Landsat 9

The current operational successor in the Landsat program, which has continuously imaged Earth’s land surface since 1972 — the longest-running civilian Earth-observation record. Operates 8 days out of phase with Landsat 8 so the combined constellation revisits any point every 8 days.

What it sees

• OLI-2: 9 spectral bands from visible blue to shortwave infrared (435 nm – 2294 nm), plus a panchromatic band. 30 m ground sample distance for multispectral bands, 15 m for pan.
• TIRS-2: 2 thermal bands (10.6 µm, 12.0 µm) at 100 m, resampled to 30 m. Land-surface temperature, evapotranspiration proxies.

Why it matters

• The Landsat archive is the only ~50-year global land-cover record at 30 m resolution (Landsat 1: 1972; original NASA budget cut in 2007–2008 nearly killed the program but Senator Mikulski rescued it).
• The HLS product (Harmonized Landsat-Sentinel) — the #1 most-downloaded NASA Earth-data product in FY2024 — joins Landsat 8/9 with Sentinel-2 to ≤3-day revisit at 30 m.
• Free, redistributable, foundational. Everything in the “land surface change” lane builds on this.

Where to get the data

• Cloud (recommended): HLS via LP DAAC on s3://lp-prod-protected/HLSL30.020/... (cloud-direct in us-west-2; auth via Earthdata Login)
• Original Landsat collections: USGS EarthExplorer (earthexplorer.usgs.gov) for the raw Collection 2 product line
• earthaccess Python: short_name="HLSL30" for the harmonized cloud-optimized version

What it enables

• Deforestation / forest change (q01 →)
• Urban expansion mapping
• Crop classification (when paired with MODIS or Sentinel-2)
• Burn-scar mapping (when paired with HLS S30 from Sentinel-2)
• Surface water extent

Gotchas

• Landsat 9 is NOT a drop-in replacement for Landsat 8 — OLI-2 is improved (14-bit vs 12-bit radiometric) but most downstream pipelines treat both interchangeably. Be explicit about which sensor when reporting.
• HLS != Landsat raw. HLS is atmospherically corrected + BRDF-normalized + spatially co-registered with Sentinel-2. If you need original radiances, go to USGS Collection 2 L1.
• Cloud-cover filter at 20% is aggressive for cloudy biomes (Western Ghats monsoon, Pacific Northwest winter). Often forces a 5–10× reduction in usable scenes.

Related missions

• Landsat 8 (2013–): same instruments, 8 days out of phase with Landsat 9. Same data pipelines.
• Landsat Next (planned launch ~2030): replacement architecture with more bands and higher revisit; specifications still in flux.
• Sentinel-2 A/B (ESA): the other half of HLS. 13 bands at 10–60 m, 5-day revisit.

Related datasets