Terry Arvidson: The Blue Marble.
That was our first view of ourselves!
We really are the blue planet. We’re hanging out here in the middle of nowhere….
In fact the Apollo imagery was part of the justification for putting together a satellite
that would look at the Earth.
Marc Evan Jackson: That satellite was the first Landsat.
The Landsat mission now holds the title
for the longest continuous space-based record of Earth’s land in existence.
[rocket launch sounds]
At least one Landsat satellite has been orbiting the Earth since 1972.
That’s nearly 50 years of steadfast observation.
The program was born in the midst of several historical flashpoints
during a time when the world was changing quickly.
But the Landsat story doesn’t actually start with NASA.
It starts with the United States Geological Survey.
But let’s pause for a second.
Obviously, there was a big push to make an Earth-observing satellite.
But what exactly did it need to do?
Landsat’s entire job is to collect light.
Visible light like this, and non visible light like this.
After Landsat captures the light it sees,
it can make two kinds of pictures:
True color images and false color images.
Did you know your eyes can only detect red, green and blue?
It sounds crazy, but it’s true.
In fact, if you took a magnifying glass to the screen you’re probably looking at right now,
you’d see a jumble of red, green, and blue dots.
Mix those colors together with different intensities
and your brain interprets all the colors of the rainbow.
True color images are made
by combining red, blue and green light.
But what’s even more amazing?
Landsat also captures infrared light beyond what we can see.
And that light can reveal some incredible things when you look at a false color image.
Like the difference between types of plants,
how healthy those plants are,
healthy coral reefs and even dead coral reefs,
fire-tracking, ocean pollution…
The possibilities are nearly endless.
The true test came when Landsat 1 launched, on July 23, 1972.
But with this launch, the United States and soon the world,
would step into a new paradigm of Earth observation.
Never-before seen snapshots of land resources and the environment
would be key for critical decision making decades into the future.
go.nasa.gov/LandsatLegacy