Asteroid Defense

Asteroid impact on Tephis, Terragen Federal Hinterregions

comet impact mars
Image from Anders Sandberg
An asteroid impactor about to strike the world of Tephis (Pajuun System, allied with the Terragen Federation) after the conclusion of a game of Asteroid Defense - 8683 AT.

Asteroid Defense is a game in which a team of sophonts defend against an asteroid on a collision course with a planet. The game can be played either in ril or in a virch. While a small rocky planet is usually the main target in the game, a gas giant may also be used. The game is split into two main modes: Long Form and Short Form. Long Form is the primary way the game is usually played. Over the centuries, literally thousands of variations of Asteroid Defense have been developed across millions of solar systems. The following is a description of the most basic form of the game and should not be considered all-inclusive.

When the game is ready to be played (team is ready, asteroid is ready, and spectators are watching), the asteroid (ranging from 4-12km in diameter) is put on a collision course with the planet at a sufficient velocity that it will take a standard week to arrive. The game is usually supervised by an autowar that closely monitors the players, their progress and status during the game. The frequency of outgassing, the frequency of monster placement, and other hazards are controlled by non-sophont vots.


  • A team of 5 to 10 sophonts must land on the surface of the asteroid and make their way across hazardous terrain infested with hostile bots and neogens to a predetermined drilling site, where a bomb must be planted to demolish it. The primary method of demolition is a boostbomb, configured to fully vaporize the asteroid.
  • Players that require an atmospheric environment to live are provided with a space suit with their specified atmosphere. This suit retains most functions of modern space suits, but is not equipped with self-repair capabilities. If a suit becomes damaged, players are notified of a tear or puncture as well as its location, and must seal it with anything available.
  • If a player is thrown a kilometer off the surface by any means and has no way of coming back down, they are disqualified, caught by the supervising autowar, and brought to the supervising control ship.
  • If any spectators desire to watch the impact of the asteroid from the surface of the target planet, remote bodies are made available for use. These bodies are placed on the planet's surface in various locations determined to be optimal for viewing different phases of any potential impact (or in the case of a gas giant, aboard specially designed airships located near the vicinity of the impact site.)
  • Any structures (launch pads, seating stands, communication equipment, etc) on the planet are fabricated when needed, and disassembled when the game is over, if desired. In the case of a gas giant, the structures are deorbited into the gas giant itself.
  • In most cases, for a planet to be used in the game, it must be lifeless and uninhabited. However, a planet inhabited by sophont life may volunteer itself to be used in the game, in which case measures must be taken to back-up all sophonts and the planetary biosphere, and preserve as many of the planet's non-sapient organisms (including micro-organisms) as practically possible, to ensure rapid restoration of the planetary civilization and biosphere after an asteroid impact.
  • The asteroid is only allowed to impact the planet if the participating team and local planetary population both agree that it should do so.


  • The asteroid itself can either be constructed from local raw materials (this type is referred to as a con-rock) or collected from somewhere else in the planetary system where the embodied game is being played.
  • A predetermined time period after which recovering/deconstructing the asteroid is infeasible/impossible OR the resulting destruction of the asteroid would do unacceptable amounts of damage to the planet is dubbed the "Minimum Buffer Time". The default MBT is 24 standard hours, however, this can be adjusted based on the planetary dimensions.
  • When the asteroid is destroyed in either game mode, the game ends.



NoteA difficulty system, referred to as ENDCON (Enemy Danger Condition) is enabled in this game mode, based on how quickly the enemies will attack a player once detected. There are 5 levels of ENDCON.

1. Alpha (Green - Low Difficulty - Hazard Rating Equivalent: 3)
2. Beta (Blue - Medium Difficulty - Hazard Rating Equivalent: 4)
3. Gamma (Red - High Difficulty - Hazard Rating Equivalent: 6 to 7)

(The following levels are usually reserved for transapients only)

4. Sigma (Amber - Very High Difficulty - Hazard Rating Equivalent: 8)
5. Omega (Black - Master/Highest Difficulty - Hazard Rating Equivalent: 9 to 10)
  • All players must be in a body form that is incapable of flight (jumping is permitted), is possessed of some kind of manipulators, and is not constructed from materials that are impervious to enemy attacks. Ultimate Muscle is not allowed in any form. An upright humanoid form is not required to play the game.
  • If a player is killed during the game, they are deemed disqualified and cannot rejoin the game or assist their teammates in any way. Any remains that are still present following a player's death are collected and revived back at the starting station. The disqualified player will only be able to spectate from then on.
  • In the virch form of the game, players have the option to revive after a specified amount of time. This can either be extended (up to five minutes) or shortened (minimum of 10 seconds), or completely disabled during game setup. If everyone dies before they can all rejoin the game, the team will lose and the game will be over.
  • The spacecraft that is available to the players consists of a conversion drive-equipped primary vessel and a single shuttle lander. The shuttle is required to land at a minimum of 1 km from the drilling site and players must make their way across the landscape on foot while fighting off various enemy combatants to reach the drill site. The shuttle's outward appearance can be customized.
  • The boostbomb will be transported via a "cart", a basic vehicle (its main body built from durable and lightweight material, resembling an Information Age automobile chassis) with several methods of moving itself across the surface of the asteroid. By default, it is equipped as follows:

Asteroid Defense - Long Form - Cart - Data Panel

Specifications- Four flexible legs with a radially symmetrical, four-toed foot; the toes have powerful electromagnets to grip to more metal-heavy asteroids. A diamondoid-tipped drill is incorporated into the center of each foot to provide further security.

- A reaction control system, in case the asteroid has such low gravity that walking is infeasible/impossible.

- Winches with buckyfiber cables, tipped with diamondoid-capped drills.
  • When the bomb is being planted, it begins broadcasting a specific signal, causing the bot and neogen enemy units to become more aggressive. The drill is designed to take about one hour to reach its predetermined depth, and players must defend both the drill and themselves during this period. The players must remain within the immediate vicinity (20m sphere) of the drill site to ensure the bomb has reached the required depth.
  • Once the bomb reaches its pre-calculated depth, the countdown starts and the team has one hour (or more) to return to the shuttle and leave the asteroid. However, during this period the bomb begins broadcasting another signal and any remaining bots/neogens will no longer target the bomb, and instead focus exclusively on attacking the escaping team.

Asteroid Defense - Long Form - Railgun

Railgun - Asteroid Defense
Image from MrOnyx
Personal defense automation is prohibited. The players' primary method of defending themselves is a handheld railgun with the following specifications:

Data Panel

Specifications> Bullpup Configuration
> Fire Modes: Fully Automatic (800 rounds per minute)
> 12.7x70mm Inert Diamondoid Slug with Ferromagnetic Core
> 50 Round Casket Magazine
> Hybrid Holographic Optical Sight with Adjustable Magnification (40x Max Zoom)

- Players may carry as many magazines as practically possible. Refabricating the weapon itself along with ammunition is not allowed.

- Kinetic Energy Output is configured during game setup to a specific value (Min kEO = n>1 kilojoule, Max kEO = n<10 kilojoules). This is to correspond with the bot/neogen resilience to kinetic damage.
  • If at least one player is able to reach the shuttle, launch from the surface, dock with the primary vessel and leave the area before the bomb explodes, the team wins. If every player is killed, or the asteroid reaches the Minimum Buffer Time, the team loses.
  • Individual players are scored on how many of the bots/neogens they kill, and the entire team is scored on how long it took to fully complete the game.

Asteroid Defense - Long Form - Antagonist Units - Data Panel

ENEMY EXAMPLESThe design/morphology of the enemy bots/neogens is not static and is different in every game session. However, enemy intelligence is fixed at a non-sophont, animal level.

Below are representative examples of antagonists that have appeared in past games of Asteroid Defense:

Bot Enemy 1: Spikeball - First Appeared in Game 2

Appearance: A reflective/polished metal graphite-grey sphere with a diameter of 1.5 meters.

The Spikeball is a gelbot with a centralized computronium core inside. Destroying the core kills the bot.

The Spikeball moves by extruding a variable number of limbs to raise itself above the asteroid's surface (1m max height) and then push or pull itself across the ground. New limbs are rapidly extruded and old ones reabsorbed as the bot moves or changes direction. Each limb may extrude one or more spikes for the purpose of gripping the surface or attacking players. The bot can jump or roll, if desired.

To attack a player, the bot approaches (Attack distance - min: 1m, max: 3m) and very quickly extends a blade/spike from its body to stab or cut them. Occasionally, Spikeballs extrude short arms with 1 meter long blades and use them as swords. While injury to the player is allowed (via impaling/bisecting), the primary goal is to slice, tear, or puncture a player's spacesuit so that they will asphyxiate and/or freeze to death. If the player is a vec or vacuum-adapted sophont, the Spikeball will attempt to cut up the player however it can.

Neogen Enemy 1: Beast - First Appeared in Game 15

Appearance: The Beast is a bilaterally-symmetrical, vacuum-adapted quadruped, physically resembling an Old Earth lioness and having roughly the same physical dimensions. The body is completely hairless, with jet-black leathery skin and an 83cm-long prehensile tail, with a 20cm-long diamondoid blade at the tip. Destroying the brain is the only way to kill the beast.

The primary attack method is biting (45000 kPa of pressure) and swipes from the diamondoid-infused claws.

Beasts will not eat players, due to using internal organic batteries for energy, but will attempt to dismember them as much as possible, all while leaving a player's head undamaged.

Bot Enemy 2: UFO - First Appeared in Game 222

Appearance: The UFO is a soft-edged, silvery, discus-shaped bot (7m diameter, 1.75m height at highest) equipped with a plasma-based reaction control system and a 1 meter diameter hole in the center. A total of 6 computronium cores are located within it, all cores must be destroyed to completely destroy the bot. The bot is very quick and agile compared to the bodyforms allowed for the players.

The main sensor array consists of two cameras, one located on the rim, one looking down out of the hole.

The UFO's primary attack mode is a weapon's grade laser on the end of a flexible arm, protruding from its underside via the hole. The beam is powerful enough to cut players to pieces.

Neogen Enemy 2: Pancake - First Appeared in Game 430

Appearance: The Pancake is a large siphonophore-like organism (20m diameter, 0.3m height) which uses a starflish-like foot to move around the surface of the asteroid. The default color of the neogen is black, but it can change its color and skin texture to match that of its immediate surroundings.

A Pancake has the ability to separate itself into multiple pieces that can move independently (max of 3 pieces, each with its own nucleus), and still coordinate with each other via organic radio emitters and receivers. The Pancake's body is very flexible and can change its shape horizontally as required. It has a maximum speed of 10 m/s.

The Pancake attacks by enveloping players like an amoeba, and using tentacles within it to undo the player's space suit. This exposes the player to the vacuum of space, and they will eventually suffocate from lack of oxygen. When a player is killed, the neogen will release the body and continue to the next player. The body is collected for resurrection. When enveloping a vacuum-adapted sophont or vec, the Pancake will pierce there brain/brain equivalent with a long sharp diamondoid-infused bone it keeps within itself.

To defeat the neogen, players must destroy three nuclei located within the organism. They glow with a faint red light and are the size of an Old Earth baseline apple.


In the Short Form of Asteroid Defense, four teams, each made up of five sophonts, must neutralize a 1 km wide asteroid as creatively as possible, and by any means they can devise.

  • The asteroid has no environmental hazards on its surface or within it, and can be built in a specific shape if the teams desire it. Previous examples of requested forms include: a perfect sphere, a pyramid, statues resembling Old Earth Greco-Roman sculpture, a NoCoZo coin, a human hand making the "thumbs-up" gesture, and the erect penis of any of various mammalian species.
  • There are no limits or restrictions on spacecraft, nor are there restrictions on what the teams can use to destroy the asteroid.
  • Teams are judged on the originality and creativity of their asteroid destruction by a panel of four judges. The judges review each team's efforts and each gives a rating, ranging from Outstanding to Fail. If a team just destroys the asteroid with nothing outstanding creatively (such as simply vaporizing the asteroid via high-energy explosives such as is done in Long Form Mode) they will be automatically graded as a Fail.
  • If the asteroid reaches the Minimum Safe Distance boundary without being destroyed, all teams are given a Failing grade.
  • Players sabotaging the destruction methods of other teams is allowed, but must not involve killing any of the opposing team members.
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Development Notes
Text by MrOnyx
Initially published on 09 April 2023.