EarthDaily Constellation

Built to measure change,
not to take pictures.

Nine satellites carrying 22 calibrated bands, imaging the same place at the same local time every day. Every instrument choice follows from one requirement: today’s measurement has to be comparable to yesterday’s.

EarthDaily satellite with solar panels deployed

The design requirement

Change detection sets the specification

  • Spectral Diversity

    22 calibrated bands spanning visible, shortwave infrared and thermal, so one pass answers questions about vegetation, moisture, minerals and heat.

  • Signal Quality

    A 5 m pixel with a full photon budget, collected pushbroom with time-delayed integration and binned where signal matters more than sampling.

  • Geometry held still

    Nadir imaging within 12 degrees across track, sun-synchronous crossing at 10:15 and 10:45 local, orbit control maintained across mission life.

  • Coverage without tasking

    A 240 km swath from nine satellites reaches 92% of Earth’s landmass every day. Nobody has to request a collection for it to exist.

Spectral Diversity

Twenty-two bands, each answering something the others cannot

Bands cost mass, power and downlink, so a commercial imager usually carries four: red, green, blue and near infrared. That is enough to make a recognisable picture and not much else. EarthDaily carries 22, because moisture, chlorophyll stress, minerals, thin cirrus and surface temperature all sit at wavelengths those four bands cannot see. Select a band to read what it measures.

Band table

All 22 bands ordered by wavelength, grouped by detector

VNIR 5 m

SWIR 95 m

TIR 120 m

Visible and near infrared

Near Infrared

Vegetation scatters near infrared strongly while water absorbs it, so this band carries canopy structure and biomass, and draws a hard line at the water's edge.

Central wavelength
864 nm
Bandwidth
36 nm
Native ground sample distance
5 m
Detector group
VNIR

Tile colour follows wavelength; the marker sits at the selected band's position on a logarithmic wavelength axis

reserved, publishes at full operations

All bands as a table
Band Name Detector Centre Bandwidth Ground sample distance What it measures
1 Cst Coastal VNIR 442.5 nm to confirm 5 m

Short blue light scatters off fine particles and penetrates clear water, so this band reads aerosols, haze and shallow coastal water.
2 B Blue VNIR 492 nm to confirm 5 m

The blue channel of a true-colour picture. It separates water from land and carries detail in shallow water and atmospheric haze.
3 Aq Aqua VNIR 530 nm to confirm 5 m

Between blue and green, this band follows chlorophyll and suspended sediment in water, where algal blooms and turbidity show first.
4 G Green VNIR 559.5 nm to confirm 5 m

Healthy leaves reflect green, so this band peaks over vigorous vegetation and supplies the green channel of a true-colour picture.
5 Y Yellow VNIR 605 nm to confirm 5 m

Yellow sits where leaves begin to yellow as they senesce, so it helps date crop maturity and separate soil from sparse cover.
6 R Red VNIR 664.5 nm to confirm 5 m

Chlorophyll absorbs red light strongly, so healthy canopy reads dark here. It is the red half of every vegetation index.
7 Re1 Red Edge 1 VNIR 703.8 nm to confirm 5 m

The first step of the red edge, where reflectance climbs out of the chlorophyll trough. Its slope moves with leaf chlorophyll content.
8 Re2 Red Edge 2 VNIR 740 nm to confirm 5 m

Midway up the red edge, this band is sensitive to canopy nitrogen and early stress before it is visible to the eye.
9 Re3 Red Edge 3 VNIR 781.5 nm to confirm 5 m

The top of the red edge, where leaf structure takes over from pigment. It tracks leaf area and canopy density.
10 Nir Near Infrared VNIR 864 nm 36 nm 5 m

Vegetation scatters near infrared strongly while water absorbs it, so this band carries canopy structure and biomass, and draws a hard line at the water's edge.
11 Wv1 Water Vapour 1 VNIR 912 nm to confirm 5 m

Atmospheric water vapour absorbs here, so this band measures the moisture column above each pixel and is used to correct the others.
12 Wv2 Water Vapour 2 SWIR 945 nm to confirm 95 m

A second water vapour absorption feature. Read against Water Vapour 1, it sharpens the atmospheric correction.
13 Sw1 SWIR 1 SWIR 1245 nm to confirm 95 m

Liquid water in leaves absorbs at this wavelength, so this band tracks canopy moisture and drought stress before it shows in the visible, and helps separate snow and ice from cloud.
14 Cir Cirrus SWIR 1375 nm to confirm 95 m

Strong water vapour absorption hides the ground at this wavelength, so only high, thin cirrus reflects. The band flags cloud the other bands cannot see.
15 Sw2 SWIR 2 SWIR 1610 nm to confirm 95 m

Sensitive to soil and leaf moisture and to minerals, this band separates burned ground, bare soil and snow.
16 Ch1 Methane 1 SWIR reserved reserved 95 m

Methane absorbs in narrow shortwave lines. Read against a neighbouring band, this channel separates a plume from the ground beneath it. It is carried on board now and publishes at full operations.
17 Ch2 Methane 2 SWIR reserved reserved 95 m

The reference channel for methane: close enough in wavelength to share the ground signal, outside the absorption line. It publishes at full operations.
18 Fir Wildfire TIR reserved reserved 120 m

Hot targets radiate strongly in the mid-wave infrared, so this band picks out active fire fronts and their intensity. It publishes at full operations.
19 Th1 Thermal 1 TIR reserved reserved 120 m

The first of four thermal channels measuring emitted heat, for land surface temperature and evapotranspiration. It publishes at full operations.
20 Th2 Thermal 2 TIR reserved reserved 120 m

A second thermal channel. Several thermal bands together separate surface temperature from emissivity. It publishes at full operations.
21 Th3 Thermal 3 TIR reserved reserved 120 m

A third thermal channel, used with the others to correct for atmospheric water vapour in temperature retrievals. It publishes at full operations.
22 Th4 Thermal 4 TIR reserved reserved 120 m

The longest-wave thermal channel, which completes the split-window set for surface temperature. It publishes at full operations.

Signal before pixel size

A smaller pixel is not a better measurement

Resolution is the number most imaging fleets compete on, and it is the wrong number for measurement. Light arriving at a detector is finite: halve the pixel and it collects roughly a quarter of the photons, so the noise floor rises. Once noise exceeds the difference between two dates, the change you are looking for is no longer measurable at any resolution. The imagers were sized for a 5 m pixel that still carries clean signal. Drag the slider to see the trade.

Photon budget per pixel

Signal scales with collecting area, so it falls with the square of pixel size

EarthDaily near-infrared false-colour image of Cananea, Mexico

EarthDaily imagery: Cananea, Mexico. Near-infrared false colour.

5.0 m

Relative light collected per pixel 100%

Noise floor Low

5 m is where EarthDaily's visible and near-infrared bands sit: fine enough to resolve a field, a vessel or a construction site, with a full photon budget behind every pixel.

  • Pushbroom collection

    A line of detectors sweeps the ground track continuously instead of snapping frames, so every pixel in a scene is built the same way.

  • Time-delayed integration

    Charge is shifted along the detector in step with the ground motion, adding exposures of the same ground point to raise signal-to-noise without a longer dwell.

  • Binning where it pays

    Several bands combine neighbouring pixels into one aggregate pixel. Sampling is coarser and the measurement is cleaner, which is the correct trade for those bands.

Geometry held still

The same view, at the same hour, every day

A tasked satellite points sideways to reach a target sooner. That is useful once and destructive over time: off-nadir viewing stretches pixels, leans vertical structures away from the sensor, and changes which surfaces the sensor can see. EarthDaily images at nadir, within 12 degrees across track, from a sun-synchronous orbit at 608 km that crosses the equator at 10:15 and 10:45 local. Shadows fall the same way in January and July.

Viewing angle

0°
EarthDaily image of Berlin Brandenburg Airport, Germany

Nadir. Ground point holds its pixel.

EarthDaily imagery: Berlin, Germany.

EarthDaily: nadir

Straight down. The footprint is square, buildings sit on their own footprint, and pixels register to the same ground position on every pass.

Footprint 240 km, undistorted

Off-nadir collection

Tilted. The footprint stretches, tall features lean away from the sensor, and the same ground point lands on different pixels from pass to pass.

Footprint stretched, features leaning

At 8 degrees the ground pixel is stretched 1.01 times across track and a 30 m building leans 4.2 m in the image. EarthDaily operates inside this range, so successive days line up without resampling away the difference you are trying to measure. Inclination is 97.7 degrees at reference altitude and the orbit is precisely maintained for consistent viewing over mission life.

Coverage without tasking

Wide enough that nobody has to ask

A high-resolution imager sees a narrow strip, so it has to be pointed, which means somebody decides in advance what is worth looking at. Anything not requested is not collected, and cannot be recovered later. EarthDaily’s imagers were specified for a 240 km swath so the whole landmass fits into a systematic daily plan. When a question arrives next year, the imagery from last year already exists.

Swath per pass

Both strips drawn to the same ground scale

EarthDaily image of centre-pivot cropland

EarthDaily imagery: centre pivot cropland, North America.

Ground width per pass, drawn to scale on a 0 to 360 km ruler: EarthDaily, 240 km; Tasked strip, 20 km.

  • 240 km

    Swath width

    Identical for the VNIR, SWIR and TIR bands.

  • 92%

    Landmass daily

    Average systematic coverage with nine satellites, excluding Antarctica.

  • 9 + 1

    Satellites

    Nine operational, one in-orbit spare.

  • 0

    Tasking requests

    Landmass and coastal waters to 100 km offshore are collected by plan.

The systematic plan covers Earth’s landmass excluding Antarctica and select small islands, plus coastal regions up to 100 km offshore.

Read the specification

Every number on this page
is published

Calibration, the comparison against other mission classes and what the constellation adds over time are set out on the technical specification page.