The above image represents what the current Tracking and Data Relay Satellite (TDRS) configuration is as March 2019 with 10 in-orbit TDRS in space (four first generation, three second generation and three third generation satellites). 
After 20+ years of service, two of the first generation TDRS are retired (TDRS-1 and TDRS-4) and super-synced into an orbit about 300 miles higher than geosynchronous (GEO) where the operational fleet sits.
National Aeronautics and Space Administration
<a rel="nofollow" class="external text" href="https://www.nasa.gov/directorates/heo/scan/services/networks/tdrs_fleet">Tracking and Data Relay Satellite (TDRS) Fleet</a><br>Image: <a rel="nofollow" class="external autonumber" href="https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/sn-constellation-map-march2019.png">[1]</a>