Astronomers discovered a rocket body heading toward a lunar collision late last year. Impact occurred on March 4, with NASA’s Lunar Reconnaissance Orbiter later spotting the resulting crater. Surprisingly the crater is actually two craters, an eastern crater (18-meter diameter, about 19.5 yards) superimposed on a western crater (16-meter diameter, about 17.5 yards).
The double crater was unexpected and may indicate that the rocket body had large masses at each end. Typically a spent rocket has mass concentrated at the motor end; the rest of the rocket stage mainly consists of an empty fuel tank. Since the origin of the rocket body remains uncertain, the double nature of the crater may indicate its identity.
No other rocket body impacts on the Moon created double craters. The four Apollo SIV-B craters were somewhat irregular in outline (Apollos 13, 14, 15, 17) and were substantially larger (greater than 35 meters, about 38 yards) than each of the double craters.
The maximum width (29 meters, about 31.7 yards) of the double crater of the mystery rocket body was near that of the S-IVBs.