Overview

At Planet, we are committed to providing our customers with high-quality, scientifically robust data that is reliable for long-term analysis. To ensure the continuity and quality of our Surface Reflectance (SR) products, we are transitioning the underlying atmospheric correction input from the retiring MODIS (Moderate Resolution Imaging Spectroradiometer) sensor to the more modern VIIRS (Visible Infrared Imaging Radiometer Suite) sensor on November 3, 2025.

This article provides a comprehensive overview of this change, its technical rationale, and the potential impacts on your data and workflows.

Why the Transition is Happening

The MODIS sensors on board the Terra and Aqua satellites have been instrumental in Earth observation for over two decades. However, the MODIS mission is in its final operational phase, and in late 2026/early 2027 “will begin shutting down operations” (Transition From MODIS to VIIRS). This planned end-of-life for the MODIS program necessitates a proactive and forward looking solution to ensure uninterrupted service for our customers.

VIIRS is the designated successor to MODIS and is a key component of the Joint Polar Satellite System (JPSS). By transitioning to VIIRS data, we are:

• Ensuring Long Term Stability: Moving to a modern, actively maintained data source guarantees the long-term availability of the necessary inputs for our atmospheric correction processes.
• Maintaining Product Quality: The VIIRS sensor is designed with improved radiometric performance and a wider swath, which enhances our ability to accurately correct for atmospheric effects.
• Providing Continuity: The VIIRS mission was specifically designed to continue the long-term data record of MODIS, ensuring a high degree of compatibility between the two data sets.

What This Means for Your Data

1. Date of Transition: The SR product generation pipeline will be officially switched to use VIIRS data on Monday, November 3, 2025. All new SR products generated after this date will be based on the new inputs.
2. Metadata Transparency: To ensure complete transparency, every SR product generated using the new data will contain a specific metadata tag in the GeoTIFF header. This tag will explicitly state that the product was atmospherically corrected using VIIRS data.
3. Data Consistency: We have taken great care to minimize any disruption to data consistency. Our SR algorithm, which uses a look-up table (LUT) approach based on the 6SV2.1 radiative transfer code, has been updated to use VIIRS-derived atmospheric parameters. While the absolute values may be slightly different, the relative spectral relationships and overall quality will be consistent. The Surface Reflectance White Paper will be updated with VIIRS details on November 3, 2025. In addition, Planet provider quarterly reports for the surface reflectance PlanetScope and SkySat products: L2 Data Quality Reports.
4. No Impact on Latency: We do not anticipate any changes to our current SR product delivery latency.

How to Identify the Data Source for Your SR Product

To determine which data source was used to generate your Surface Reflectance product, simply check the GeoTIFF metadata header. All newly generated products will contain a specific metadata field that explicitly states the source.

• For products generated on or after November 3, 2025: The metadata will indicate that the product was generated using VIIRS data.

"aot_source": "viirs"
"water_vapor_source": "viirs"
"ozone_source": “viirs"

• For products generated before November 3, 2025: The metadata will indicate that the product was generated using MODIS data.
• MODIS Terra

"aot_source": "mod09cma_nrt"
"water_vapor_source": "mod09cma_nrt"
"ozone_source": "mod09cmg_nrt"

• MODIS Aqua

"aot_source": "myd09cma_nrt"
"water_vapor_source": "myd09cma_nrt"
"ozone_source": "myd09cmg_nrt"

Which Planet Satellites Does This Apply To?

This transition applies to the Surface Reflectance products generated from the following Planet satellite constellations:

• PlanetScope
• SkySat

The change affects the atmospheric correction process for both of these product lines, ensuring a consistent and reliable data source for all of our customers.

Frequently Asked Questions (FAQ)

Will this change break my existing workflows?

For most customers, the transition should be seamless. However, if your applications are sensitive to minor shifts in absolute SR values, we recommend validating your workflows with a small set of newly generated data. The metadata tag is a reliable way to identify new products.

Will Planet reprocess old data using VIIRS?

There are currently no plans to reprocess historical SR products using VIIRS. All products generated before November 3, 2025, will remain in their original form.

Which item-type and asset-type will this apply to?

Item-types: PSScene, SkySatScene, SkySatCollect

Asset-Types: 

• PSScene: ortho_analytic_4b_sr, ortho_analytic_8b_sr
• SkySatCollect/SkySatScene: ortho_analytic_sr

How do I identify which sensor was used for atmospheric correction?

The GeoTIFF header of each SR product will contain a metadata string that specifies the source of the atmospheric data.

• VIIRS

"aot_source": "viirs"
"water_vapor_source": "viirs"
"ozone_source": “viirs"

• MODIS Terra

"aot_source": "mod09cma_nrt"
"water_vapor_source": "mod09cma_nrt"
"ozone_source": "mod09cmg_nrt"

• MODIS Aqua

"aot_source": "myd09cma_nrt"
"water_vapor_source": "myd09cma_nrt"
"ozone_source": "myd09cmg_nrt"

Is there a fallback for VIIRS in case VIIRS sensors have issues?

Until the end of life of MODIS Terra, MODIS Terra will be the fall back while Planet assesses  additional fallback to VIIRS can be incorporated to the pipeline in case of emergencies.

What is the impact on latency?

We do not anticipate any changes to our current SR product delivery latency.

When requesting the archive (processed using MODIS) as well as new images (using VIIRS), will there be noticeable differences in SR values given that some part of the archive was processed using MODIS data vs VIIRS?

We have run a global land mass comparison of VIIRS generated SR to production MODIS generated SR data and have found minimal differences between the surface reflectance values. The following table and charts show the gain, offset, % uncertainty, and r2.

MODIS versus VIIRS 

What if I have additional questions?

Our support team is fully briefed on this change and is available to assist you with any questions. Please contact us at support@planet.com