diff --git a/source/scriptinterface/ScriptInterface.cpp b/source/scriptinterface/ScriptInterface.cpp
index 71cc9e9786..b8efb32a3b 100644
--- a/source/scriptinterface/ScriptInterface.cpp
+++ b/source/scriptinterface/ScriptInterface.cpp
@@ -239,6 +239,9 @@ struct ScriptInterface_impl
 	JSContext* m_cx;
 	JSObject* m_glob; // global scope object
 	JSObject* m_nativeScope; // native function scope object
+
+	typedef std::map<ScriptInterface::CACHED_VAL, CScriptValRooted> ScriptValCache;
+	ScriptValCache m_ScriptValCache;
 };
 
 namespace
@@ -529,6 +532,9 @@ ScriptInterface_impl::ScriptInterface_impl(const char* nativeScopeName, const sh
 
 ScriptInterface_impl::~ScriptInterface_impl()
 {
+	// Important: this must come before JS_DestroyContext because CScriptValRooted needs the context to unroot the values!
+	// TODO: Check again when SpiderMonkey is upgraded and when/if CScriptValRooted gets replaces by JS::Heap<T>.
+	m_ScriptValCache.clear(); 
 	JS_DestroyContext(m_cx);
 }
 
@@ -610,6 +616,12 @@ ScriptInterface::CxPrivate* ScriptInterface::GetScriptInterfaceAndCBData(JSConte
 	return pCxPrivate;
 }
 
+CScriptValRooted ScriptInterface::GetCachedValue(CACHED_VAL valueIdentifier)
+{
+	return m->m_ScriptValCache[valueIdentifier];
+}
+
+
 bool ScriptInterface::LoadGlobalScripts()
 {
 	// Ignore this failure in tests
@@ -629,9 +641,9 @@ bool ScriptInterface::LoadGlobalScripts()
 	}
 	jsval proto;
 	if (JS_GetProperty(m->m_cx, JS_GetGlobalObject(m->m_cx), "Vector2Dprototype", &proto))
-		vector2Dprototype = CScriptValRooted(m->m_cx, proto);
+		m->m_ScriptValCache[CACHE_VECTOR2DPROTO] = CScriptValRooted(m->m_cx, proto);
 	if (JS_GetProperty(m->m_cx, JS_GetGlobalObject(m->m_cx), "Vector3Dprototype", &proto))
-		vector3Dprototype = CScriptValRooted(m->m_cx, proto);
+		m->m_ScriptValCache[CACHE_VECTOR3DPROTO] = CScriptValRooted(m->m_cx, proto);
 	return true;
 }
 
diff --git a/source/scriptinterface/ScriptInterface.h b/source/scriptinterface/ScriptInterface.h
index e5b88798ce..8aa569a28f 100644
--- a/source/scriptinterface/ScriptInterface.h
+++ b/source/scriptinterface/ScriptInterface.h
@@ -91,8 +91,6 @@ public:
 	 */
 	static shared_ptr<ScriptRuntime> CreateRuntime(int runtimeSize = DEFAULT_RUNTIME_SIZE);
 
-	CScriptValRooted vector2Dprototype;
-	CScriptValRooted vector3Dprototype;
 
 	/**
 	 * Constructor.
@@ -130,6 +128,9 @@ public:
 	 */
 	bool LoadGlobalScripts();
 
+	enum CACHED_VAL { CACHE_VECTOR2DPROTO, CACHE_VECTOR3DPROTO };
+	CScriptValRooted GetCachedValue(CACHED_VAL valueIdentifier);
+
 	/**
 	 * Replace the default JS random number geenrator with a seeded, network-sync'd one.
 	 */
diff --git a/source/simulation2/scripting/EngineScriptConversions.cpp b/source/simulation2/scripting/EngineScriptConversions.cpp
index f902a00775..5e87a5ba20 100644
--- a/source/simulation2/scripting/EngineScriptConversions.cpp
+++ b/source/simulation2/scripting/EngineScriptConversions.cpp
@@ -165,7 +165,7 @@ template<> jsval ScriptInterface::ToJSVal<CFixedVector3D>(JSContext* cx, const C
 {
 	// apply the Vector3D prototype to the return value;
  	ScriptInterface::CxPrivate* pCxPrivate = ScriptInterface::GetScriptInterfaceAndCBData(cx);
-	JSObject* obj = JS_NewObject(cx, NULL, JSVAL_TO_OBJECT(pCxPrivate->pScriptInterface->vector3Dprototype.get()), NULL);
+	JSObject* obj = JS_NewObject(cx, NULL, JSVAL_TO_OBJECT(pCxPrivate->pScriptInterface->GetCachedValue(ScriptInterface::CACHE_VECTOR3DPROTO).get()), NULL);
 
 	if (!obj)
 		return JSVAL_VOID;
@@ -202,7 +202,7 @@ template<> jsval ScriptInterface::ToJSVal<CFixedVector2D>(JSContext* cx, const C
 {
 	// apply the Vector2D prototype to the return value
  	ScriptInterface::CxPrivate* pCxPrivate = ScriptInterface::GetScriptInterfaceAndCBData(cx);
-	JSObject* obj = JS_NewObject(cx, NULL, JSVAL_TO_OBJECT(pCxPrivate->pScriptInterface->vector2Dprototype.get()), NULL);
+	JSObject* obj = JS_NewObject(cx, NULL, JSVAL_TO_OBJECT(pCxPrivate->pScriptInterface->GetCachedValue(ScriptInterface::CACHE_VECTOR2DPROTO).get()), NULL);
 
 	if (!obj)
 		return JSVAL_VOID;