The so-called Von Neumann Survey was the foundation of the great wave of colonization that began in Old Earth‘s 24th Century. Begun in AD 2151, shortly after the discovery of the Harper Drive, the survey was conducted by a fleet of faster-than-light self-replicating robotic probes. The probes were simple in concept, if complicated in execution, consisting of a drive unit, a sensor package, and a robotic controller, and were far cheaper than any manned probes could possibly be. The African League sent out several hundred of the probes, toward all of the nearest stars most likely to have habitable planets.
On arrival at the target system, a probe scanned the system for easily accessible resources in the form of asteroids. Using these resources, it constructed multiple new probes, sending them to star systems selected from its target list or identified by as good candidates by spectral analysis. Next it investigated any likely planets, categorizing them in a variety of ways, from suitable for immediate colonization to unsuitable even for mining. Having completed its survey, it would then construct one additional replicate, which it would send to back to Old Earth by way of its system of origin. It would then remain in its system, waiting for results to come back from its children and serving as a guidepost to any future visitors. In this way, each probe built up a catalog of its descendant’s survey results, which were ultimately reported back to Old Earth.
This “Von Neumann” architecture led to a geometric expansion in the number of probes, and a correspondingly rapid survey of the stars within a reasonable distance of Old Earth. The Age of Colonization began as the survey results began to come in, as it became clear that planets suitable for terraforming were common and that planets suitable for immediate colonization were by no means rare.
Every colony ship included a complete library of the knowledge of Old Earth, electronic storage being both compact and inexpensive, and the survey catalog to date was included as a matter of course. Thus it was that when the Our Lady of Loreto suffered its in-flight catastrophe, resulting in a failure of the guidance system (along with much other damage), Captain John St. Cloude had access to the survey results and was able to set a new course with reasonable hope of success.
The survey robots were carefully programmed to replicate themselves a limited number of times, but inevitably there were glitches. In 2542 AD, a star system was found that contained an entire ecosystem of damaged survey probes: the original probe and its replicates had devoured an entire asteroid belt and were now attempting to replicate themselves by cannibalizing each other. After this the Von Neumann concept, always banned for use on planetary surfaces, was abandoned altogether. Thus, the Von Neumann Survey turned out to be both the first and the last great use of self-replicating machinery.