The Gemini 8 Flight Journal
Gemini 8
Part 17: After the tumble
Corrected Transcript and Commentary Copyright © 2025 by Tracy L. Scott and W. David Woods. All rights reserved.
Last updated 2025-09-09
007:37:23 Hawaii CC: Gemini VIII, Hawaii.
007:37:24 Scott: Hello Hawaii, Gemini VIII.
007:37:25 Hawaii CC: Roger. We'd like a readout on your switch positions and OAMS, and on-board reading of your OAMS remaining. Over.
007:37:30 Scott: Okay. We have 22 percent showing on the gauge. We don't have any yaw or roll control, and cannot regain control of the yaw thrusters, apparently none of them. We do have - apparently the pitch thrusters are operative. And also, we're slowly getting back to the proper attitude here.
007:38:07 Hawaii CC: Roger. Copy, Gemini, and be advised they're planning to come into a -3 area. They're looking into 6 or 7-3 at this time. They would like you to enter Module 4 and the ATM computer. Over.
007:38:23 Armstrong: Okay. We'll go ahead and do that.
007:38:27 Hawaii CC: And also get into Retro Attitude as soon as possible. Over.
007:38:33 Armstrong: [Garble.]
Hawaii CC: Gemini VIII, Hawaii.
007:38:51 Armstrong: Go ahead.
007:38:55 Hawaii CC: Roger. Which systems are you using now? OAMS or RCS?
007:39:01 Armstrong: We're on OAMS right now.
007:39:05 Hawaii CC: Roger. And do you have any problem at all with the RCS control?
007:39:12 Armstrong: In Direct we're okay. We haven't really thoroughly checked out the RCS. That's the only way we got it to fire a while ago.
007:39:19 Hawaii CC: Roger. Copy.
007:39:36 Hawaii CC: Gemini VIII, Hawaii.
007:39:37 Armstrong: Go ahead.
007:39:39 Hawaii CC: Roger. We'd like you to place your Entry C-Band beacon to Continuous and Flight advises they personally prefer 7-3. That will give you approximately 1½ more hours.
007:39:53 Armstrong: Okay. We do have the spacecraft under control at the present time. We're in slowly drifting flight - do have a slight amount of control. We have - 1,550 pounds showing on RCS B and 2,400 on A.
007:40:18 Hawaii CC: Say again on B, please.
007:40:20 Armstrong: 1550.
007:40:21 Hawaii CC: Copy.
007:42:15 Hawaii CC: Gemini VIII, Hawaii.
007:42:16 Armstrong: Go ahead.
007:42:21 Hawaii CC: Do you have any idea of the Agena position at present? Over.
007:42:24 Armstrong: We saw it about 10 minutes ago. It looked to be a mile or so underneath us.
007:42:32 Hawaii CC: Roger. Copy. Would you place your T/M switch to Real-Time/ACQ-Aid, please?
007:42:35 Armstrong: Real-Time/ACQ-Aid.
007:42:44 Hawaii CC: Could you give us a sequence of events on just what happened? Over.
007:42:52 Armstrong: It happened when we were in Agena-spacecraft combination of 0, 180, 0 and we were stabilized there. We had the Attitude Control Power off in the spacecraft, OAMS Attitude Control Power off and we sent 041 Command to Agena to turn the recorder on. The spacecraft-Agena combination started a violent roll.
1966-03-16, 6:44 pm This is Gemini Control, Houston. We are 8 hours and 3 minutes into the flight of Gemini 8. And in view of the trouble encountered at 7 hours into the flight as reported earlier, the Flight Director has determined to terminate the flight in the 7-3 area. We plan to bring the flight down on the 7th orbit in the 3rd, what we call the 3rd zone, which is approximately 500 miles east of Okinawa, it's in the far west Pacific. Our situation out there is as follows - a destroyer named the Mason is about 160 miles away at this time, it is proceeding towards the point, and it should take that destroyer probably 5 to 6 hours to reach the point, which should come very close to the - well it may be a little delayed, get there after the landing itself. The first estimate I have on the retrofire time is 10 hours and four minutes into the mission, in other words two hours from now. Landing should take place some 25 to 26 minutes later. In addition to the Mason, a C-54 has been dispatched from Tachikawa Air Force Base in Japan. Its proceeding to the point. Another C-54 is proceeding to the point from Okinawa. The - another location here on the landing point is quoted to me as 630 nautical miles south of Yokosuka, Japan. The weather conditions out there are partly cloudy, visibility ten miles, and the landing will be made in full daylight, it's 12:30 pm out in the 7-3 area. Again to recap our situation as best we understand it at this point, at 7 hours into the mission, Neil Armstrong noted some maneuvers, the spacecraft-Agena combination getting into some rates that he did not like. He elected to back off from the Agena, undock, which he did. We do not know whether the problem developed in the Agena or in the spacecraft. We do know that the maneuver thrusters on the aft end of the Gemini 8 spacecraft became inoperative in yaw. He did report later he had his pitch thrusters and he also reported he had used one of his Reentry Control System rings to bring the spacecraft under complete control. That pretty well sums up our situation here. We'll pass along additional information as it develops. This is Gemini Control at 8 hours, 6 minutes into the flight.
008:10:44 RKV CC: Gemini VIII, RKV CapCom.
008:10:47 Armstrong: Go ahead RKV, Gemini VIII.
008:10:50 RKV CC: Roger. Do you have any idea where the Agena is?
008:10:55 Armstrong: No, we haven't seen it.
008:11:00 RKV CC: Over Hawaii, we were having LOS at the time that you were giving us your switch positions. We copied as far as you had sent Commmnd 041 Recorder, On, and at that time the spacecraft started to roll. Would you continue from there, specifically what your on-board switch positions were and what you did with it?
008:11:23 Armstrong: We had Attitude Control Power, On, and went to Rate Command.
008:11:47 Armstrong: And when we started to yaw - it seems that it was the Agena control system.
008:11:54 Armstrong: Since we did not hear any of our thrusters fire.
008:12:03 RKV CC: Stand by [garble].
008:12:05 Armstrong: And we sent ACS Off and turned the spacecraft power On, OAMS power On, and tried to regain control of the combination.
008:12:19 Armstrong: And we were just barely able to hold our own, but the rates were too excessive for an undocking, so we continued to attempt to send an ACS Off-cycle [garble] and at the same time we checked our OAMS switch position.
008:12:39 Armstrong: We switched it - we tried to turn our own Spacecraft Control System, Off, and the combination continued to wind up, so we had to go back On before the rates became intolerable.
008:13:00 Armstrong: After we got the rates down to a point where we felt we could safely undock, we did so, and maneuvered away from the Agena at several feet per second as quickly as possible. We had been watching our propellant quantity go down from 50 to below 30 percent. After turning the OAMS, Off, and still in bias power and everything - motor valves off, we were still rolling; we activated the RCS. Did not have any ACME, and we regained control of the spacecraft in Direct, slowly.
008:13:55 Armstrong: Then after getting stabilized, we checked out our whole Thrust Control System and found that we had no yaw or roll control - or we had no yaw control of the yaw thrusters since our roll was in the yaw jets, and after that...
008:14:15 Scott: ACS was really going.
Armstrong: ...we had - vision; we could see the ACS thrusters firing on the Agena when we had ACS off, so we felt that something was definitely wrong.
008:14:30 Armstrong: After checking the spacecraft systems we found Thruster Number 8 apparently failed Open at the present time and this could have been true at the time of the incident, although we can't - cannot verify that at this time.
008:14:44 RKV CC: Roger. Stand by. We'll update that new T
R time.
008:14:54 RKV CC: Okay. And I'd also like to send your Load.
008:15:00 Scott: Reentry Load.
008:15:04 Scott: DCS light on.
008:15:05 RKV CC: The ATM okay?
008:15:06 Scott: ATM has loaded Module 4A snd verified 4A.
008:15:09 Armstrong: Roger [garble].
008:15:10 RKV CC: Roger. We're having LOS. We haven't updated your Load and T
R.
008:15:16 Armstrong: Okay.
008:15:17 RKV CC: Okay. Did he have that...
008:15:18 Armstrong: What's the T
R?
008:15:19 RKV CC: T
R time is for Area 7-3, which is approximately an hour and 15 minutes from now.
008:15:29 Armstrong: What 's our next AOS?
008:15:33 RKV CC: Next AOS should be CSQ.
008:15:36 Scott: Give us a time for that, please.
008:15:51 Scott: 8:52, T
R is at 9...
008:15:53 RKV CC: Roger. Should be 8 hours, 52 minutes - 8 hours, 52 minutes.
008:16:00 Scott: Okay. Thank you.
008:16:03 Armstrong: We're in the process of restowing for Reentry.
008:16:21 RKV CC: Gemini VIII, RKV. Did you blow the OAMS Reg switch?
008:16:27 Armstrong: No, we have not yet. We thought about it but we don't need to yet, I guess.
008:16:48 Scott: Oh shoot! How am I ever going to stow that visor? I've got to put the TV monitor in, too.
008:16:58 Armstrong: Yes, I know you do.
008:17:00 Armstrong: Do you went to do that before you get too tied up?
008:18:10 Scott: We should have asked them about purging the fuel cells.
008:18:12 Armstrong: Yes. Well, let's go ahead and do it.
008:18:22 Armstrong: Purging fuel cells at 8 minutes and 8 seconds - correction, that's 8 hours, 18 minutes.
1966-03-16, 7:01 pm This is Gemini Control, Houston. At this time the flight control team are reviewing retrofire parameters to bring the spacecraft in the 7-3 area. We have been further advised that an HU-16 amphibian type aircraft is being dispatched to the scene, again located about 506 miles east and slightly south of Okinawa. In additional discussions with Gemini 8 over the Rose Knot Victor, it was a fairly short pass, Neil did advise that the thruster number 8 apparently failed in an open position. We don't know that that was the complete extent of the difficulty, but he did verify that that thruster failed. We don't know whether it failed while he was still docked to the Agena or after he had undocked and backed off from the Agena, but that's of no consequence at this point. He does have the spacecraft in a very stable attitude, using his RCS system. The Agena is described as ahead and below him, which apparently is a favorable condition for the kind of landing maneuver we want to attempt, of retrocommand is 10 hours and 4 minutes into the mission. And to correct an earlier statement, it is approximately 32 minutes later that the spacecraft should touch down in the West Pacific. This is Gemini Control, Houston.