The "mole" is actually an interesting bit of engineering, since they wanted to dig to a depth of something like 16 ft IIRC, and obviously needed to keep the weight down. It's a sort of self-hammering nail.
And it almost turned into a highly engineered dud producing no scientific results for all the effort that went into it. I'm glad that they didn't give up on it easily.
The "mole" is actually an interesting bit of engineering, since they wanted to dig to a depth of something like 16 ft IIRC, and obviously needed to keep the weight down. It's a sort of self-hammering nail.