The Decent Engines Arrive Cocoon’s payload for its latest flight into space has been two of the decent engines for the ML One spacecraft currently docked at the enlarged American section of the International Space Station. Each ML spacecraft needs to be fitted with four of these huge liquid fuelled, variable thrust engines as part of the next phase of its assembly sequence. Moving in slowly, ever so slowly, in a well rehearsed and co-ordinated capture procedure the Orbital Shuttle’s Atlantis and Discovery each use their two cargo-bay based robotic arms to lock-on to one of the huge decent engines.