Solar Illumination Visualizer

Mission Layer • Space Environment
v2.0.0 MIT License Updated: 2025-09-08

Interactive 3D visualization of the Sun-Earth system with satellite orbits. Analyze solar illumination conditions, beta angles, and orbital dynamics in real-time.

0.000
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420 km
51.6°
Elapsed Days: 0.0
Orbital Position: 0.000
Solar β Angle: 0.0°
Sun: Radius 696,000 km
Earth: Radius 6,371 km (1/109 of Sun)
Distance: 1 AU (149,597,871 km)
※ Scaled for visibility
Mouse: drag to rotate, scroll to zoom

How to Use

  • 3D Navigation: Click and drag to rotate the view, scroll to zoom in/out
  • Simulation Control: Use the Pause/Play button to control animation, or drag the Orbital Position slider to jump to any point in Earth's orbit
  • Scale Adjustment: Adjust Sun and Earth scales for better visibility (actual scale ratios are preserved)
  • Satellite Parameters: Modify altitude and inclination to simulate different orbits
  • Reset: Click Reset View to return to default camera position. Shift+Click to also reset simulation time

Key Features

  • Solar Beta Angle: Real-time calculation of the angle between satellite orbital plane and Sun vector
  • Satellite Illumination: Visual indication when satellite is in Earth's shadow (blue) or sunlight (yellow)
  • Accurate Orbital Mechanics: Based on Kepler's laws with proper orbital periods
  • Earth's Axial Tilt: 23.5° tilt properly modeled for seasonal variations
  • ISS Default: Pre-configured with International Space Station parameters (420 km altitude, 51.6° inclination)

Physical Parameters

Parameter Value Description
Sun Radius 696,000 km Photosphere radius
Earth Radius 6,371 km Mean radius
1 AU 149,597,871 km Mean Earth-Sun distance
Earth's Axial Tilt 23.5° Obliquity of the ecliptic
ISS Altitude ~420 km Average orbital altitude
ISS Inclination 51.6° Orbital inclination to equator
ISS Period ~90 minutes Orbital period

Understanding Solar Beta Angle

The solar beta angle (β) is crucial for spacecraft thermal control and power generation. It represents the angle between the orbital plane and the Sun vector:

  • β = 0°: Sun is in the orbital plane - maximum eclipse duration per orbit
  • β = ±90°: Sun is perpendicular to orbital plane - continuous sunlight (no eclipse)
  • ISS Range: Varies between approximately ±75° throughout the year due to orbital precession and Earth's axial tilt
  • Critical Operations: High beta angles (|β| > 60°) require special thermal management procedures