He headed the group transmitting Team Encounter's interstellar messages[5] using the Yevpatoria (Evpatoria) Deep Space Center (EDSC).

[citation needed] In June 1995, Zaitsev was responsible for initiating the world's first intercontinental radar astronomy experiment; the radar groups participating in this experiment were led by Steven Ostro at JPL, Zaitsev in Yevpatoria, and Yasuhiro Koyama in Kashima, Japan.

[citation needed] Zaitsev supervised the transmission of the 1999 and 2003 Cosmic Calls[12] from Yevpatoria Planetary Radar[13] (EPR).

Zaitsev proposed three-section structure of interstellar radio messages, coined the acronym METI (Messaging to Extra-Terrestrial Intelligence)[17][18] and the phrase 'SETI paradox',[19] which refers to an apparent "paradox" where two distant civilizations capable of interstellar communication will always remain silent unless one of them contacts the other first, resulting in a deadlock of silence.

In 2005, in article "The Drake Equation: Adding a METI Factor" he suggested that a high technology is not enough for establishing contact with Aliens because appropriate behavior directed to practical realization of sending signals is necessary too.