QB50 is a network of 50 CubeSats in a string of pearls configuration that will be launched in the mid April of 2015 by a single launch vehicle into a circular orbit at 350 km altitude. The mission lifetime according to the launch date of CubeSats from the initial altitude to 90 km is currently estimated to be about 3 months. The use of a single launch vehicle to deploy CubeSats into a formation is faster and cheaper; however, there is greater risk of collision. The risk must be reduced with the proper deployment direction, sequence and frequency. This paper gives one of the solutions for the minimization of the risk of collision between the deployed CubeSat and the upper stage and the optimization of the distribution of double unit CubeSats all the way around the Earth.