the kestrel uses what fuel?
Entity Entity
m.021vvd m.01tm_5
RP-1 Liquid oxygen
class class entity
spaceflight.rocket_fuel spaceflight.rocket_stage m.03g0sk
spaceflight.rocket_fuel spaceflight.rocket_stage spaceflight.bipropellant_rocket_engine
Rocket Fuel Rocket Stage Kestrel
none none none
spaceflight.rocket_stage.fuel spaceflight.rocket_stage.engine
Fuels Engine
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.rocket_fuel . 
?x1 :type.object.type :spaceflight.rocket_stage . 
VALUES ?x2 { :m.03g0sk } 
?x1 :spaceflight.rocket_stage.fuel ?x0 . 
?x1 :spaceflight.rocket_stage.engine ?x2 . 
FILTER ( ?x0 != ?x1 && ?x0 != ?x2 && ?x1 != ?x2  )
}
}
(AND spaceflight.rocket_fuel (JOIN (R spaceflight.rocket_stage.fuel) (JOIN spaceflight.rocket_stage.engine m.03g0sk)))