As robots are increasingly designed and marketed for social adoption, questions emerge about manufacturers’ ethical responsibilities for ensuring continuity of their creations. However, addressing such questions first requires advancing empirical understandings of how humans experience robots’ metaphorical death (i.e., functional cessation). This study advances that aim by exploring an interstitial: public reactions to a known robot’s functional cessation (RFC). Focusing on a specific RFC event—the official announced demise of the “Opportunity” Mars rover—this study unpacked experience dimensions by inductively analyzing public tweets about the event. Semantic network analysis of N = 10,303 tweets is interpreted as indicating 11 key expressed themes (robot legacy, journey, last words, persistence, contributions, and death finality; physiological and emotional reactions; formal and meme-based salutations and memorializing). Interpretation of network content suggests three potential overarching orientations toward the RFC event: cessation as death, as milestone, and as material loss.