diff --git a/core/src/main/java/info/openrocket/core/document/Simulation.java b/core/src/main/java/info/openrocket/core/document/Simulation.java
index d9d1530fb..3ec5ae0f3 100644
--- a/core/src/main/java/info/openrocket/core/document/Simulation.java
+++ b/core/src/main/java/info/openrocket/core/document/Simulation.java
@@ -399,14 +399,14 @@ public class Simulation implements ChangeSource, Cloneable {
 	public void simulate(SimulationListener... additionalListeners)
 			throws SimulationException {
 		mutex.lock("simulate");
+		SimulationEngine simulator = null;
+		simulatedData = null;
 		try {
 			
 			if (this.status == Status.EXTERNAL) {
 				throw new SimulationException("Cannot simulate imported simulation.");
 			}
 			
-			SimulationEngine simulator;
-			
 			try {
 				simulator = simulationEngineClass.getConstructor().newInstance();
 			} catch (InstantiationException e) {
@@ -430,18 +430,20 @@ public class Simulation implements ChangeSource, Cloneable {
 			long t1, t2;
 			log.debug("Simulation: calling simulator");
 			t1 = System.currentTimeMillis();
-			simulatedData = simulator.simulate(simulationConditions);
+			simulator.simulate(simulationConditions);
 			t2 = System.currentTimeMillis();
 			log.debug("Simulation: returning from simulator, simulation took " + (t2 - t1) + "ms");
 
 		} catch (SimulationException e) {
-			simulatedData = e.getFlightData();
 			throw e;
 		} finally {
 			// Set simulated info after simulation
 			simulatedConditions = options.clone();
 			simulatedConfigurationDescription = descriptor.format(this.rocket, getId());
 			simulatedConfigurationID = getActiveConfiguration().getModID();
+			if (simulator != null) {
+				simulatedData = simulator.getFlightData();
+			}
 			
 			status = Status.UPTODATE;
 			fireChangeEvent();
diff --git a/core/src/main/java/info/openrocket/core/simulation/BasicEventSimulationEngine.java b/core/src/main/java/info/openrocket/core/simulation/BasicEventSimulationEngine.java
index 54796229f..9df170e61 100644
--- a/core/src/main/java/info/openrocket/core/simulation/BasicEventSimulationEngine.java
+++ b/core/src/main/java/info/openrocket/core/simulation/BasicEventSimulationEngine.java
@@ -62,7 +62,7 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 	FlightData flightData;
 	
 	@Override
-	public FlightData simulate(SimulationConditions simulationConditions) throws SimulationException {
+	public void simulate(SimulationConditions simulationConditions) throws SimulationException {
 		
 		// Set up flight data
 		flightData = new FlightData();
@@ -148,7 +148,6 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 		}
 
 		flightData.calculateInterestingValues();
-		return flightData;
 	}
 	
 	private void simulateLoop() throws SimulationException {
@@ -740,10 +739,10 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 		try {
 			SimulationConditions conds = currentStatus.getSimulationConditions().clone();
 			conds.getSimulationListenerList().add(OptimumCoastListener.INSTANCE);
-			BasicEventSimulationEngine e = new BasicEventSimulationEngine();
+			BasicEventSimulationEngine coastEngine = new BasicEventSimulationEngine();
 		
-			FlightData d = e.simulate(conds);
-			return d;
+			coastEngine.simulate(conds);
+			return coastEngine.getFlightData();
 		} catch (SimulationException e) {
 			throw e;
 		} catch (Exception e) {
@@ -751,4 +750,8 @@ public class BasicEventSimulationEngine implements SimulationEngine {
 			return null;
 		}
 	}
+
+	public FlightData getFlightData() {
+		return flightData;
+	}
 }
diff --git a/core/src/main/java/info/openrocket/core/simulation/SimulationEngine.java b/core/src/main/java/info/openrocket/core/simulation/SimulationEngine.java
index fcda5efec..d4ddb3e8f 100644
--- a/core/src/main/java/info/openrocket/core/simulation/SimulationEngine.java
+++ b/core/src/main/java/info/openrocket/core/simulation/SimulationEngine.java
@@ -17,10 +17,16 @@ public interface SimulationEngine {
 	 * Simulate the flight of a rocket.
 	 * 
 	 * @param simulation the simulation conditions which to simulate.
-	 * @return a FlightData object containing the simulated data.
 	 * @throws SimulationException if an error occurs during simulation
 	 */
-	public FlightData simulate(SimulationConditions simulation)
+	public void simulate(SimulationConditions simulation)
 			throws SimulationException;
 
+	/**
+	 * Obtain data generated by simulation
+	 *
+	 * @return flight data
+	 */
+	public FlightData getFlightData();
+
 }