In the world of Earth observation, two major satellite missions stand out: Sentinel (from the European Space Agency) and Landsat (from NASA and USGS). Both provide open and free satellite imagery to monitor changes on the planet, but they differ in resolution, frequency, and focus.
Let’s explore their differences through a clear and engaging comparison.
- What Do They Observe?
Both Sentinel and Landsat observe Earth’s surface to support agriculture, forestry, urban planning, disaster monitoring, and environmental protection.
Illustration suggestion: A graphic of the Earth with satellite icons monitoring vegetation, cities, water bodies, and bare land.
- Image Resolution: Sharpness of Detail
Sentinel-2 captures images at a 10-meter resolution, allowing finer detail. Landsat 8/9 typically has 30-meter resolution, but includes thermal and atmospheric bands.
Illustration suggestion: Side-by-side satellite images — left: sharp Sentinel image, right: slightly blurrier Landsat image of the same area.
- Frequency of Capture
Sentinel-2 revisits the same location every 5 days with both satellites in orbit. Landsat revisits approximately every 16 days.
Illustration suggestion: Calendar icons showing satellite pass intervals — Sentinel (5 days), Landsat (16 days).
- Spectral Bands: What They See
Both satellites capture visible, near-infrared (NIR), and shortwave infrared (SWIR) bands, but with different combinations and resolutions. Landsat offers thermal bands, which Sentinel-2 lacks.
Illustration suggestion: A labeled electromagnetic spectrum showing the spectral bands covered by each satellite.
- Applications
Sentinel is excellent for frequent crop monitoring, urban expansion, and land cover changes.
Landsat is best for long-term environmental trends, climate research, and surface temperature analysis.
Illustration suggestion: Two split panels — left: land and vegetation map (Sentinel use), right: climate and heat trend graph (Landsat use).
- Strengths at a Glance
Sentinel: Higher resolution, frequent updates.
Landsat: Deeper historical archive, more spectral data including temperature.
Illustration suggestion: Two big buttons: one labeled “Sentinel = Fast Updates” and the other “Landsat = Long-Term Insight”.
- Final Thoughts
While Sentinel provides sharper and more frequent imagery, Landsat brings unmatched continuity in Earth observation with over four decades of data. Together, they form a powerful duo for tracking environmental change, planning resource use, and responding to disasters.