  During the On-Station Thermal Test campaign of the LISA Pathfinder the data
and diagnostics subsystem was tested in nearly space conditions for the first
time after integration in the satellite. The results showed the compliance of
the temperature measurement system, obtaining temperature noise around
$10^{-4}\,{\rm K}\, {\rm Hz}^{-1/2}$ in the frequency band of $1-30\;{\rm
mHz}$. In addition, controlled injection of heat signals to the suspension
struts anchoring the LISA Technology Package (LTP) Core Assembly to the
satellite structure allowed to experimentally estimate for the first time the
phase noise contribution through thermo-elastic distortion of the LTP
interferometer, the satellite's main instrument. Such contribution was found to
be at $10^{-12}\,{\rm m}\, {\rm Hz}^{-1/2}$, a factor of 30 below the measured
noise at the lower end of the measurement bandwidth ($1\,{\rm mHz}$).
