The Gemini 8 Flight Journal
Gemini 8
Part 9: Coelliptic maneuver
Corrected Transcript and Commentary Copyright © 2025 by Tracy L. Scott and W. David Woods. All rights reserved.
Last updated 2025-09-03
003:17:50 Lovell: Gemini VIII, Houston CapCom. Over.
003:17:53 Armstrong: Go ahead.
003:17:56 Lovell: I have your Coelliptic Maneuver update if you're ready to copy.
003:18:03 Armstrong: Okay. Go ahead.
003:18:05 Lovell: GET AB: 03:47:34; Delta-V, 61.6; Delta-T, 01 plus 22; yaw zero, pitch 23 degrees down; Core 25, 00567; Core 26, 00240; Core 27, all zeros; thrusters aft; Posigrade Down. Did you read?
003:18:54 Armstrong: Understand. GET [garble] plus 22, yaw zero, pitch 23 degrees down [garble].
003:23:33 RKV CC: Gemini VIII, RKV CapCom.
003:23:38 Armstrong: [Garble.] [PAO transcript has "Go ahead".]
003:23:41 RKV CC: Roger. We did not get the confirmation on that maneuver update...
Houston Flight: Standby RKV, standby RKV, we have another one coming through.
RKV CC: Roger.
003:23:51 Armstrong: Okay NSR: 03:47:34; 61.6; 01 plus 22; yaw zero, pitch 23 degrees down; 25, 00567; 26, 00240; 27, 0000; thruster aft; Posigrade Down.
Houston Flight: RKV, Houston Flight.
RKV CC: Roger, Flight.
Houston Flight: Standby to take another burn.
RKV CC: Roger, go.
Houston Flight: GETB 03:47:35, Delta-V 61.2, burn time 01 plus 22, yaw 0, pitch 21 degrees down, core 25 00570, core 26 00224, core 27 all zeros, aft thrusters, posigrade down. Read it back.
003:25:23 RKV CC: Gemini VIII, RKV CapCom. We have an update...
Houston Flight: Read that back to me first.
003:25:28 RKV CC: Stand by one, please.
Houston Flight: Roger.
003:25:58 RKV CC: Roger, Gemini VIII. Time on that is 03:47:35: Delta-V, 61.2; Delta-T, 1 plus 22; yaw, zero degrees; pitch, 21 degrees down; Core 25, 00570; Core 26, 00224; Core 27, all zeros; thrusters aft; Maneuver Posigrade Down. Do you copy?
003:26:46 Armstrong: Roger. Understand 03:47:35; 61.2; 01 plus 22; yaw zero, pitch 21 degrees down; 25, 00570; 26, 00224; 27 all zeros; aft thrusters; Posigrade Down.
003:27:11 RKV CC: Roger. That is affirmative.
Houston Flight: RKV, Houston Flight.
RKV CC: Okay, Flight.
Houston Flight: Ask him if he has managed to get that ACQ light on yet. That is Agena ACQ lights on. He was going to send that command 251.
RKV CC: Roger. We have no indication of it here. We do have phase lock and I think we should get him to take that lock off and try to get that fresh load in. We have been unable to get fresh load in.
Houston Flight: You mean coder on, encoder on?
RKV CC: Yes. Tell him to turn the encoder off.
Houston Flight: Okay. Go ahead and do that.
003:27:57 RKV CC: Gemini VIII, RKV CapCom. Will you turn your Encoder off. We would like to update the Agena with a fresh load.
003:28:07 Armstrong: Coder's off, and we are making [garble].
003:28:09 RKV CC: Roger. Understand.
Houston Flight: RKV, can we have a Gemini main?
RKV CC: Up Gemini. Did you copy, Flight. He had been unable to get lock on.
Houston Flight: Say again.
RKV CC: He had been unable to get radar lock on.
Houston Flight: Okay. Did you get the fresh load in?
RKV CC: We are transmitting right now. Thats affirmative. We have a map...
Houston Flight: Okay. Why don't you get those ACQ lights on from the ground. Tell him you are going to do that.
RKV CC: Roger.
003:28:54 RKV CC: Gemini VIII, RKV CapCom. We're going to send the ACQ lights, On, to the Agena from the ground here.
003:29:01 Armstrong: Go ahead.
003:29:04 RKV CC: Roger. We have it verified by MAP.
003:29:07 Armstrong: Roger. We're getting intermittent lock-on at this time.
003:29:11 RKV CC: You may turn your Encoder back on.
003:29:17 Armstrong: Coder on.
RKV CC: Go ahead, Flight.
Houston Flight: It is okay. We read that. Very good, RKV.
RKV CC: Thank you. We will have a LOS. We are having a break up right now on Agena.
Houston Flight: Roger.
RKV CC: Okay. We are getting an indication occasionally of a radar lock.
Houston Flight: Roger.
RKV CC: We have radar indication again. We have had our first LOS of Gemini and Agena. We expect maybe some more here shortly.
Houston Flight: RKV, Houston.
RKV CC: RKV.
Houston Flight: Did you get indications of power output on the transponder?
RKV CC: Station is LOS.
This is Gemini Control, Houston at 3 hours, 39 minutes into the flight of Gemini 8. We are about 9 minutes away from our next burn and major maneuver which will h&ve the effect of circularizing this Gemini 8 orbit at roughly 147 nautical miles. This is to occur at 3 hours, 47 minutes, 35 seconds into the mission. Rather large burn, a Delta-V at 61.2 feet per second. After the burn the spacecraft should read something like 546 pounds of fuel remaining on board, Presently the spacecraft is 170 miles behind the Agena. When we last heard from Gemini 8, they were having intermittent radar lock. It looked like it was locking up fairly well toward the end of the pass over the Rose Knot Victor parked off the east coast of South America. Meanwhile the backup crew members for the Gemini 8 mission, Pete Conrad and Dick Gordon have reached the Control Room here in Houston after a one hour and 50 minute flight from the Cape, Coming with them were Donald Slayton and astronaut Walter Cunningham also. They came here directly from Ellington Field next to the Manned Spacecraft Center and are conferring with Jim Lovell on the flight progress to date. We have the tape conservation via the Rose Knot Victor station and here it is.
Tananarive remote: This is Tannanarive remote.
003:43:39 Lovell: Gemini VIII, Houston CapCom.
003:43:43 Armstrong: This is Gemini VIII. Go ahead.
003:43:46 Lovell: Roger. Do you have solid radar lock-on with the Agena? Over.
003:43:49 Armstrong: Houston, Gemini VIII reads you loud and clear.
003:43:55 Lovell: Roger. Do you have solid radar lock-on with the Agena? Over.
003:43:59 Armstrong: That's affirmative. We have solid radar lock. Just a minute and I'll give you our current range.
003:44:05 Lovell: Roger. Thank you. Sounds good.
003:44:16 Armstrong: We're indicating a 158-mile range and elevation of about 4 degrees.
003:44:22 Lovell: Roger. Sounds good and I'm seeing about 3 minutes and 9 seconds to your burn.
003:44:29 Armstrong: Roger.
This is Gemini Control, Houston. About two minutes ago, Neil Armstrong called in over Tananarive and he was able to confirm at that time that radar lock had been established. A solid radar lock was - had been linked up and he gave us, about two minutes ago. He said the range was 158 nautical miles. This is an all important element of a rendezvous mission - the establishment of that radar link. The pilots say that if they had to lose any of the several things involved in a rendezvous mission, that is the platform, the computer or the radar, they would much prefer the least. The one they would rather have over anything else is the radar. At 3 hours, 47 minutes into the mission we do have this brief conversation via Tananarive. We will play the tape for you now.
Gemini Control, Houston here. We are 3 hours, 48 minutes, 51 seconds into the flight which would indicate we should be just about completing the circularization burn. We will stand by, we should have confirmation on that from the Tananarive station. Signal loss not due for another two minutes I would say. Our big rendezvous display chart here in the Control Center is etching a circular ring for the spacecraft, matching it up with the circular Agena orbit. Jim Lovell is putting in a call now. Let's listen.
003:49:53 Lovell: Gemini VIII, Houston CapCom. If you have time, let us know about your burn.
003:49:58 Armstrong: Okay. We're just [garble].
003:50:40 Armstrong: Okay. Our burn is complete and the residuals are null.
003:50:50 Lovell: Roger. Left-hand burn complete; residuals are null. Did not get the rest.
This is Gemini Control, Houston. You heard Neil Armstrong confirm that he had completed his circularization burn. He had no residuals left, apparently a clean manuever. And now we are advised that Tananarive has had LOS, Loss of Signal. Our next maneuver, coming up at 5 hours and 13 minutes, 35 seconds into the mission - and appreciate that this is an update over the time given earlier - we now show for the Terminal Phase Initiation maneuver, 5 hours, 13 minutes and 35 seconds. This is Gemini Control, Houston.
003:57:02 Armstrong: [Garble.]
003:57:04 Armstrong: We had lock-on at about 179 [nautical] miles, and we got radar boresighted at something like 156; and the needles are relatively steady; they look pretty good. The yaw needle is wavering back and forth, perhaps plus or minus 1 degree. And a note here that the trouble we've had is getting rid of the residuals. We bring the residuals down to a small number, and then the next reading they would increase, and the next reading they would decrease. It would be difficult to tell when we got to actual zero residual. The Ground said we didn't have any. The accelerometer bias had looked good, but it looks like something is getting to us here.
