Unlike fighters they would almost stop in their forward velocity and change 90 degrees, sometimes in their flight path… We had practically all the fighters we could muster on the base up climbing as high as they could climb with guys that have binoculars with them… they were round in shape and very metallic looking. And they would come over and do the same maneuvers that we make except everyone once in a while one of them goes ‘zip’ [hand motion]. And you just can’t do that in a fighter.— Gordon CooperMercury & Gemini Astronaut
I was testing a P-51 fighter in Minneapolis when I spotted this object. […] It looked like a saucer, a disk. About the same time, I realized that it was suddenly going away from me – and there I was, running at about 300 miles per hour. I tracked it for a little way, and then all of a sudden the damn thing just took off. It pulled about a 45 degree climbing turn and accelerated and just flat disappeared.— Donald SlaytonMercury Astronaut
It followed us during half of our orbit. We observed it on the light side, and when we entered the shadow side, it disappeared completely. It was an engineered structure, made from some type of metal, approximately 40 meters long with inner hulls. The object was narrow here and wider here, and inside there were openings. Some places had projections like small wings. The object stayed very close to us. We photographed it, and our photos showed it to be 23 to 28 meters away.
[…] Many cosmonauts have seen phenomena which are far beyond the experiences of earthmen. For ten years I never spoke on such things. […] It only flew straight, but then a kind of explosion happened, very beautiful to watch, of golden light. This was the first part. Then, one or two seconds later, a second explosion followed somewhere else and two spheres appeared, golden and very beautiful. After this explosion I just saw white smoke, then a cloud-like sphere.— Victor AfanasyevCosmonaut