Artemis II Trajectory Analysis — Interactive 3D Visualization

Interactive 3D visualization of the NASA Artemis II mission trajectory, built from the official CCSDS OEM ephemeris data released by NASA/JSC/FOD/FDO.<strong>Source ephemeris:</strong> The OEM file (<code>Artemis_II_OEM_2026_04_04_to_EI.asc</code>) is available for download from NASA's Artemis II Real-Time Tracking page.<strong>Contents:</strong><code>Artemis_II_OEM_2026_04_04_to_EI.spk</code> — NAIF SPICE SPK kernel converted from OEM using oem2spk (body ID 24, center 399/Earth, Type 13 Hermite, J2000 frame). Verified identical to an independently produced mkspk conversion (body ID -224): state vector differences at 1000 evenly-spaced sample points were at machine epsilon (~10⁻¹⁵ km), confirming both tools produce numerically equivalent results.<code>orion_3d_animated.html</code> — Self-contained interactive 3D Plotly visualization with time slider, play/pause animation, and focus buttons (Earth, Moon, Closest Approach, Full Trajectory, current Orion position)<code>plot_3d_animated.py</code> — Python script to generate the interactive visualization (requires spiceypy, plotly, numpy)<code>plot_moon_distance.py</code> — Python script for 2D altitude-above-Moon plot<code>pck00011.tpc</code> — NAIF text PCK (planetary constants, for Moon radius)<code>naif0012.tls</code> — NAIF leapseconds kernel<code>mkspk_setup.txt</code> — NAIF mkspk setup file (alternative conversion method, produces body ID -224)<strong>Additional required kernel (not included, 114 MB):</strong> <code>de430.bsp</code> — available from NAIF generic kernels<strong>Key results:</strong> Closest approach to Moon: 6,547 km altitude (4,068 miles) on 2026-04-06 at 23:03 UTC — matches NASA's official value of 4,066 miles.