beryllium-hydrazine mix is the fuel for what bipropellant rocket engine?
Entity
m.02xlt61
RD-550
class entity
spaceflight.bipropellant_rocket_engine m.02xhb60
spaceflight.bipropellant_rocket_engine spaceflight.rocket_engine_fuel
Bipropellant rocket engine Beryllium-hydrazine mix
none none
spaceflight.bipropellant_rocket_engine.fuel
Fuel
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :spaceflight.bipropellant_rocket_engine . 
VALUES ?x1 { :m.02xhb60 } 
?x0 :spaceflight.bipropellant_rocket_engine.fuel ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND spaceflight.bipropellant_rocket_engine (JOIN spaceflight.bipropellant_rocket_engine.fuel m.02xhb60))