Astroengineering is the construction of very large artificial objects in space by technologically advanced beings. Searching for the radiation signatures of such objects, it has been suggested, represents an important alternative strategy in SETI. Among those to put forward specific suggestions in this regard are Freeman Dyson, with his remarkable Dyson spheres, and Nikolai Kardashev, with his classification scheme for advanced technological civilizations.

References

1. Beech, M. "Blue Stragglers as Indicators of Extraterrestrial Civilizations?," Earth, Moon, and Planets, 49, 177-186 (1990).
2. Dyson, F. J., "The Search for Extraterrestrial Technology," in Perspectives in Modern Physics (Essays in Honor of Hans Bethe), R. E. Marshak, ed., New York: John Wiley & Sons (1966).