The Tarija Fallen Space Object (Cerro El Zaire, 1978)

The border between Tarija Department in Bolivia and northern Salta Province in Argentina is high, steep country. Mining towns and villages sit among the ridges. On Saturday, 6 May 1978, late in the afternoon, people on both sides of that frontier looked up and saw the same thing.

It crossed the sky from east to west at enormous speed. It looked out of control, in free fall. Some saw a long object shooting fire. Others saw a cylinder with a flaming tail, or an incandescent oval with a metallic tone. A La Paz newspaper called it egg-shaped, metal, about four meters in diameter.

Juan Hurtado, an agent of the Bolivian Border Intelligence Service, said it was like a huge wine container. It passed silently overhead, he said, at about 90 meters. The impact threw him to the ground. "The whole Earth trembled." Corporal Natalio Farfán Ruiz thought the end of the world was coming.

The object dropped behind the mountains. Seconds later, a tremendous explosion. The ground shook in Tarija, Bermejo, Los Toldos and Orán. Engineer Velez Orozco said it was "much louder than one caused by a meteorite."

Tarija's mayor, Gen. Yamil Taja Kruger, commissioned an inquiry. Geologist Daniel Centeno, then 31, led it. His team made two ground expeditions and flew over Cañas, Mecoya and Argentine territory. No crater. No debris. Only colluvial material. Yet the witnesses stayed with him. "People who had never been together or known each other told us the same thing," he said in 2021.

The Argentine Gendarmerie sent three patrols. The Bolivian Air Force flew searches. An expedition from El Tribuno and Canal 13 walked for two days and came back with a different story. A hill called El Salle, they said, was completely destroyed. They described a crater 1,500 meters long, with heat-crystallized rocks at its base.

CIA reports from mid May said Bolivian authorities had urgently requested assistance from NASA. The same reports noted "uncertainty as to the truth of these reports." On 15 May the US Embassy in La Paz cabled a "Report of Fallen Space Object." Washington replied that it found "no direct correlation with known space objects." On 24 May a Defense Attaché message marked "Moon Dust" went to the Foreign Technology Division at Wright-Patterson Air Force Base. Col. Robert Simmons and Maj. John Heise flew to Tarija in connection with Project Moon Dust. The Bolivian Army concluded that "there may or may not be an object."

Some proposed a meteorite. Against that, sources note that the Smithsonian's databank lists no meteorite fall on that border in May 1978. Argentine authorities reportedly suggested an artificial satellite. Bob Pratt of the National Enquirer spent three weeks in Bolivia and never reached the site. He later wrote that "a lot of misinformation has been published about this incident." In his account nothing was recovered, and he believed the object lay buried under the landslide it created.

Other claims grew around the case. One tells of a C-130 Hercules and a package so heavy it took six men to lift. Researchers such as Kevin Randle argue that Moon Dust was really about retrieving alien craft.

Locals still say the gringos already took whatever fell. The case lives on as the caso Mamora, the caso Mecoya and el Roswell boliviano-argentino. Documentaries and anniversary reports keep returning to Cerro El Zaire. The cables are declassified. The object, if there was one, has never been found.