Science fiction novels and Hollywood movies have explored the subject of alien encounters for decades, but they provide little in the way of practical guidance on how humankind should respond to a verified discovery of extraterrestrial (ET) life. Today we are in the midst of unprecedented advances in our understanding of the potential for life in space. Without exaggeration, the prospects for finding ET life seem more likely all the time, raising questions of how well we are prepared to respond to a discovery. Do we Earthlings have the necessary plans and preparations for responding to potential risks and impacts of different discovery scenarios? Would it matter what kind of life is discovered first? Who would be involved in decision making on behalf of humankind?

This chapter takes a systematic approach to evaluating in detail how current decision-making processes and policies are prepared to deal with future discoveries and the associated risks and consequences of interacting with different types of ET life. It examines the three main search types (SETI, extrasolar planets, and Solar System searches), at three different search phases (during searches, upon discovery, and post discovery) and assesses comparative preparedness for systematic deliberations involving multiple stakeholders, scientific and otherwise. The evaluation borrows heavily from approaches used by the hazard-management and risk-analysis communities, which have extensive experience and research involving threats of many types, whether natural or man-made, and predictable, deliberate, or accidental (Alexander 2000; Eisner et al. 2012; Tierney 2014). In addition to providing a detailed comparison of current search efforts, this risk-centered approach also serves to highlight particular topics or procedural steps that may need more attention in order to develop practical and coordinated implementation plans for responding to any future discovery of ET life, whenever and wherever it may occur.

Putting searches in context

Before discussing the similarities and differences between current searches, it is important to recognize that there is no such thing as planning a response to the discovery of ET life, but rather multiple responses, built upon the characteristics of the different search efforts under way. Each anticipates different scenarios and types of life (intelligent, complex, or simple) as well as potential impacts, risks, and timeframes. In addition, each raises assorted questions that will require inputs from different perspectives – scientific and otherwise – regardless of who makes the first discovery.