We use images from the Hubble Space Telescope to determine the distances to a dozen objects with low surface brightness recently observed around the bright nearby spiral M101 .
Only two dwarf galaxies , M101-DwA and M101-Dw9 , turn out to be actual satellites of M101 at distances of about 7 Mpc .
The other objects are probably members of a distant group around the S0-galaxies NGC 5485/5473 .
Based on the radial velocities and projected separations of the 9 satellites , we obtain an estimate of ( 8.5 \pm 3.0 ) \times 10 ^ { 11 } M _ { \odot } for the total mass of M101 , which is consistent with a ratio 16 \pm 6 for the total mass to the stellar mass of the galaxy .