Shuttle communciations during re-entry
hello
No more blackouts
The solution came about after NASA launched the Tracking and Data Relay Satellite System. The first satellite was launched in 1983, and the next two went into orbit in 1988 and 1989. (One TDRS satellite was lost in the 1986 Challenger accident.) The system was built to provide communications for all space flights, from launch to reentry.
When the shuttle enters the atmosphere, the brunt of the heat is on the underside of the orbiter. The thermo protection tiles are facedown, so the plasma or ionization layer is open at the trailing end behind the shuttle, providing a hole through which communications with the shuttle can be maintained with the TDRS. Even if the TDRS satellites had been in use when Mercury, Gemini and Apollo were in flight, the spacecrafts still may have experienced blackouts because of their body shapes.
copied from
http://www.columbiassacrifice.com/pages_support/Snews.htm
best regards