"In 2002, X-Rocket LLC worked with XCOR Aerospace to study the concept of an aerospace trainer derived from the Russian MiG-21UM supersonic fighter-trainer. Unlike the NF-104, the MiG-21 derivative (called Archangel) would be a completely rocket-powered vehicle. The 13,000-pound-thrust turbojet would be replaced by four 5,000-pound-thrust XCOR rocket engines, allowing zoom climbs to 160,000 feet.
The Archangel design incorporated substantial improvements over the NF-104. XCOR’s liquid-oxygen/kerosene rocket engines do not require constant maintenance, like the NF-104 engine, nor are they prone to explode. The MiG-21UM airframe is a two-seater, allowing an experienced instructor to train students who are not top military pilots. The airframe has a conventional tail, so is not subject to the pitch-up problem that plagued the F-104, and it has excellent spin recovery characteristics.
A feasibility study showed that the Archangel development could be completed with minimal risk. The required modifications to the airframe were extensive, however, and it was unclear whether the design actually provided a cost advantage compared new airframe from scratch. As a result, X-Rocket elected not to pursue development."
No pictures of the project itself, only the one photo of the support MiG-UM.