In message , Franz writes
I've been looking for the TLE of the first Mars Exploration Rover (MER-A,
also know as 'Spirit') currently underway from Earth to Mars, but could not
find any. Can someone give me a hint where I can find these?

I don't think you will find TLE in the usual form, because Spirit is in
an orbit like a comet, with a perihelion and an eccentricity, so that's
the sort of elements you need.
Can I add a request for the elements for Mars Express and Nozomi,
though?