Landsat 1, 2, and 3 (1972-1983)

The Pioneering Era

The first three Landsat satellites established the foundation for continuous Earth observation. Originally named the Earth Resources Technology Satellite (ERTS), Landsat 1 demonstrated the viability and value of systematic land imaging from space.

Instruments:

• Multispectral Scanner (MSS): 4 spectral bands, 80-meter resolution
• Return Beam Vidicon (RBV): Television-style cameras (limited use due to technical issues)
• Landsat 3 Enhancement: Added thermal band to MSS

Source: USGS EROS - Landsat 1-3 Mission Information, NASA Landsat Science

Landsat 4 and 5 (1982-2013)

The Thematic Mapper Revolution

These satellites introduced the revolutionary Thematic Mapper (TM) instrument, which dramatically improved spatial resolution and spectral capabilities. Landsat 5's unprecedented 28-year, 10-month operational life made it the longest-operating Earth observation satellite in history.

Instruments:

• Thematic Mapper (TM): 7 spectral bands, 30-meter resolution (120m thermal)
• Multispectral Scanner (MSS): Continued for data continuity

TM Spectral Bands:

• Band 1 (0.45-0.52 μm): Blue - water body penetration, soil/vegetation discrimination
• Band 2 (0.52-0.60 μm): Green - vegetation vigor assessment
• Band 3 (0.63-0.69 μm): Red - chlorophyll absorption, vegetation differentiation
• Band 4 (0.76-0.90 μm): Near-infrared - biomass surveys, water body delineation
• Band 5 (1.55-1.75 μm): Shortwave infrared - vegetation moisture, snow/cloud differentiation
• Band 6 (10.40-12.50 μm): Thermal infrared - surface temperature, thermal mapping
• Band 7 (2.08-2.35 μm): Shortwave infrared - mineral/rock discrimination

Legacy Impact: Landsat 5 collected over 2.5 million images during its lifetime, creating an invaluable record of Earth's changes over nearly three decades.

Source: USGS Landsat 4-5 Documentation, NASA Landsat Science, Guinness World Records

Landsat 6 (1993)

A Setback in the Journey

Landsat 6 was intended to carry an Enhanced Thematic Mapper (ETM) with improved capabilities. Unfortunately, the satellite failed to achieve orbit due to a ruptured hydrazine manifold in the launch vehicle, resulting in mission loss.

This failure created a critical gap in Landsat data availability between the aging Landsat 5 and the planned Landsat 7, emphasizing the importance of mission redundancy and robust launch systems.

Source: NASA Mission Reports, USGS Landsat Program History

Landsat 7 (1999-Present)

Enhanced Capabilities with Enduring Service

Launched in 1999, Landsat 7 introduced the Enhanced Thematic Mapper Plus (ETM+), featuring all the capabilities of the Thematic Mapper plus several important enhancements. Despite a Scan Line Corrector (SLC) failure in 2003, Landsat 7 continues to provide valuable data over 25 years after launch.

Instruments:

• Enhanced Thematic Mapper Plus (ETM+): 8 spectral bands

Key Improvements:

• Panchromatic Band: 15-meter resolution for enhanced detail
• Thermal Band: 60-meter resolution (improved from 120m)
• Full Aperture Solar Calibrator: Improved radiometric calibration
• 5% Absolute Radiometric Calibration: Unprecedented accuracy

SLC Failure (2003): While the Scan Line Corrector failure resulted in data gaps in images, innovative processing techniques and the satellite's continued operation have maintained its scientific value.

Orbital Characteristics:

• Altitude: 705 km
• Sun-synchronous orbit
• 16-day repeat cycle
• 10:00 AM descending node

Source: USGS Landsat 7 Mission Guide, NASA Goddard Space Flight Center

Landsat 8 (2013-Present)

Modern Era Begins

Originally called the Landsat Data Continuity Mission (LDCM), Landsat 8 represents a significant technological advancement with two state-of-the-art instruments designed for improved performance and new capabilities.

Instruments:

• Operational Land Imager (OLI): 9 spectral bands, push-broom design
• Thermal Infrared Sensor (TIRS): 2 thermal bands

Major Advancements:

• 12-bit Radiometric Resolution: 4,096 gray levels (vs. 256 for previous missions)
• Improved Signal-to-Noise Ratio (SNR): Better image quality and feature detection
• New Spectral Bands:
  • Coastal/Aerosol Band (Band 1): Coastal zone observations and aerosol studies
  • Cirrus Band (Band 9): Cloud contamination detection
• Narrower NIR Band: Reduced water vapor absorption for improved atmospheric correction

Technical Specifications:

• Spatial Resolution: 30m (multispectral), 15m (panchromatic), 100m (thermal)
• Swath Width: 185 km
• Data Rate: Up to 384 Mbps
• Orbital Period: 99 minutes

Data Volume: Landsat 8 collects over 700 scenes per day, approximately 1.5 million scenes to date.

Source: USGS Landsat 8 Data Users Handbook, NASA Landsat Science

Landsat 9 (2021-Present)

Enhanced Continuity and Capability

Landsat 9 is essentially a successor to Landsat 8, carrying improved versions of the same instruments. Operating in tandem with Landsat 8, the two satellites provide 8-day global coverage, ensuring no gaps in the Landsat data record.

Instruments:

• Operational Land Imager 2 (OLI-2): Improved version of OLI
• Thermal Infrared Sensor 2 (TIRS-2): Enhanced thermal sensor

Key Improvements over Landsat 8:

• 14-bit Radiometric Resolution: 16,384 gray levels for even finer detail
• Improved TIRS Design: Reduced stray light issues
• Enhanced Calibration: Better long-term stability
• Higher Reliability: TIRS-2 upgraded to Class B (vs. Class C for TIRS)

Mission Configuration:

• Orbit: Same as Landsat 8, offset by 8 days
• Design Life: 5 years (10-year goal)
• Launch Vehicle: Atlas V 401
• Launch Site: Vandenberg Space Force Base

Tandem Operations: Together, Landsat 8 and 9 image the entire Earth every 8 days, providing unprecedented temporal resolution for the Landsat program.

Source: USGS Landsat 9 Documentation, NASA Goddard Space Flight Center

Landsat Next (2030s)

The Next Quantum Leap

Landsat Next represents the most ambitious evolution of the program, featuring a constellation of three satellites with revolutionary capabilities that will transform Earth observation science.

Revolutionary Features:

• Three-Satellite Constellation: Unprecedented temporal coverage
• 26 Spectral Bands: More than double Landsat 8/9
• Enhanced Resolution: 10-20 meters (vs. 30 meters)
• 6-Day Revisit: At the equator (vs. 16 days for single Landsat)
• Five Thermal Bands: Advanced surface temperature measurement

Learn More About Landsat Next

Source: NASA Landsat Science, USGS Landsat Next Program