(upbeat music)
- [Announcer] Launch Conductor proceed with terminal count
at the end of the built-in hold.
- [Launch Conductor] Roger.
- [Narrator] April 15, 1999.
- [Announcer] T-Minus 20 seconds.
We are go for launch.
- [Narrator] A Delta II rocket
lifts off (rocket roaring)
from Southern California's Vandenberg Air Force Base.
- [Announcer] And lift off of the Delta II Rocket
with the advanced Landsat 7 spacecraft.
- [Narrator] Its payload, Landsat 7,
the seventh satellite in the series,
part of a decades-long collaboration
between NASA and the US Geological Survey.
Its mission?
To continue the Landsat legacy,
by providing a continuous, detailed portrait
of Earth's changing landscapes.
Just three days later, 438 miles above the Earth,
Landsat 7 would use its Enhanced Thematic Mapper Plus,
or ETM+, the most sophisticated Landsat sensor yet,
to capture its first image above Sioux Falls, South Dakota.
For the next two decades, Landsat 7 would circle the globe
every 99 minutes, collecting high-resolution imagery
of our planet's surface
across eight distinct spectral bands,
from visible to thermal infrared, every 16 days.
From agricultural monitoring to urban planning,
disaster management to climate research,
Landsat 7's data is essential for scientists, policymakers,
and communities worldwide,
to continue the record of our changing home planet
over the last half century.
One of Landsat 7's most valuable contributions
was its ability to classify and map different types
of land cover on a global scale
and how they change over time.
By distinguishing between forests and wetlands,
urban areas versus agricultural areas,
like this map of Portland, Oregon,
assembled from data collected over the course of 2001,
scientists could monitor ecological health,
plan for sustainable development,
and better understand environmental changes.
The data Landsat 7 collected across the visible spectrum
helped detect early signs of drought stress and disease,
allowing farmers to make better management decisions,
ensuring healthier crops and higher yields.
During catastrophic wildfires,
Landsat 7 became our watchful eye from above,
mapping the extent of burned areas,
helping firefighters strategize,
and assisting communities and other stakeholders
in recovery and resilience planning.
And Landsat 7's utility wasn't just limited to the land,
playing a key role
in the Millennium Coral Reef Mapping project.
Its ability to capture detailed cloud-free images
over remote tropical regions proved to be a critical tool
in helping scientists create the first consistent
global map of our planet's coral reefs.
And Landsat 7 imagery played an integral role
in the Landsat Image Mosaic of Antarctica project,
helping to create the first-ever, true-color,
high-resolution satellite view of the Antarctic continent.
The Landsat 7 mission, however,
was not without its challenges.
In May 2003, the onboard Scan Line Corrector,
a key component of the ETM+ meant to compensate
for the forward motion of the satellite, malfunctioned,
resulting in gaps in the imagery
and creating noticeable stripes
of missing data across scenes.
Despite this setback, 78% of the data from each scene
remained intact, and scientists at NASA and USGS,
along with significant contributions
from university-based members of the Landsat Science Team,
were able to quickly develop techniques
to compensate for these gaps,
enabling Landsat 7 to continue providing
valuable imagery and scientific insights
for many more years.
Landsat 7's nominal science mission came to a close
in the spring of 2022,
as its orbit was lowered following launch
of Landsat 9 the previous fall.
And, despite surpassing its original expected
5-year lifespan by nearly two decades,
Landsat 7 continued to collect valuable data
even at its lower altitude.
Unfortunately, Landsat 7's lowered orbit
led to increasing drift, which impacted battery maintenance,
imaging opportunities, and data processing.
As a result, the USGS decided to bring an end to imaging,
with Landsat 7 collecting its final images above Las Vegas
in May 2024, returning to where it had collected
some of its first imagery 25 years earlier.
In those 25 years, Landsat 7 captured over 3 million images
of our planet, collecting data that would be used
in over 2,000 scientific publications,
generating billions of dollars in economic benefits,
and paving the way for the development
of new and improved instruments
for future Earth observing missions.
The Landsat 7 mission established new high-water marks
in the Landsat Earth Imaging program,
with respect to quality, quantity,
and repetitive global coverage,
creating the new baseline standard
for future Landsat missions to match and surpass.
The sheer volume, exceptional quality,
and precise calibration of Landsat 7's data
have provided humanity with a deeper
and broader understanding of our planet's land surfaces
and their changes over time.
Data that will remain a core component
of the extensive Landsat archive,
continuing to support scientific innovation
long into the future.
So, after USGS engineers powered down its batteries
for good in 2025, we bid Landsat 7 a fond farewell.
Thank you for over two decades of unprecedented vision,
forever reshaping how we see and protect our home planet.