diff --git a/gui/MainWindow.cpp b/gui/MainWindow.cpp
index 8ff61db..d7fecc7 100644
--- a/gui/MainWindow.cpp
+++ b/gui/MainWindow.cpp
@@ -83,24 +83,24 @@ void MainWindow::on_testButton2_clicked()
    double ts = 0.01;
 
    // X position/velocity. x[0] is X position, x[1] is X velocity
-   double x[2] = {0.0, initialVelocityX};
+   std::vector<double> x = {0.0, initialVelocityX};
 
    // Y position/velocity. y[0] is Y position, y[1] is Y velocity
-   double y[2] = {0.0, initialVelocityY};
+   std::vector<double> y = {0.0, initialVelocityY};
 
-   auto xvelODE = [mass, dragCoeff](double, double* x) -> double
+   auto xvelODE = [mass, dragCoeff](double, const std::vector<double>& x) -> double
       {
 
          return -dragCoeff * 1.225 * 0.00774192 / (2.0 * mass) * x[1]*x[1]; };
-   auto xposODE = [](double, double* x) -> double { return x[1]; };
+   auto xposODE = [](double, const std::vector<double>& x) -> double { return x[1]; };
    sim::RK4Solver xSolver(xposODE, xvelODE);
    xSolver.setTimeStep(0.01);
 
-   auto yvelODE = [mass, dragCoeff](double, double* y) -> double
+   auto yvelODE = [mass, dragCoeff](double, const std::vector<double>& y) -> double
       {
 
          return -dragCoeff * 1.225 * 0.00774192 / (2.0 * mass) * y[1]*y[1] - 9.8; };
-   auto yposODE = [](double, double* y) -> double { return y[1]; };
+   auto yposODE = [](double, const std::vector<double>& y) -> double { return y[1]; };
    sim::RK4Solver ySolver(yposODE, yvelODE);
    ySolver.setTimeStep(0.01);
 
@@ -110,18 +110,16 @@ void MainWindow::on_testButton2_clicked()
    QTextStream cout(stdout);
    cout << "Initial X velocity: " << initialVelocityX << "\n";
    cout << "Initial Y velocity: " << initialVelocityY << "\n";
-   double resX[2];
-   double resY[2];
+   std::vector<double> resX(2);
+   std::vector<double> resY(2);
    for(size_t i = 0; i < maxTs; ++i)
    {
       xSolver.step(i * ts, x, resX);
       ySolver.step(i * ts, y, resY);
       position.emplace_back(resX[0], resY[0], 0.0);
 
-      x[0] = resX[0];
-      x[1] = resX[1];
-      y[0] = resY[0];
-      y[1] = resY[1];
+      x = resX;
+      y = resY;
 
       cout << "(" << position[i].getX1() << ", " << position[i].getX2() << ")\n";
       if(y[0] < 0.0)
diff --git a/main.cpp b/main.cpp
index db1c204..3b3b466 100644
--- a/main.cpp
+++ b/main.cpp
@@ -4,7 +4,9 @@
 #include <QLocale>
 #include <QTranslator>
 
-int main(int argc, char *argv[])
+#include <thread>
+
+void worker(int argc, char* argv[], int& ret)
 {
    QApplication a(argc, argv);
    a.setWindowIcon(QIcon(":/qtrocket.png"));
@@ -26,5 +28,37 @@ int main(int argc, char *argv[])
    // Go!
    MainWindow w;
    w.show();
-   return a.exec();
+   ret = a.exec();
+
+}
+
+int main(int argc, char *argv[])
+{
+   /*
+   QApplication a(argc, argv);
+   a.setWindowIcon(QIcon(":/qtrocket.png"));
+
+   // Start translation component.
+   // TODO: Only support US English at the moment. Anyone want to help translate?
+   QTranslator translator;
+   const QStringList uiLanguages = QLocale::system().uiLanguages();
+   for (const QString &locale : uiLanguages)
+   {
+      const QString baseName = "qtrocket_" + QLocale(locale).name();
+      if (translator.load(":/i18n/" + baseName))
+      {
+         a.installTranslator(&translator);
+         break;
+      }
+   }
+
+   // Go!
+   //MainWindow w;
+   //w.show();
+   //return a.exec();
+   */
+   int ret = 0;
+   std::thread guiThread(worker, argc, argv, std::ref(ret));
+   guiThread.join();
+   return ret;
 }
diff --git a/model/Rocket.cpp b/model/Rocket.cpp
index 90c3e92..6e8b268 100644
--- a/model/Rocket.cpp
+++ b/model/Rocket.cpp
@@ -2,5 +2,7 @@
 
 Rocket::Rocket()
 {
+   propagator.setTimeStep(0.01);
+   //propagator.set
 
 }
diff --git a/qtrocket.pro b/qtrocket.pro
index 5af0822..bae0fb1 100644
--- a/qtrocket.pro
+++ b/qtrocket.pro
@@ -59,6 +59,7 @@ HEADERS += \
     utils/BinMap.h \
     utils/CurlConnection.h \
     utils/Logger.h \
+    utils/TSQueue.h \
     utils/ThreadPool.h \
     utils/ThrustCurveAPI.h \
     utils/math/Constants.h \
diff --git a/sim/DESolver.h b/sim/DESolver.h
index f1cb655..2ee33e9 100644
--- a/sim/DESolver.h
+++ b/sim/DESolver.h
@@ -1,6 +1,8 @@
 #ifndef SIM_DESOLVER_H
 #define SIM_DESOLVER_H
 
+#include <vector>
+
 namespace sim
 {
 
@@ -11,7 +13,7 @@ public:
    virtual ~DESolver() {}
 
    virtual void setTimeStep(double ts) = 0;
-   virtual void step(double t, double* curVal, double* res ) = 0;
+   virtual void step(double t, const std::vector<double>& curVal, std::vector<double>& res ) = 0;
 };
 
 } // namespace sim
diff --git a/sim/Propagator.cpp b/sim/Propagator.cpp
index 2a072b0..cb58536 100644
--- a/sim/Propagator.cpp
+++ b/sim/Propagator.cpp
@@ -2,27 +2,56 @@
 
 #include "sim/RK4Solver.h"
 
+#include <utility>
+
 namespace sim {
 
 Propagator::Propagator()
+   : integrator()
+
 {
 
-//   solver = std::make_unique<sim::DESolver>(
-//            new(RK4Solver(/* xvel */ [this](double, double* x) -> double { return })))
+
+   // This is a little strange, but I have to populate the integrator unique_ptr
+   // with reset. make_unique() doesn't work because the compiler can't seem to
+   // deduce the template parameters correctly, and I don't want to specify them
+   // manually either. RK4Solver constructor is perfectly capable of deducing it's
+   // template types, and it derives from DESolver, so we can just reset the unique_ptr
+   // and pass it a freshly allocated RK4Solver pointer
 
    // The state vector has components of the form: (x, y, z, xdot, ydot, zdot)
-
-   integrator = std::make_unique<sim::DESolver>(new RK4Solver(
-      /* dvx/dt */ [this](double, double* ) -> double { return getForceX() / getMass(); },
-      /* dx/dt  */ [this](double, double* s) -> double {return s[3]; },
-      /* dvy/dt */ [this](double, double* ) -> double { return getForceY() / getMass() },
-      /* dy/dt  */ [this](double, double* s) -> double {return s[4]; },
-      /* dvz/dt */ [this](double, double* ) -> double { return getForceZ() / getMass() },
-      /* dz/dt  */ [this](double, double* s) -> double {return s[5]; }));
+   integrator.reset(new RK4Solver(
+      /* dx/dt  */ [](double, const std::vector<double>& s) -> double {return s[3]; },
+      /* dy/dt  */ [](double, const std::vector<double>& s) -> double {return s[4]; },
+      /* dz/dt  */ [](double, const std::vector<double>& s) -> double {return s[5]; },
+      /* dvx/dt */ [this](double, const std::vector<double>& ) -> double { return getForceX() / getMass(); },
+      /* dvy/dt */ [this](double, const std::vector<double>& ) -> double { return getForceY() / getMass(); },
+      /* dvz/dt */ [this](double, const std::vector<double>& ) -> double { return getForceZ() / getMass(); }));
 
 
+   integrator->setTimeStep(timeStep);
+}
 
+Propagator::~Propagator()
+{
+}
 
+void Propagator::runUntilTerminate()
+{
+   while(true)
+   {
+      // nextState gets overwritten
+      integrator->step(currentTime, currentState, nextState);
+      std::swap(currentState, nextState);
+      if(saveStates)
+      {
+         states.push_back(currentState);
+      }
+      if(currentState[1] < 0.0)
+         break;
+
+      currentTime += timeStep;
+   }
 }
 
 } // namespace sim
diff --git a/sim/Propagator.h b/sim/Propagator.h
index dfcfaf5..bbe79d7 100644
--- a/sim/Propagator.h
+++ b/sim/Propagator.h
@@ -4,6 +4,7 @@
 #include "sim/DESolver.h"
 
 #include <memory>
+#include <vector>
 
 namespace sim
 {
@@ -12,23 +13,50 @@ class Propagator
 {
 public:
     Propagator();
+    ~Propagator();
 
-   double getForceX();
-   double getForceY();
-   double getForceZ();
+    void setInitialState(std::vector<double>& initialState)
+    {
+       currentState = initialState;
+    }
 
-   double getTorqueP();
-   double getTorqueQ();
-   double getTorqueR();
+    const std::vector<double>& getCurrentState() const
+    {
+       return currentState;
+    }
 
-   double getMass();
+    void runUntilTerminate();
+
+    void retainStates(bool s)
+    {
+       saveStates = s;
+    }
+
+    const std::vector<std::vector<double>>& getStates() const { return states; }
+
+    void setTimeStep(double ts) { timeStep = ts; }
 
 private:
+    double getForceX() { return 0.0; }
+    double getForceY() { return 0.0; }
+    double getForceZ() { return 0.0; }
+
+    double getTorqueP() { return 0.0; }
+    double getTorqueQ() { return 0.0; }
+    double getTorqueR() { return 0.0; }
+
+   double getMass() { return 0.0; }
+
+//private:
 
    std::unique_ptr<sim::DESolver> integrator;
 
-   double currentState[6]{0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
-   double nextState[6]{0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+   std::vector<double> currentState{0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+   std::vector<double> nextState{0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+   bool saveStates{true};
+   double currentTime{0.0};
+   double timeStep{0.01};
+   std::vector<std::vector<double>> states;
 };
 
 } // namespace sim
diff --git a/sim/RK4Solver.h b/sim/RK4Solver.h
index be3f7d5..ec065bc 100644
--- a/sim/RK4Solver.h
+++ b/sim/RK4Solver.h
@@ -19,13 +19,14 @@ public:
    RK4Solver(Ts... funcs)
    {
       (odes.push_back(funcs), ...);
+      temp.resize(sizeof...(Ts));
 
    }
    virtual ~RK4Solver() {}
 
    void setTimeStep(double inTs) override { dt = inTs;  halfDT = dt / 2.0; }
 
-   void step(double t, double* curVal, double* res) override
+   void step(double t, const std::vector<double>& curVal, std::vector<double>& res) override
    {
       if(dt == std::numeric_limits<double>::quiet_NaN())
       {
@@ -76,7 +77,7 @@ public:
    }
 
 private:
-   std::vector<std::function<double(double, double*)>> odes;
+   std::vector<std::function<double(double, const std::vector<double>&)>> odes;
 
    static constexpr size_t len = sizeof...(Ts);
    double k1[len];
@@ -84,7 +85,7 @@ private:
    double k3[len];
    double k4[len];
 
-   double temp[len];
+   std::vector<double> temp;
 
    double dt = std::numeric_limits<double>::quiet_NaN();
    double halfDT = 0.0;
diff --git a/sim/StateData.h b/sim/StateData.h
index adb654d..33ea7ef 100644
--- a/sim/StateData.h
+++ b/sim/StateData.h
@@ -14,6 +14,7 @@ class StateData
 public:
    StateData();
 
+
 private:
    math::Vector3 position{0.0, 0.0, 0.0};
    math::Vector3 velocity{0.0, 0.0, 0.0};
@@ -23,6 +24,8 @@ private:
    // Necessary?
    //math::Vector3 orientationAccel;
 
+   // This is an array because the integrator expects it
+   double data[6];
 
 };
 
diff --git a/utils/TSQueue.h b/utils/TSQueue.h
new file mode 100644
index 0000000..7862c4a
--- /dev/null
+++ b/utils/TSQueue.h
@@ -0,0 +1,83 @@
+#ifndef TSQUEUE_H
+#define TSQUEUE_H
+
+#include <mutex>
+#include <memory>
+#include <queue>
+#include <condition_variable>
+
+/**
+ * @brief The TSQueue class is a very basic thread-safe queue
+ */
+template<typename T>
+class TSQueue
+{
+public:
+   TSQueue()
+      : mtx(),
+        q(),
+        cv()
+   {}
+
+   void push(T newVal)
+   {
+      std::lock_guard<std::mutex> lck(mtx);
+      q.push(newVal);
+      cv.notify_one();
+   }
+
+   void waitAndPop(T& val)
+   {
+      std::unique_lock<std::mutex> lck(mtx);
+      cv.wait(lck, [this]{return !q.empty(); });
+      val = std::move(q.front());
+      q.pop();
+   }
+
+   std::shared_ptr<T> waitAndPop()
+   {
+      std::unique_lock<std::mutex> lck(mtx);
+      cv.wait(lck, [this] { return !q.empty(); });
+      std::shared_ptr<T> res(std::make_shared<T>(std::move(q.front())));
+      q.pop();
+      return res;
+   }
+
+   bool tryPop(T& val)
+   {
+      std::unique_lock<std::mutex> lck(mtx);
+      if(q.empty())
+      {
+         return false;
+      }
+      val = std::move(q.front());
+      q.pop();
+      return true;
+   }
+
+   std::shared_ptr<T> tryPop()
+   {
+      std::unique_lock<std::mutex> lck(mtx);
+      if(q.empty())
+      {
+         return std::shared_ptr<T>(); // nullptr
+      }
+      std::shared_ptr<T> retVal(std::move(q.front()));
+      q.pop();
+      return retVal;
+   }
+
+   bool empty() const
+   {
+      std::lock_guard<std::mutex> lck(mtx);
+      return q.empty();
+   }
+
+
+private:
+   mutable std::mutex mtx;
+   std::queue<T> q;
+   std::condition_variable cv;
+};
+
+#endif // TSQUEUE_H
diff --git a/utils/ThreadPool.cpp b/utils/ThreadPool.cpp
index 6f03add..d3e16d7 100644
--- a/utils/ThreadPool.cpp
+++ b/utils/ThreadPool.cpp
@@ -1,6 +1,45 @@
 #include "ThreadPool.h"
 
-ThreadPool::ThreadPool()
-{
+#include <cstdint>
 
+ThreadPool::ThreadPool()
+   : done(false),
+     q(),
+     threads(),
+     joiner(threads)
+{
+   const std::size_t threadCount = std::thread::hardware_concurrency();
+
+   try
+   {
+      for(size_t i = 0; i < threadCount; ++i)
+      {
+         threads.push_back(std::thread(&ThreadPool::worker, this));
+      }
+   }
+   catch(...)
+   {
+      done = true;
+      throw;
+   }
+}
+
+ThreadPool::~ThreadPool()
+{
+   done = true;
+}
+void ThreadPool::worker()
+{
+   while(!done)
+   {
+      std::function<void()> task;
+      if(q.tryPop(task))
+      {
+         task();
+      }
+      else
+      {
+         std::this_thread::yield();
+      }
+   }
 }
diff --git a/utils/ThreadPool.h b/utils/ThreadPool.h
index fd75a4e..459a560 100644
--- a/utils/ThreadPool.h
+++ b/utils/ThreadPool.h
@@ -2,6 +2,12 @@
 #define THREADPOOL_H
 
 #include <atomic>
+#include <functional>
+#include <vector>
+#include <thread>
+
+#include "TSQueue.h"
+
 
 /**
  * @brief A basic ThreadPool class
@@ -10,8 +16,46 @@ class ThreadPool
 {
 public:
    ThreadPool();
+   ~ThreadPool();
+
+   template<typename FunctionType>
+   void submit(FunctionType f)
+   {
+      q.push(std::function<void()>(f));
+   }
+
 private:
+   class JoinThreads
+   {
+   public:
+      explicit JoinThreads(std::vector<std::thread>& inThreads)
+         : threads(inThreads)
+      {}
+
+      ~JoinThreads()
+      {
+         for(auto& i : threads)
+         {
+            if(i.joinable())
+            {
+               i.join();
+            }
+         }
+      }
+   private:
+      std::vector<std::thread>& threads;
+   };
+
    std::atomic_bool done;
+   TSQueue<std::function<void()>> q;
+   std::vector<std::thread> threads;
+
+   JoinThreads joiner;
+
+   void worker();
+
 };
 
+
+
 #endif // THREADPOOL_H