A worked Events and Causal Factors (ECF) teaching chart of the 28 January 1986 Challenger mishap, based on the Rogers Commission report. The history is real; the selection, CF numbering, link explanations and verification questions are this example’s educational analysis, not an official NASA ECF chart or a new investigation.
Start here
Read MISHAP and its stack for the outcome, evidence limits and analytical summary.
Zoom to 28 January 1986, 11:38–11:40 EST for the flight sequence. Zoom further to distinguish the final millisecond-spaced observations. The stored origin is 11:38:00.010 EST, taken from the report’s T0 ignition-command entry.
Pan back to 27 January, 20:45–23:45 EST to inspect the launch decision. Open the three CF condition markers and use Related to to follow their connections.
Open T+2.733 and compare its two dashed hypothesis cards with the dashed UNRESOLVED duration band before first flame. They remain alternatives; do not combine them into a confirmed account. The shared band marks an evidence gap, not a measured lifetime of either mechanism.
Open the proposed corrective-action entries and identify what evidence would be required to verify effectiveness. The example does not claim those actions were completed.
The causal factor analysis suite in use
Feature
Meaning here
Process rectangles
Selected primary events; chronology is not automatically causation.
Ellipses
Conditions, including the red CF-1, CF-2 and CF-3 contributing-factor annotations.
Red diamond
The mishap reference within the rapid breakup sequence.
Document symbols / blue
Records, measurements and supporting evidence.
Purple document entries
Recommended controls and verification questions; not completed actions.
Stacks
Evidence, condition summaries and analysis attached to a parent. They inherit its time; these retrospective notes are not newly timed historical events.
Dashed stack entries and duration outline
Two alternative mechanism hypotheses and their shared uncertain interval; neither is promoted to a finding.
Arrowed arcs
Event-to-event reading sequence or factor-to-effect progression. Open the originating entity’s notes for the explicitly named connection type and rationale.
Arcs without arrowheads
Supporting evidence or context, not causal assertions.
All five suite plugins are enabled from the live official Causal factor analysis v2 manifest: Moment stacks, Moment shapes v3 (ellipses), Moment colors, Presumptive outline and Relationship arrows. Sources, date context, rich notes and hover helpers support inspection. The software displays the analysis; it does not determine causes.
Boundaries and evidence discipline
The direct physical failure, underlying design vulnerability, environmental condition and organizational contributing cause are kept distinct. CF-1 is the joint/seal vulnerability; CF-2 is cold-dependent seal response; CF-3 is the failure to carry critical technical information through the launch decision. The report supports these relationships; this chart’s grouping is interpretive. No single numerical causal weight or exhaustive set of root causes is claimed.
Times are displayed in EST (UTC−05:00). Flight-table milliseconds are stored as exact rational seconds. Day-dated memoranda use midnight solely as an anchor; approximate testimony times, inferred mechanisms and editorial band boundaries say so in Dating context. The MISHAP marker uses a documented cloud observation within breakup, not an exact time of crew death. Solid outlines mean the reported observation or finding is supported, not that all timing is exact.
Arrows are display metadata on ordinary relationships. The platform’s relationships remain undirected and unlabeled; their connection type, reasoning and supporting sources are written in the linked entities’ notes and analysisLinks metadata. No causal inference is generated by the plugin. The proposed controls map to the Commission’s recommendations; their completion and effectiveness are outside this example’s scope.
Every event, condition band and stack entry also carries its own references. No invented interviews, records or historical facts are presented as evidence.
Camera evidence: NASA, first visible flame at T+58.788 s; public domain (PD-USGov-NASA). Wikimedia Commons file and license. This image is attached to the first-flame evidence stack so the main event and condition symbols remain readable.
26 moments · 1985-07-31T00:00:00-05:00 CE – 1986-01-28T11:39:50.01-05:00 CE · by @athan · @athan
T+0.000 · Solid motors commanded to ignite
primary event
The flight-event table places the solid-motor ignition command at 16:38:00.010 GMT (UTC), establishing this chart’s elapsed-time origin. All flight timestamps below are calculated as exact rational seconds relative to that origin. The three launch-time markers at this coordinate include condition snapshots, not three separately timed physical actions. **Sources:** [Flight](https://www.nasa.gov/history/rogersrep/v1ch3.htm). **Next in the selected sequence: T+0.250 · First continuous upward motion.** Chronological reading order only. This connection does not by itself assert that the earlier event caused the later one.
Date precision
Commission flight-event table (Vol. I, pp. 37–39); source precision is milliseconds. T0 = 16:38:00.010 UTC / 11:38:00.010 EST. Exact storage does not imply zero measurement uncertainty.
timescale.info