March 30, 2012Try this out:
The SJ are responsible for panspermia. They wear protective suits to avoid being contaminated by the "panspermia substance" (contained in the ampules). The chair is a protocol to disinfect after coming in direct contact with the substance.
The substance is a biological and mechanical. When an ampule is sent to a new planet, the substance attenuates itself to the planet, creating a form of life best fit for the planetary circumstance.
The substance itself attenuates itself to whatever it comes in contact with. When a human comes in direct contact with the substance, it begins a process of inhabiting the individual as if it is a planet. Because this substance's main goal is to create a life form that survives, and thrives, in any possible condition relating to the origin of its attenuation, any person infected by the substance would then evolve.
The infection caused by coming in direct contact with the substance would not kill its host, but would make it stronger. The infection itself would not be able to survive without its original host. If one of the Prometheus crew is infected, this would explain where the SJ came from.