Apollo 11 EVA planned vs. actual timeline
How the first moonwalk as flown compared with its pre-flight script. The Lunar Surface Operations Plan (§3.4 nominal timeline sheets) scheduled a 2 h 40 min EVA (cabin depress to repress) at 112:30–115:18 GET, after a first rest period; the Mission Report sets the record straight in Table 11-I, “Comparative times for planned lunar surface events” (p. 11-27), reproduced below. The headline: the crew flew the scripted task sequence almost intact, but nearly every task in the first two hours ran over, the overrun was repaid by cutting the lowest-priority task (the documented sample), and the whole EVA happened ~3½ hours earlier than the timeline page because the crew swapped the EVA ahead of the rest period.
The schedule brackets (GET)
Section titled “The schedule brackets (GET)”| Event | Time | Source |
|---|---|---|
| Decision to go before the rest period | 104:40:00 | Mission Report §4.12.2 |
| EVA preparation begins | 106:11:00 | Mission Report §4.12.2 (simulations had allotted ~2 h; prep took ~3 h) |
| Planned cabin-depress slot | 112:30 | LSOP §3.4 timeline sheets |
| ”GO for cabin depressurization” | 108:22:06 | transcript |
| ”The hatch is coming open” | 109:07:33 | transcript |
| Armstrong on the porch | 109:19:16 | transcript |
| First step | 109:24:48 | transcript |
| Hatch closed and latched | 111:39:13 | transcript |
The prep overran for three reasons (Mission Report §4.12.2; debriefing §10): a real cockpit cluttered with non-EVA items, each demanding a real-time stowage decision; the RCU-to-PLSS 50-pin connector at ≥10 minutes per unit (a known pre-flight problem); and a ~30-minute depressurization through the bacteria filter that had never been fully rehearsed — cabin pressure never indicated below 0.1 psi and the hatch bent as it was opened against the residual pressure. The loop carries that tail live: “about 0.1 on our gage” at 109:06:22 and “the hatch is coming open” at 109:07:33 (the full prep hour is traced layer-by-layer in One hour, four layers).
Table 11-I — planned vs. actual times (min:sec)
Section titled “Table 11-I — planned vs. actual times (min:sec)”| Event | Planned | Actual | Δ | Table’s remarks |
|---|---|---|---|---|
| Final preparation for egress | 10:00 | 20:45 | +10:45 | ~8 min 30 s from 0.2-psia cabin reading to hatch opening |
| Commander egress to surface | 10:00 | 8:00 | −2:00 | |
| Commander environmental familiarization | 5:00 | 2:05 | −2:55* | |
| Contingency sample collection | 4:30 | 3:36 | −0:55 | Performed out of sequence with planned timeline |
| Preliminary spacecraft checks | 6:30 | 6:35 | +0:05 | Out of sequence |
| LMP egress to surface | 7:00 | 7:00 | 0:00 | ~2 min 10 s for PLSS checks |
| Commander photography and observation | — | 2:40 | +2:40 | (no discrete planned slot) |
| TV camera deployment (partial) | 4:00 | 4:50 | +0:50 | Deployment interrupted for activity with plaque |
| LMP environmental familiarization | 6:00 | 15:00 | +9:00 | Includes assisting Commander with plaque and TV camera deployment |
| TV camera deployment (complete) | 7:00 | 11:50 | +4:50 | Includes photography of SWC and comments on surface characteristics |
| Solar wind composition deployment | 4:00 | 6:20 | +2:20 | |
| Bulk sample + EMU evaluation (complete) | 14:30 | 18:45 | +4:15 | |
| LM inspection by LMP | 14:00 | 18:15 | +4:15 | |
| LM inspection by Commander | 15:30 | 17:10 | +1:40 | Includes closeup (ALSCC) photographs |
| Off-load experiment package | 7:00 | 5:20 | −1:40 | From SEQ-bay door open to door closed |
| Deploy experiment package | 9:00 | 13:00 | +4:00 | Site selection to end of photography; trouble leveling the equipment |
| Documented sample collection | 34:00 | 17:50 | −16:10 | Partially completed |
| LMP ingress | 4:00 | 4:00 | 0:00 | |
| Transfer sample return containers | 14:00 | 9:00 | −5:00 | |
| Commander ingress | 9:30 | 6:14 | −3:16 | Includes cabin repressurization |
* The scan prints −2:00; −2:55 is the arithmetic of the planned/actual cells. Values transcribed from a rough scan, cross-checked planned + Δ = actual where legible.
Reading the table
Section titled “Reading the table”- The science spine ran in scripted priority order — contingency sample → bulk sample → experiments → documented sample — but the ceremonial acts (plaque, flag, the President’s call), which appear nowhere in the LSOP nominal timeline, were wedged into the middle; the table books them as interruptions to the TV deployment and a +9:00 overrun on Aldrin’s familiarization slot.
- Big overruns: final egress prep (+10:45, the slow depress), the ceremonial wedge (+9:00), and the EASEP deployment (+4:00 — no horizon reference, weak 1/6-g balance cues, and a PSE bubble level that wouldn’t settle). The bulk-sample scooping itself ran “about double the planned time” (§4.12), with ~20 sunlit trips because the MESA table sat in shadow.
- The recovery: the documented sample was cut from 34 to ~18 minutes (“insufficient time remained… as wide a variety of rocks was selected as remaining time permitted”), and every closeout task beat its estimate. Porch-to-hatch-close took ~2 h 20 min; the Mission Report books the surface exploration as completed within the allotted ~2½ hours.
- The plan’s own design absorbed the slips: the LSOP’s priority-ordered tasks and conservative pacing were written so that “should the EVA be terminated at any point… the maximum data return for the time spent on the surface will be assured.” That is exactly how it played out.
The full narrative analysis is in Plan vs. actual: where Apollo 11 diverged from the script.
Related
Section titled “Related”- Apollo 11 nominal mission timeline
- Apollo 11 EVA (first moonwalk)
- Ceremonial and symbolic surface activities
- Early Apollo Scientific Experiments Package (EASEP)
- Passive Seismic Experiment (S‑031)
- Lunar sample collection and containers
- Apollo 11 EVA life-support and mobility equipment
- Powered descent and landing
Sources
Section titled “Sources”- Apollo 11 Mission Report (MSC-00171) — Table 11-I (p. 11-27), §4.12
- Apollo 11 Lunar Surface Operations Plan — §3.1 rationale, §3.4 nominal timeline
- Apollo 11 Flight Plan (Final, AS-506) — the GET-tagged “as-planned” timeline independently corroborating the 112:30–115:18 EVA bracket
- Apollo 11 Technical Crew Debriefing — Volume 1 — §10
- Apollo 11 Technical Air-to-Ground Voice Transcription — GET anchors