Separation from the service module prepared the command module for reentry by exposing the heat shield and shedding unneeded mass.
sˌɛpɚɹˈeɪʃən fɹʌmðə sˈɜːvɪs mˈɑːdʒuːl pɹɪpˈɛɹd ðə kəmˈænd mˈɑːdʒuːl fɔːɹ ɹiːˈɛntɹi baɪ ɛkspˈoʊzɪŋ ðə hˈiːt ʃˈiːld ænd ʃˈɛdɪŋ ʌnnˈiːdᵻd mˈæs.