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Inicial quote.png It's a tin can with legs! Final quote.png

—Sergeant Francis Brutto

C.H.A.S. unit on the battlefield.

The XM-550 Cybernetic Humanoid Assault System, or C.H.A.S., is a robotic machine used by SICON.

Roughnecks: Starship Troopers Chronicles[]


A CHAS unit on Tophet

These machines consisted of a titanium reinforced superstructure and contained the firepower of an entire Mobile Infantry squad. The primary processor of the CHAS ran on a bio-enhanced logic matrix which meant that the units were completely autonomous. Its CPU is essentially a learning computer with cognitive skills that were human-like.

The units are capable of moving at far faster speeds compared to a trooper and have thrusters by the base of its feet allowing it limited flight capabilities.

C.H.A.S is armed with two miniguns on each hand along with a rocket launcher. A machine gun on the shoulder and grenade launcher inside its chest.



The first recorded deployment of a CHAS unit was during the Tophet Campaign where it was assigned on a mission with Razak's Roughnecks on a mission to clear a region on Tophet from Arachnid control. The CHAS proved to be quite successful, however, during its first mission in the Roughnecks, it was forced to hold off an Arachnids attack whilst the squad escaped unharmed. In this engagement the C.H.A.S. was destroyed after triggering a mine whilst under attack. Afterward, SICON decided that the CHAS units were not cost effective for front line deployment where casualties would be high.

Two CHAS serving as guards.

C.H.A.S. units deployments did not end there however, as SICON merely redeployed them to guard duties on board starships and military bases. The CHAS units began appearing in such operations around the beginning of the Klendathu Campaign. Two CHAS units were used to protect the command deck of the Valley Forge to protect the captain when the Zander Bug was loose on board. A further two were deployed as guard units at the Mobile Infantry base on the surface of Klendathu though these were easily destroyed by the first sighting of an Imposter bug infiltrating the base. After that incident, further C.H.A.S. units were on high alert for further infiltrations of the base camp.

During the Homefront Campaign with earth under partial control by Arachnid forces, all available CHAS units are deployed with Mobile Infantry units on the front line.

Starship Troopers games by Mongoose Publishing[]

The CHAS is an independant robot with autonomous capabilities making it capable of working as a solo unit. They were designed to face threats that were too dangerous to allow normal Mobile Infantry troopers to combat. The units are equipped with the firepower of an entire infantry squad as well as possessed enough armour to shrug off the claws from most forms of Arachnid bugs. These strengths make it a valuable addition to the Mobile Infantry, however, many officers remain suspicious of these thinking machines.

A single CHAS is armed with Morita Ape Specials, a Hell Infantry Flamer, Javelin Missile Launcher and a Trip Hammer Mortar. When required, they are able to begin a single "Alpha Strike" sequence where they fire all their weaponry in one shot. Should all other options fail, the CHAS is equipped with Deathwish Circuits whereupon it selflessly begins a self-destruct sequence.


In the long history of human warfare, no soldier has ever been as well trained or as well equipped as the Mobile Infantry trooper. Armed with the most sophisticated weaponry ever developed and encased in the bulwark of power armor, Mobile infantry troopers are intended to stride like gods across the battlefield. Still, at their core, these troopers are only humans. For all its qualities, the human race is a physically frail form of life, at least when compared to the bugs. Despite the best equipment and training the Federation provides, there are some places troopers cannot go, not without absorbing immense casualties. For these situations, SICON created the CHAS unit.


The CHAS stands nine feet tall and weighs in at half a ton. Its titanium reinforced superstructure harbors all the weapons it can handle plus a bio-enhanced logic matrix, the most sophisticated computer processor SICON has ever produced and boasting human-like cognitive abilities. Though the CHAS is humanoid, it is clearly not human, a mere glance is enough to determine that it is not a man in any kind of power suit, it is a robot. However, it is capable of approximately 95% of the full range of human motion; it can walk, run, gesture or climb a cliff face. Its hands are fully articulated, meaning the Chas unit can easily pick up a dropped weapon and continue fighting even when its own ammunition reserves are exhausted.


A new CHAS unit is essentially a tabula rasa, a blank slate. Though it comes equipped with numerous weapons and the knowledge of how to use them, as well as a great deal of ‘hard’ knowledge, including tactical theory, bug physiology and elementary physics, the CHAS is in many ways as innocent as a newborn. A newly activated CHAS has no personality whatsoever, it is little more than a walking tank with access to a wide range of technical information.

All CHAS units are identical upon initial activation. They are machines of war and they are programmed to prosecute that war as efficiently and effectively as they can. All the knowledge incorporated into their processors at the time of activation is selected to enable the CHAS to be the best and most effective soldier it can be. Noticeably absent from the CHAS’ programming is any example of ‘soft’ knowledge, such as the manifestly human values of honour, loyalty and friendship.

The CHAS sees everything through the prism of its primary directive – to fi ght and kill the enemy and advance the goals of SICON in the war. The world is viewed as a series of gain-andloss calculations; the CHAS always chooses the path that offers the shortest and surest route to victory. If that involves leaving one of two troopers wounded on the battlefield while it pursues an enemy, then so be it.

The CHAS is intended to function as part of a combat team and as such is programmed to sacrifice itself for the good of a squad if called on to do so. However, it is also programmed to protect itself from all perceived threats, something that caused a few unfortunate incidents within a rough and tumble Mobile Infantry squad before the last quirks were worked out of the programming.

However, the CHAS is a learning computer and, as mentioned above, is essentially a blank slate when fi rst activated. The CHAS tends to ‘imprint’ upon the troopers to whom it is assigned, picking up everything from their habits to their turns of phrase to their very values and incorporating them all into its core programming. Eventually, the CHAS will learn and grow to the point that it is truly its own individual.

Restrictions on CHAS Level Advancement[]

A CHAS unit is an incredibly effective fi ghting machine, but it is just that – a machine. The CHAS holds no rank within the Mobile Infantry; theoretically, even a private could give it a command, though in truth it answers only to the ranking offi cer of whatever squad with which it is serving. Though the CHAS may take levels in the Mobile Infantry Trooper class and may even request cross training, it may never assume a position of command. A CHAS unit receives no medals for service, and will never gain a rank in the military.

The above represents the legal standing of the CHAS within SICON. It is entirely possible an experienced CHAS could be a good offi cer, but it will never be given the chance. There is one area of the service that the CHAS cannot enter simply because it is physically impossible for it to do so – the Special Services. A CHAS unit, sophisticated and self aware though it may be, cannot ever be psychic. It is impossible for a CHAS to take the Psychic Talent feat.

Future of the CHAS unit[]

Though it is an outstanding weapon of war, the future of the CHAS unit is uncertain. A few mishaps and a little friction with human troopers aside, it is ultimately monetary concerns that may spell the end of the CHAS.

A CHAS unit is an incredibly expensive weapon for SICON to manufacture. The precise cost has not been made public but it has been speculated that a single CHAS costs more than 20 Marauder power suits – mostly because of its processing components and its power plant. There has been discussion within SICON about going a less expensive route on both of these but doing so has been deemed infeasible. A CHAS with more primitive processing capability would be an unreliable weapon at best, while a CHAS that had to recharge as often as a Marauder suit would be ill-suited for the kinds of missions the CHAS is intended to carry out.

Essentially, the CHAS has created a kind of ‘Catch 22’ at SICON. The sheer expense of manufacturing a CHAS makes assigning it to light duty a tremendous waste of resources. However, the kind of heavy duty the CHAS is intended for – primarily long-term operations on a bug-ridden planet – tend to result in high attrition rates for the CHAS. Thus, SICON is faced with either wasting the CHAS in duties better carried out by light troopers, or coping with the immense expense of multiple CHAS ‘fatalities’ in the field.

The future of the CHAS is by no means decided. It may well be that SICON will pull the plug on the program, or it may be that production of these armoured robots will continue apace. Either way, the CHAS unit will keep on doing what it does best, fighting the Arachnid menace until the last bug is squashed or the last CHAS falls in a heap of spare parts.



  • Starship Troopers: The Roleplaying Game - Mobile Infantry Field manual