The imperative of developing artificial intelligence (AI) could not be more clear when it comes to exploring space beyond the Solar System. Even today, when working with unmanned probes like New Horizons and the Voyagers that preceded it, we are dealing with long communication times, making probes that can adapt to situations without assistance from controllers a necessity. Increasing autonomy promises challenges of its own, but given the length of the journeys involved, earlier interstellar efforts will almost certainly be unmanned and rely on AI.

The field has been rife with speculation by science fiction writers as well as scientists thinking about future missions. When the British Interplanetary Society set about putting together the first serious design for an interstellar vehicle — Project Daedalus in the 1970s — self-repair and autonomous operation were a given. The mission would operate far from home, performing a flyby of Barnard’s Star and the presumed planets there with no intervention from Earth.

We’re at an interesting place here because each step we take in the direction of artificial intelligence leads toward the development of what Andreas Hein and Stephen Baxter call ‘artificial general intelligence’ (AGI), which they describe in an absorbing new paper called “Artificial Intelligence for Interstellar Travel,” now submitted to the Journal of the British Interplanetary Society. The authors define AGI as “[a]n artificial intelligence that is able to perform a broad range of cognitive tasks at similar levels or better than humans.”

This is hardly new terrain for Hein, a space systems engineer who is executive director of the Initiative for Interstellar Studies, or Baxter, an award-winning and highly prolific science fiction novelist. A fascinating Baxter story titled “Star Call” appears in the Starship Century volume (2013), wherein we hear the voice of just such an intelligence:

I am called Sannah III because I am the third of four copies who were created in the NuMind Laboratory at the NASA Ames research base. I was the one who was most keen to volunteer for this duty. One of my sisters will be kept at NASA Ames as backup and mirror, which means that if anything goes wrong with me the sentience engineers will study her to help me. The other sisters will be assigned to different tasks. I want you to know that I understand that I will not come home from this mission. I chose this path freely. I believe it is a worthy cause.

What happens to Sannah III and the poignancy of its journey as it reports home illuminates some of the issues we’ll face as we develop AGI and send it outward.

Image: A visualization of the British Interplanetary Society’s Daedalus Probe by the gifted Adrian Mann.

On the one hand, deep space mandates our work in AI, leading to this far more comprehensive, human-like intelligence, while at the same time human activities in nearby space face directly into the fact that space is a hostile place for biological creatures. There may develop evolutionary offshoots from Earth’s human stock as pioneering colonists move to Mars and perhaps the asteroids, tapping cyborg technologies and perhaps beginning a posthuman era.

I notice that in Martin Rees’ new book On the Future, the famed astrophysicist and Astronomer Royal speculates that pressures such as these may lead to the end of Darwinian evolution. Developing AGI would replace it with artificial enhancement of intelligence directed by increasingly capable generations of machines. It’s a conceivable outcome, and it’s one that would emerge more swiftly away from Earth, in Rees’ view. The need for powerful AGI for our explorations beyond the Kuiper Belt could well be a driving force in this development.

Of course, we don’t have to see future AI as excluding a human presence. One science fiction trope of considerable interest has been what Andreas Hein explored in earlier work (see Transcendence Going Interstellar: How the Singularity Might Revolutionize Interstellar Travel). One option for exploration: Send probes equipped with AGI to create the colonies that humans will eventually use. Could AGI raise a generation of humans from individual embryos upon arrival?

We can also think about self-replication. A first generation of probes could, as Frank Tipler and Robert Freitas have discussed, continually produce new generations, resulting in a step-by-step exploration of the galaxy.

Whether or not humans go with them or send them as humanity’s emissaries will depend on the decisions and technologies of the time. We have rich background speculations in science fiction to rely on, which the authors tap to analyze AI and AGI for a range of interstellar scenarios and the consequent mission architectures.

Thus AXIS (Automated eXplorer of Interstellar Space), the creation of Greg Bear in his novel Queen of Angels, which runs its own scientific investigations. Long-time Centauri Dreams readers will know of my interest in this novel because of the issues it raises about autonomy and growing self-awareness in AI far from human intervention. AXIS is an example of what Hein and Baxter refer to as ‘Philosopher’ probes. These are probes that, in contrast to probes with specific missions, are able to support open-ended exploration.

Probes like this are able, at least to some extent, to use local resources, which could involve manufacturing, hence the potential wave of new probes to further destinations. Agile and adaptive, they can cope with unexpected situations and produce and test hypotheses. A ‘Gödel machine’ contains a program that interacts with its environment and is capable of modification as it searches for proofs that such changes will produce benefits for the mission. Such a machine, write the authors, could “…modify any part of its code, including the proof searcher itself and the utility function which sums up the rewards…” and could “…modify its soft- and hardware with respect to a specific environment and even set its goals.”

‘Philosopher’ probes deserve more exploration, which I’ll get into tomorrow. But Hein and Baxter develop a taxonomy that includes four types, distinguished in terms of their objectives. We’ll need to look at samples of each as we consider AI and AGI as currently envisioned. The mix of formal and qualitative analysis available in this paper opens many a speculative door, pointing toward the paper’s design of a generic AI probe and predictions about AI availability.

The paper is Hein & Baxter, “Artificial Intelligence for Interstellar Travel,” submitted to JBIS (preprint).