Tracking an desending spacecraft from space?

I know that the plasma halo cause by atmospheric friction cuts out
radio contact from a returning space craft i.e. the Shuttle, Apollo
Comand module, Gemini/Mercury/Suyous capsule..., but does it also
block out radar waves/transmission, as radar like radio is just
electromagnetic energy but at a different wave length?

i.e. NASA and the Russian space agency knew which trajectory they
would be returning, but could they be able to track the desent during
the radio 'blackout' phase if they didn't know which desent path the
craft was taking. In other words does a dense ionised layer around
the craft block radar signals?


Christopher
+++++++++++++++++++++++++
"Only those who risk going too far,
can know how far they can go."
T.S. Elliot