Simplify the following text for a Grade 4 native English-speaking person.
Original: The light Angara 1.1 and 1.2 versions will replace the Kosmos-3M , Tsyklon and Rockot launchers ; Angara 3 will replace the Ukrainian Zenit and Angara 5 will replace the heavy-lift Proton . The Angara 5 version is expected to be most in demand , since this is the main version required by the Russian Ministry of Defense .
Simplified: The small version , Angara 1.1 has only one URM , while the heavier Angara 5 has 5 URMs .