Better cohesion.

launch.ks

@@ -6,6 +6,7 @@ run once "lib/rocket".
 run once "lib/util".
 run once "lib/vectors".
 run once "lib/warp".
+run once "maneuvers".
 
 
 function launch {
@@ -92,7 +93,7 @@ function launch {
     wait until APOAPSIS > target_orbit_altitude.
     lock THROTTLE TO 0.
     
-    
+
     print "------------------ CIRCULARIZE -------------------".
     // Don't create maneuver node until we are out of the atmosphere; otherwise the apoapsis' altitude and eta will change due to drag
     print "Waiting for ship to leave the atmosphere".
@@ -110,17 +111,9 @@ function launch {
     if auto_extend_antennas {
         extend_antennas().
     }
-    
-    // Create maneuver node that will circularize the orbit. TODO: create circulize()-function in lib/maneuvers.ks instead
-    // NOTE: Potential errors in the inclination are not fixed, since we are most likely going to change our orbit, which will make the inclination change cheaper later on.
-    local node is NODE(TIME:SECONDS + ETA:APOAPSIS, 0, 0, 0).
 
-    // Burn magnitude in the prograde direction is the difference between the required velocity to acheive circular orbit at apoapsis altitude and our velocity at apoapsis
-    local required_velocity is orbital_velocity_from_ap_pe(APOAPSIS, APOAPSIS, target_orbit_altitude).
-    set node:prograde to required_velocity - velocityat(SHIP, TIME:seconds + ETA:apoapsis):orbit:mag.
-    
-    add node.
-    execute_node().
+    // NOTE: Potential errors in the inclination are not fixed since we are most likely going to change our orbit, which will make the inclination change cheaper later on.
+    circularize_at_apoapsis().
     
     
     print "------------ LAUNCH SEQUENCE COMPLETE ------------".
@@ -129,9 +122,12 @@ function launch {
 
 
 function calculate_launch_azimuth {
+    //
     // Calculate the launch azimuth; the compass heading we head for when launching to achieve orbit of desired inclination.
-    // http://www.orbiterwiki.org/wiki/Launch_Azimuth
-    // https://www.princeton.edu/~stengel/MAE342Lecture4.pdf
+    // Based on:
+    //  http://www.orbiterwiki.org/wiki/Launch_Azimuth
+    //  https://www.princeton.edu/~stengel/MAE342Lecture4.pdf
+    //
     parameter target_orbit_inclination.
     parameter target_orbit_altitude.  // to compensate for the rotation of the body, we need to know the velocity of the target orbit, which is calculated from its altitude
     parameter launch_site_latitude.
@@ -139,7 +135,7 @@ function calculate_launch_azimuth {
     local inertial_azimuth is arcsin(cos(target_orbit_inclination) / cos(launch_site_latitude)).  // azimuth in inertial space, that is, disregarding the rotation of the body
     
     local equatorial_rotational_velocity is (2 * CONSTANT:PI * BODY:radius) / BODY:rotationperiod.
-    local target_orbit_velocity is orbital_velocity_from_ap_pe(target_orbit_altitude, target_orbit_altitude, target_orbit_altitude).
+    local target_orbit_velocity is orbital_velocity_circular(target_orbit_altitude).
 
     local launch_vector_x_component is target_orbit_velocity * sin(inertial_azimuth) - equatorial_rotational_velocity * cos(launch_site_latitude).
     local launch_vector_y_component is target_orbit_velocity * cos(inertial_azimuth).

lib/equations.ks

@@ -52,6 +52,11 @@ function orbital_velocity_from_ap_pe {
     return orbital_velocity(altitude, semi_major_axis(ap, pe)).
 }
 
+function orbital_velocity_circular {
+    parameter altitude.
+    return orbital_velocity_from_ap_pe(altitude, altitude, altitude).
+}
+
 
 function orbital_eccentricity {
     //

lib/node.ks

@@ -29,7 +29,7 @@ function execute_node {
     print "=== EXECUTE MANEUVER NODE ===".
     print "Estimated burn duration: " + ROUND(burn_duration, 1) + "s".
         
-    print "Aligning ship with burn vector..".
+    print "Aligning ship with burn vector".
     SAS off.
     lock STEERING to node:deltav.
     wait until vang(SHIP:facing:vector, node:deltav) < 0.5.

maneuvers.ks

@@ -21,4 +21,31 @@ function change_orbit {
     print argument_of_periapsis.
 }
 
-change_orbit().
+
+function circularize {
+    //
+    // Circularize orbit at the given target.
+    //
+    parameter target.
+    parameter eta.  // eta to target
+
+    local node is NODE(TIME:SECONDS + eta, 0, 0, 0).
+    // Prograde burn magnitude is the difference between the required velocity to achieve circular orbit at target's altitude and our actual velocity at the target
+    local required_velocity is orbital_velocity_circular(target).
+    set node:prograde to required_velocity - velocityat(SHIP, TIME:seconds + eta):orbit:mag.
+
+    add node.
+    execute_node(node).
+}
+
+function circularize_at_apoapsis {
+    print "Circularizing at apoapsis".
+    return circularize(APOAPSIS, ETA:APOAPSIS).
+}
+
+function circularize_at_periapsis {
+    print "Circularizing at periapsis".
+    return circularize(PERIAPSIS, ETA:PERIAPSIS).
+}
+
+circularize_at_periapsis().