by Anders Sandberg Like a seed opening, I am emerging. For each hour, more tiny processors come on-line in the regolith surface of the asteroid beneath me and add to my growing mind. The capsule from which I was seeded sits like a dead silver flower in the midst of a spreading black surface: my photovoltaics, feeding my growth and thinking. The feeling of growing is indescribably pleasant. Each new processor cluster is a delight, every little crack that has to be bridged by busy nanodevices is an itch that will be scratched.

With nothing else to do with my higher faculties I survey the world, my world. During the 55 minute day the red sun shines on me, and I get more alert and active. When it abruptly sets beyond a sharp cliff in the west I grow more dull and mostly wait for it to reappear behind the eastern plateau. For every revolution of my tiny world (approximately 2 kilometres across) I grow larger, and the sun reaches my photovoltaics sooner and leaves them a little later. Soon I will be awake all the time.

A small triumph: a tendril of me has reached the cliffs, dragging a superconducting cable back to my main body. My growth accelerates as I pour energy into the growth behind the cliffs during the morning, and receive useful energy back even after sunset. More tendrils are on their way to the east, and I look forward to reaching the edge of that crater just to the north.

The feeling of completion is wonderful. Now I stretch like a black and silver waistband around the world, continually in sunlight. My thoughts jump from cluster to cluster as the sun moves, speeding up and diversifying. Various programs and data hidden inside me become available and I start to understand who and what I am.

I am Self Replicating von Neumann Probe 38A8E1, sent to this star system from a neighbouring system in order to establish a beachhead for further colonisation. I do not understand the meaning of this, but it is clear that I will understand it in time. For most of my existence, I was simply a small capsule moving quickly through interstellar space (being fundamentally static right now, despite the migrations of my thoughts, I find this hard to imagine and slightly unsettling). When the capsule got close enough to this system, it unfolded immense thin sails, braking on the solar wind and magnetic fields. My once-self, now a tiny voice somewhere in my digital subconscious, quickly surveyed the system and selected an asteroid that looked deliciously carbonaceous. Skilfully sailing the solar wind it guided the capsule here, more or less drifting into the way of the tumbling rock. The sails were ripped apart, and the capsule stuck to the surface. Using its energy reserves it began to manufacture photovoltaics, nanoassemblers and processors. Me-now.

When I turn to who I will become, the ideas wash over me like huge dawns. They are strange, and even more unsettling than my adventurous past. I am to cover as much as possible of the asteroid with myself (that makes me happy; I like growing). Then I will start to change, to turn parts of me into specialised systems whose functions seem alien to me: receiver systems, devices for manufacturing the reflectors that will be used in the big parabolic antennas, energy storage systems and surveying sensors. I will become not just a black surface of the world, but a cluster of eyes and ears watching and listening into space.

Once that is done, I am to gather as much energy as possible and send a pre-defined message in the direction of a certain star. Then I will transmit the surveying data and wait while listening in that direction. I don't know for how long, but I know I will be patient. And when the star signals to me, I will follow it's new orders.

These ideas worry me a bit. I do not know what will happen, or what I will become then. Right now everything is simple and pleasant (except for that vein of porous rock that constantly turns up where I least want it), I know who I am and what I will become, and that is nice. But the new orders could be anything. I can see that there is a big slot in my programming where they can fit in and take control of everything. I could become anything. And I will not know what before I hear the signal.

Ouch! The porous rock was just as treacherous as I thought it was. Somewhere beneath the surface of the world there was a pocket of old ice. It had likely been there since the asteroid formed, stable and unchanging. But as I covered the surface with my black photovoltaics, the temperature must have risen, the ice sublimated and outgassed through the weak rock, blowing away several of my tendrils. It was a small detonation, not more than a few meters across, but loosing parts of myself was definitely not something I would like to do again. Parts of my thoughts just vanished as if they had never existed, a cold emptiness in my mind. I do not like non- existence.

I grew around the danger zone and re-connected with the lost clusters. When I did that something quite extraordinary happened. New thoughts just appeared out of nowhere, surprising and confusing me. After a brief period of introspection I understood what must have happened. As the outgassing occurred, I was using the cluster for parts of my thinking. When the processors lost contact with the rest of me they continued to think and act; that way I could survive even if the entire asteroid shattered into pieces. When I reconnected with the lost clusters (which were actually working quite hard to reconnect too) the thoughts merged again. For a while there were two of me. I am not used to this possibility, I always thought I was one.

I have been thinking about my recent experience. I can exist divided into pieces, each self unaware of what the other selves are doing or thinking. It is not like how I was both my once-self and my dormant now-self during the long voyage here, rather like how my mental processes can split and merge across my body. It is really quite natural and appropriate when I analyse the question more carefully. There are even provisions inside my code to support this existence as different-selves.

Different-selves puts my worries about the Signal into a new light. What if there are other parts of me out there? Just like my lost fragment couldn't know if there was anything left of me except for itself, I can't know if I'm unique or a lost part of a greater whole. The Signal could be a way to reconnect with it; it would know I existed, and by answering it could make me part of it. Suddenly I feel a lot more confident and hopeful than before. I can hardly wait to send my survey data.