215 Cost Analysis of Space Exploration for an Extraterrestrial Civilization Yvan Dutil and Stéphane Dumas 1.0. Introduction Are some civilizations bound to their home planet because the local gravitational field is too strong? Can space exploration be so difficult that a civilization might just give up before even trying? Are we favored compared to our galactic neighbors? Analysis of the relative cost of space exploration between planets, in light of the physical characteristics of a civilization’s planet of origin, might provide some insight into the problem of the Fermi paradox or in a more general way the possibility of physical contact between civilizations. This is not a trivial issue, since there may be some advantage to using space probes as an effective way to communicate between civilizations (Rose and Wright 2004). Such contacts do not need to be done by sentient beings themselves, as advanced automated space probes could achieve the same goal (Bracewell 1960; von Neumann and Burks 1966; Boyce 1979). Nevertheless, even classical SETI can benefit from space exploration capabilities. For example, it would be helpful to place a SETI observatory on the lunar far side to avoid local radio interference (Heidmann 1994). Ironically, spacefaring capabilities would make this type of SETI project even more attractive, as interference shielding is more complex when interfering sources are themselves in space. Alternatively, an extraterrestrial civilization might want to take advantage of the gravitational focusing of the Sun to increase the sensitivity of its SETI project, which would require significant spacefaring capabilities, as noted in the immediately preceding chapter in this volume (Maccone 2011). We are constructing our analysis around a simple and sound scenario. Before exploring interstellar space, a civilization must first succeed in achieving two earlier steps of exploration: getting above the atmosphere in the lowest possible orbit and moving between planets within their own stellar system. Once these steps have been mastered, there will be little variation in interstellar mission costs. In consequence, if the cost of launching a satellite in low orbit and reaching another nearby planet is prohibitive, an extraterrestrial civilization might simply give up space exploration and direct its resources elsewhere. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 SP_VAK_14_215-222.indd 215 1/6/11 4:03 PM