we're nowhere close to building anything sophisticated that's mechanically self-replicating. Imagine how much infrastructure we would need on Mars say, in order

we're nowhere close to building anything sophisticated that's mechanically self-replicating. Imagine how much infrastructure we would need on Mars say, in order to have a self sufficient civilisation capable of building robot probes. They'd need ore extraction and refining, smelting, chemical synthesis for a huge range of materials, silicon chip fabrication. Now package all of that into a single vehicle. The management system alone for all of that under automatic control would likely have to be a functional strong AI and we're a very long way from knowing how to build one of those.