Terra

Terra is the core satellite of a multi-satellite project called the Earth Observing System (EOS). EOS is a NASA program that uses satellites and scientific instruments to make long-term observations of the Earth's surface, atmosphere, and oceans, and the connections among them.

Terra was launched just over 20 years ago! This anniversary video shows Terra's instruments and the way they help us learn about the Earth.

Two people in white decontamination suits stand on an elevate platform overlooking a very large gold foil cylinder, which is the satellite. In the background, other men look on.

NASA engineers prepare Terra

Before launch, NASA engineers work on preparing Terra for its mission. The main section of Terra is the length of a short school bus.

Photo Credit: NASA

A cartoon image of the satellite Terra. It is a large rectangular cube with another large rectangle of solar panels extending from it.

Terra's instruments

Here is an artist's drawing of Terra and its instruments. Terra is powered by the solar panels extending to the right.

Photo Credit: NASA

When was Terra launched?

Terra was launched on December 18th, 1999 and began collecting data mid-February 2000. Terra is still in space and still sending data back to Earth!

What was Terra's mission?

Terra was sent into Space to monitor the Earth's environment and its changing climate conditions. Terra takes images in many different frequencies to track the land and atmosphere in order to see how the Earth is changing in response to human impact on the environment.

What kinds of instruments does Terra have onboard?

Terra has five different instruments aboard. These instruments track different measures of climate, atmosphere, terrain, and life on Earth:

  • ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer): uses three different types of sensors to create images of clouds, ice, water, and land.

  • CERES (Clouds and the Earth Radiant Energy System): tracks radiation and cloud properties.

  • MISR (Multi-angle imaging Spectroradiometer): uses nine cameras to track particles in the atmosphere, amount, types, and heights of clouds, and how much of the land on Earth is covered by trees or other vegetation.

  • MODIS (Moderate-resolution Imaging Spectroradiometer): tracks clouds, maps snow and ice, measures the activity of plants, and tracks natural disasters like floods, droughts, and fires.

  • MOPITT (Measurements of Pollution in the Troposphere): tracks the distribution, sources, and amount of carbon monoxide in the troposphere.

What have we learned from Terra's time in space?

During the past 20 years, Terra has helped us understand our planet and how natural events and human actions impact it. Terra images help us analyze how earthquakes, volcanos, floods, landslides, coastal erosion, and natural disasters alter how areas of the Earth look. Terra tracks changes in the weather and atmosphere to see how they are impacted by conditions on the surface of the planet - and vice versa! Finally, Terra also helps track natural disasters like fires, floods, and hurricanes to help governments and first responders prepare or recover.

The background of the image shows a large gray mountain with a deep valley in the forefront. At the bottom of the valley is a river.

Death Valley, California

This image from Terra shows the deep valleys and high mountain ranges of Death Valley. How do you think weathering and erosion contributed to how these formed?

Photo Credit: NASA

Brown land is streaked with long lighter colored streams running from the top of the image to the bottom

China & Mongolia

On the border between Mongolia and China, the Terra satellite has captured a series of parallel channels carved by downward flowing streams. What process caused these channels?

Photo Credit: NASA

Dirt darkens the band between land and river, showing intense flooding.

Parana River, Brazil

During the Summer of 2015, intense rain caused the Parana River to flood, moving sediment and mud far from where they started. What is this process called?

Photo Credit: NASA

What can we see in these images that we couldn't see on Earth?

Satellite imagery helps us see the world on a scale we wouldn't be able to see from Earth! In these images we see large scale patterns of weathering, erosion, and disposition that helps us to make sense of the geological formations around us.

What do these images tell us about the landscape they capture?

These images help us to understand how rivers and streams can change the terrain by carving channels or valleys and by moving sediment from one place to another. Using satellite images like these can give us a new perspective on geological formations like Death Valley or can help track natural disasters like floods or oil spills.