diff --git a/MarinerGuidance.java b/MarinerGuidance.java
new file mode 100644
index 0000000..c83ba60
--- /dev/null
+++ b/MarinerGuidance.java
@@ -0,0 +1,23 @@
+public class MarinerGuidance {
+    public static double getRawDerivative(double[] radius, int n) {
+        if (n == 0) return 0.0;
+        return radius[n] - radius[n - 1];
+    }
+
+    public static double computeGuidance(double[] radius, int n) {
+        double rawDerivative = getRawDerivative(radius, n);
+        return someControlLaw(radius[n], rawDerivative);
+    }
+
+    public static double someControlLaw(double radius, double derivative) {
+        return -0.5 * radius + 2.0 * derivative;
+    }
+
+    public static void main(String[] args) {
+        double[] radius = {100, 99.5, 99.2, 99.1, 100.5, 102.0, 98.0};
+        for (int n = 1; n < radius.length; n++) {
+            double guidance = computeGuidance(radius, n);
+            System.out.printf("Step %d: Guidance = %.2f%n", n, guidance);
+        }
+    }
+}