Astra's rhymes with:
extras, orchestra's, orchestras, artra's, chitra's, cleopatra's, contras, contras', extras, matra's, orchestra's, orchestras, petras, pietras, sinatra's, spectra's, ultra's
Astra's sounds like:
actor's, actors, actors', actress, actress's, actresses, actuaries, actuators, agitators, ashtrays, asterisk, asters, astor's, astorga, astros, austrasia, austria's, awestruck