Trajectroy Files are in ZIP format because each file is approx 8+ MB.
Download the trajectory files using Binary Mode and unzip them; the
extracted file(s) will be "*.pmt".

If you need a copy of the unzip program(s), visit
ftp://ftp.uu.net/pub/archiving/zip

Please feel free to contact us "gte+archive@larc.nasa.gov", if you
have any questions.