From this point on, a cloak of mystery fell upon the SAMOS program. SAMOS 4 was notable in that it was the first satellite to be launched without being identified; it was inferred that the craft was SAMOS 4 from the launch vehicle and other clues, and this was confirmed when launch reports were later declassified. The satellite was the first Program 101B SAMOS and carried the E-5 recoverable capsule. According to a 1965 memo by the CIA's Albert Wheelon, the E-5 capsule was designed so that it could be used as a piloted space vehicle for a military counterpart to NASA's Mercury program.
The Jul 1960 documents indicate that 101B carried solar panels, but a later Lockheed document  shows that no solar panels were used. At the time of recovery, the panels and the camera mirror were jettisoned, the Agena retrofired and spun up, and the capsule separated for recovery by air snatch over sea or land.
SAMOS 4 failed to reach orbit when its Atlas first stage pitch control failed after launch on 1961 Nov 22. The Atlas separated five minutes into the flight, and the Agena operated correctly; however because the Atlas had pitched upward 160 degrees by separation, the Agena started off pointing down and back to front, and powered itself rapidly towards the ocean.
|1961 Nov 22||2045:47||Launch by Atlas Agena B||NMFPA|
|2049:51||Pitch control lost (T+4:04)|
|2050:59||Atlas sep (T+5:12)|
|2051:31||Agena burn (T+5:44)|
|2055:12||Agena MECO due (T+9:25)|
|Agena impact Pacific|