Sabotage?
Or maybe it was successful but this is a false story to fool the parties that the satellite was to observe into thinking it is not up there?
1. The launch failure was optically observable. The payload was not seen to separate from the final stage properly and was not seen on optical, IR or radar observation.
2. There is no stealth in space at our current level of technical development or for any of the forseeable future. Physics precludes it. We’d have to invent some sort of wormhole technology and even *that* would be detectable on earth even with our primitive gravimetric sensing.