Say Again Apollo 14 · Gallery of lunar exploration
← Stop 3 · The keypad

The keypad - Historical Evidence

The keypad - Historical Evidence

The following claims appear in stop 3, in Marion and Theo's lines or in the archive clips, and are assessed against primary and secondary sources. Numbered citations refer to the Sources list at the end of this page. Times are ground elapsed time (GET), counted from lift-off on 31 January 1971.

Marion and Theo are invented, and so is the gallery. Marion's copy of the list, and the slip she says she let through, are part of the invented story and are not assessed here: only what they say about Apollo 14, and the archive recordings they listen to.

From the dialogue

Claim: The keypad's keys include VERB, NOUN and ENTER, the words heard on the radio.

Status: Confirmed

Line: "Verb. Noun. Enter." / "Every word you've been hearing."

The display and keyboard (DSKY) of the Apollo guidance computer had "19 keys including VERB, NOUN, CLEAR, KEY RELEASE, PROCEED, RESET, ENTER, PLUS, MINUS, and the digits 0-9". To give an instruction, an astronaut would "press the VERB key followed by the digits 3 and 7, and then the ENTER key" [4, pp. 53-54]. The read-ups in this story are sequences of those keys: "VERB 21 NOUN 01 ENTER; 10 10 ENTER; 107 ENTER" [2, p. 362].

Claim: The fix was keyed in on that keypad.

Status: Confirmed

Line: "This is where it went."

The procedure was "relayed to the crew for manual entry into the lunar module computer" [1, p. 8-11]. The mission commentary described it at the time as "considerable amount of stroking of the keyset of the DSKY to enter numbers into the LM guidance computer" [3, 304/3]. Mitchell did the keying. Shepard offered, "Rather have me put it in?", and Mitchell answered, "No, I've got it" [2, p. 372]. Later he called out the remaining entries as he made them: "All right. I'm DISABLING. VERB 25 NOUN 7 ENTER, 105 ENTER" [2, p. 375].

Claim: Part one went in four minutes before the engine lit.

Status: Confirmed

The Mission Report's sequence of events has "Start loading abort bit work-around routine" at 107:58:13.80, 4 minutes 12.72 seconds before ignition at 108:02:26.52 [1, p. 8-10]. Part one went in "just after the final attitude maneuver for powered descent" [1, p. 8-11], and Mitchell reported "Okay, Houston. It's in" at 107:58:26 [2, p. 373].

Claim: Shepard called part one out as it went in.

Status: Confirmed

Line: "Shepard called it out as it went in."

Shepard spoke the entry at 107:58:11: "NOUN 62s VERB 21, NOUN 01 ENTER, 10 10, ENTER; 107, ENTER" [2, p. 373], while Mitchell keyed it [2, p. 372]. He speaks the ENTER presses as well as the numbers, and three minutes earlier he had told Mitchell "Got a VERB 21 NOUN 01, 10 10 and a 107 is your first call" [6]. Mitchell's "Okay, Houston. It's in" follows at 107:58:26 [2, p. 373].

Claim: It was the same line as the one on the page.

Status: Confirmed

Line: "Same line as the page."

Shepard's "VERB 21, NOUN 01 ENTER, 10 10, ENTER; 107, ENTER" [2, p. 373] is the line handwritten in the margin of the LM Timeline Book page in stop 2: "V21 N1E / 1010E / 107E" [5].

Claim: Haise caught Mitchell's "one-oh-one".

Status: Confirmed

Line: "When he said one-oh-one ... Haise caught it."

At 107:34:22 Mitchell read back "101 ENTER". Sixteen seconds later Haise came back with "Correction on your readback. It's VERB 21 NOUN 01 ENTER; 10 10 ENTER; 107 ENTER" [2, p. 362]. (Marion's copy and her tick are invented.)

Claim: The rest of the fix went in with the engine already firing.

Status: Confirmed

"The remainder was accomplished after the increase to the full-throttle position" [1, p. 8-11]. The engine lit at 108:02:26.52 and was throttled up by hand at 108:02:53.80 [1, p. 8-10]. Mitchell keyed the remaining entries from 108:02:58 and reported "Okay, Houston. The procedure is complete" at 108:03:57 [2, pp. 375-376].

Claim: Nobody on the radio mentioned the switch again.

Status: Confirmed, until after the landing

Line: "Nobody on the radio mentioned it again."

The last exchange about the bit was at 107:47. Shepard asked whether to check it before the first entry; Haise said "It - it doesn't matter, Al", and Shepard asked Houston to "let us know" if it showed [2, pp. 367-368]. After that the transcript has only a routine checklist call to "check out ABORT and ABORT STAGE, RESET" (107:49:42) [2, p. 369] and the keying of the fix itself. Houston made no call about the bit, the switch or tapping during the descent [2, pp. 375-382]. The next mention is Mitchell's thanks six minutes after landing: "Say, Fred, that was really great work you did on that abort - problem" (108:21:21) [2, p. 385]. Whether the bit stayed clear on telemetry is not recorded: the transcript is voice only.

Claim: The landing radar had a fault of its own: it was set to the wrong scale, which had nothing to do with the switch.

Status: Confirmed by the Mission Report; disputed in Mitchell's later recollection

"Prior to powered descent maneuver ignition, the landing radar scale factor switched to low, which prevented acquisition of data through the first 400 seconds of descent" [1, p. 8-11]. It switched at 107:57:34.66, 39 seconds before the crew started loading the fix at 107:58:13.80 [1, p. 8-10]. The report puts the cause in the radar. It was being operated beyond its "maximum range measurement design limit", where "the system will be sensitive to any received noise", and a test with "low-level noise for a fraction of a second" reproduced the switch. A wiring change was made for later spacecraft [1, pp. 14-35 to 14-37]. Grumman's evaluation, as reported by Fjeld, "claimed that the entire procedure did not affect the radar in any way" [7].

Mitchell remembered it differently twenty years later: "it turns out we created one: the landing radar" [6]. The fix did touch the radar in one designed way: part one "affected the processing of the landing radar data", which is why part four put the computer's mode register back to P63 [1, p. 8-11]. That is not the scale fault.

Claim: Cycling a circuit breaker fixed it.

Status: Confirmed

Haise, 108:08:42: "Antares, Houston. We'd like you to cycle the LANDING RADAR breaker." Shepard: "Okay. It's cycled" [2, p. 378]. The sequence of events has "Landing radar to high scale (circuit breaker cycle)" at 108:08:50.66, with velocity and range data good about 20 seconds later [1, p. 8-10]. "The crew cycled the radar circuit breaker, which reset scaling to the high scale" [1, p. 8-11].

Claim: They landed.

Status: Confirmed

"Landing in the Fra Mauro highlands occurred at 108:15:09.3" [1, p. 1-1], about 3:18 am in Houston (stop 1).

From the archive clips

Claim: Shepard, 107:58:11: "VERB 21, NOUN 01 ENTER, 10 10, ENTER; 107, ENTER." Mitchell, 107:58:26: "Okay, Houston. It's in." Haise, 107:58:34: "Roger, Antares." Shepard, 107:58:37: "And - Antares is standing by for a PDI GO." Haise, 107:58:51: "And, Antares; Houston. You're GO for Fra Mauro."

Status: Confirmed

All five lines are word for word in the NASA voice transcript [2, p. 373] and in the Lunar Surface Journal [6]. The clip starts partway into Shepard's line, which begins "NOUN 62s" ("NOUN 62 is" in the Journal), meaning the display that cued the entry. PDI is powered descent initiation: "GO for Fra Mauro" cleared Antares to start the descent to the landing site.

Claim: Mitchell, 108:15:18: "We're on the surface." Shepard, 108:15:19: "Okay, we made a good landing." Haise, 108:15:23: "Roger, Antares."

Status: Confirmed

The words and speakers are as above in the NASA voice transcript (LMP for "We're on the surface", CDR for "Okay, we made a good landing") [2, p. 382] and in the Lunar Surface Journal [6].

Claim: Fred Haise was the CapCom in these clips.

Status: Confirmed

The mission commentary named Haise as CapCom for the shift that ran through the landing [3, 287/3 and 316/2]. Mitchell's thanks after landing are addressed to "Fred" [2, p. 385], and the Lunar Surface Journal gives these lines to Haise [6].

Sources

  1. Apollo 14 Mission Report, MSC-04112, NASA Manned Spacecraft Center (May 1971). Text also at the Apollo Lunar Surface Journal.
  2. Apollo 14 Technical Air-to-Ground Voice Transcription, NASA Manned Spacecraft Center (1971). Pages are the transcript's printed page numbers.
  3. Apollo 14 Mission Commentary, NASA Public Affairs Office transcript (1971). Cited by tape and page.
  4. James E. Tomayko, Computers in Spaceflight: The NASA Experience, NASA CR-182505 (1988), chapter 2
  5. LM Timeline Book, page 5, annotated scan, Apollo Lunar Surface Journal
  6. Eric M. Jones (ed.), "Landing at Fra Mauro", Apollo Lunar Surface Journal, with audio by Thomas Schwagmeier
  7. Paul Fjeld, "Masking the Abort Discrete", Apollo Lunar Surface Journal (2009)