there is a lack of data that related performance to team composition and cohesion due to the evolution of job duties and selection practices over the history of manned spaceflight as well as the limited number of astronauts actually selected (340 u.s. astronauts to date). these issues are relevant to other space agencies as well. in 1990, a european astronaut working group reevaluated selection criteria for the selection of european astronauts as russian researchers have collected personality data on cosmonauts for a number of years. the empirical linking of personality factors to specific performance levels still eludes researchers.