Encyclopedia entry A-350-1 Stage · Russia Original archive entry. The text, images and links below are kept as they were written. N2O4/UDMH rocket stage. Mass 15,000 kg (33,069 lb). RelatedFamilyStorable liquidCountryRussiaLaunch VehiclesA-350RPropellantsN2O4/UDMHStagesA-350-1AgencySKB-350