PRATT & WHITNEY THERMAL NUCLEAR ROCKET ENTRY: TRITON

This engine is not a jet, however and is powered by Nuclear Fission. It seems that P&W has responded to the need for Mars transportation by inventing the first commercially viable nuclear thermal rocket. They have improved upon the NERVA NRX design from the 60's, and have even solved the graphite ablation problem! This engine makes an "inexpensive" trip to Mars is possible."