About Spacewar! Fleet Action

In the extended version of Stewart Brand's famous article "Fanatic Life and Symbolic Death Among the Computer Bums," in the book "II Cybernetic Frontiers," we find the following quote:

Steve Russell still dreams: "Something I wanted to do is get some interesting sort of fleet action. There are some versions of Spacewar which allow multiple ships, but as far as I know no one has been sufficiently clever to set things up so there are ships with noticeably different characteristics that could fight in interesting combinations."

(Brand, Stewart, II Cybernetic Frontiers; Random House, NY, NY and Bookworks, Berkley, CA; 1974. p. 59)

Now, we're still not sufficiently clever to set up a Doc E. E. Smith-like story-closing fleet confrontation comprising heavy armored battle ships and agile space corvettes. In stead, we're setting up an experiment in fleet control in a way that might have been doable in the early 1960s.

The game is based on the original 1962 Spacewar! game for the DEC PDP-1, but features multiple ships that may be controlled synchronously just like the single ships in the original game. To add some variety, there is an additional control for adjusting the angular trim of the individual ships of a fleet, so that a fleet may be focused on a certain point or may spread apart, when thrusting the rockets of the ships. (Gamepads are suported in some browsers, use shoulder-buttons for angular fleet trim.)

As in the original game, there's gravity (and an additional option for torpedo gravity not found in the PDP-1 version). It is stricktly recommended to not fight gravity, but use it as an aid in fighting the opposing fleet, in stead. A well known pattern for this is the so called "CBS Opening Maneuver", where the ships are turned perpendicularly to the gravitational star in the center and orbits are optained by giving thrust for a few seconds. (In this game, due to the initial setup of the ships, the exact angle and turn will matter for the maneuvers to be performed by the fleets.)

Spacewar! CBS Opening Maneuver

The "CBS Opening Maneuver" in Spacewar!.
(You probably see why it's called so. Think CBS-logo.)

In order to win a game and gain a score, at least one ship of your fleet has to be amongst the final survivers. (Scores are displayed after each game, if the related option switch is activated.)


The original Spacewar! was conceived in 1961 by Martin Graetz, Stephen Russell, and Wayne Wiitanen. It was first realized 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. – Spacewar! is in the public domain, but this credit paragraph must accompany all distributed versions of the program.

"Spacewar! Fleet Action" by Norbert Landsteiner, 2016.

Technical Realism

Could this have run on the original hardware? No.
It's not that there's anything in the game that would have been beyond the capabilities of the original machine or its programmers, but calculating gravity for up to ten ships and putting them onto the display would have resulted in a very flickery display experience. The sine-cosine computations for gravity are quite expensive, per se, but the real performance killer would have been the rendering part. Mind that each display instruction to put a single dot onto the Type 30 CRT display required a hefty 50 microseconds to complete. But soon there were similar but faster displays and also faster 18-bit machines, like the DEC PDP-7 (1965) or the PDP-9 (1966), the very machines on which originated C and UNIX. So, yes, it could have been done on 1960s hardware, but not on a DEC PDP-1.