First, the crater is not at the indicated coordinates in any image. The coordinates were probably assigned early in the LRO mission and have not been updated as registration has improved. The crater is about 20 m across. Ranger craters were 10 m across, Apollo Saturn upper stage craters were 40 m across. This might be OK for something coming in fast like those things, but it's too big for something which was braking for a landing So what happened to Luna 18?