diff --git a/public/auth_helpers.php b/public/auth_helpers.php
index e27ee7f..b0f3ecd 100644
--- a/public/auth_helpers.php
+++ b/public/auth_helpers.php
@@ -61,6 +61,7 @@ function manageablePublicPages(): array
         'astronomical_conversions.php' => 'Astronomical Conversions',
         'tcrb_lightcurve.php' => 'T CrB Lichtkurve',
         'solarsystem.php' => 'Sonnensystem',
+        'mars.php' => 'Mars',
         'jupitersystem.php' => 'Jupitersystem',
         'tagbogen.php' => 'Tagbogen',
         'sternenhimmel.php' => 'Sternenhimmel',
diff --git a/public/header.php b/public/header.php
index 8917ff8..4e94ad2 100644
--- a/public/header.php
+++ b/public/header.php
@@ -1,5 +1,9 @@
 <?php
 require_once __DIR__ . '/auth_helpers.php';
+if (!isset($loggedIn)) {
+    $loggedIn = isset($_SESSION['user_id']);
+}
+
 $title = isset($pageTitle) && is_string($pageTitle) && $pageTitle !== ''
     ? $pageTitle
     : 'Skyview & AstroTools - Astronomiemuseum der Sternwarte Sonneberg';
@@ -123,6 +127,7 @@ $menuGroups = [
             ['href' => 'astronomical_conversions.php', 'label' => 'Astronomical Conversions'],
             ['href' => 'tcrb_lightcurve.php',      'label' => 'T CrB Lichtkurve'],
             ['href' => 'solarsystem.php',           'label' => 'Sonnensystem'],
+            ['href' => 'mars.php',                  'label' => 'Mars'],
             ['href' => 'jupitersystem.php',         'label' => 'Jupitersystem'],
             ['href' => 'tagbogen.php',              'label' => 'Tagbogen'],
             ['href' => 'sternenhimmel.php',         'label' => 'Sternenhimmel'],
@@ -178,9 +183,9 @@ if ($loggedIn && !$hasFullAdminAccess && $pdoHeader !== null) {
     foreach ($menuGroups as &$group) {
         $group['links'] = array_values(array_filter(
             $group['links'],
-            static function (array $link) use ($allowedPageKeys): bool {
+            static function (array $link) use ($allowedPageKeys, $publicAccessAllowlist): bool {
                 $href = trim((string) ($link['href'] ?? ''));
-                return $href !== '' && isset($allowedPageKeys[$href]);
+                return $href !== '' && (isset($allowedPageKeys[$href]) || in_array($href, $publicAccessAllowlist, true));
             }
         ));
     }
@@ -193,9 +198,9 @@ if ($loggedIn && !$hasFullAdminAccess && $pdoHeader !== null) {
 
     $accountLinks = array_values(array_filter(
         $accountLinks,
-        static function (array $link) use ($allowedPageKeys): bool {
+        static function (array $link) use ($allowedPageKeys, $publicAccessAllowlist): bool {
             $href = trim((string) ($link['href'] ?? ''));
-            return $href !== '' && isset($allowedPageKeys[$href]);
+            return $href !== '' && (isset($allowedPageKeys[$href]) || in_array($href, $publicAccessAllowlist, true));
         }
     ));
 }
diff --git a/public/images/planets/mars_1024.jpg b/public/images/planets/mars_1024.jpg
index f09381a..d0f3131 100644
Binary files a/public/images/planets/mars_1024.jpg and b/public/images/planets/mars_1024.jpg differ
diff --git a/public/images/planets/mars_2048.jpg b/public/images/planets/mars_2048.jpg
index 891c686..eacdcfd 100644
Binary files a/public/images/planets/mars_2048.jpg and b/public/images/planets/mars_2048.jpg differ
diff --git a/public/images/planets/mars_4096.jpg b/public/images/planets/mars_4096.jpg
index 252db4f..c3c43c8 100644
Binary files a/public/images/planets/mars_4096.jpg and b/public/images/planets/mars_4096.jpg differ
diff --git a/public/images/planets/mars_8192.jpg b/public/images/planets/mars_8192.jpg
index 09a804b..9a0137c 100644
Binary files a/public/images/planets/mars_8192.jpg and b/public/images/planets/mars_8192.jpg differ
diff --git a/public/images/planets/mars_displacement_5760.jpg b/public/images/planets/mars_displacement_5760.jpg
new file mode 100644
index 0000000..e52a2ce
Binary files /dev/null and b/public/images/planets/mars_displacement_5760.jpg differ
diff --git a/public/images/planets/netptun_1024.jpg b/public/images/planets/netptun_1024.jpg
deleted file mode 100644
index 26ca0b2..0000000
Binary files a/public/images/planets/netptun_1024.jpg and /dev/null differ
diff --git a/public/images/planets/netptun_2048.jpg b/public/images/planets/netptun_2048.jpg
deleted file mode 100644
index 30e7ac5..0000000
Binary files a/public/images/planets/netptun_2048.jpg and /dev/null differ
diff --git a/public/mars.php b/public/mars.php
new file mode 100644
index 0000000..fb27875
--- /dev/null
+++ b/public/mars.php
@@ -0,0 +1,240 @@
+<?php
+declare(strict_types=1);
+
+ini_set('display_errors', '1');
+error_reporting(E_ALL);
+session_start();
+
+$pageTitle = 'Mars - AstroTools';
+$bodyClass = 'mars-page';
+$headerIntroPre = 'Planetendarstellung';
+$headerIntroTitle = 'Mars';
+$headerIntroSub = 'Eine einfache 3D-Ansicht mit Marstextur.';
+?>
+<?php require __DIR__ . '/header.php'; ?>
+
+<style>
+.mars-stage-card {
+    padding: 0;
+    overflow: hidden;
+}
+
+.mars-stage {
+    position: relative;
+    min-height: 70vh;
+    background:
+        radial-gradient(circle at top, rgba(255, 153, 102, 0.12), transparent 40%),
+        linear-gradient(180deg, rgba(14, 10, 10, 0.94), rgba(8, 8, 12, 0.98));
+}
+
+#marsViewport {
+    width: 100%;
+    height: 70vh;
+    display: block;
+}
+
+.mars-overlay {
+    position: absolute;
+    left: 1rem;
+    bottom: 1rem;
+    padding: 0.6rem 0.85rem;
+    border-radius: 999px;
+    background: rgba(15, 15, 22, 0.72);
+    color: #f4e7de;
+    font-size: 0.95rem;
+    letter-spacing: 0.02em;
+    backdrop-filter: blur(10px);
+}
+
+@media (max-width: 768px) {
+    .mars-stage,
+    #marsViewport {
+        height: 58vh;
+        min-height: 420px;
+    }
+}
+</style>
+
+<section class="card mars-stage-card">
+    <div class="mars-stage">
+        <canvas id="marsViewport" aria-label="3D-Ansicht des Mars"></canvas>
+        <div class="mars-overlay">Ziehen zum Drehen, Mausrad zum Zoomen</div>
+    </div>
+</section>
+
+<script type="module">
+let THREE;
+
+async function initMars() {
+    THREE = await import('./js/three.module.js');
+
+    const canvas = document.getElementById('marsViewport');
+    if (!canvas) {
+        return;
+    }
+
+    const renderer = new THREE.WebGLRenderer({
+        canvas,
+        antialias: true,
+        alpha: true
+    });
+    renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2));
+    renderer.outputColorSpace = THREE.SRGBColorSpace;
+    renderer.shadowMap.enabled = true;
+    renderer.shadowMap.type = THREE.PCFSoftShadowMap;
+    renderer.toneMapping = THREE.ACESFilmicToneMapping;
+    renderer.toneMappingExposure = 1.05;
+
+    const scene = new THREE.Scene();
+
+    const camera = new THREE.PerspectiveCamera(45, 1, 0.1, 100);
+    camera.position.set(0, 0, 4.8);
+
+    const hemisphereLight = new THREE.HemisphereLight(0x9db4d8, 0x120d0b, 0.16);
+    scene.add(hemisphereLight);
+
+    const sunLight = new THREE.DirectionalLight(0xfff1d6, 2.8);
+    sunLight.position.set(7, 1.8, 5.5);
+    sunLight.castShadow = true;
+    sunLight.shadow.mapSize.set(2048, 2048);
+    sunLight.shadow.bias = -0.0008;
+    sunLight.shadow.normalBias = 0.02;
+    sunLight.shadow.camera.near = 1;
+    sunLight.shadow.camera.far = 20;
+    sunLight.shadow.camera.left = -4;
+    sunLight.shadow.camera.right = 4;
+    sunLight.shadow.camera.top = 4;
+    sunLight.shadow.camera.bottom = -4;
+    sunLight.target.position.set(0, 0, 0);
+    scene.add(sunLight);
+    scene.add(sunLight.target);
+
+    const fillLight = new THREE.DirectionalLight(0xa4b4d8, 0.18);
+    fillLight.position.set(-4, -1.5, -3.5);
+    scene.add(fillLight);
+
+    const loader = new THREE.TextureLoader();
+    const marsTexture = loader.load('./images/planets/mars_4096.jpg');
+    marsTexture.colorSpace = THREE.SRGBColorSpace;
+    marsTexture.anisotropy = renderer.capabilities.getMaxAnisotropy();
+    const marsDisplacement = loader.load('./images/planets/mars_displacement_5760.jpg');
+    marsDisplacement.anisotropy = renderer.capabilities.getMaxAnisotropy();
+
+    const geometry = new THREE.SphereGeometry(1.45, 192, 192);
+    const material = new THREE.MeshStandardMaterial({
+        map: marsTexture,
+        displacementMap: marsDisplacement,
+        displacementScale: 0.065,
+        displacementBias: -0.02,
+        bumpMap: marsDisplacement,
+        bumpScale: 0.03,
+        roughness: 0.96,
+        metalness: 0
+    });
+
+    const mars = new THREE.Mesh(geometry, material);
+    mars.castShadow = true;
+    mars.receiveShadow = true;
+    scene.add(mars);
+
+    const state = {
+        isPointerDown: false,
+        lastX: 0,
+        lastY: 0,
+        velocityX: 0,
+        velocityY: 0
+    };
+
+    canvas.style.touchAction = 'none';
+
+    function resizeRenderer() {
+        const width = canvas.clientWidth;
+        const height = canvas.clientHeight;
+        if (width === 0 || height === 0) {
+            return;
+        }
+
+        renderer.setSize(width, height, false);
+        camera.aspect = width / height;
+        camera.updateProjectionMatrix();
+    }
+
+    function clampCameraDistance(nextZ) {
+        return Math.min(Math.max(nextZ, 3.2), 8.5);
+    }
+
+    function onPointerDown(event) {
+        state.isPointerDown = true;
+        state.lastX = event.clientX;
+        state.lastY = event.clientY;
+        canvas.setPointerCapture(event.pointerId);
+    }
+
+    function onPointerMove(event) {
+        if (!state.isPointerDown) {
+            return;
+        }
+
+        const deltaX = event.clientX - state.lastX;
+        const deltaY = event.clientY - state.lastY;
+        state.lastX = event.clientX;
+        state.lastY = event.clientY;
+
+        const rotationSpeed = 0.008;
+        mars.rotation.y += deltaX * rotationSpeed;
+        mars.rotation.x += deltaY * rotationSpeed;
+        mars.rotation.x = Math.max(-1.25, Math.min(1.25, mars.rotation.x));
+
+        state.velocityX = deltaX * 0.0009;
+        state.velocityY = deltaY * 0.0009;
+    }
+
+    function onPointerUp(event) {
+        state.isPointerDown = false;
+        if (canvas.hasPointerCapture(event.pointerId)) {
+            canvas.releasePointerCapture(event.pointerId);
+        }
+    }
+
+    function onWheel(event) {
+        event.preventDefault();
+        camera.position.z = clampCameraDistance(camera.position.z + event.deltaY * 0.0035);
+    }
+
+    function renderFrame() {
+        if (!state.isPointerDown) {
+            mars.rotation.y += state.velocityX;
+            mars.rotation.x += state.velocityY;
+            mars.rotation.x = Math.max(-1.25, Math.min(1.25, mars.rotation.x));
+            state.velocityX *= 0.94;
+            state.velocityY *= 0.94;
+
+            if (Math.abs(state.velocityX) < 0.00001) {
+                state.velocityX = 0;
+            }
+            if (Math.abs(state.velocityY) < 0.00001) {
+                state.velocityY = 0;
+            }
+        }
+
+        renderer.render(scene, camera);
+        requestAnimationFrame(renderFrame);
+    }
+
+    canvas.addEventListener('pointerdown', onPointerDown);
+    canvas.addEventListener('pointermove', onPointerMove);
+    canvas.addEventListener('pointerup', onPointerUp);
+    canvas.addEventListener('pointercancel', onPointerUp);
+    canvas.addEventListener('wheel', onWheel, { passive: false });
+
+    window.addEventListener('resize', resizeRenderer);
+    resizeRenderer();
+    renderFrame();
+}
+
+initMars().catch((error) => {
+    console.error('Mars-Ansicht konnte nicht initialisiert werden.', error);
+});
+</script>
+
+<?php require __DIR__ . '/footer.php'; ?>