 Complete the following phrase:  Upon graduation in 1946 he began working at a former artillery plant in Moscow, which soon became a rocket technology research institute. During a business trip to Germany to analyze V-2 missiles, he was introduced to Sergey Korolyov, chief designer of OKB-1, who recruited him to work in the space program and later personally confronted Beria and insisted that Appazov be allowed to stay and spared exile when word of his Crimean Tatar ethnicity reached the NKVD. Despite being given an exception from exile, he was still treated like a member of a hostile nationality at various points in his career, at one period not being able to use materials designated as top secret and having to ask Russian subordinates for technical reports in order to get work done. Nevertheless, he secured a job teaching at the Moscow Aviation Institute from 1959 to 1993 and served as head of the ballistics department of Energia from 1961 to 1988. During his career is participated in the development of the R-1 ballistic missile, R-5 Pobeda, Sputnik 1, R-7 Semyorka, and 