FENGYUN 3B

Constellation timing matters because multiple polar spacecraft can sample different local times of day, improving the temporal picture of changing weather systems.

Constellation timing matters because multiple polar spacecraft can sample different local times of day, improving the temporal picture of changing weather systems.

Weather spacecraft carry instruments that observe Earth and its atmosphere in visible, infrared, microwave, or other wavelengths. Different orbits provide either repeated regional views or broad global coverage.

• Constellation timing matters because multiple polar spacecraft can sample different local times of day, improving the temporal picture of changing weather systems.

Constellation timing matters because multiple polar spacecraft can sample different local times of day, improving the temporal picture of changing weather systems.

The current two-line element set reports approximately 14.1486 revolutions per day. Dividing 1,440 minutes by that value gives an estimated orbital period of 101.8 minutes.

Fengyun-3B launched on 4 November 2010 aboard a Long March 4C from Taiyuan.

Low Earth orbit is the region closest to Earth used by most crewed spacecraft, many science missions, Earth-observation satellites, and large constellations. Objects move quickly and commonly complete an orbit in roughly 90 to 130 minutes.

LEO can provide detailed Earth views, lower communications delay, and easier access than higher orbits, but it covers less area per spacecraft and is more affected by atmospheric drag.

• Why can infrared instruments observe clouds at night?
• What is the difference between continuous regional coverage and global coverage?

Current identity and orbital elements come from CelesTrak’s public GP data. Calculated orbit values are derived from the current TLE and may change after catalog updates. Mission-history claims are added separately and require authoritative sources.

• CelesTrak NORAD GP Element Sets