MTG-S1/Sentinel-4A

MTG-S1/Sentinel-4A

Artistic Representation of MTG-S1/Sentinel-4A Satellite
Mission type	Meteorology/Earth observation
Operator	ESA, EUMETSAT
Website	MTG (ESA) Sentinel-4 (ESA)
Mission duration	Planned: 8.5 years [1]
Spacecraft properties
Spacecraft type	MTG-S
Bus	SmallGEO [2]
Manufacturer	Thales Alenia Space
Launch mass	3,800 kg (8,400 lb) [3]
Start of mission
Launch date	1 July 2025, 21:04 (2025-07-01UTC21:04) UTC
Rocket	Falcon 9 Block 5 (F9-499)
Launch site	Kennedy LC-39A
Contractor	SpaceX
Orbital parameters
Reference system	Geocentric
Regime	GEO [4]
MTG/Sentinel-4 ←  MTG-I1 MTG-I2 Sentinel-4B  → Sentinel ←  Sentinel-1C Sentinel-5A  →

MTG-S1/Sentinel-4A is a European Meteorology and Earth Observation satellite. It is the first of two satellites in the Sentinel-4 constellation, part of the European Union's Copernicus programme on Earth observation and also one of two Meteosat Third Generation-Sounder (MTG-S) spacecraft. ^{[5] [6] [7] [8] [9]}

Timeline

Development

• In July 2011, ESA awarded a contract to Astrium (now part of Airbus Defence and Space) to develop and build two Sentinel-4 instruments to be carried on MTG-S satellites. At the time, the launches were expected to happen in 2019 and 2027. ^[10]
• In February 2023, the Sentinel-4 instrument module, containing the UVN spectrometer, was shipped from Rutherford Appleton Laboratory in the UK to OHB in Germany. ^[11]
• In August 2023, the three MTG-S instruments (Sentinel 4, RMU and IRS) were installed on the MTG-S1 satellite at OHB's facilities in Germany. ^[12]

Launch campaign

• In July 2024, the MTG-S1 satellite successfully passed its environmental test campaign at IABG’s facilities near Munich. ^[13]
• In February 2025, the MTG-S1 satellite had completed all functional and environmental tests in Bremen and was pronounced ready for transport to the launch site. ^[14]
• On 23 April 2025, the MTG-S1 satellite left Bremen on board the MNColibri cargo ship and arrived at Cape Canaveral on 6 May. ^[15] It was later transported to the AstroTech facilities cleanroom. ^[16]
• On 26 June 2025, ESA announced that the MTG-S1 satellite would launch no earlier than 1 July 2025, 21:03 UTC with a launch window of 2 hours. ^[17]

MTG-S1 launches from Kennedy Space Center

• Falcon 9 B1085 with the MTG-S1 satellite and the Sentinel-4A instrument launched on 1 July 2025 at 21:04 UTC toward geostationary transfer orbit. ^{[18] [19] [20]} The satellite separated from the rocket's upper stage approximately 35 minutes after liftoff and begun its 17-day transfer period. After reaching its position in a geostationary Earth orbit, the satellite undergoes a commissioning period of 9 to 12 months. ^[21]

In orbit

• On 18 July 2025, the Launch and Early Orbit Phase (LEOP) of MTG-S1 has been successfully concluded and the satellite was handed over to Eumetsat. The LEOP was managed by Telespazio (with support from ESA, OHB, and Thales Alenia Space) from the Fucino Space Centre, Italy. ^[22]

See also

• Spaceflight portal

• 2025 in spaceflight
• List of European Space Agency programmes and missions

References

1. "MTG-S 1, 2 (Meteosat 13, 16 / Sentinel 4A, 4B)". Gunter's Space Page. Retrieved 2025-10-07.
2. "MTG-S 1, 2 (Meteosat 13, 16 / Sentinel 4A, 4B)". Gunter's Space Page. Retrieved 2025-10-07.
3. "MTG-S 1, 2 (Meteosat 13, 16 / Sentinel 4A, 4B)". Gunter's Space Page. Retrieved 2025-10-07.
4. "ESA - Sentinel-4" . Retrieved 2022-01-18.
5. "MTG-S 1, 2 (Meteosat 13, 16 / Sentinel 4A, 4B)". Gunter's Space Page. Retrieved 2025-10-07.
6. "Sentinel-4 A Satellite Mission Summary | CEOS Database". database.eohandbook.com. Retrieved 2025-10-07.
7. "MTG-S1 and Sentinel-4 launch to change how we see our atmosphere". www.esa.int. Retrieved 2025-10-07.
8. "Copernicus: Sentinel-4 - eoPortal". www.eoportal.org. Archived from the original on 2024-09-19. Retrieved 2025-10-07.
9. "Facts and figures". www.esa.int. Retrieved 2025-10-07.
10. "Astrium to build ESA's Sentinel-4 atmospheric sensors". www.esa.int. Retrieved 2025-06-04.
11. "Sentinel-4 set to join next weather satellite". www.esa.int. Retrieved 2025-06-04.
12. "Putting the S in the first Meteosat Third Generation Sounder". www.esa.int. Retrieved 2025-06-04.
13. "Weather satellite passes bake and shake tests with flying colours". www.esa.int. Retrieved 2025-06-04.
14. "Two atmospheric missions on one satellite". www.esa.int. Retrieved 2025-06-04.
15. "MTG-S1 and Sentinel-4 take a step closer to space". www.esa.int. Retrieved 2025-06-04.
16. "MTG-S and Sentinel-4 undergo pre-launch manoeuvres". www.esa.int. Retrieved 2025-06-04.
17. "Watch MTG-S1 and Sentinel-4 launch live". www.esa.int. Retrieved 2025-06-26.
18. Wall, Mike (2025-07-01). "SpaceX launches advanced European weather satellite, lands rocket at sea (video, photos)". Space. Retrieved 2025-07-01.
19. "MTG-S1 and Copernicus Sentinel-4 launch from Florida". www.esa.int. Retrieved 2025-07-01.
20. "Falcon 9 Block 5 | MTG-S1/Sentinel-4A". nextspaceflight.com. Retrieved 2025-07-01.
21. Robinson-Smith, Will (1 July 2025). "EUMETSAT, ESA launches combo MTG-S1, Sentinel-4 satellite on SpaceX Falcon 9 rocket from NASA's Kennedy Space Center". Spaceflight Now. Retrieved 2025-07-02.
22. "Another milestone for the future of European weather observation". www.esa.int. Retrieved 2025-09-04.