NASA-UAP-D017, Preliminary Gemini 4 Crew Debriefing, Part II, 1965

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By authority of-E---'-:---'--'-=--::....-~-=-__,___.c.....:::=---1 Cha nged bY--..£:::%:.:~~!l"~~==-- GT-4 FLIGHT CREW DEBRIEFING TRANSCRIPT PART II Prepared By Spacecraft Operations Branch Flight Crew Support Division This material contains information affecting the national defense of the United States within the meaning of the Espionage Laws, Title 18. U. S. c. Section 793 and 794, the transmission or revela­ tion of which in any manner to an unauthorized person is prohibited by law. I Group 4: Downgrade at 3 year intervals Declassified after 12 years NOTICE: This document may be exempt from public disclosure under the Freedom of Infor­ lease to persons outside the U.S. Government should be handled under the provisions of

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This preliminary transcript was made from voice tape -recording3 of the GT-4 flight crew debriefing conducted aboard the recovery ship, the USS Wasp, on June~' 1965, and concluded at the Manned Spacecraft Center on June 12, 1965. Although all the material contained in this transcript has been edited, the urgent need for the preliminary transcript by mission analysis personnel precluded a thorough editorial review prior to its publication. Errors in this transcript will be corrected as soon as possible and an official transcript will be published at a later date. Thia document contains a transcript of the second part of the total debriefing. A preliminary transcript of the first part was published on June 16, 1965, and it contains the crew' s description of the mission from an operational standpoint.

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TABLE OF CONTENTS Paragraph Page number 8.0 SYSTEMS OPERATION 8.4 Environmental Control System •••·················••••···22 9.0 OPERATIONAL CHEDKS 9.2 Apollo Yaw Orientation •••·•··•·•••·•··••·•••···•·•·•••168 9.3 One Attitude Thruster Failure Check ...................171 9.8 Relative Humidity Test ................................185 9.9 Zodiacal Light Check ..................................186 10.0 VISUAL SIGHTINGS 11.2 Synoptic Terrain and Weather Photography (S-5 and S-6).219 11.3 Simple Navigation with the Sextant ....................219 11.5 Proton-Electron Spectrometer and Tri-Axis Flus-Ga.te

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8.0 SYSTEMS OPERATION McDivitt Actually, the first portion of any alinement is to cage the thing. The case of caging the thing is much more important than the alinement itself. In the daytime I felt that I could cage the plat­ form to a reference with an error plus or minus about 3 or 4 degrees in all axes. Did you think we could do that wel l? White Only in the daytime. McDivitt The yaw was a little problem. It took longer to get it, but if you kept after it for awhile, I felt that you could get down to just a few White Within a couple of degrees. McDivitt The big thing is that you have to stop your yaw rates, and then sit there and look outside for awhile and see which way you're going, straight ahead or sideways. If you are going sideways you rotate around for awhile and stop the rate and then look out again. Ri ght? I felt you could get the thing caged quite well. We. didn't do it BEF at all, did we? We never did cage in BEF.

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McDivitt The caging of the thing with small-end-forward in the daytime was relatively easy. At night I don't think it would be quite that simple. I think what you would have to do at night time is to point the spacecraft down at the ground pretty much so you can see the track across the ground, I could see which way the land was moving under me . I felt--although I never did this--that if I could do that and then roll around to where I had no bank angle, and face in my yaw direction, either small-end or blunt-end-forward, stop the roll there and pitch up to the horizon I could cage there within plus or minus 10 degrees for sure. It was much less accurate at night, I felt, than in the White You aren' t kidding! We both felt that on those dark nights when you really couldn 't see anything on the ground, pure star reference for yaw was pretty rough. McDivitt Pure star reference for yaw was almost impossible to use. That was the only place where that thing we decided not to take with us--the view of the stars through the window--might have been of some

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use to us. We knew the stars along our track but you couldn't see enough of them. The quickest way to get the yaw reference was to look down at the ground. Once we got the platform caged, aline­ ment was quite simple. All you had to do was just hold the needles at zero and the platform alined itself. Of course you had to have the scanners on, The modes--the SEF and the EEF were identically the same except the spacecraft is pointing in different directions . You tended to null the needles by using pulses and just hold the needles very close to null and the platform alined itself through the horizon scanners. Orbit Rate was a satisfactory mode, I thought. As a matter of fact, it was very good. White I liked that Orbit Rate, McDivitt Yes, because we finally had a reference where we didn't have to look out and see the ground. It's like having the old altitude indicator back in an airplane. The only thing was, we had the wrong orbit rate in the spacecraft because it was set for an orbit rate that was to take care of, I think, a 60 nautical mile circular orbit. This was to take care of the short period of time between

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going to Orbit Rate at T-5 and firing the retros at TR. We wanted to have exactly the right rate in there so when we did our closed-loop reentry we wouldn' t have an error. As I said, I had the most accurate platform in the world with nothing to do with it. I think the displays were adequate and the controls were adequate. After the first couple of revs I really didn' t have any confidence at all in the platform. I had done nothing to