After selection in 1989 as a Payload Specialist by the Italian Space Agency (ASI) and NASA, he became a staff member of ASI and was assigned to the NASA Johnson Space Center, Houston, Texas, for training. In September 1991, he was designated Prime Payload Specialist for the TSS-1 Space Shuttle mission. Malerba flew as the first Italian citizen in space on STS-46 (31 July 1992 to 7 August 1992). He is now involved with the Italian Space Agency (ASI) manned space flight program follow-on activities.