  Satellite galaxies of the Milky Way are among the most promising targets for
dark matter searches in gamma rays. We present a search for dark matter
consisting of weakly interacting massive particles, applying a joint likelihood
analysis to 10 satellite galaxies with 24 months of data of the Fermi Large
Area Telescope. No dark matter signal is detected. Including the uncertainty in
the dark matter distribution, robust upper limits are placed on dark matter
annihilation cross sections. The 95% confidence level upper limits range from
about 1e-26 cm^3 s^-1 at 5 GeV to about 5e-23 cm^3 s^-1 at 1 TeV, depending on
the dark matter annihilation final state. For the first time, using gamma rays,
we are able to rule out models with the most generic cross section (~3e-26 cm^3
s^-1 for a purely s-wave cross section), without assuming additional boost
factors.
