Major satellite systems

Since when has Landsat been collecting data?

Landsat has been collecting data since 1972

What is Landsat’s spatial resolution?

30 metre

What is Landsat’s revisit time?

16 days

What altitude does Landsat orbit at?

705km

What is the width of Landsat’s measurements?

185km

How many images does Landsat collect every day?

>700 images

How have Landsat’s sensors changed (or not) over time?

• Somewhat increased spatial + spectral resolution

• Similar types of measurement has allowed long-term comparison

What is Sentinel MSI’s spectral resolution?

• Multispectral

• 13 bands in the visible, NIR, and SWIR ranges

What levels of spatial resolution does Sentinel MSI have?

10, 20, and 60m resolution.

What is the width of Sentinel MSI’s measurements?

290km

What is Sentinel MSI’s revisit time?

5 days using 2 satellites

Give a key feature of Sentinel MSI’s measurements:

Wavebands in the red-edge allows vegetation monitoring (680-730nm) 

Describe Planet Labs’ CubeSats:

• About the size of a shoebox

• Many satellites in orbit acting as constellations

What is the spatial resolution of the CubeSats?

3-5m resolution

How many spectral bands do the CubeSats measure?

4 or 8 bands

What is the size of the CubeSat swath?

32×40km

What are the CubeSats useful for?

• Mapping heterogeneous surfaces e.g. urban areas

• Mapping selective logging

Describe NASA’s Terra and Aqua satellites:

• Measure the whole Earth system e.g. vegetation + SST

• Data collected at different spectral + spatial resolutions

• 4x daily revisit frequency