The snarky memos of Apollo’s unsung genius
“Well, I just got back from MIT with my weekly quota of new ulcers, which I thought might interest you.”
Bill Tindall, June 13 1966

In 1966, as the American space program was working furiously towards a moon landing, Howard W. “Bill” Tindall, Jr., an expert on orbital mechanics, was sent by NASA to MIT to oversee the development of software for the spacecraft guidance systems. Tindall found a lot of brilliant people at MIT working in development program that was behind schedule, was failing to meet its requirements, and threatened to become, in his words, “the most pacing item for the Apollo flights.” He dove into the task of refashioning every aspect of the software development process, writing a series of frank memos that entered NASA lore under the name “Tindallgrams” that continued as he moved on to lead the planning of all “mission techniques” for Apollo.

Flight Director Gene Kranz said of Tindall “if there should have been a lunar plaque left on the Moon from somebody in Mission Control or Flight Control - it should have been for Bill Tindall. Tindall was the guy who put all the pieces together, and all we did is execute them.”


Tindallgrams (known) converted to text: 12.93% (60 of 464). How you can contribute.

Selected Tindallgrams

Also see indices by year, source, and topic.

May 12 1966 66-FM1-59 Spacecraft computer program requirements for AS-207/208, AS-503, and AS-504
May 16 1966 66-FM1-60 Comments on the AS-207/208 Preliminary Spacecraft Reference Trajectory
May 27 1966 66-FM1-64 CSM orbit determination using the LEM radar
May 31 1966 66-FM1-68 Apollo spacecraft computer program development newsletter
Jun 2 1966 66-FM1-70 Spacecraft computer program status report
Jun 13 1966 66-FM1-75 Apollo spacecraft computer programs--or, a bucket of worms
Jul 1 1966 66-FM1-78 Another Apollo spacecraft computer program status report
Jul 8 1966 66-FM1-86 No special program available for targeting the CSM plane change in lunar orbit
Jul 8 1966 66-FM1-85 Determination of relative CSM orbit.
Jul 11 1966 66-FM1-84 Capability to do orbit navigation in earth orbit will not be implemented for AS-207 or AS-504.
Jul 11 1966 66-FM1-83 Apollo rendezvous guidance computer program options report
Jul 11 1966 66-FM1-89 LEM radar angle bias correction
Jul 18 1966 66-FM1-94 Rendezvous terminal phase guidance program in the Apollo spacecraft computer
Jul 21 1966 66-FM1-95 AS-204 computer program status
Aug 30 1966 66-FM1-100 Notes regarding the AS-207/208 Guidance Systems Operation Plan (GSOP) meeting with MIT
Aug 30 1966 66-FM1-103 Automatic rendezvous braking maneuver
Sep 2 1966 66-FM1-104 Status of the lunar module "quick return" guidance capability
Sep 19 1966 66-FM1-107 Alternate rendezvous technique - mission planning status
Sep 21 1966 66-FM1-110 LGC computer requirements to provide DPS backup of SPS
Sep 21 1966 66-FM1-111 Rendezvous search modes of various types
Sep 21 1966 66-FM1-112 Apollo rendezvous navigation data edit is too complicated
Sep 21 1966 66-FM1-109 Mission rules needed for use with AGC self-check
Sep 21 1966 66-FM1-113 There are differences in the descent guidance programs on AS-503 and AS-504
Sep 22 1966 66-FM1-114 Apollo spacecraft guidance navigation modes currently planned for AS-503 and AS-504
Sep 27 1966 66-FM1-115 LGC program development for the AS-278B
Oct 4 1966 66-FM1-118 No extra memory for the Apollo Spacecraft Computer
Oct 10 1966 66-FM1-131 More on Program Development
Oct 11 1966 66-FM1-124 Program Development Plans are coming!!
Oct 11 1966 66-FM1-123 Procedure for obtaining Apollo Spacecraft Computer Program schedule information
Oct 12 1966 66-FM1-130 Altitude and velocity limits imposed by the spacecraft computer program on the AS-503 mission
Oct 12 1966 66-FM1-129 Cursory definition of Spacecraft Computer Program capabilities currently planned for AS-503 and AS-504
Jan 9 1967 67-FM1-1 Uplink will be on LM-4
May 17 1967 67-FM1-39 A new spacecraft computer program development working philosophy is taking shape
May 23 1967 67-FM-T-41 Spacecraft computer program names
Jul 27 1967 67-FM-T-45 Spacecraft computer program flow chart status
Oct 18 1967 67-FM-T-85 Spacecraft computer program development improvements to be utilized by MIT
Dec 26 1967 67-PA-T-127A LM rendezvous radar during Ascent is about to go over the brink.
Dec 26 1967 67-PA-T-126A Third Trajectory Control Data Priority Meeting for Spacecraft 101
Dec 26 1967 67-PA-T-129A Rendezvous meeting reminder
Dec 26 1967 67-PA-T-128A Lunar lift off shall be planned at discrete times only.
Jan 11 1968 68-PA-T-2A First 2 hours on the moon is a countdown to launch - simulated or real thing.
Mar 7 1968 68-PA-T-54A Sixth "C" Mission Rendezvous Mission Techniques Meeting
May 10 1968 68-PA-T-99A "C" rendezvous open item clean up
Jun 25 1968 68-PA-T-138A "C" Rendezvous W-Matrix
Jul 9 1968 68-PA-T-153A Good news on "C" mission SPS burns
Jul 23 1968 68-PA-T-162A "C" Mission Retrofire and Reentry Mission Techniques Meeting
Jul 24 1968 68-PA-T-167A July 19 "C" Rendezvous Mission Techniques Meeting
Jun 13 1969 69-PA-T-93A Some significant LUMINARY program changes you should know about
Aug 1 1969 69-PA-T-114A How to land next to a Surveyor - a short novel for do-it-yourselfers
Jan 05 1970 70-PA-T-2A A small change in CSM DOI confirmation procedures
Jan 07 1970 70-PA-T-1A Important LM computer program change for Apollo 13 descent
Jan 13 1970 70-FM-T-5 AAP CSM Computer Program Requirements meeting
Jan 13 1970 70-FM-T-4 AAP Rendezvous Mission Techniques
Jan 15 1970 70-FM-T-6 Cabbages and Kings
Jan 19 1970 70-FM-T-7 MSFC/MSC OWS Computer Program Meeting
Jan 20 1970 70-PA-T-8A The Apollo rendezvous can be shortened by 2 hours
Feb 09 1970 70-PA-T-11A Mission H-2 and Subsequent Lunar Orbit Activities
Feb 10 1970 70-FA-T-12 Status report on the "P66" fix
Feb 12 1970 70-FA-T-13 Software for the AAP CSM spacecraft computer
Feb 19 1970 70-FA-T-16 \"For whom does the bell toll?\" ... \"Delta Guidance\" ... \"Oh!\"