  Let G be a reductive group. The geometric Satake equivalence realized the
category of representations of the Langlands dual group ^LG in terms of
spherical perverse sheaves (or D-modules) on the affine Grassmannian
Gr_G=G((t))/G[[t]] of the original group G.
  In the present paper we perform a first step in realizing the category of
representations of the quantum group corresponding to ^LG in terms of the
geometry of Gr_G.
  The idea of the construction belongs to Jacob Lurie.
