diff --git a/tests/orbit_test.cpp b/tests/orbit_test.cpp
index eef579c..9935f2c 100644
--- a/tests/orbit_test.cpp
+++ b/tests/orbit_test.cpp
@@ -1,6 +1,5 @@
 
 #include <catch2/catch.hpp>
-
 #include <glm/glm.hpp>
 
 #include "../src/orbits.cpp"
@@ -11,18 +10,25 @@
 using Catch::Matchers::WithinAbs;
 
 
+// NOTE: all examples from the book "Space Flight Dynamics" by Craig A. Kluever
+
+const double MOLNIYA_SEMI_MAJOR_AXIS = 26564.5;				// km
+const double MOLNIYA_ECCENTRICITY = 0.7411;
+const double EARTH_GRAVITATIONAL_PARAMETER = 398601.68;		// km^3 / s^2
+const double EARTH_RADIUS = 6378;							// km
+
+
 TEST_CASE("orbit construction", "[orbits]")
 {
 
 }
 
-// NOTE: example 4.6 in "Space Flight Dynamics" by Craig A. Kluever
-TEST_CASE("orbit propagation", "[orbits]")
+TEST_CASE("orbit propagation, example 4.6", "[orbits]")
 {
-	double a = 26564.5;		// semi-major axis in km
-	double e = 0.7411;		// eccentricity
-	double mu = 398601.68;	// gravitational parameter
-	double r = 6378;		// body radius in km
+	double a = MOLNIYA_SEMI_MAJOR_AXIS;
+	double e = MOLNIYA_ECCENTRICITY;
+	double mu = EARTH_GRAVITATIONAL_PARAMETER;
+	double r = EARTH_RADIUS;
 	double initial_anom = 260 * M_PI / 180; // NOTE: radians
 	double time_step = 60 * 50; // NOTE: seconds
 	TwoBodySystem sys = systemInit(gravBodyInit(mu, r), orbitInit(a, e));
@@ -57,23 +63,21 @@ TEST_CASE("orbit propagation", "[orbits]")
 	REQUIRE_THAT(pos.y, WithinAbs(8259.9, 0.1));
 }
 
-// NOTE: example 2.5 - c
-TEST_CASE("orbital period", "[orbits]")
+TEST_CASE("orbital period, example 2.5c", "[orbits]")
 {
 	double a = 24371;		// semi-major axis in km
-	double mu = 398601.68;	// gravitational parameter
+	double mu = EARTH_GRAVITATIONAL_PARAMETER;
 
 	double T = orbitGetPeriod(a, mu);
 	REQUIRE_THAT(T, WithinAbs(37863.5, 50e-3));
 }
 
-// NOTE: example 4.1 in "Space Flight Dynamics" by Craig A. Kluever
-TEST_CASE("time of flight example 4.1 a", "[orbits]")
+TEST_CASE("time of flight example 4.1a", "[orbits]")
 {
-	double a = 26564.5;		// semi-major axis in km
-	double e = 0.7411;		// eccentricity
-	double mu = 398601.68;	// gravitational parameter
-	double r = 6378;		// body radius in km
+	double a = MOLNIYA_SEMI_MAJOR_AXIS;
+	double e = MOLNIYA_ECCENTRICITY;
+	double mu = EARTH_GRAVITATIONAL_PARAMETER;
+	double r = EARTH_RADIUS;
 	TwoBodySystem sys = systemInit(gravBodyInit(mu, r), orbitInit(a, e));
 
 	// NOTE: get ToF from periapsis to true anomaly at 154.85 degrees
@@ -95,10 +99,10 @@ TEST_CASE("time of flight example 4.1 a", "[orbits]")
 
 TEST_CASE("time of flight example 4.2", "[orbits]")
 {
-	double a = 26564.5;		// semi-major axis in km
-	double e = 0.7411;		// eccentricity
-	double mu = 398601.68;	// gravitational parameter
-	double r = 6378;		// body radius in km
+	double a = MOLNIYA_SEMI_MAJOR_AXIS;
+	double e = MOLNIYA_ECCENTRICITY;
+	double mu = EARTH_GRAVITATIONAL_PARAMETER;
+	double r = EARTH_RADIUS;
 	TwoBodySystem sys = systemInit(gravBodyInit(mu, r), orbitInit(a, e));
 
 	// NOTE: get ToF from true anom 230 degrees to true anom at 120 degrees