Aboard a Delta 900 rocket, NASA’s Earth Resources Technology Satellite (ERTS) launched July 23, 1972, from Vandenburg Air Force Base in California. Later renamed, Landsat 1 became the first earth-observing satellite explicitly designed to study planet Earth. It contributed invaluable data and launched a revolution in remote sensing technology.
The satellite was designed to last one year, but surpassed expectations by orbiting an additional five years before being decommissioned on January 6, 1978. During its six-years, Landsat 1 acquired images covering about 75% of the Earth’s surface. Inside Landsat 1 was a Return Beam Vidicon (RBV) and a secondary, experimental Multi-Spectral Scanner (MSS). The RBV was supposed to be the prime instrument, but the MSS data was demonstrably superior.
Within days of the launch, Landsat 1 collected imagery of an astounding 81,000-acre (327.8 square kilometers) fire burning in isolated, central Alaska. For the first time ever, scientists and resource management officials were able to see the full extent of damage from a fire in a single image while it was still burning.
Landsat 1 data led to immediate and fundamental changes to practices of the cartographic and geographic communities. Country boundaries were redrawn, and entire islands were discovered. Along the coast in Canada, one newly discovered, uninhabited island was named “Landsat Island.”
Of course, there is no point to data if it is not used. NASA created the Landsat Principal Investigators Program (LPIP) to search for applications of the new remote sensing technology. Three hundred scientists were involved in the program from a wide array of Earth science disciplines, one-third of the participants were from countries outside of the United States. The quality and impact of the data exceeded all expectations.
This first image of Dallas-Fort Worth, Texas, was captured by Landsat 1 in 1972. The resolution is 60 meters per pixel in this false-color image, where shades of red indicate vegetated land and grays and whites are urban or rocky surfaces.
Landsat 1 Satellite Orbit Facts
- Orbited the Earth at 917 km (570 mi) in a sun-synchronous, near-polar orbit
- Circled the Earth every 103 minutes, or fourteen orbits a day
- Had an 18-day repeat cycle with an equatorial crossing time of 9:30 a.m. +/- 15 minutes
- Acquired data on the Worldwide Reference System-1 (WRS-1) path/row system, with swath overlap (or sidelap) varying from 14 percent at the Equator to a maximum of approximately 85 percent at 81 degrees extreme latitudes
Landsat 1 Instruments
Landsat 1 carried the Return Beam Vidicon (RBV) and the Multispectral Scanner System (MSS).
Return Beam Vidicon (RBV)
The RBV sensor utilized vidicon tube instruments containing an electron gun that read images from a photoconductive faceplate similar to television cameras. The data stream received from the satellite was analog-to-digital preprocessed to correct for radiometric and geometric errors.
- Collected about 1,600 sub-scenes
- 80 meter-ground resolution
- Three cameras operating in the following spectral bands:
- Band 1 Visible blue-green (475-575 nm)
- Band 2 Visible orange-red (580-680 nm)
- Band 3 Visible red to Near-Infrared (690-830 nm)
- Data recorded to 70 millimeter (mm) black and white film rolls
- Data: 3.5 MHz FM video
The RBV was supposed to be the prime instrument, but the MSS data were found to be superior. In addition, the RBV instrument was the source of an electrical transient that caused the satellite to briefly lose altitude control. It became necessary to shut down the RBV instrument in order to maintain the operation of the satellite.
Visit RBV Film Only for more information.
Multispectral Scanner (MSS)
The MSS sensors were line-scanning devices observing the Earth perpendicular to the orbital track. The cross-track scanning was accomplished by an oscillating mirror; six lines were scanned simultaneously in each of the four spectral bands for each mirror sweep. The forward motion of the satellite provided the along-track scan line progression.
- 80-meter ground resolution in four spectral bands:
- Band 4 Visible green (0.5 to 0.6 µm)
- Band 5 Visible red (0.6 to 0.7 µm)
- Band 6 Near-Infrared (0.7 to 0.8 µm)
- Band 7 Near-Infrared (0.8 to 1.1 µm)
- Six detectors for each spectral band provided six scan lines on each active scan
- Ground Sampling Interval (pixel size): 57 x 79 m
- Scene size: 170 km x 185 km (106 mi x 115 mi)
Visit Landsat 1-5 MSS for more information.
Landsats 1, 2, and 3 were modified Nimbus meteorological satellites.
- Weight: approximately 953 kg (2,100 lbs)
- Overall height: 3 m (10 ft)
- Diameter: 1.5 m (5 ft)
- Solar array paddles extend out to a total of 4 m (13 ft)
- 3-axis stabilized using 4 wheels to +/-0.7° attitude control
- Twin solar array paddles (single-axis articulation)
- S-Band and Very High Frequency (VHF) communications
- Hydrazine propulsion system with 3 thrusters
Landsat 1 History (NASA Landsat Science)
ERTS-1 Launch picture (courtesy NASA)
Earth Resources Technology Satellite (ERTS) - 1973 (courtesy U.S. National Archives)
The Multispectral Scanner (NASA Landsat Science)