Yangel had been Korolev's assistant but with the support of the military, he was given his own design bureau in 1954 to work primarily on the military space program. This had the stronger rocket engine design team including the use of hypergolic fuels but following the Nedelin catastrophe in 1960 Yangel was directed to concentrate on ICBM development. He also continued to develop his own heavy booster designs similar to Korolev's N-1 both for military applications and for cargo flights into space to build future space stations.