As far as i know the nassp5 source is unavailable, but the nassp 4 source is on jean-luc's webite.
If you have no c++ skill then adding particle trails may be slightly difficult, but it is a good way to learn
![:)](http://orbiter.dansteph.com/forum/Smileys/orbitersmiley/smilie5.gif)
All you need to do is read through the section in the orbiter SDK manual on particles, then take a look at the DG code
(comes with orbiter) or the Shuttle-A code (ditto).
You should be able to spot the relavent sections of code quite easily, they start with lines like PARTICLESTREAMSPEC,
iirc.
Now you must simply find th exhaust definitions in the nassp source and then copy and paste the correct code from
the DG into the nassp source. A few quick wording alterations and away you go.
Sorry this is a bit vague, but i dont have the code in front of me at the moment...
(PS: I thought nassp5 already had particle emissions as default?!)
Cheers,
Simon