Please make a donation to support Gunter's Space Page.
Thank you very much for visiting Gunter's Space Page. I hope that this site is useful and informative for you.
If you appreciate the information provided on this site, please consider supporting my work by making a simple and secure donation via PayPal. Please help to run the website and keep everything free of charge. Thank you very much.

ALOS 4 (Daichi 4)


JAXA's ALOS 4 (Advanced Land Observation Satellite 4) is a planned radar Earth observation satellite. It is the follow up to ALOS 2.

The Advanced Land Observing Satellite-4 (ALOS-4) is a satellite to observe the Earth's surface using its onboard phased array type L-band synthetic aperture radar (PALSAR-3). The L-band radar technology has continuously been developed in Japan. With further improved observation performance compared to the predecessor PALSAR-2 aboard the Daichi-2 (ALOS-2), JAXA and its prime contractor, Mitsubishi Electric Corporation, are developing the satellite aiming at achieving both high resolution and a broader observation swath. Unlike observations by an optical sensor, radar images can be acquired day and night as it does not require sunlight. Moreover, since radio waves can penetrate cloud, the images can be obtained regardless of weather condition. The ALOS-4 will leverage these merits for observing and monitoring disaster-hit areas, forests, and sea ice. In addition, it will also challenge new areas such as monitoring infrastructure displacement.

ALOS-4 will also be equipped with the Automatic Identification System for ships (AIS) receiver, as was Daichi-2, so that the satellite will also monitor oceans by receiving AIS signals from vessels as well as by acquiring the PALSAR-3 images. The SPace based AIS Experiment (SPAISE3) is a high performance satellite AIS. Effective countermeasures against radio wave interference regions are taken for the SPAISE3 with multiple antennas and groundbased data processing; therefore, the detection success rate of a ship in the heavy marine traffic areas will be improved compared to Daichi-2. SPAISE3 development is JAXA's ongoing project in cooperation with NEC Corporation.

ALOS 4 was originally to be launched on a H-3-30S, but was later changed to a H-3-22S version.

Nation: Japan
Type / Application: Earth Observation, Radar
Operator: JAXA
Contractors: Mitsubishi Electric Corporation
Equipment: PALSAR-3 L-band SAR, SPAISE3 (AIS-receiver)
Power: 2 deployable solar arrays, batteries
Lifetime: 7 years
Mass: ~3000 kg
Orbit: 6301 km, 97.8 SSO
Satellite COSPAR Date LS Launch Vehicle Remarks
ALOS 4 (Daichi 4) - 2024 Ta YLP-2 H-3-22S

Cite this page: