Three self-captured display frames illustrate specific claims in the draft study. They reproduce Spacewar! 3.1, 24 September 1962, for the DEC PDP-1, made at MIT and distributed through program exchange rather than a retail publisher. They are not original Code198x game artwork and are not offered under the licence for our prose or original diagrams. Underlying works remain with their respective rights holders. They appear for criticism and explanation under the existing family capture policy; no game binary, recording or audio is distributed.
Spacewar! was conceived in 1961 by Martin Graetz, Stephen Russell and Wayne Wiitanen. It was first realised on the PDP-1 in 1962 by Stephen Russell, Peter Samson, Dan Edwards and Martin Graetz, together with Alan Kotok, Steve Piner and Robert A. Saunders. This credit follows the original-program attribution supplied by the preservation hosts; it does not assert that every contributor wrote every part of edition 3.1.
Capture implementation: Norbert Landsteiner’s Spacewar! PDP-1 emulation engine, version 3.0.2 NG (2012–2022), based on the earlier emulation by Barry Silverman, Brian Silverman and Vadim Gerasimov. Implementation and credits; original preservation-host credit. The GUI retains its own rights. Only the 512 × 512 game-display canvas is captured: no page photographs, borrowed screenshots or interface decoration are reproduced.
Capture conditions: 18 October 2026; Chromium; reference module spacewar3.1; all six sense switches off; testword zero; normal emulation speed. Frames are PNG, unaltered and captured directly from the displayed canvas. The phosphor appearance and colour come from this emulator. They are not photographic evidence of an original Type 30 display. Full configuration, response hashes, state events and PNG hashes are in capture-report.json.
| Frame | Claim it illustrates |
|---|---|
| opening.png | Two distinct ship outlines, starting positions, central gravitational star and background stars. |
| exchange.png | Turned ships, visible torpedoes and the emulator’s fading display marks during an exchange. A still does not prove projectile physics. |
| destruction.png | Both ships change from intact outlines to bursts of points. State inspection establishes destruction, inactive state and a later restart with restored supplies; the still alone cannot show the restart. |
The encounter was driven by a scripted two-sided aiming policy through ordinary keyboard controls, with read-only memory inspection. It is not a two-human-player playtest or a claim that the original game had computer-controlled pilots. The observed automatic continuation belongs to this browser implementation; the original program executes HLT with scores in processor registers for the console lights. The policy repeatedly aims at the opponent’s current position and holds fire; it does not demonstrate optimal play. Input intervals are approximate wall-clock intervals, not measured PDP-1 frame times. Reproduction can vary with scheduling.
The module’s embedded 8,681-byte tape was compared byte for byte with the matching member of the Steve Russell archive. tape-identity.json records the archive container/member names and hashes. The archive now packages the tapes in ZIP files; the formerly published unpacked-file URLs return 404. The comparison pins that archived program, not every behaviour of this emulator or an original machine.
To reproduce the three capture roles using an existing website checkout and its already-installed Playwright/Chromium:
node studies/spacewar/capture-encounter.mjs --website ../website --output-dir /tmp/spacewar-capturesThe script fails if the implementation responses change, the selected edition/settings differ, the three capture roles are not collected, a browser error occurs, or it cannot observe destruction followed by inactivity and a restart. It closes the browser on success and failure. Review every resulting frame before replacing the curated PNGs; an execution success does not establish image quality or historical hardware fidelity.
This study has not yet been fact-checked. Sources and capture conditions are included so you can follow the evidence.
Game captures: Spacewar!, MIT contributors, 1962, PDP-1; captured in Norbert Landsteiner's emulator. Full credits and capture conditions. Original illustration is separate from the historical game imagery.