Single Spin Asymmetry $A_N$ (SSA) was measured at the Protvino 70 GeV accelerator. Asymmetry in the reaction $ppdup$ is close to zero within error bars at small $|xf|$ and $p_T<1.5$ GeV/c. SSA in the reaction $pimp$ at polarized target fragmentation region equals to $(-13.8 pm 3.8)%$ at $|x_f|>0.4$. There is an indication that the asymmetry begins to rise up at the same centre of mass system pion energy.