Thermal infrared sensor, 12 m

Surface temperature by day or night. Irrigated fields stay cool, dry ground and roofs run hot, and an industrial leak or a fire shows up before the smoke does.

Thermal infrared image of farmland: circular irrigated fields appear dark purple and cool, dry ground bright yellow and hot — Land surface temperature, 28 July 2025, around 13:00 local time. Purple is cool, yellow is hot, 31 to 56 °C. Imagery: Landsat 9 surface temperature, courtesy of the U.S. Geological Survey (public domain). 100 m native resolution; Perihel thermal is 12 m.

Specification

PH-T payload on the Perihel standard bus, orbit 525 km sun-synchronous.

Ground sample distance	12 m (long-wave infrared, resampled from 11 m)
Swath width	22 km
Spectral bands	Two long-wave bands: 10.3 to 11.3 µm and 11.5 to 12.5 µm
Radiometric resolution	14 bit
Absolute accuracy	±1.5 K (blackbody-referenced, once per orbit)
Sensitivity (NEdT)	0.1 K at 300 K
Revisit, one satellite	4 days, day and night
Local overpass times	10:30 and 22:30
Pointing	Up to ±25° off nadir
Calibration	On-board blackbody and deep-space view each orbit
Downlink	X-band, 800 Mbit/s

Products and formats

Every scene is delivered as a cloud-optimised GeoTIFF with a STAC item. Levels are cumulative: you can order L1B and reprocess to L2 later.

Product levels
Level	Content	Format	Delivery after downlink
L1B	Calibrated at-sensor radiance, sensor geometry	COG GeoTIFF, float32	30 min
L2	Land surface temperature in kelvin, emissivity corrected	COG GeoTIFF, int16, scale 0.01	50 min
L2 anomaly	Thermal anomaly mask against 30-day local baseline	COG GeoTIFF + GeoJSON polygons	50 min
L3	Monthly day and night temperature composites	COG GeoTIFF	Within 24 h

Example products

Optical image of the same fields in natural colour — The same area in natural colour. Every cool disc in the thermal frame is a green, irrigated field. Imagery: Contains modified Copernicus Sentinel data (2025), Sentinel-2.

Resolution and revisit

Revisit of a mid-latitude point improves with every satellite you add to the plane. See the coverage page for the ground tracks.

Revisit by fleet size
Satellites	Revisit
1	96 h
3	32 h
6	16 h
12	8 h

Try the coverage calculator

Typical uses

Irrigation and water stress: Irrigated pivots read about 17 °C cooler than dry ground in the example frame; a failing pivot warms within days.
Urban heat: Surface temperature per block for heat action plans and cooling investment.
Industrial monitoring: Flares, cooling towers, stockpile fires and process heat at plants and mines.
Wildfire and burn scars: Active fire detection on every pass, day and night, plus burn severity afterwards.

Sample delivery

Each scene arrives with a STAC item that any STAC client reads. Query it through our API or find it next to the data in your own bucket.

Delivered item, abbreviated

{
  "type": "Feature",
  "stac_version": "1.0.0",
  "id": "PH-THE-20250728-173012-0412",
  "collection": "perihel-thermal-l2",
  "properties": {
"datetime": "2025-07-28T17:41:08Z",
    "perihel:level": "L2",
    "gsd": 12,
    "perihel:lst_scale": 0.01,
    "perihel:lst_unit": "K",
    "eo:cloud_cover": 0.4,
    "proj:epsg": 32614
  },
  "assets": {
    "data": { "href": "s3://your-bucket/perihel/perihel-thermal-l2/PH-THE-20250728-173012-0412.tif",
              "type": "image/tiff; application=geotiff; profile=cloud-optimized" },
    "metadata": { "href": "s3://your-bucket/perihel/perihel-thermal-l2/PH-THE-20250728-173012-0412.json" }
  }
}

Questions about thermal

Task a thermal satellite

Tell us the area and the revisit you need. An engineer replies with orbit, sensor and fee.

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