Daqi-1

Daqi-1

Mission type	Remote sensing
Operator	China National Space Administration
COSPAR ID	2022-039A
SATCAT no.	52257
Mission duration	8 years (planned)
Spacecraft properties
Bus	SAST-5000B
Manufacturer	Shanghai Academy of Spaceflight Technology
Start of mission
Launch date	15 April 2022, 18:16 (2022-04-15UTC18:16)  UTC
Rocket	Long March 4C
Launch site	Taiyuan Satellite Launch Center, Launch Complex 9, Shanxi, China
Contractor	China Aerospace Science and Technology Corporation
Instruments
ACDL, DPC-II, EMI-II, POSP, WSI

Daqi-1 or Atmospheric Environment Monitoring Satellite is a Chinese atmospheric environmental monitoring satellite in sun-synchronous orbit which was launched on 15 April 2022. ^[1]

Its Aerosol and Carbon Detection Lidar (ACDL) instrument is thought to be the most likely cause of a green laser light observed over Hawaii on 28 January 2023 by the Subaru Telescope. ^[2] Some believe the satellite was using the ACDL sensor to conduct laser topographic intelligence collection being done for military purposes. ^[3]

Spacecraft architecture

The spacecraft is based on the Shanghai Academy of Spaceflight Technology's SAST-5000B bus and is similar to the Gaofen 5 satellite. ^{[4] [5] [6]}

The satellite was launched from the Taiyuan Satellite Launch Center's Launch Site 9, via a Long March 4C rocket. ^{[4] [5] [6]}

Sensors onboard

• ACDL (Aerosol and Carbon dioxide Detection Lidar) ^[4]
• DPC-II (Directional Polarimetric Camera) ^[4]
• EMI-II (Environmental Trace Gas Monitoring Instrument) ^[4]
• POSP (Particulate Observing Scanning Polarization) ^[4]
• WSI (Wide Spectral Imager) ^[4]
  • The wide-swath imager (WSI) equipped on the DaQi-1 satellite uses a 45° rotary scanning mirror, a K-mirror, and several linear-array charge-coupled devices (CCDs) to collect ground images in a whiskbroom mode. ^[7]

References

1. Justin Davenport (15 April 2022), China launches Chang Zheng 4C from Taiyuan with Daqi-1 environmental satellite
2. "Night tricks" of the Chinese satellite become a "surprise" for Americans, Universe, 10 February 2023
3. Moore, Bryce (12 February 2023). "Chinese satellite beams green lasers over Hawaii". KHON-TV .
4. Krebs, Gunter D. "Daqi 1 (DQ 1, AEMS 1)". Gunter's Space Page.
5. Percival, Claire (24 April 2022). "Daqi-1 | Long March 4C". Everyday Astronaut. Retrieved 10 July 2025.
6. Davenport, Justin (16 April 2022). "China launches Chang Zheng 4C from Taiyuan with Daqi-1 environmental satellite". NASASpaceFlight.com. Retrieved 10 July 2025.
7. Cao, Jinshan (2023). "Geometric Calibration of the Whiskbroom DaQi-1 WSI Based on an Equivalent Linear-Array CCD". IEEE Transactions on Geoscience and Remote Sensing. 61: 1–13. Bibcode:2023ITGRS..6100013C. doi:10.1109/TGRS.2023.3300013. ISSN   1558-0644.