 The score was composed by Gray , who served as musical director for all of the Anderson productions up to the first series of Space : 1999 . In response to Gerry Anderson 's request that the main theme have a " military feel " , Gray produced a brass @-@ dominated piece titled " The Thunderbirds March " , which was recorded in December 1964 at Olympic Studios in London . The end titles were originally to have been accompanied by " Flying High " , a lyrical track sung by Gary Miller with backing by Ken <unk> . Ultimately , a variation of the march was used instead . <unk> music was recorded over nine months between March and December 1965 . As most of the music budget was spent on the series ' earlier episodes , later instalments drew heavily on APF 's ever @-@ expanding music library . 
