HIMAWARI-9

Redundancy is part of system engineering: weather forecasting depends on uninterrupted observations, so backup spacecraft can be nearly as important as the primary one.

Redundancy is part of system engineering: weather forecasting depends on uninterrupted observations, so backup spacecraft can be nearly as important as the primary one.

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.

• Redundancy is part of system engineering: weather forecasting depends on uninterrupted observations, so backup spacecraft can be nearly as important as the primary one.

Redundancy is part of system engineering: weather forecasting depends on uninterrupted observations, so backup spacecraft can be nearly as important as the primary one.

The current two-line element set reports approximately 1.0027 revolutions per day. Dividing 1,440 minutes by that value gives an estimated orbital period of 1,436.1 minutes.

Himawari-9 launched on 2 November 2016 aboard an H-IIA from Tanegashima Space Center.

A geosynchronous satellite takes about one sidereal day to orbit Earth. A circular equatorial geostationary satellite appears to remain near one longitude in the sky.

GEO is valuable when continuous coverage of a broad region matters, although the great distance increases signal delay and reduces image detail compared with lower orbits.

• 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