Landsat 4

The satellite housekeeping telemetry and tracking continued to be maintained by NASA until it was decommissioned on June 15, 2001.

It was powered by three nickel-cadmium batteries (NiCd), which were charged via a single solar array that had one axis of articulation.

[10][11] Landsat 4 was placed into a north–south near polar orbit,[7] approximately 700 kilometers (430 mi) above Earth's surface, and circling the globe every 99 minutes.

[12] Landsat 4 was able to resume science operations when the Tracking and Data Relay Satellite System (TDRS) came online, then was placed in standby in January 1986.

[10] Landsat 4 was brought back online to provide international coverage in 1987, when Landsat 5 lost its TDRS link, and thus the ability to image areas beyond line of sight to a ground station, and continued to do so until it, too, lost its TDRS link in 1993, ending science data return.

[13] Landsat 4 continued to broadcast telemetry, tracking, and command data, which was transmitted on the still-functional S-band, until the satellite was decommissioned June 15, 2001.

[10][14] As early as 1982, a mission was in the planning stages to retrieve Landsat 4 for servicing back on Earth.

The 1982 edition of the STS Flight Assignment Manifest scheduled the second Space Shuttle mission from Vandenberg AFB for that task.

The Space Shuttle orbiter Discovery was scheduled to launch on 15 June 1986 for a three-day mission to capture Landsat 4 for return to Earth (designated STS-2V).

Later on, the idea to retrieve Landsat 4 were first replaced by a servicing mission in early 1987, before any mention of it was removed from the flight manifest published in June 1985.

1/4 scale model on display at the National Air and Space Museum in Washington DC