Daylight imagery: NASA Earth Observatory, Blue Marble: Next Generation, November 2004, with shaded topography (Reto Stöckli).
https://science.nasa.gov/earth/earth-observatory/blue-marble-next-generation/base-topography/
Global source: world.topo.200411.3x21600x10800.jpg. North American detail comes from the 500 m A1 and B1 tiles; contiguous high-resolution coverage spans 135°W–60°W, 15°N–60°N.

Nighttime light intensity: NASA Earth Observatory, Black Marble 2016 grayscale, based on Suomi NPP VIIRS data.
https://science.nasa.gov/earth/earth-observatory/earth-at-night/maps/
BlackMarble_2016_3km_gray.jpg; BlackMarble_2016_A1_gray.jpg and BlackMarble_2016_B1_gray.jpg for the same North American detail area. Lamp colors are rendered in-game, not measured colors.

Cloud density: Solar System Scope (8k_earth_clouds.jpg), based on NASA imagery.
https://www.solarsystemscope.com/textures/
CC BY 4.0: https://creativecommons.org/licenses/by/4.0/
Converted to grayscale for single-channel sampling; smaller copy used on mobile.
Cloud imagery is a fixed composite, not a current weather observation.

All source imagery is stored locally. To regenerate, run tools/build-earth.py with a directory containing the above day sources named orbio-bm-nov.jpg, orbio-day-a.jpg, orbio-day-b.jpg, the night sources named orbio-lights-3km.jpg, orbio-lights-A1.jpg, orbio-lights-B1.jpg, and the cloud source named orbio-cloud8.jpg.

The flight and landing Earth windows play locally baked H.264 loops. Their terrain
and city lights use the Blue Marble and Black Marble imagery credited above. The
cloud layer adapts the Solar System Scope composite credited above (CC BY 4.0).
tools/build-orbit-films.py projects the imagery, lights the limb, and encodes each
US view for desktop and mobile. The navigation chart tracks the simulated ISS
independently of the selected film.