A deep-sea exploration robot — one of the first successful submersible vehicles that was both unmanned and untethered to surface ships — was lost at sea Friday, March 5, on a research expedition off the coast of Chile. The 15-year-old Autonomous Benthic Explorer, affectionately nicknamed ABE, was launched late on the night of Thursday, March 4, and had reached the seafloor to begin its 222nd research dive when, in the early hours of Friday morning, all contact with the surface vessel abruptly ceased. All efforts to reestablish contact failed.