SWIR: THEOS-3 Satellite Sensor for Agricultural Benefits from Space

THEOS-3, Thailand's latest high-resolution earth observation satellite, will incorporate a vital payload: the Short-Wave Infrared (SWIR) sensor. This advanced sensor, designed for observations in the invisible spectrum, will significantly enhance Thailand's space technology capabilities.

The SWIR sensor is an instrument used to record data in the shortwave infrared spectrum. Data acquired from a SWIR sensor on a satellite offers substantial benefits for agriculture, including: analyzing plant and soil moisture, monitoring crop health, assessing drought severity, and supporting efficient planting scheme optimization.

SWIR sensors are particularly effective due to their ability to detect the reflection and absorption of light waves in the near-infrared range, specifically within wavelengths from 1,000 to 1,750 nanometers. (For reference, light visible to the human eye has wavelengths between 350 and 780 nanometers). This spectral range allows SWIR waves to indicate the structure of plant leaves than visible light and is more suitable for monitoring crop and soil moisture. This allows for the detection of abnormal conditions in plants or changes in soil moisture content, leading to more effective use of data in agriculture than ever before.

This advanced equipment will be developed through a collaboration between the Geo-Informatics and Space Technology Development Agency (Public Organization), or GISTDA, and LatConnect60, a leading AI company from Australia specializing in transforming Earth observation data from space into actionable insights.

GISTDA and LatConnect 60 signed a Memorandum of Understanding (MOU) on April 17, 2025, to jointly develop the SWIR imaging sensor for the THEOS-3 satellite. The collaboration will cover feasibility studies, integration, system compatibility, testing, and validation of the payload to ensure optimal performance with Thailand's satellite.

The signing ceremony was attended by Dr. Pakorn Apaphant, Executive Director of GISTDA, and Mr. Venkat Pillay, CEO of LatConnect60. The event was honored by the presence of Her Excellency Dr. Angela Macdonald PSM, the Australian Ambassador to Thailand.

Dr. Pakorn Apaphant stated, "This collaboration not only reinforces GISTDA's role as the country's leading space technology organization but also reflects a new direction for Thailand in fostering high-tech cooperation with international partners. This is a crucial foundation for driving the digital economy, resource management, and sustainable development in the future."

The SWIR instrument on THEOS-3 will consist of four spectral bands per sensor set. The sensor will have a post-processing spatial resolution of approximately 9 meters and a swath width of about 11 kilometers per sensor set, from an average orbital altitude of 500 kilometers.

In addition to the joint development of the sensor, GISTDA and LatConnect 60 will expand the application of satellite data to enhance its potential usage, including knowledge sharing, workforce development, and future collaboration in the multi-disciplinary space industry.

THEOS-3 will be Thailand's fourth natural resources survey microsatellite. Scheduled to be launched into a Sun-synchronous orbit by 2027, the same type of orbit as the currently operational THEOS-2 satellite.

Parts for the THEOS-3 satellite will be manufactured by Thai operators, who will also be involved in the design, testing, and assembly processes. This follows a process of gathering input from agencies with a need for satellite data to develop various payloads, such as the SWIR sensor. GISTDA engineers will collaborate on integrating it into the Engineering Model of THEOS-3, with plans to proceed with the Flight Model assembly in 2026.

This initiative is a prime example of leveraging satellite technology to effectively support and advance agriculture, as well as to monitor and assess carbon and methane gas levels, which play a significant role in Thailand's Net Zero goals, in line with GISTDA's vision of "Delivering Value from Space and Geo-Informatics to Society."