TDRS-8

First of the second-generation TDRS satellites, adding Ka-band relay to the Ku- and S-band services NASA used to keep near-continuous contact with the Shuttle, the space station, and orbiting observatories. Soon after reaching orbit its multiple-access phased-array antenna was found to underperform, degrading some services; the same flaw was caught and fixed on the two follow-on satellites before they flew.