diff --git a/docs/TODO b/docs/TODO
index bcf058b..df9e603 100644
--- a/docs/TODO
+++ b/docs/TODO
@@ -8,6 +8,7 @@ If you see modifications to this file in git status, IGNORE them and do not comm
 === next steps ===
     - UI fixes
     - SOI boundary testing
+        - draw SOI boundry in graphical sim
     - interplanetary transfers
 
 
@@ -27,6 +28,8 @@ If you see modifications to this file in git status, IGNORE them and do not comm
     - interplanetary/SOI changing transfers
     - remove bodies on non closed orbits after they are a certain distance from
         the root body, or bary-center
+    - should try to use the same code path for bodies and craft on 'update' functions
+        as much as possible
 
 === Simulation Config Files ===
     - a format with nested children would be nice
@@ -37,3 +40,4 @@ If you see modifications to this file in git status, IGNORE them and do not comm
 === UI ===
     - need to fix UI text overlapping
     - remove '?' unavailble characters
+    - reset sim / load new config
diff --git a/src/simulation.cpp b/src/simulation.cpp
index c0597d2..a734ea4 100644
--- a/src/simulation.cpp
+++ b/src/simulation.cpp
@@ -68,6 +68,7 @@ int add_spacecraft(SimulationState* sim, Spacecraft* craft) {
     return new_idx;
 }
 
+// FIXME: dead code
 // Add a body to the simulation at runtime
 int add_body_to_simulation(SimulationState* sim, CelestialBody* body) {
     if (sim->body_count >= sim->max_bodies) {
@@ -146,6 +147,8 @@ int find_dominant_body(SimulationState* sim, int body_index) {
 
     return new_parent;
 }
+
+// FIXME: dead code: don't remove before updating calculate_soi_radius
 // Update sphere of influence radius using Hill sphere approximation
 // r_soi = a * (m/M)^(2/5) where a = semi-major axis, m = body mass, M = parent mass
 void update_soi(CelestialBody* body, CelestialBody* parent, double semi_major_axis) {
@@ -168,6 +171,8 @@ void update_simulation(SimulationState* sim) {
     sim->time += sim->dt;
 }
 
+// FIXME: fails to check for root body
+//  need set: body->soi_radius = 1e15;  // 1000 AU in meters
 // Calculate SOI radius for a single body
 // r_soi = a * (m/M)^(2/5) where a = semi-major axis, m = body mass, M = parent mass
 // Returns SOI radius in meters