The scientific rationale behind it is that at km-depth there could be a) water resources (which could support a biosphere) and b) understand the formation of Mars. I would argue that an efficient drilling (robot) is also valuable for possible developing underground habitation (caves) at some point.
This paper mentions two drilling concepts, but we could come up with many more (bio-inspired) probably. Daniel already came up with a nice one.. microwave drilling
Also, the NASA InSight probe to Mars in 2016 is using a DLR-designed 'Mole' drill that is designed to reach a depth of... 5 meters
"Over the past couple of decades, the research literature has filled up with endless new nature-based metaphors for algorithms. You can find algorithms based on the behaviour of cuckoos, bees, bats, cats, wolves, galaxy formation and black holes. (...) All researchers have been doing is wasting time on developing new approaches that are probably little better than existing ones. And the language of each metaphor then invades the literature, distracting people from using the already sufficiently expressive terminology of mathematics and, above all, working together to find the best way forward."
The golden era of fireworks-like algorithm is about to end