This is a mix powered aircraft designed primarily as a point interceptor ( if it would have gone to production ).
It has a set of rocket motors in the aft fuselage ( like the German Me-163 Komet ) as well as turbojets mounted in pods on the stubby wing tips.
Speed was of the essence for this interceptor which is why the rocket engines were installed ( jet engines in the 1950's were still anemic ).
This plane would have carried a single missile under its belly.
The interest to me is the elegant smooth lines and all round fuselage and engine nacelles. It is slick and still looks futuristic today.
Some reference here:
S.N.C.A.S.O SO-9000 Trident and SO-9050 Trident II | Let Let Let - Warplanes
https://en.wikipedia.org/wiki/SNCASO_Trident
Isaac