The protomolecule, also known as the Phoebe bug, is an infectious agent of extra-terrestrial origin first discovered on Phoebe by the Martian Congressional Republic in 0 XTE. It has the ability to radically alter infected life forms and utilize their biomass in various ways.

Not a life-form in itself, the protomolecule is described by Antony Dresden as "a set of free-floating instructions designed to adapt to and guide other replicating systems". It is able to maintain its primary structure in a wide variety of conditions, and it has an affinity for carbon and silicon structures, but is likely anaerobic and will not degrade upon exposure to oxygen.[Citation needed] It can use ionizing radiation as an energy source, and its growth can speed up considerably if exposed to high doses.

Origin Edit

It was initially believed by Protogen's scientists that Phoebe was intended as a weapon. The Investigator informs James Holden, however, that it functions as an advanced terraforming platform. It was created by extra-terrestrials around two billion years in the past, and launched in a Bracewell probe at a trajectory towards the Earth, which had only developed primitive life at the time. It was, however, captured by Saturn's gravity, where it became a satellite, and settled there as one of its moons.

At some point between its launch and the present day, the civilization that launched the protomolecule was attacked and seemingly destroyed by an as-yet-unidentified aggressor.

History Edit

In 0 XTEMars landed on the ice moon Phoebe to survey it for ice mining. When core samples from the moon were investigated, however, silicate samples were found, and the Martian government approached Protogen as a cosponsor of a long-term research facility. Protogen discovered the alien agent, dubbed it the protomolecule, and began experimenting with it.

Eros incident Edit

Main article: Eros incident

In 9 XTE, the first major outbreak of the protomolecule, known as the Eros incident, took place. It was a controlled infection of the entire population of Eros, numbering one and a half million humans. With this amount of biomass, it was revealed that the protomolecule had the ability to create a hive mind of sorts, which integrated itself with the computer systems of Eros station.

Life cycle Edit

Infection Edit

The protomolecule can infect other life forms on contact (it is anaerobic, and cannot be transmitted through the air).[Citation needed] While supposedly designed for use on simple, single-celled organisms, it is effective on multi-cellular life as well. In humans, it spreads internally and starts altering its host through a process that may take several weeks, during which the host hibernates, but which can be significantly sped up via exposure to ionizing radiation.

Spread Edit

After awakening from hibernation, the host becomes disoriented and feverish, with symptoms similar to a hemorrhagic fever. Shortly after, a brown fluid begins leaking out of its orifices. Human hosts at this stage are nicknamed "vomit zombies" because of their tendency to stagger around, spewing the brown fluid, which is highly infectious to other creatures.

Alteration Edit

The protomolecule will eventually begin to alter its host in a variety of ways, most frequently melding the biomass of multiple hosts and repurposing specific organs to carry out new functions.[Citation needed] Changes beyond this point seem to be highly variable and unpredictable, but recognizable features that might be incorporated in the resulting structures are black filaments, brown slime and blue luminescence.

Hive mind Edit

The protomolecule's original construction appears tuned for simple unicellular life, though able to operate with a wide variety of hosts including advanced, intelligent multi-cellular organisms. Given enough biomass from several intelligent hosts, the protomolecule is able to create a hive mind. In the only known instance of this occurring, an initial victim (Julie Mao) was used as a "seed" or template for the nascent consciousness, which then guided the utilization of all subsequent biomass.

It is unclear whether normal functioning with an active connection to its creators would result in a host gaining some measure of control over the development and behavior of the resulting structures as Julie did.

Human-protomolecule hybrid Edit

Project Caliban Edit

Main article: Project Caliban

Project Caliban is the secret Protogen developed plan (backed by Mao-Kwikowski Mercantile) to create a human-protomolecule hybrid for use as a weapon. The Ganymede incident took place 18 months after the Eros Incident in 11XTE.[1]

Closeup of HPH in Roci cargo bay-enhanced

Activity on Venus Edit

Following the descent of Eros Station to the surface of Venus in 9 XTE, the protomolecule began rapidly reshaping the planet. Observers throughout the Sol system observed these changes with great interest, but, despite the wealth of data, the objectives of the alien organism remained obscure.

The military science vessel Arboghast was tasked with observing Venus from orbit and relaying instrumental data to the UN. Eight months into her mission, the Arboghast received or emitted a brief radiation pulse of unknown nature and origin that interfered with all observing telescopes in the non-visible spectrum. Immediately following this, the entire vessel was disassembled into its structural components, down to the level of screws and bolts, methodically and with no discernible mechanism of action. The crew of 572 personnel were lost to vacuum exposure.

On Venus and beyond, the protomolecule hive mind displayed an ability for instantaneous communication, with events involving the substance anywhere in the system (mainly the activation or destruction of human-protomolecule hybrids) triggering a response from Venus' surface.

Ring Edit

In 12 XTE, the protomolecule launched a massive complex of structures just outside the orbit of Uranus and built a thousand-kilometer-wide object known as the Ring. This is the final stage of the protomolecule life cycle: to convert itself into a wormhole leading to the Slow Zone and Ring station.Following the attack by OPA extremists on Tycho Station, the last known sample of the protomolecule is believed to be in the hands of the Free Navy. However, after the Free Navy Conflict, the whereabouts of the sample are unknown.

Certain items originating from the colony of Laconia, which had ceased all contact with the Sol system and other human colonies as of the rise of the Free Navy, show signs of unusual and advanced manufacturing techniques. These items include carbon-silicate lace ship armor and the six massive railguns affixed to Ring Station. It is suspected that the methods used to make these items have been reverse-engineered from the protomolecule and related alien technology, or makes use of the protomolecule itself.

Media Edit

Eros infection

For TV viewers


  1. "The Expanse: Caliban's War'", Chapter One: Bobbie
    "Eighteen months before, there hadn't been sides.… Then Eros,…

External links Edit

For TV viewers