package net.sf.openrocket.simulation;
+import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import net.sf.openrocket.rocketcomponent.RecoveryDevice;
import net.sf.openrocket.rocketcomponent.RocketComponent;
import net.sf.openrocket.rocketcomponent.Stage;
+import net.sf.openrocket.simulation.customexpression.CustomExpression;
import net.sf.openrocket.simulation.exception.MotorIgnitionException;
import net.sf.openrocket.simulation.exception.SimulationException;
import net.sf.openrocket.simulation.exception.SimulationLaunchException;