Landsat 4 Credit - NASA

The Landsat 4 and 5 operational civilian earth resource spacecraft were placed into lower orbits than the previous Landsat spacecraft and carried improved instrument suites.

Beginning in 1983, Landsat 4 lost use of half its solar power and began experiencing numerous spacecraft malfunctions which limited spacecraft functionality. This prompted the early launch of Landsat 5 to guarantee continued coverage. Landsat 5 lost two of its primary communications systems (X-Band downlink and a Ku-Band TDRSS transponder) and backup systems were activated. Management of the spacecraft was transferred from NASA to NOAA with Landsat 4. The spacecraft was 3-axis stabilized, zero momentum with control to 0.01 deg using reaction wheels, and had a structure of aluminum with graphite struts. A hydrazine propulsion system was used, and a single solar array with 1-axis articulation produced 1430 W (BOL), Two NiCd batteries provided 100 AHr total. A retractable boom (4 m long) with 2 powered joints supported the articulated high gain antenna which downlinked data via TDRSS. The communications system used S, X, L, and Ku-Bands.

Landsat 4 and 5 carried Multi-Spectral Scanner (MSS) and Thematic Mapper (TM) imaging sensors. TM provided 7 bands of coverage and the MSS had 4 bands. The MSS covered 0.5 to 12.6 µ m and provided 80 m resolution with a 185 km swath width. TM covered 0.45 to 12.5 µ m with resolution of 30 meters in the VIS/IR bands and 120 m in the thermal/IR bands.

Design Life: 5 years. Typical orbit: 705 km circular, polar, sun-synchronous, repeating. Length: 4.30 m (14.10 ft). Maximum Diameter: 2.20 m (7.20 ft). Mass: 1,940 kg (4,270 lb).

• 1982 July 16 - Landsat 4 - Program: Landsat. Launch Site: Vandenberg. Launch Complex: SLC2W. Launch Vehicle: Delta. Mass: 1,942 kg (4,281 lb). Perigee: 693 km (430 mi). Apogee: 705 km (438 mi). Inclination: 98.20 deg. Period: 98.80 min.
  Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).

• 1984 March 1 - Landsat 5 - Program: Landsat. Launch Site: Vandenberg. Launch Complex: SLC2W. Launch Vehicle: Delta. Mass: 1,938 kg (4,272 lb). Perigee: 702 km (436 mi). Apogee: 703 km (436 mi). Inclination: 98.20 deg. Period: 98.80 min.
  Spacecraft engaged in practical applications and uses of space technology such as weather or communication (US Cat C).