> how do you ensure that the people 400 years from now would know what they are for or how to implant them?
A ship travelling at 0.01c for 400 years could get 4 ly away. They'd still be able to be coached. More likely: their computers would still be able to be updated.
Of course there is this thing is that while they were coasting faster technology was developed and another ship arrived way before them, with better computers, engines, everything.
Well, that, and how do you ensure that the people 400 years from now would know what they are for or how to implant them?
Lots of unknowns. Would make for an interesting story though