Nuclear testing at Bikini Atoll consisted of the detonation of 23 (or 24) nuclear weapons by the United States between 1946 and 1958 on Bikini Atoll in the Marshall Islands. Tests occurred at 7 test sites on the reef itself, on the sea, in the air, and underwater. The test weapons produced a combined yield of about 77–78.6 Mt of TNT in explosive power. After the inhabitants agreed to a temporary evacuation, to allow nuclear testing on Bikini, which they were told was of great importance to humankind, two nuclear weapons were detonated in 1946. About ten years later, additional tests with thermonuclear weapons in the late 1950s were also conducted. The first thermonuclear explosion was much more powerful than expected, and created a number of issues, but did demonstrate the dangers of such devices.
From Library of Congress.
Michigan State University has an exhibition/page about nuclear photography featuring this "aerial still camera sitting on its lens", which looks similar. I haven't found more details though.
Looking at this picture, it does seem like the camera in OP's picture is missing its lens. Also, the camera in OP's picture is not actually pointing out of the window, so unless there is a different window, it's likely that he's not currently taking pictures, and is probably just setting the camera up. I suspect that the cameras were mounted somehow while they were in use, because otherwise they'd be super-awkward like the one in OP's pic.