diff --git a/proto/gz/msgs/spherical_coordinates.proto b/proto/gz/msgs/spherical_coordinates.proto
index 8511d8ea..9b485277 100644
--- a/proto/gz/msgs/spherical_coordinates.proto
+++ b/proto/gz/msgs/spherical_coordinates.proto
@@ -33,28 +33,42 @@ message SphericalCoordinates
   enum SurfaceModel
   {
     /// \brief World Geodetic System 1984
-    EARTH_WGS84 = 0;
+    EARTH_WGS84                   = 0;
+
+    /// \brief Model of the moon, based on the Selenographic
+    /// coordinate system, see wikipedia: Selenographic
+    /// Coordinate System.
+    MOON_SCS                      = 1;
+
+    /// \brief Custom surface type
+    CUSTOM_SURFACE                = 2;
   }
 
   /// \brief Optional header data.
-  Header header                = 1;
+  Header header                   = 1;
 
   /// \brief Planetary surface model.
-  SurfaceModel surface_model   = 2;
+  SurfaceModel surface_model      = 2;
 
   /// \brief Latitude in degrees.
-  double latitude_deg          = 3;
+  double latitude_deg             = 3;
 
   /// \brief Longitude in degrees.
-  double longitude_deg         = 4;
+  double longitude_deg            = 4;
 
   /// \brief Elevation in meters.
-  double elevation             = 5;
+  double elevation                = 5;
 
   /// \brief Heading in degrees.
-  double heading_deg           = 6;
+  double heading_deg              = 6;
 
   /// \brief Entity that the coordinates apply to.
   /// If not set, defaults to the world origin.
-  Entity entity                = 7;
+  Entity entity                   = 7;
+
+  /// \brief Equatorial axis in meters.
+  double surface_axis_equatorial  = 8;
+
+  /// \brief Polar axis in meters.
+  double surface_axis_polar       = 9;
 }
diff --git a/src/Utility.cc b/src/Utility.cc
index 491b4e38..ee8ee541 100644
--- a/src/Utility.cc
+++ b/src/Utility.cc
@@ -130,6 +130,16 @@ namespace gz
       {
         out.SetSurface(math::SphericalCoordinates::EARTH_WGS84);
       }
+      else if (_sc.surface_model() == msgs::SphericalCoordinates::MOON_SCS)
+      {
+        out.SetSurface(math::SphericalCoordinates::MOON_SCS);
+      }
+      else if (_sc.surface_model() ==
+          msgs::SphericalCoordinates::CUSTOM_SURFACE)
+      {
+        out.SetSurface(math::SphericalCoordinates::CUSTOM_SURFACE,
+            _sc.surface_axis_equatorial(), _sc.surface_axis_polar());
+      }
       else
       {
         std::cerr << "Unrecognized spherical surface type ["
@@ -472,6 +482,18 @@ namespace gz
       {
         _sc->set_surface_model(msgs::SphericalCoordinates::EARTH_WGS84);
       }
+      else if (_m.Surface() == math::SphericalCoordinates::MOON_SCS)
+      {
+        _sc->set_surface_model(msgs::SphericalCoordinates::MOON_SCS);
+      }
+      else if (_m.Surface() ==
+          math::SphericalCoordinates::CUSTOM_SURFACE)
+      {
+        _sc->set_surface_model(
+            msgs::SphericalCoordinates::CUSTOM_SURFACE);
+        _sc->set_surface_axis_equatorial(_m.SurfaceAxisEquatorial());
+        _sc->set_surface_axis_polar(_m.SurfaceAxisPolar());
+      }
       else
       {
         std::cerr << "Unrecognized spherical surface type ["
diff --git a/src/Utility_TEST.cc b/src/Utility_TEST.cc
index 78182555..1d22d9a3 100644
--- a/src/Utility_TEST.cc
+++ b/src/Utility_TEST.cc
@@ -258,6 +258,59 @@ TEST(MsgsTest, ConvertMathSphericalCoordinatesToMsgs)
   EXPECT_DOUBLE_EQ(2.2, math.LongitudeReference().Degree());
   EXPECT_DOUBLE_EQ(3.3, math.ElevationReference());
   EXPECT_DOUBLE_EQ(0.4, math.HeadingOffset().Degree());
+
+  // For Moon's surface.
+  auto msgMoon = msgs::Convert(
+      math::SphericalCoordinates(
+      math::SphericalCoordinates::SurfaceType::MOON_SCS,
+      GZ_DTOR(1.1), GZ_DTOR(2.2), 3.3, GZ_DTOR(0.4)));
+
+  EXPECT_EQ(msgs::SphericalCoordinates::MOON_SCS,
+      msgMoon.surface_model());
+  EXPECT_DOUBLE_EQ(1.1, msgMoon.latitude_deg());
+  EXPECT_DOUBLE_EQ(2.2, msgMoon.longitude_deg());
+  EXPECT_DOUBLE_EQ(3.3, msgMoon.elevation());
+  EXPECT_DOUBLE_EQ(0.4, msgMoon.heading_deg());
+
+  auto mathMoon = msgs::Convert(msgMoon);
+
+  EXPECT_EQ(math::SphericalCoordinates::MOON_SCS,
+      mathMoon.Surface());
+  EXPECT_DOUBLE_EQ(1.1, mathMoon.LatitudeReference().Degree());
+  EXPECT_DOUBLE_EQ(2.2, mathMoon.LongitudeReference().Degree());
+  EXPECT_DOUBLE_EQ(3.3, mathMoon.ElevationReference());
+  EXPECT_DOUBLE_EQ(0.4, mathMoon.HeadingOffset().Degree());
+
+  // For custom surfaces.
+  auto sc = math::SphericalCoordinates(
+      math::SphericalCoordinates::CUSTOM_SURFACE,
+      12000, 10000);
+  sc.SetLatitudeReference(GZ_DTOR(1.1));
+  sc.SetLongitudeReference(GZ_DTOR(2.2));
+  sc.SetElevationReference(3.3);
+  sc.SetHeadingOffset(GZ_DTOR(0.4));
+
+  auto msgCustom = msgs::Convert(sc);
+
+  EXPECT_EQ(msgs::SphericalCoordinates::CUSTOM_SURFACE,
+      msgCustom.surface_model());
+  EXPECT_DOUBLE_EQ(1.1, msgCustom.latitude_deg());
+  EXPECT_DOUBLE_EQ(2.2, msgCustom.longitude_deg());
+  EXPECT_DOUBLE_EQ(3.3, msgCustom.elevation());
+  EXPECT_DOUBLE_EQ(0.4, msgCustom.heading_deg());
+  EXPECT_DOUBLE_EQ(12000, msgCustom.surface_axis_equatorial());
+  EXPECT_DOUBLE_EQ(10000, msgCustom.surface_axis_polar());
+
+  auto mathCustom = msgs::Convert(msgCustom);
+
+  EXPECT_EQ(math::SphericalCoordinates::CUSTOM_SURFACE,
+      mathCustom.Surface());
+  EXPECT_DOUBLE_EQ(1.1, mathCustom.LatitudeReference().Degree());
+  EXPECT_DOUBLE_EQ(2.2, mathCustom.LongitudeReference().Degree());
+  EXPECT_DOUBLE_EQ(3.3, mathCustom.ElevationReference());
+  EXPECT_DOUBLE_EQ(0.4, mathCustom.HeadingOffset().Degree());
+  EXPECT_DOUBLE_EQ(12000, mathCustom.SurfaceAxisEquatorial());
+  EXPECT_DOUBLE_EQ(10000, mathCustom.SurfaceAxisPolar());
 }
 
 /////////////////////////////////////////////////
@@ -488,6 +541,40 @@ TEST(MsgsTest, SetSphericalCoordinates)
   EXPECT_DOUBLE_EQ(2.2, msg.longitude_deg());
   EXPECT_DOUBLE_EQ(3.3, msg.elevation());
   EXPECT_DOUBLE_EQ(0.4, msg.heading_deg());
+
+  // For Moon's surface.
+  msgs::SphericalCoordinates msgMoon;
+  msgs::Set(&msgMoon, math::SphericalCoordinates(
+      math::SphericalCoordinates::SurfaceType::MOON_SCS,
+      GZ_DTOR(1.2), GZ_DTOR(2.3), 3.4, GZ_DTOR(0.5)));
+
+  EXPECT_EQ(msgs::SphericalCoordinates::MOON_SCS,
+      msgMoon.surface_model());
+  EXPECT_DOUBLE_EQ(1.2, msgMoon.latitude_deg());
+  EXPECT_DOUBLE_EQ(2.3, msgMoon.longitude_deg());
+  EXPECT_DOUBLE_EQ(3.4, msgMoon.elevation());
+  EXPECT_DOUBLE_EQ(0.5, msgMoon.heading_deg());
+
+  // For a custom surface.
+  msgs::SphericalCoordinates msgCustom;
+  auto sc = math::SphericalCoordinates(
+      math::SphericalCoordinates::CUSTOM_SURFACE,
+      12000, 10000);
+  sc.SetLatitudeReference(GZ_DTOR(1.9));
+  sc.SetLongitudeReference(GZ_DTOR(2.8));
+  sc.SetElevationReference(3.7);
+  sc.SetHeadingOffset(GZ_DTOR(0.6));
+
+  msgs::Set(&msgCustom, sc);
+
+  EXPECT_EQ(msgs::SphericalCoordinates::CUSTOM_SURFACE,
+      msgCustom.surface_model());
+  EXPECT_DOUBLE_EQ(1.9, msgCustom.latitude_deg());
+  EXPECT_DOUBLE_EQ(2.8, msgCustom.longitude_deg());
+  EXPECT_DOUBLE_EQ(3.7, msgCustom.elevation());
+  EXPECT_DOUBLE_EQ(0.6, msgCustom.heading_deg());
+  EXPECT_DOUBLE_EQ(12000, msgCustom.surface_axis_equatorial());
+  EXPECT_DOUBLE_EQ(10000, msgCustom.surface_axis_polar());
 }
 
 /////////////////////////////////////////////////