for us.
001:38:14 Lovell: Roger. Coming up.
001:38:23 Armstrong: We have not gotten a light yet.
001:38:26 Lovell: Stand by. It's coming, VIII.
001:39:01 Armstrong: Now my impression, Partner, is that 82 hit the button.
001:39:06 Scott: So you're right.
001:39:11 Armstrong: Roger.
001:39:15 Armstrong: Got a light. Reset.
001:39:16 Lovell: Roger. Understand you have the light.
001:39:29 Scott: Okay. You have the Tape Playback in Continuous.
001:39:39 Scott: Hey, we still - they got the Tape Playback in Continuous now. You know that?
001:39:54 Lovell: Gemini VIII, this is Houston. The accelerometer bias update was good.
001:39:59 Armstrong: Roger. Thank you.
001:40:01 Armstrong: Say again, Dave.
001:40:03 Scott: They have the Tape Playback in Continuous. We're not going to [garble].
001:40:13 Armstrong: We're really [garble] update [garble].
001:40:50 Lovell: Gemini VIII, Houston CapCom here.
001:40:53 Armstrong: Go ahead.
001:40:54 Lovell: Roger. Would you please verify that your Antenna Select switch is in Adapter? Over.
001:41:01 Armstrong: Roger.
001:41:03 Lovell: Thank you.
001:41:41 Lovell: Gemini VIII, Houston CapCom. I have your Phase Adjustment Maneuver update if you're ready to copy.
001:41:47 Scott: Roger. Go ahead.
001:41:49 Lovell: Roger. GET B: 2:18:26; Delta-V, 49.3; Delta-T, 1 plus 07; yaw 0, pitch 0; Core 25, 00493; Cores 26 and 27, all zeros; thrusters aft; Maneuver Posigrade. Did you copy?
001:42:27 Scott: Roger. Understand. Phase-Adjust at 02:18:26: 49.3; 1 plus 07; yaw 0, pitch 0; 25, 00493; 26 and 27, all zeros; aft thrusters; Posigrade.
001:42:51 Lovell: Roger, Dave. Okay.
001:42:56 Armstrong: What was that time, Dave?
001:43:00 Scott: The time? 02:18:26.
001:43:06 Lovell: And Gemini VIII, would you put your Tape Playback switch to Command?
001:43:12 Armstrong: Tape Playback in Command.
001:43:14 Lovell: Roger. And T/M switch to Real-Time and ACQ.
001:43:14 Armstrong: Real-Time and ACQ.
001:43:33 Scott: Say, you sort of lose a little bit of voice up here, you know.
001:43:39 Scott: I noticed it on everybody that has flown.
001:43:49 Armstrong: Let's see now. Is this - this is just a one-man package?
001:43:53 Scott: We have some food in here, if you want some food.
001:43:56 Armstrong: Well, this is Day 1 Meal B for me, and I think yours is in there. I think we ought to go ahead and have one because...
001:44:02 Scott: Yes. You're right.
001:44:04 Armstrong: ...because we're not going to get much of a chance after - we've got the best part of an hour here.
001:44:35 Lovell: Gemini VIII, this is Houston. You'll probably expect an update on that Phase-Adjust Maneuver over Ascension. Over.
001:44:42 Armstrong: Okay. Understand.
1966-03-16, 12:20 pm. This is Gemini Control, Houston. That will conclude the conversation for this pass as the spacecraft moves we've had LOS from the Antigua station. We expect further contact several minutes from now when they are in the zone of the Ascension Island station. At 1 hour and 46 minutes into the flight of Gemini 8, this is the Control Center in Houston.