Anatomy of Landsat 8
Have you ever wondered what all the parts of a satellite do? This video identifies a few of the main components onboard Landsat 8 and tells you about their role in flying the satellite and capturing images of the Earth's surface below. Learn more about USGS Landsat.
Location Taken: Sioux Falls, SD, US
The 9-meter (29.5-foot) solar array is a long sheet of solar panels that convert sunlight into electricity to power the instruments on board the spacecraft and to charge the flight battery.
The flight battery provides power for the instruments when the spacecraft is on the dark side of the Earth and the solar is in shadow.
Operational Land Imager
The OLI is one of two primary imaging instruments on Landsat 8. The OLI acquires images of the Earth’s surface in nine different bands of visible and invisible (infrared) light.
Bands 1 through 7 and 9 have a 30-meter resolution while band 8, called the panchromatic band, has a higher 15-m resolution.
Thermal Infrared Sensor
The TIRS is the second of Landsat 8’s two primary imaging instruments.
The TIRS gathers images of the Earth’s surface in two infrared (thermal) bands that are particularly useful in providing accurate surface temperatures of the planet’s land areas.
The main body of Landsat 8 is wrapped in an insulating blanket made of multiple layers of Mylar® film with an outer layer of shiny, aluminized Kapton® film, which can withstand temperatures ranging from -269̊ C to 400° C (-452° F to 752° F).
This MLI, as it’s called, helps maintain the overall internal temperature of the spacecraft, preventing it from getting too cold or hot. The MLI also provides protection from micrometeorites.
Landsat 8’s propulsion system includes eight thrusters surrounding a fuel tank.
Like tiny rockets, the thrusters can be fired to move the spacecraft to maintain its proper orbit around the Earth.
X- and S-Band Antennas
Landsat 8 is equipped with two sets of communication antennas:
S -band antennas are used by ground control to “talk” to the satellite and issue commands.
X-band antennas are involved in broadcasting images acquired by the onboard instruments down to the Earth.
Solid State Recorder
A solid state recorder stores images acquired by OLI and TIRS prior to those images being sent down, via X-band antennas, to date-receiving ground stations on the Earth.
Attitude Control System
Landsat satellites maintain a precise attitude or orientation, in space to capture images of the Earth’s surface from exactly the same position every time. Several elements work together to accomplish this, including:
- Star trackers calculate the spacecraft’s orientation by looking at a catalog of navigational stars through a sensor that matches patterns of stars and their relation to the Earth’s position in space.
- A Global Positioning Systems (GPS) similar to what is found on smart phones, tells the spacecraft where it is in relation to the Earth with even greater accuracy than the star trackers.
- Three pairs of reaction wheels allow tipping and turning of the spacecraft to achieve the perfect orientation for imaging the Earth’s surface in a consistent way.