<Page> EXHIBIT 12.1 XM SATELLITE RADIO HOLDINGS INC. AND SUBSIDIARIES COMPUTATION OF RATIOS OF EARNINGS TO FIXED CHARGES ($ IN THOUSANDS) <Table> <Caption> RATIO OF EARNINGS (LOSS) TO FIXED CHARGES ----------------------------------------------------------------------------------------------- YEAR ENDED DECEMBER 31, PRO FORMA THREE MONTHS ENDED PRO FORMA --------------------------------------- DECEMBER 31, MARCH 31, MARCH 31, 1998 1999 2000 2001 2002 2002 (2) 2002 2003 2003 (2) ---- ---- ---- ---- ---- ------------ ---- ---- ---------- FIXED CHARGES: Capitalized interest......... 13,145 15,821 39,052 45,211 -- -- -- -- -- Interest expensed............ -- 9,120 -- 18,131 63,573 85,430 15,999 23,799 29,263 Portion of rent expense representative of interest (1)............... 76 216 2,027 7,575 6,646 6,646 1,182 2,441 2,441 -------- -------- -------- --------- --------- --------- --------- --------- -------- Total fixed charges........ $ 13,221 $ 25,157 $ 41,079 $ 70,917 $ 70,219 $ 92,076 $ 17,181 $ 26,240 $ 31,704 ======== ======== ======== ========= ========= ========= ========= ========= ========= EARNINGS: Loss before income taxes..... $(16,167) $(36,896) $(51,873) $(284,379) $(495,012) $(516,869) $(112,250) $(126,282) $(131,746) Fixed charges, less capitalized interest....... 76 9,336 2,027 25,706 70,219 92,076 17,181 26,240 31,704 Depreciation and write-off of capitalized interest preferred dividends........ -- -- -- 6,888 9,136 9,136 2,909 2,765 2,765 -------- -------- -------- --------- --------- --------- --------- --------- --------- Earnings (loss) adjusted for fixed charges.............. (16,091) (27,560) (49,846) (251,785) (415,657) (415,657) (92,160) (97,277) (97,277) Ratio of earnings (loss) to combined fixed charges and preferred dividends.......... -- -- -- -- -- -- -- -- -- Deficiency in earnings to cover fixed charges................ 29,312 52,717 90,925 322,702 485,876 507,733 109,341 123,517 128,981 </Table> - --------------- (1) One-third of rent expense is deemed to be representative of interest. (2) Pro forma deficiency of earnings to cover fixed charges is calculated based on the annual interest rate on the 12% senior secured notes due 2010 plus the amortization of deferred financing fees as of the beginning of the period.