diff --git a/docs/rendering.md b/docs/rendering.md
index 6f5f4a9..b3bf9c3 100644
--- a/docs/rendering.md
+++ b/docs/rendering.md
@@ -177,7 +177,7 @@ float scale_radius(double radius, double scale) {
 4. Spacecraft
 5. Maneuver markers
 
-## UI System (raygui)
+## UI System (ui_renderer + raygui)
 
 ### Info Panel (Bottom-Left)
 **Content:**
@@ -258,29 +258,35 @@ float scale_radius(double radius, double scale) {
 
 ## Module Functions
 
-### Initialization
+### Renderer Module (renderer.cpp/h)
+
+#### Initialization
 - `init_renderer(width, height, title)` - Setup raylib window
 - `close_renderer()` - Cleanup raylib
 - `setup_camera(render_state)` - Initialize camera parameters
 
-### Camera
+#### Camera
 - `update_camera(render_state, sim)` - Handle input and camera follow
 
-### Rendering
+#### Rendering
 - `render_body(body, render_state)` - Draw single celestial body
 - `render_spacecraft(craft, render_state)` - Draw spacecraft marker
 - `render_maneuver_marker(craft, maneuver, render_state)` - Draw burn indicator
-- `render_simulation(sim, render_state)` - Full scene rendering
+- `render_simulation(sim, render_state)` - Full scene rendering (3D only)
+
+#### Scaling
+- `scale_position(pos, scale)` - Transform simulation to render position
+- `scale_radius(radius, scale)` - Apply size scaling with minimum
 
-### UI
+### UI Renderer Module (ui_renderer.cpp/h)
+
+#### UI Rendering
 - `render_info(sim)` - Bottom-left info panel
-- `render_body_list_ui(sim, render_state)` - Objects selection panel
+- `render_body_list_ui(sim, render_state, ui_state)` - Objects selection panel
 - `render_body_info_ui(sim, render_state)` - Top-right info panel
 - `render_maneuver_list_ui(sim, render_state)` - Maneuver list panel
 
-### Scaling
-- `scale_position(pos, scale)` - Transform simulation to render position
-- `scale_radius(radius, scale)` - Apply size scaling with minimum
+Note: UI rendering functions are called after `render_simulation()` to ensure UI overlays appear on top of the 3D scene.
 
 ## Technical Notes
 
diff --git a/docs/technical_reference.md b/docs/technical_reference.md
index 7fb1d33..51dc1d2 100644
--- a/docs/technical_reference.md
+++ b/docs/technical_reference.md
@@ -307,9 +307,26 @@ Raylib 3D visualization system. See **[docs/rendering.md](rendering.md)** for co
 - Camera controls and follow system
 - Object rendering (bodies, spacecraft, maneuvers)
 - Orbit path rendering (elliptical, parabolic, hyperbolic)
-- UI panels (info, body list, maneuver list)
 - Coordinate transformation and scaling
 
+### UI Renderer (ui_renderer.cpp/h)
+Raygui-based UI system for rendering interactive panels. Handles all 2D overlay elements.
+
+**Key functions:**
+- `render_info()` - Bottom-left info panel showing simulation time, FPS, and controls
+- `render_body_list_ui()` - Top-left objects list panel for selecting bodies/spacecraft
+- `render_body_info_ui()` - Top-right panel showing selected object details
+- `render_maneuver_list_ui()` - Maneuver list panel for spacecraft planning
+
+**UI State:**
+- `body_list_scroll` - Scroll position for objects list
+- `body_list_active` - Currently selected item index
+
+**Implementation:**
+- Uses raygui header-only library
+- All UI rendering happens after 3D scene rendering
+- Manages user interaction for object selection and camera following
+
 ### Test Utilities (test_utilities.cpp/h)
 Test helper functions for orbital mechanics validation.
 
diff --git a/src/main.cpp b/src/main.cpp
index bf92db1..f606338 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,6 +2,7 @@
 #include "simulation.h"
 #include "config_loader.h"
 #include "renderer.h"
+#include "ui_renderer.h"
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
@@ -36,6 +37,10 @@ void run_gui_simulation(SimulationState* sim) {
     RenderState render_state;
     setup_camera(&render_state);
 
+    UIState ui_state;
+    ui_state.body_list_scroll = 0;
+    ui_state.body_list_active = -1;
+
     // Find root body (body with parent_index == -1)
     int root_body_index = -1;
     for (int i = 0; i < sim->body_count; i++) {
@@ -45,16 +50,18 @@ void run_gui_simulation(SimulationState* sim) {
         }
     }
 
-    // Initialize UI state
+    // Initialize render state
     render_state.selected_body_index = root_body_index >= 0 ? root_body_index : -1;
     render_state.selected_craft_index = -1;  // No spacecraft selected initially
     render_state.previous_selected_body = -1;  // Previous selected body index
-    render_state.body_list_scroll = 0;     // Initial scroll position
-    render_state.body_list_active = root_body_index >= 0 ? root_body_index : -1;  // Sync with selected body
     render_state.camera_follow_body = root_body_index >= 0; // Follow root body if found
     render_state.camera_offset = (Vector3){ 0, 50, 100 }; // Default offset
     render_state.was_following_body = false;
 
+    // Initialize UI state
+    ui_state.body_list_scroll = 0;     // Initial scroll position
+    ui_state.body_list_active = root_body_index >= 0 ? root_body_index : -1;  // Sync with selected body
+
     bool paused = false;
     double speed_multiplier = 1.0;
     int physics_steps_per_frame = 100;
@@ -94,6 +101,12 @@ void run_gui_simulation(SimulationState* sim) {
         update_camera(&render_state, sim);
 
         render_simulation(sim, &render_state);
+
+        // Render UI panels
+        render_info(sim);
+        render_body_list_ui(sim, &render_state, &ui_state);
+        render_body_info_ui(sim, &render_state);
+        render_maneuver_list_ui(sim, &render_state);
     }
 
     close_renderer(&render_state);
diff --git a/src/renderer.cpp b/src/renderer.cpp
index f8d3f9e..ada2c2e 100644
--- a/src/renderer.cpp
+++ b/src/renderer.cpp
@@ -3,10 +3,6 @@
 #include <cmath>
 #include <cstdio>
 
-// raygui implementation (header-only library)
-#define RAYGUI_IMPLEMENTATION
-#include "raygui.h"
-
 // Forward declarations
 static Vector3 sim_to_render(Vec3 pos, double scale);
 
@@ -553,422 +549,5 @@ void render_simulation(SimulationState* sim, RenderState* render_state) {
 
     EndMode3D();
 
-    // Render UI panels (always shown)
-    render_info(sim);
-    render_body_list_ui(sim, render_state);
-    render_body_info_ui(sim, render_state);
-    render_maneuver_list_ui(sim, render_state);
-
     EndDrawing();
 }
-
-// Render simulation information overlay
-void render_info(SimulationState* sim) {
-    // Panel dimensions
-    int panel_width = 300;
-    int panel_height = 300;
-    int panel_x = 10;
-    int panel_y = GetScreenHeight() - panel_height - 10;
-
-    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
-
-    // Draw window
-    if (GuiWindowBox(panel_bounds, "Info")) {
-        // Window box close button doesn't close this panel
-    }
-
-    // Prepare info text
-    char info_text[1024];
-    char temp_buffer[512];
-
-    snprintf(info_text, sizeof(info_text), "Orbital Mechanics Simulation\n\n");
-
-    // Config name
-    if (sim->config_name[0] != '\0') {
-        snprintf(temp_buffer, sizeof(temp_buffer), "Config: %s\n\n", sim->config_name);
-        strcat(info_text, temp_buffer);
-    }
-
-    // Simulation time (in days)
-    double days = sim->time / 86400.0;  // seconds to days
-    snprintf(temp_buffer, sizeof(temp_buffer), "Time: %.2f days\n", days);
-    strcat(info_text, temp_buffer);
-
-    // Body count
-    snprintf(temp_buffer, sizeof(temp_buffer), "Bodies: %d\n", sim->body_count);
-    strcat(info_text, temp_buffer);
-
-    // FPS
-    snprintf(temp_buffer, sizeof(temp_buffer), "FPS: %d\n\n", GetFPS());
-    strcat(info_text, temp_buffer);
-
-    // Controls
-    strcat(info_text, "Controls:\n");
-    strcat(info_text, "  Arrows: Rotate/Zoom\n");
-    strcat(info_text, "  Space: Pause/Resume\n");
-    strcat(info_text, "  +/-: Speed control\n");
-    strcat(info_text, "  ESC: Quit\n");
-
-    // Draw info text (inside window, leave space for title bar)
-    Rectangle text_bounds = {
-        (float)panel_x + 8,
-        (float)panel_y + 25,
-        (float)panel_width - 16,
-        (float)panel_height - 29
-    };
-
-    GuiLabel(text_bounds, info_text);
-}
-
-// Render body list UI panel
-void render_body_list_ui(SimulationState* sim, RenderState* render_state) {
-    // Panel dimensions
-    int panel_width = 200;
-    int panel_height = 400;
-    int panel_x = 10;
-    int panel_y = 10;
-
-    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
-
-    // Create list string for raygui (NULL-terminated)
-    // Include both bodies and spacecraft
-    int total_items = sim->body_count + sim->craft_count;
-    int buffer_size = total_items * (64 + 3 + 1) + 1; // Extra space for "🚀 " prefix
-    char* list_text = (char*)malloc(buffer_size);
-    if (!list_text) return;
-
-    list_text[0] = '\0';
-    int offset = 0;
-    int item_index = 0;
-
-    // Add bodies to list
-    for (int i = 0; i < sim->body_count; i++) {
-        if (item_index > 0) {
-            offset += snprintf(list_text + offset, buffer_size - offset, ";");
-        }
-        offset += snprintf(list_text + offset, buffer_size - offset, "%s", sim->bodies[i].name);
-        item_index++;
-    }
-
-    // Add spacecraft to list with "🚀 " prefix
-    for (int i = 0; i < sim->craft_count; i++) {
-        offset += snprintf(list_text + offset, buffer_size - offset, ";");
-        offset += snprintf(list_text + offset, buffer_size - offset, "🚀 %s", sim->spacecraft[i].name);
-        item_index++;
-    }
-
-    // Draw window (no close button - panels always shown)
-    GuiWindowBox(panel_bounds, "Objects");
-
-    // Draw list view (inside window, leave space for title bar)
-    Rectangle list_bounds = {
-        (float)panel_x + 4,
-        (float)panel_y + 25,
-        (float)panel_width - 8,
-        (float)panel_height - 29
-    };
-
-    int previous_active = render_state->body_list_active;
-    GuiListView(list_bounds, list_text, &render_state->body_list_scroll, &render_state->body_list_active);
-
-    // Check if an item was selected
-    if (render_state->body_list_active >= 0 && render_state->body_list_active != previous_active) {
-        if (render_state->body_list_active < sim->body_count) {
-            // A body was selected
-            render_state->selected_body_index = render_state->body_list_active;
-            render_state->selected_craft_index = -1;
-            render_state->camera_follow_body = true;
-            printf("Camera follow enabled for body: %s\n", sim->bodies[render_state->selected_body_index].name);
-        } else {
-            // A spacecraft was selected
-            int craft_index = render_state->body_list_active - sim->body_count;
-            if (craft_index >= 0 && craft_index < sim->craft_count) {
-                render_state->selected_body_index = -1;
-                render_state->selected_craft_index = craft_index;
-                render_state->camera_follow_body = true;
-                printf("Camera follow enabled for spacecraft: %s\n", sim->spacecraft[craft_index].name);
-            }
-        }
-    }
-
-    free(list_text);
-}
-
-// Render body information UI panel
-void render_body_info_ui(SimulationState* sim, RenderState* render_state) {
-    // Panel dimensions
-    int panel_width = 250;
-    int panel_height = 300;
-    int panel_x = GetScreenWidth() - panel_width - 10;
-    int panel_y = 10;
-
-    if ((render_state->selected_body_index < 0 || render_state->selected_body_index >= sim->body_count) &&
-        (render_state->selected_craft_index < 0 || render_state->selected_craft_index >= sim->craft_count)) {
-        // No body or spacecraft selected - render empty panel
-        Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
-        GuiWindowBox(panel_bounds, "Info");
-        return;
-    }
-
-    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
-
-    // Check if a body is selected
-    if (render_state->selected_body_index >= 0 && render_state->selected_body_index < sim->body_count) {
-        CelestialBody* body = &sim->bodies[render_state->selected_body_index];
-
-        // Draw window (no close button - panels always shown)
-        GuiWindowBox(panel_bounds, body->name);
-
-        // Prepare info text
-        char info_text[1024];
-        char temp_buffer[256];
-
-        snprintf(info_text, sizeof(info_text), "Name: %s", body->name);
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Mass: %.2e kg", body->mass);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Radius: %.2e m", body->radius);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        if (body->parent_index <= 0) {
-            // Position
-            snprintf(temp_buffer, sizeof(temp_buffer), "Position: (%.2e, %.2e, %.2e)",
-                     body->position.x, body->position.y, body->position.z);
-            strcat(info_text, "\n");
-            strcat(info_text, temp_buffer);
-
-            // Velocity
-            double vel_mag = vec3_magnitude(body->velocity);
-            snprintf(temp_buffer, sizeof(temp_buffer), "Velocity: %.2f m/s", vel_mag);
-            strcat(info_text, "\n");
-            strcat(info_text, temp_buffer);
-        } else {
-            // Position (Local)
-            snprintf(temp_buffer, sizeof(temp_buffer), "local_position: (%.2e, %.2e, %.2e)",
-                     body->local_position.x, body->local_position.y, body->local_position.z);
-            strcat(info_text, "\n");
-            strcat(info_text, temp_buffer);
-
-            // Velocity (Local)
-            double parent_vel_mag = vec3_magnitude(sim->bodies[body->parent_index].velocity);
-            double vel_mag = vec3_magnitude(body->velocity) - parent_vel_mag;
-            snprintf(temp_buffer, sizeof(temp_buffer), "local_velocity: %.2f m/s", vel_mag);
-            strcat(info_text, "\n");
-            strcat(info_text, temp_buffer);
-        }
-
-        // Orbital elements
-        snprintf(temp_buffer, sizeof(temp_buffer), "Eccentricity: %.3f", body->eccentricity);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Semi-major axis: %.2e m", body->semi_major_axis);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Parent body
-        if (body->parent_index >= 0 && body->parent_index < sim->body_count) {
-            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: %s", sim->bodies[body->parent_index].name);
-        } else {
-            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: None");
-        }
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // SOI
-        snprintf(temp_buffer, sizeof(temp_buffer), "SOI radius: %.2e m", body->soi_radius);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Draw info text (inside window, leave space for title bar)
-        Rectangle text_bounds = {
-            (float)panel_x + 8,
-            (float)panel_y + 25,
-            (float)panel_width - 16,
-            (float)panel_height - 29
-        };
-
-        GuiLabel(text_bounds, info_text);
-        return;
-    }
-
-    // Check if a spacecraft is selected
-    if (render_state->selected_craft_index >= 0 && render_state->selected_craft_index < sim->craft_count) {
-        Spacecraft* craft = &sim->spacecraft[render_state->selected_craft_index];
-
-        // Draw window (no close button - panels always shown)
-        GuiWindowBox(panel_bounds, craft->name);
-
-        // Prepare info text
-        char info_text[1024];
-        char temp_buffer[256];
-
-        snprintf(info_text, sizeof(info_text), "Name: %s", craft->name);
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Mass: %.2e kg", craft->mass);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Position (Local)
-        snprintf(temp_buffer, sizeof(temp_buffer), "local_position: (%.2e, %.2e, %.2e)",
-                 craft->local_position.x, craft->local_position.y, craft->local_position.z);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Velocity (Local)
-        double vel_mag = vec3_magnitude(craft->local_velocity);
-        snprintf(temp_buffer, sizeof(temp_buffer), "local_velocity: %.2f m/s", vel_mag);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Parent body
-        if (craft->parent_index >= 0 && craft->parent_index < sim->body_count) {
-            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: %s", sim->bodies[craft->parent_index].name);
-        } else {
-            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: None");
-        }
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Maneuver info
-        int pending_maneuvers = 0;
-        int executed_maneuvers = 0;
-        for (int i = 0; i < sim->maneuver_count; i++) {
-            if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
-                if (sim->maneuvers[i].executed) {
-                    executed_maneuvers++;
-                } else {
-                    pending_maneuvers++;
-                }
-            }
-        }
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Pending maneuvers: %d", pending_maneuvers);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        snprintf(temp_buffer, sizeof(temp_buffer), "Executed maneuvers: %d", executed_maneuvers);
-        strcat(info_text, "\n");
-        strcat(info_text, temp_buffer);
-
-        // Draw info text (inside window, leave space for title bar)
-        Rectangle text_bounds = {
-            (float)panel_x + 8,
-            (float)panel_y + 25,
-            (float)panel_width - 16,
-            (float)panel_height - 29
-        };
-
-        GuiLabel(text_bounds, info_text);
-        return;
-    }
-}
-
-// Render maneuver list UI panel
-void render_maneuver_list_ui(SimulationState* sim, RenderState* render_state) {
-    if (render_state->selected_craft_index < 0 || render_state->selected_craft_index >= sim->craft_count) {
-        return; // No spacecraft selected
-    }
-
-    int panel_width = 300;
-    int panel_height = 400;
-    int panel_x = GetScreenWidth() - panel_width - 10;
-    int panel_y = 320; // Below info panel
-
-    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
-
-    Spacecraft* craft = &sim->spacecraft[render_state->selected_craft_index];
-
-    // Create title with spacecraft name
-    char title[128];
-    snprintf(title, sizeof(title), "Maneuvers: %s", craft->name);
-
-    // Draw window
-    GuiWindowBox(panel_bounds, title);
-
-    // Count maneuvers for this spacecraft
-    int craft_maneuver_count = 0;
-    for (int i = 0; i < sim->maneuver_count; i++) {
-        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
-            craft_maneuver_count++;
-        }
-    }
-
-    if (craft_maneuver_count == 0) {
-        // No maneuvers for this spacecraft
-        Rectangle text_bounds = {
-            (float)panel_x + 8,
-            (float)panel_y + 25,
-            (float)panel_width - 16,
-            (float)panel_height - 29
-        };
-        GuiLabel(text_bounds, "No maneuvers defined");
-        return;
-    }
-
-    // Create maneuver list string for raygui
-    int buffer_size = craft_maneuver_count * (64 + 10 + 1) + 1;
-    char* maneuver_list_text = (char*)malloc(buffer_size);
-    if (!maneuver_list_text) return;
-
-    maneuver_list_text[0] = '\0';
-    int offset = 0;
-
-    for (int i = 0; i < sim->maneuver_count; i++) {
-        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
-            if (offset > 0) {
-                offset += snprintf(maneuver_list_text + offset, buffer_size - offset, ";");
-            }
-
-            const char* status_char = sim->maneuvers[i].executed ? "[DONE]" : "[PENDING]";
-            offset += snprintf(maneuver_list_text + offset, buffer_size - offset, "%s %s",
-                           status_char, sim->maneuvers[i].name);
-        }
-    }
-
-    // Draw list view (inside window, leave space for title bar)
-    Rectangle list_bounds = {
-        (float)panel_x + 4,
-        (float)panel_y + 25,
-        (float)panel_width - 8,
-        (float)panel_height - 100 // Leave space for details below
-    };
-
-    int maneuver_scroll = 0;
-    int maneuver_active = -1;
-    GuiListView(list_bounds, maneuver_list_text, &maneuver_scroll, &maneuver_active);
-
-    // Show details for first pending or last executed maneuver
-    char details_text[512];
-    details_text[0] = '\0';
-
-    for (int i = 0; i < sim->maneuver_count; i++) {
-        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
-            if (sim->maneuvers[i].executed) {
-                snprintf(details_text, sizeof(details_text),
-                         "Last executed:\n%s\nΔv: %.1f m/s\nTime: %.1f s",
-                         sim->maneuvers[i].name, sim->maneuvers[i].delta_v, sim->maneuvers[i].executed_time);
-            } else {
-                snprintf(details_text, sizeof(details_text),
-                         "Next pending:\n%s\nΔv: %.1f m/s",
-                         sim->maneuvers[i].name, sim->maneuvers[i].delta_v);
-                break; // Show first pending
-            }
-        }
-    }
-
-    if (details_text[0] != '\0') {
-        Rectangle details_bounds = {
-            (float)panel_x + 8,
-            (float)panel_y + (float)panel_height - 70,
-            (float)panel_width - 16,
-            65
-        };
-        GuiLabel(details_bounds, details_text);
-    }
-
-    free(maneuver_list_text);
-}
diff --git a/src/renderer.h b/src/renderer.h
index 819325c..9e3bc0c 100644
--- a/src/renderer.h
+++ b/src/renderer.h
@@ -14,8 +14,6 @@ struct RenderState {
     int selected_body_index;  // -1 = no selection
     int selected_craft_index;  // -1 = no selection
     int previous_selected_body;  // Previous selected body index
-    int body_list_scroll;     // Scroll position for body list
-    int body_list_active;     // Active item index in body list
     bool camera_follow_body;  // Whether camera follows selected body
     Vector3 camera_offset;    // Offset from target when following body
     bool was_following_body;  // Previous frame follow state
@@ -48,12 +46,6 @@ void render_body(CelestialBody* body, RenderState* render_state);
 void render_spacecraft(Spacecraft* craft, RenderState* render_state);
 void render_maneuver_marker(Spacecraft* craft, Maneuver* maneuver, RenderState* render_state);
 void render_simulation(SimulationState* sim, RenderState* render_state);
-void render_info(SimulationState* sim);
-
-// UI rendering functions
-void render_body_list_ui(SimulationState* sim, RenderState* render_state);
-void render_body_info_ui(SimulationState* sim, RenderState* render_state);
-void render_maneuver_list_ui(SimulationState* sim, RenderState* render_state);
 
 // Scaling functions
 Vector3 scale_position(Vec3 pos, double scale);
diff --git a/src/ui_renderer.cpp b/src/ui_renderer.cpp
new file mode 100644
index 0000000..bac8470
--- /dev/null
+++ b/src/ui_renderer.cpp
@@ -0,0 +1,421 @@
+#include "ui_renderer.h"
+#include "spacecraft.h"
+#include "maneuver.h"
+#include <cstdio>
+#include <cstring>
+#include <cmath>
+
+// raygui implementation (header-only library)
+#define RAYGUI_IMPLEMENTATION
+#include "raygui.h"
+
+// Render simulation information overlay
+void render_info(SimulationState* sim) {
+    // Panel dimensions
+    int panel_width = 300;
+    int panel_height = 300;
+    int panel_x = 10;
+    int panel_y = GetScreenHeight() - panel_height - 10;
+
+    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
+
+    // Draw window
+    if (GuiWindowBox(panel_bounds, "Info")) {
+        // Window box close button doesn't close this panel
+    }
+
+    // Prepare info text
+    char info_text[1024];
+    char temp_buffer[512];
+
+    snprintf(info_text, sizeof(info_text), "Orbital Mechanics Simulation\n\n");
+
+    // Config name
+    if (sim->config_name[0] != '\0') {
+        snprintf(temp_buffer, sizeof(temp_buffer), "Config: %s\n\n", sim->config_name);
+        strcat(info_text, temp_buffer);
+    }
+
+    // Simulation time (in days)
+    double days = sim->time / 86400.0;  // seconds to days
+    snprintf(temp_buffer, sizeof(temp_buffer), "Time: %.2f days\n", days);
+    strcat(info_text, temp_buffer);
+
+    // Body count
+    snprintf(temp_buffer, sizeof(temp_buffer), "Bodies: %d\n", sim->body_count);
+    strcat(info_text, temp_buffer);
+
+    // FPS
+    snprintf(temp_buffer, sizeof(temp_buffer), "FPS: %d\n\n", GetFPS());
+    strcat(info_text, temp_buffer);
+
+    // Controls
+    strcat(info_text, "Controls:\n");
+    strcat(info_text, "  Arrows: Rotate/Zoom\n");
+    strcat(info_text, "  Space: Pause/Resume\n");
+    strcat(info_text, "  +/-: Speed control\n");
+    strcat(info_text, "  ESC: Quit\n");
+
+    // Draw info text (inside window, leave space for title bar)
+    Rectangle text_bounds = {
+        (float)panel_x + 8,
+        (float)panel_y + 25,
+        (float)panel_width - 16,
+        (float)panel_height - 29
+    };
+
+    GuiLabel(text_bounds, info_text);
+}
+
+// Render body list UI panel
+void render_body_list_ui(SimulationState* sim, RenderState* render_state, UIState* ui_state) {
+    // Panel dimensions
+    int panel_width = 200;
+    int panel_height = 400;
+    int panel_x = 10;
+    int panel_y = 10;
+
+    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
+
+    // Create list string for raygui (NULL-terminated)
+    // Include both bodies and spacecraft
+    int total_items = sim->body_count + sim->craft_count;
+    int buffer_size = total_items * (64 + 3 + 1) + 1; // Extra space for "🚀 " prefix
+    char* list_text = (char*)malloc(buffer_size);
+    if (!list_text) return;
+
+    list_text[0] = '\0';
+    int offset = 0;
+    int item_index = 0;
+
+    // Add bodies to list
+    for (int i = 0; i < sim->body_count; i++) {
+        if (item_index > 0) {
+            offset += snprintf(list_text + offset, buffer_size - offset, ";");
+        }
+        offset += snprintf(list_text + offset, buffer_size - offset, "%s", sim->bodies[i].name);
+        item_index++;
+    }
+
+    // Add spacecraft to list with "🚀 " prefix
+    for (int i = 0; i < sim->craft_count; i++) {
+        offset += snprintf(list_text + offset, buffer_size - offset, ";");
+        offset += snprintf(list_text + offset, buffer_size - offset, "🚀 %s", sim->spacecraft[i].name);
+        item_index++;
+    }
+
+    // Draw window (no close button - panels always shown)
+    GuiWindowBox(panel_bounds, "Objects");
+
+    // Draw list view (inside window, leave space for title bar)
+    Rectangle list_bounds = {
+        (float)panel_x + 4,
+        (float)panel_y + 25,
+        (float)panel_width - 8,
+        (float)panel_height - 29
+    };
+
+    int previous_active = ui_state->body_list_active;
+    GuiListView(list_bounds, list_text, &ui_state->body_list_scroll, &ui_state->body_list_active);
+
+    // Check if an item was selected
+    if (ui_state->body_list_active >= 0 && ui_state->body_list_active != previous_active) {
+        if (ui_state->body_list_active < sim->body_count) {
+            // A body was selected
+            render_state->selected_body_index = ui_state->body_list_active;
+            render_state->selected_craft_index = -1;
+            render_state->camera_follow_body = true;
+            printf("Camera follow enabled for body: %s\n", sim->bodies[render_state->selected_body_index].name);
+        } else {
+            // A spacecraft was selected
+            int craft_index = ui_state->body_list_active - sim->body_count;
+            if (craft_index >= 0 && craft_index < sim->craft_count) {
+                render_state->selected_body_index = -1;
+                render_state->selected_craft_index = craft_index;
+                render_state->camera_follow_body = true;
+                printf("Camera follow enabled for spacecraft: %s\n", sim->spacecraft[craft_index].name);
+            }
+        }
+    }
+
+    free(list_text);
+}
+
+// Render body information UI panel
+void render_body_info_ui(SimulationState* sim, RenderState* render_state) {
+    // Panel dimensions
+    int panel_width = 250;
+    int panel_height = 300;
+    int panel_x = GetScreenWidth() - panel_width - 10;
+    int panel_y = 10;
+
+    if ((render_state->selected_body_index < 0 || render_state->selected_body_index >= sim->body_count) &&
+        (render_state->selected_craft_index < 0 || render_state->selected_craft_index >= sim->craft_count)) {
+        // No body or spacecraft selected - render empty panel
+        Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
+        GuiWindowBox(panel_bounds, "Info");
+        return;
+    }
+
+    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
+
+    // Check if a body is selected
+    if (render_state->selected_body_index >= 0 && render_state->selected_body_index < sim->body_count) {
+        CelestialBody* body = &sim->bodies[render_state->selected_body_index];
+
+        // Draw window (no close button - panels always shown)
+        GuiWindowBox(panel_bounds, body->name);
+
+        // Prepare info text
+        char info_text[1024];
+        char temp_buffer[256];
+
+        snprintf(info_text, sizeof(info_text), "Name: %s", body->name);
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Mass: %.2e kg", body->mass);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Radius: %.2e m", body->radius);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        if (body->parent_index <= 0) {
+            // Position
+            snprintf(temp_buffer, sizeof(temp_buffer), "Position: (%.2e, %.2e, %.2e)",
+                     body->position.x, body->position.y, body->position.z);
+            strcat(info_text, "\n");
+            strcat(info_text, temp_buffer);
+
+            // Velocity
+            double vel_mag = vec3_magnitude(body->velocity);
+            snprintf(temp_buffer, sizeof(temp_buffer), "Velocity: %.2f m/s", vel_mag);
+            strcat(info_text, "\n");
+            strcat(info_text, temp_buffer);
+        } else {
+            // Position (Local)
+            snprintf(temp_buffer, sizeof(temp_buffer), "local_position: (%.2e, %.2e, %.2e)",
+                     body->local_position.x, body->local_position.y, body->local_position.z);
+            strcat(info_text, "\n");
+            strcat(info_text, temp_buffer);
+
+            // Velocity (Local)
+            double parent_vel_mag = vec3_magnitude(sim->bodies[body->parent_index].velocity);
+            double vel_mag = vec3_magnitude(body->velocity) - parent_vel_mag;
+            snprintf(temp_buffer, sizeof(temp_buffer), "local_velocity: %.2f m/s", vel_mag);
+            strcat(info_text, "\n");
+            strcat(info_text, temp_buffer);
+        }
+
+        // Orbital elements
+        snprintf(temp_buffer, sizeof(temp_buffer), "Eccentricity: %.3f", body->eccentricity);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Semi-major axis: %.2e m", body->semi_major_axis);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Parent body
+        if (body->parent_index >= 0 && body->parent_index < sim->body_count) {
+            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: %s", sim->bodies[body->parent_index].name);
+        } else {
+            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: None");
+        }
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // SOI
+        snprintf(temp_buffer, sizeof(temp_buffer), "SOI radius: %.2e m", body->soi_radius);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Draw info text (inside window, leave space for title bar)
+        Rectangle text_bounds = {
+            (float)panel_x + 8,
+            (float)panel_y + 25,
+            (float)panel_width - 16,
+            (float)panel_height - 29
+        };
+
+        GuiLabel(text_bounds, info_text);
+        return;
+    }
+
+    // Check if a spacecraft is selected
+    if (render_state->selected_craft_index >= 0 && render_state->selected_craft_index < sim->craft_count) {
+        Spacecraft* craft = &sim->spacecraft[render_state->selected_craft_index];
+
+        // Draw window (no close button - panels always shown)
+        GuiWindowBox(panel_bounds, craft->name);
+
+        // Prepare info text
+        char info_text[1024];
+        char temp_buffer[256];
+
+        snprintf(info_text, sizeof(info_text), "Name: %s", craft->name);
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Mass: %.2e kg", craft->mass);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Position (Local)
+        snprintf(temp_buffer, sizeof(temp_buffer), "local_position: (%.2e, %.2e, %.2e)",
+                 craft->local_position.x, craft->local_position.y, craft->local_position.z);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Velocity (Local)
+        double vel_mag = vec3_magnitude(craft->local_velocity);
+        snprintf(temp_buffer, sizeof(temp_buffer), "local_velocity: %.2f m/s", vel_mag);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Parent body
+        if (craft->parent_index >= 0 && craft->parent_index < sim->body_count) {
+            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: %s", sim->bodies[craft->parent_index].name);
+        } else {
+            snprintf(temp_buffer, sizeof(temp_buffer), "Parent: None");
+        }
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Maneuver info
+        int pending_maneuvers = 0;
+        int executed_maneuvers = 0;
+        for (int i = 0; i < sim->maneuver_count; i++) {
+            if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
+                if (sim->maneuvers[i].executed) {
+                    executed_maneuvers++;
+                } else {
+                    pending_maneuvers++;
+                }
+            }
+        }
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Pending maneuvers: %d", pending_maneuvers);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        snprintf(temp_buffer, sizeof(temp_buffer), "Executed maneuvers: %d", executed_maneuvers);
+        strcat(info_text, "\n");
+        strcat(info_text, temp_buffer);
+
+        // Draw info text (inside window, leave space for title bar)
+        Rectangle text_bounds = {
+            (float)panel_x + 8,
+            (float)panel_y + 25,
+            (float)panel_width - 16,
+            (float)panel_height - 29
+        };
+
+        GuiLabel(text_bounds, info_text);
+        return;
+    }
+}
+
+// Render maneuver list UI panel
+void render_maneuver_list_ui(SimulationState* sim, RenderState* render_state) {
+    if (render_state->selected_craft_index < 0 || render_state->selected_craft_index >= sim->craft_count) {
+        return; // No spacecraft selected
+    }
+
+    int panel_width = 300;
+    int panel_height = 400;
+    int panel_x = GetScreenWidth() - panel_width - 10;
+    int panel_y = 320; // Below info panel
+
+    Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
+
+    Spacecraft* craft = &sim->spacecraft[render_state->selected_craft_index];
+
+    // Create title with spacecraft name
+    char title[128];
+    snprintf(title, sizeof(title), "Maneuvers: %s", craft->name);
+
+    // Draw window
+    GuiWindowBox(panel_bounds, title);
+
+    // Count maneuvers for this spacecraft
+    int craft_maneuver_count = 0;
+    for (int i = 0; i < sim->maneuver_count; i++) {
+        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
+            craft_maneuver_count++;
+        }
+    }
+
+    if (craft_maneuver_count == 0) {
+        // No maneuvers for this spacecraft
+        Rectangle text_bounds = {
+            (float)panel_x + 8,
+            (float)panel_y + 25,
+            (float)panel_width - 16,
+            (float)panel_height - 29
+        };
+        GuiLabel(text_bounds, "No maneuvers defined");
+        return;
+    }
+
+    // Create maneuver list string for raygui
+    int buffer_size = craft_maneuver_count * (64 + 10 + 1) + 1;
+    char* maneuver_list_text = (char*)malloc(buffer_size);
+    if (!maneuver_list_text) return;
+
+    maneuver_list_text[0] = '\0';
+    int offset = 0;
+
+    for (int i = 0; i < sim->maneuver_count; i++) {
+        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
+            if (offset > 0) {
+                offset += snprintf(maneuver_list_text + offset, buffer_size - offset, ";");
+            }
+
+            const char* status_char = sim->maneuvers[i].executed ? "[DONE]" : "[PENDING]";
+            offset += snprintf(maneuver_list_text + offset, buffer_size - offset, "%s %s",
+                           status_char, sim->maneuvers[i].name);
+        }
+    }
+
+    // Draw list view (inside window, leave space for title bar)
+    Rectangle list_bounds = {
+        (float)panel_x + 4,
+        (float)panel_y + 25,
+        (float)panel_width - 8,
+        (float)panel_height - 100 // Leave space for details below
+    };
+
+    int maneuver_scroll = 0;
+    int maneuver_active = -1;
+    GuiListView(list_bounds, maneuver_list_text, &maneuver_scroll, &maneuver_active);
+
+    // Show details for first pending or last executed maneuver
+    char details_text[512];
+    details_text[0] = '\0';
+
+    for (int i = 0; i < sim->maneuver_count; i++) {
+        if (sim->maneuvers[i].craft_index == render_state->selected_craft_index) {
+            if (sim->maneuvers[i].executed) {
+                snprintf(details_text, sizeof(details_text),
+                         "Last executed:\n%s\nΔv: %.1f m/s\nTime: %.1f s",
+                         sim->maneuvers[i].name, sim->maneuvers[i].delta_v, sim->maneuvers[i].executed_time);
+            } else {
+                snprintf(details_text, sizeof(details_text),
+                         "Next pending:\n%s\nΔv: %.1f m/s",
+                         sim->maneuvers[i].name, sim->maneuvers[i].delta_v);
+                break; // Show first pending
+            }
+        }
+    }
+
+    if (details_text[0] != '\0') {
+        Rectangle details_bounds = {
+            (float)panel_x + 8,
+            (float)panel_y + (float)panel_height - 70,
+            (float)panel_width - 16,
+            65
+        };
+        GuiLabel(details_bounds, details_text);
+    }
+
+    free(maneuver_list_text);
+}
diff --git a/src/ui_renderer.h b/src/ui_renderer.h
new file mode 100644
index 0000000..e91e8d0
--- /dev/null
+++ b/src/ui_renderer.h
@@ -0,0 +1,20 @@
+#ifndef UI_RENDERER_H
+#define UI_RENDERER_H
+
+#include "simulation.h"
+#include "renderer.h"
+#include "raylib.h"
+
+// UI state
+struct UIState {
+    int body_list_scroll;     // Scroll position for body list
+    int body_list_active;     // Active item index in body list
+};
+
+// UI rendering functions
+void render_info(SimulationState* sim);
+void render_body_list_ui(SimulationState* sim, RenderState* render_state, UIState* ui_state);
+void render_body_info_ui(SimulationState* sim, RenderState* render_state);
+void render_maneuver_list_ui(SimulationState* sim, RenderState* render_state);
+
+#endif