All it takes is the power of simple viruses. No speculative approaches such as self-replicating von Neumann probes, mind uploading, or warp drives are necessary. Human colonization of our galaxy can be achievable with technology feasible within our lifetimes!

A common trope in science fiction of colonization is that of the sleeper ship. Drifting through interstellar space, the occupants are preserved cryogenically or in some type of suspended animation pod — perhaps one of the occupants is a superhuman dictator. An arguably more realizable concept is embryo space colonization. Instead of sending adult humans in some suspended animation contraption, it is sufficient to send human embryos. On arrival at a suitable planet, the probe will gestate the embryos in an artificial womb and then raise the children. However, what constitutes a ‘suitable planet’? The planet the embryos are sent to could be ultimately deeply unsuitable for humans.

I reject the above approaches. I posit that the ideal ecosystems for humans to thrive could take millions of years to produce. Thus, I think it is pertinent to borrow from the idea of directed panspermia — the concept of seeding planets in other star systems with bacteria.

Viruses and bacteria — how can we direct the evolution of organisms on the seeded exosolar planet? Our probe modifies microbes, and eventually more complex organisms, using viruses as germline gene transfer agents. The genetic changes caused by the viruses are passed to offspring — it has been suggested that viruses helped bacteria to evolve into complex multicellular organisms. By applying the viruses over many years, complex organisms such as plants, insects, and animals can emerge — mammals, apes, and finally humans shall emerge from the process directed by the Virus Probe.

Virus Probe Components

1. Propulsion, navigation, and power
2. Planetary monitoring and analysis
3. Virus design
4. Virus manufacturing
5. Virus dispersal
6. Bacteria dispersal
7. Command and control
8. Human knowledge repository

Terraforming Process

1. The probe, likely powered by solar sails, is launched.
2. It sails to other star systems over thousands of years in search of suitable planets.
3. If a suitable planet is found, the probe will seed the planet with baseline extremophile bacteria.
4. The probe will detect when the planet is sufficiently terraformed, i.e., it has appropriate atmospheric composition and temperature.
5. The probe will intervene to make corrective changes to the planet’s biosphere. Using viruses engineered by AI as germline gene transfer agents, the necessary genetic changes will be enforced by the probe. The probe will use its dispersal facility to spread the virus on the planet.
6. The viruses will introduce new genes into organism populations on the planet.
7. The probe will attempt to guide the development of organisms that are useful to humans. Corn and tangerines will emerge on the planet.
8. The probe will aim to guide a species’ development to becoming genetically exceedingly similar to humans.
9. Once humans evolve on the planet and advance technologically, they will hopefully discover the probe and recover the cultural and scientific repositories.

Challenges

1. Can the probe survive and operate functionally for potentially millions of years?
2. Will the probe possess enough resources to construct viruses for millions of years?
3. Can in situ resources be used from the planet?
4. How can the probe monitor changes in life across the entire planet?
5. How will it receive samples?
6. Will the probe be able to exert sufficient evolutionary pressure?
7. Will organisms gain resistance?

Ethical Implications

1. Is the probe inherently anthropocentric? Will it eliminate indigenous life or potential indigenous life?
2. If humans or other intelligent life evolve on the planet how will they react to the probe?