diff --git a/trick_sims/Cannon/models/cannon/gravity/src/cannon_numeric.c b/trick_sims/Cannon/models/cannon/gravity/src/cannon_numeric.c
index eb66964e..05d71443 100644
--- a/trick_sims/Cannon/models/cannon/gravity/src/cannon_numeric.c
+++ b/trick_sims/Cannon/models/cannon/gravity/src/cannon_numeric.c
@@ -49,21 +49,20 @@ int cannon_integ( CANNON* C ) {
 
 /* The cannonball sim's dynamic job */
 double cannon_impact( CANNON* C ) {
-
-    double tgo ;
-    double now ;
-    /* Set error function --- how far ball is above ground */
-    C->rf.error = C->pos[1] ;
-    now = get_integ_time() ;
-    tgo = regula_falsi( now, &(C->rf) ) ;
-    if (tgo == 0.0) {
+    double tgo ; /* time-to-go */
+    double now ; /* current integration time. */
+    
+    C->rf.error = C->pos[1] ;              /* Specify the event boundary. */
+    now = get_integ_time() ;               /* Get the current integration time */
+    tgo = regula_falsi( now, &(C->rf) ) ;  /* Estimate remaining integration time. */ 
+    if (tgo == 0.0) {                      /* If we are at the event, it's action time! */
         now = get_integ_time() ;
-        reset_regula_falsi( now, &(C->rf) ) ;
+        reset_regula_falsi( now, &(C->rf) ) ; 
         C->impact = 1 ;
-        C->impactTime = now;
+        C->impactTime = now ;
         C->vel[0] = 0.0 ; C->vel[1] = 0.0 ;
         C->acc[0] = 0.0 ; C->acc[1] = 0.0 ;
-        fprintf(stderr, "\n\nIMPACT: SimTime = %.9f, ModelTime = %.9f, pos = %.9f\n\n", now, C->impactTime, C->pos[0] ) ;
+        fprintf(stderr, "\n\nIMPACT: SimTime = %.9f, pos = %.9f\n\n", now, C->pos[0] ) ;
     }
-    return ( tgo ) ;
+    return (tgo) ;
 }