What was that venting in front of the tail?

As Discovery landed you could see something venting in front of the
upper tailfin on the infrared video what was it? Also why do some of
the titles on the side of the orbiter look dirty?

"bradley" wrote in message
...
As Discovery landed you could see something venting in front of the
upper tailfin on the infrared video what was it?

The APU used to power things like the elevons and rudder.

Also why do some of
the titles on the side of the orbiter look dirty?

Some are.

"bradley" wrote in message
...
As Discovery landed you could see something venting in front of the
upper tailfin on the infrared video what was it?

axiillery power unit, it will spray water on the hydrolic lines to cool them
etc and then vents it off in pressure bursts

Also why do some of
the titles on the side of the orbiter look dirty?

From impurities (dust etc) in the air getting stuck on because it is so hot