Frequently Asked Questions

Spacewar! is a 1962 space combat video game developed at MIT for the PDP-1 minicomputer by Steve Russell and other students. It is widely considered the first widely distributed and influential video game. Two players control spaceships (the Needle and the Wedge) dueling around a central star with gravity, firing torpedoes and using hyperspace jumps.

Spacewar! was primarily created by Steve "Slug" Russell, a graduate student at MIT, with significant contributions from Martin Graetz, Wayne Wiitanen, Dan Edwards, Peter Samson, and Alan Kotok. It was a collaborative effort by the MIT hacker community in 1961-1962. See our History page for full details.

Spacewar! was developed between 1961 and 1962. Steve Russell began writing the initial code in late 1961, and the game was publicly demonstrated at MIT's Science Open House in the spring of 1962. The game continued to be modified and improved throughout the 1960s by the PDP-1 user community.

Spacewar! is widely considered the first widely recognized and influential video game, though earlier experiments exist:

• Cathode-Ray Tube Amusement Device (1947) — a patent for a CRT-based game, never built commercially
• Tennis for Two (1958) — an oscilloscope-based tennis game by William Higinbotham
• OXO (1952) — tic-tac-toe on the EDSAC computer by A.S. Douglas

Spacewar! was the first to be widely distributed, played across multiple institutions, and directly inspire the commercial video game industry. It was inducted into the World Video Game Hall of Fame's inaugural class in 2013.

The official name of the game includes an exclamation mark: "Spacewar!" This was part of the original naming convention at MIT and reflects the enthusiastic hacker culture of the era. The game is often written without the exclamation mark as "Spacewar" or "Space War" — all refer to the same game. On this site, we use both forms interchangeably.

Spacewar! was written for the Digital Equipment Corporation (DEC) PDP-1 minicomputer. The PDP-1 was one of the first commercially available interactive computers, featuring a Type 30 CRT display capable of real-time vector graphics at 1024×1024 resolution. About 50 PDP-1s were ever produced, and fewer than 10 survive today. The computer cost $120,000 in 1960 (equivalent to about $1.2 million today).

Spacewar! was written in PDP-1 assembly language (also called PDP-1 macro language), the native machine language of the PDP-1 computer. The original code was approximately 2,000-4,000 instructions and took up about 4K-9K words of memory (each word is 18 bits). High-level languages like C and BASIC either didn't exist or weren't practical for real-time graphics on the PDP-1 in 1962. The original source code has been preserved by the Computer History Museum.

Approximately 50 PDP-1 computers were ever produced by Digital Equipment Corporation between 1960 and 1969. Today, fewer than 10 are known to survive, and only about 3-4 are in working condition. The Computer History Museum in Mountain View, California, has a fully restored PDP-1 that regularly demonstrates Spacewar! to visitors. Other surviving examples are in private collections and museums around the world.

No. The original PDP-1 version of Spacewar! did not have sound effects — the PDP-1 did not have audio hardware. The game was entirely visual, with the CRT display providing the only feedback. Some later ports and remakes added sound effects (torpedo firing, explosions, thrust sounds), but the authentic 1962 experience is silent. The clicking of the PDP-1's relays and the whir of its tape reader provided the only ambient "soundtrack."

The "Expensive Planetarium" was a starfield background added to Spacewar! by Peter Samson, an MIT student. It displayed a realistic map of the night sky (based on actual star catalogs) behind the game action, adding atmosphere and visual reference for players. The name was a joke about the PDP-1's high cost — it was an "expensive" planetarium compared to the cheap mechanical planetariums available at the time. The starfield became one of the game's most iconic visual features.

Spacewar! is a two-player game. Each player controls a spaceship (Needle for Player 1, Wedge for Player 2) using a control box with rotation, thrust, fire, and hyperspace buttons. The goal is to destroy your opponent by hitting them with torpedoes, while avoiding the central star's gravity well and collision.

Ships have inertia (no friction in space), so you need to plan your trajectory and use counter-thrust to change direction. Hyperspace teleports you randomly but carries an explosion risk. See our Gameplay Guide for full details, controls, and advanced tactics.

The two player ships are called the "Needle" (Player 1, a slim, pointed ship with tail fins) and the "Wedge" (Player 2, a broad triangular ship). They handle identically in terms of thrust, rotation, and torpedo speed, but their different shapes create visual and tactical differences — the Needle is a smaller target (harder to hit), while the Wedge is easier to track visually during fast maneuvers.

A central star exerts gravitational pull on both ships, following an approximation of the inverse square law — gravity is stronger closer to the star. This creates curved orbital trajectories. Ships can use gravity to perform slingshot maneuvers, gaining speed by diving toward the star and curving around it. Colliding with the star destroys a ship.

Important: Torpedoes are not affected by gravity in the original game — they travel in straight lines. This means you need to lead your target based on their velocity, not on where gravity will pull the torpedo.

Hyperspace is an emergency mechanic that teleports a ship to a random location on the screen. It was added to give players an escape when cornered or about to collide with the star. However, each hyperspace jump carries a significant risk (approximately 25% in most versions) of the ship exploding on re-entry.

It's a high-risk, high-reward gamble — use it only when certain destruction is the alternative. Some players use it aggressively to reposition behind an opponent, but this is risky. See our Gameplay Guide for more on hyperspace strategy.

Yes! The easiest way is through a browser-based PDP-1 emulator like the one at masswerk.at/spacewar, which runs the original 1962 code in your web browser with no downloads required. You can also find modern remakes on itch.io and Steam, or play Valve's Spacewar test app on Steam (AppID 480, though this is a different, simplified game). See our Play Now page for all options.

The original 1962 Spacewar! was strictly local two-player on a single PDP-1. However, several modern remakes and homages support online multiplayer. Valve's Spacewar test app on Steam (AppID 480) supports online multiplayer via Steam Matchmaking, though it's a simplified modern game, not the original. Search for "spacewar online multiplayer" or check itch.io and Steam for modern remakes with netplay.

Spacewar! was never copyrighted or sold commercially — it was shared freely among PDP-1 users via paper tape. This effectively makes it public domain, though the exact legal status depends on jurisdiction. The original source code has been preserved by the Computer History Museum and is available for study and emulation. Many modern remakes and ports exist, some open source and some commercial. If you create a remake, you're free to do so, but crediting the original creators (Steve Russell et al., MIT, 1962) is appreciated.

Steam's "Spacewar" (AppID 480) is a free test/demo application created by Valve for Steamworks developers to test multiplayer, achievements, and other SDK features. It is NOT the original 1962 PDP-1 game. It is also frequently used by game pirates to disguise cracked games. If you see it unexpectedly in your library, it may indicate pirated software was used. See our dedicated Steam FAQ for full details.

Spacewar may appear in your Steam library if:

1. You or someone using your account added it via the Steam console command app_install 480
2. Most common: You used a cracked/pirated game that uses Spacewar's AppID as a disguise (tools like CreamAPI, Goldberg Emulator, etc.)
3. A family-shared account has it installed

It is not automatically added by Valve. If you didn't intentionally install it, check for cracked games on your system. See our Steam FAQ for how to investigate.

The official Valve Spacewar test application (AppID 480) itself is safe — it's Valve-signed and contains no malware. However, if it appeared unexpectedly, it may indicate pirated/cracked games were played on your account, and cracked games often come bundled with malware, keyloggers, or crypto miners.

Recommendation: If you didn't install it intentionally, run a full antivirus/malware scan, remove any cracked games or pirate tools, and consider changing your Steam password. See our Steam FAQ for more details.

Method 1 (Standard):

1. Open your Steam Library
2. Right-click "Spacewar"
3. Select "Manage" > "Uninstall"
4. Confirm the uninstallation

Method 2 (Steam Console):

1. Open steam://open/console in your browser
2. Type app_uninstall 480 and press Enter

If it keeps reappearing, it's being re-added by cracked game launchers — remove all pirated games and pirate tools first. See our Steam FAQ for detailed troubleshooting.

Spacewar! had a profound influence on the video game industry:

1. Atari & the arcade industry: It inspired Nolan Bushnell to create Computer Space (1971), the first commercial arcade video game, which led directly to the founding of Atari and the release of Pong (1972).
2. Birth of esports: The 1972 Intergalactic Spacewar Olympics at Stanford was the first organized video game competition.
3. Space shooter genre: It established the template for Asteroids, Star Control, Elite, Wing Commander, and countless other space games.
4. Game design innovations: It pioneered physics-based gameplay, competitive multiplayer, risk-reward mechanics (hyperspace), environmental hazards (the star), and vector graphics aesthetics.

See our Legacy page for the full story.

The Intergalactic Spacewar Olympics was held on October 19, 1972, at the Stanford Artificial Intelligence Laboratory. Organized by Stewart Brand and covered by Rolling Stone magazine, it is widely considered the first organized video game competition in history — the birth of esports.

About 20-30 players from Stanford, MIT, and the Bay Area tech community competed in free-for-all and team formats. Bruce Baumgart of Stanford won the grand championship. The Rolling Stone article, titled "Spacewar: Fanatic Life and Symbolic Death Among the Computer Bums," became a landmark document in video game history. See our Legacy page for more.