Sudán.Chali · the "cloud" the missionaries saw on the night Mars 1 was launched (1962)

On the night of Thursday 1 November 1962, an American missionary couple at Chali, a village in south-eastern Sudan near Kurmuk and the Ethiopian border, some ten degrees north of the equator, saw something strange in the sky. Around 19:30 local time —17:30 GMT, two hours after sunset— what looked like a small cloud seemed to rise in the west. It moved until it passed overhead, seemed to change course towards the north and there gradually faded away, although it had moved only a little in that direction. From the time they saw it until it disappeared about twenty minutes passed.

Six days later, on 7 November, the husband wrote an airmail letter to the "Atomic Testing Commission, Cape Canaveral, Florida", convinced it was some American experiment. He describes a round mass, like a cloud, that stayed together. The night was clear and starry, with a sliver of moon. To estimate its size they held up a six-inch saucer and moved back until it just covered the mass: the saucer was then about twelve feet away. They had no idea how high it was, but it was much higher than the clouds and had a glow somewhat like the moon's, though it changed shape. It was almost colourless, a smoky silver. They supposed the mass was travelling east around the Earth and that, as it passed overhead, it was moving out of the Sun's rays, hence disappearing; but they could not understand why it had turned north.

They made two guesses: that it was the cloud formed by the water released in one of the American experiments —in 1962 NASA twice released the tonnes of water ballast of a Saturn rocket into the upper atmosphere, on the Project Highwater flights, with wide press coverage—, or a cloud of radioactive fallout from some recent nuclear test. They also said some local people thought it was a spirit and came running, frightened, to ask what it was. The letter, stamped at Cape Canaveral on 27 November, ended up at Blue Book. The card summarises the observation and concludes: "Other: cloud"; from the description, "probably a noctilucent cloud", which disappeared when it stopped reflecting sunlight.

Blue Book's explanation does not fit: noctilucent clouds form at about 80 kilometres and are seen only at high latitudes in summer, not ten degrees from the equator in November. Jonathan McDowell's satellite catalogue points to something else. That same afternoon, 1 November 1962, the Soviet Union launched the Mars 1 probe from Baikonur on a Molniya rocket. The catalogue records the launch at 16:14 GMT, the upper stage reaching parking orbit around 16:23 and the probe separating, after that stage fired to escape Earth orbit, at 17:19 GMT: eleven minutes before the missionaries saw their "cloud".

It is the corpus's first case in Sudan, and one of the finest of its kind, because the witnesses' description is very good and their own explanation, read carefully, almost solves it. A round, greyish, glowing mass far above the clouds, appearing in the west two hours after sunset, crossing the sky and fading as if leaving the sunlight: that is exactly what one sees when a rocket engine's exhaust, or a chemical payload, expands in the vacuum hundreds of kilometres up and is lit by the Sun while the ground is already dark. The missionaries themselves sensed it when they thought of the Highwater water.

The coincidence with Mars 1 is striking: the firing of the Soviet upper stage and the probe's separation happened between twenty and fifteen minutes before the observation, and an exhaust cloud at high altitude can stay visible for much longer. But there is a limit worth stating: we have not been able to check where the stage was when it fired its engine or whether its track passed over East Africa. Histories of the Soviet Venus and Mars programmes of those years place those firings over the equatorial Atlantic and the Gulf of Guinea, where the USSR stationed tracking ships, and an expanding cloud at great height there could be seen on Sudan's western horizon; but without the exact trajectory, the identification remains a strong hypothesis, not a fact.

The case also illustrates two things that recur in this corpus. First, how a routine official explanation —"noctilucent cloud"— can be physically impossible and still close a file. Second, how Cold War space launches, announced to nobody in the countries they passed over, left phenomena in the sky that were read as spirits, atomic tests or UFOs. The case weighs almost entirely on the mundane explanation.