See list belowFEB 20 1969FA/Director of Flight OperationsSpacecraft guidance for TLI
(2-18-69) After yesterday's meeting/on the F mission, I have had some second thoughts and prompting by others about using the spacecraft guidance and platform for S-IVB TLI. The following summarizes my position and is to be used as policy in FOD.
The primary (and originally my only) reason for using the space- craft guidance as a backup to the launch vehicle platform is to assure crew safety during first stage flight where a platform failure could cause a nasty abort situation at or near max q. Fol- lowing this decision, it was fairly reasonable and relatively easy to provide the crew with the capability of guiding the launch vehicle into orbit, and I therefore subscribed to this position. The switchover to spacecraft guidance was to be utilized when and only when the platform fail lights were given to the crew and for no other reasons. My concern here was that we would get ourselves back in the same box as Gemini where an inordinate amount of work was required to provide switchover criteria throughout the powered flight phase. The probabilities associated with Apollo 10 platform failures just plainly don't warrant that kind of effort when faced with the work load we have in the Apollo program.
After listening to yesterday's discussion on the work we're about to set out on in order to be able to perform TLI with the spacecraft guidance, it began to be painfully obvious to me that we were putting ourselves back in the same box mentioned above. Further, as Sig Sjoberg pointed out to me, Sam Phillips gave very specific in- structions to both MSFC and MSC that we were to limit our studies to backup guidance during the launch phase and, in fact, gave explicit instructions not to consider any other backup modes other than the polynomial in the first stage and manual guidance during the second and third stage for orbital insertion.
Based on the above, it is my direction that we cease work on any switchover or backup guidance schemes that would be used beyond normal orbital insertion. I realize that this will make some people in FCOD unhappy, but I don't feel that the work necessary to accom- plish TLI guidance with the spacecraft is worth the effort at this time.