The ministry is also trying to enhance the capability of the missile intercept command system known as the Japan Aerospace Defense Ground Environment to efficiently operate the nation's two-stage missile defense, along with the acquisition of additional missiles, according to the sources. Hypersonic missiles come in two types: hypersonic cruise missiles (HCM) powered by engines; and hypersonic glide vehicles (HGV), which glide to their targets after being launched from rocket boosters. Russia and China are ahead of other countries in HGV technology, according to defense experts. Japan plans to introduce a missile defense system that can deal with HGVs to future Aegis ships, the sources said.