find bipropellant rocket engine, with a status of flown, whose thrust (sea level) is more than or equal to 0.0.
(AND spaceflight.bipropellant_rocket_engine (AND (JOIN spaceflight.rocket_engine.status m.03p41f7) (ge spaceflight.rocket_engine.thrust_sea_level 0.0^^http://www.w3.org/2001/XMLSchema#float)))