Note that you can still buy
GURPS TRAVELLER ebooks for the rest of 2015. If you have bought them by then, you will be able to download them again in 2016 and beyond.
There is one GURPS Traveller book still available in paper form,
GURPS Traveller Classic: Planetary Survey 1 - Kamsii
I don't know if the 5 paper copies will still be available until they run out.
As mentioned above, the GURPS books may become available again somhow in future. Or maybe not.