A Ground Observations Corps observer in Black Hawk, South Dakota, (about 8 miles northwest of Rapid City), reported to Ellsworth AFB a bright object, first stationary to the northeast, then heading south 30° to the right, toward Rapid City. A radar controller found two targets heading south, but had difficulty tracking them due to ground clutter. Three airmen were sent outside to look, and saw a high speed light heading south.

A few minutes later the Ground Observations Corps observer reported the object had returned. An F-84 was vectored and made visual contact, then was directed toward a stationary radar target about 15 miles northeast of Black Hawk. The target started moving 320° magnetic out to 70 miles range and the F-84 intercept was called off.

The F-84 pilot was about to land in Rapid City when he noticed a silvery object like "the brightest star he'd ever seen", to the northwest, which he pursued on 350° magnetic, keeping it at 11 o'clock high, 30°-45° elevation. It disappeared after 30 seconds, reappeared for 30 seconds, then faded from sight.

A second F-84 was scrambled from Ellsworth AFB on a north magnetic heading. At 15,000 feet the pilot saw a target 30°-40° to his right and at level elevation which "jumped" in elevation to 15°-30°, changed color from white to green, was much brighter than a star, and was moving in relation to the stars (compared to three specific stars he picked out for reference). The pilot turned on his radar gunsight, which showed a possible target beyond maximum range of 4,000 yards. GCI ground radar tracked a target 5-10 miles ahead of the F-84 out to 80 miles for 5 minutes, when intercept was broken off. The target went off the scope at about 11:42 pm.

About 20 miles from base the F-84 pilot, now at 12,000-14,000 feet, saw a red and white pair of lights 10° below the horizon at 180° magnetic. Height-finder ground radar showed a target at 8,000 feet. These lights were visible for 30 second periods. Radar scope and gun cameras reportedly were not functioning.

The green-red ball-shaped object was tracked by radar and sighted visually intermittently by military witnesses at the airfield over a period of four hours. No sound was heard.

Ruppelt's account incorrectly gives the dates as 12-13 August:

August 13, 1953, when Max Futch called me from ATIC. A few minutes before a wire had come in carrying a priority just under that reserved for flashing the word the U.S. has been attacked. Max had been called over to ATIC by the OD to see the report, and he thought that I should see it. I was a little hesitant to get dressed and go out to the base, so I asked Max what he thought about the report. His classic answer will go down in UFO history, "Captain," Max said in his slow, pure Louisiana drawl, "you know that for a year I've read every flying saucer report that's come in and that I never really believed in the things." Then he hesitated and added, so fast that I could hardly understand him, "But you should read this wire." The speed with which he uttered this last statement was in itself enough to convince me. When Max talked fast, something was important.

A half hour later I was at ATIC--just in time to get a call from the Pentagon. Someone else had gotten out of bed to read his copy of the wire. I used the emergency orders that I always kept in my desk and caught the first airliner out of Dayton to Rapid City, South Dakota. I didn't call the 4602nd because I wanted to investigate this one personally. I talked to everyone involved in the incident and pieced together an amazing story.

Shortly after dark on the night of the twelfth, the Air Defense Command radar station at Ellsworth AFB, just east of Rapid City, had received a call from the local Ground Observer Corps filter center. A lady spotter at Black Hawk, about 10 miles west of Ellsworth, had reported an extremely bright light low on the horizon, off to the northeast. The radar had been scanning an area to the west, working a jet fighter in some practice patrols, but when they got the report they moved the sector scan to the northeast quadrant. There was a target exactly where the lady reported the light to be. The warrant officer, who was the duty controller for the night, told me that he'd studied the target for several minutes. He knew how weather could affect radar but this target was "well defined, solid, and bright." It seemed to be moving, but very slowly. He called for an altitude reading, and the man on the height-finding radar checked his scope. He also had the target--it was at 16,000 feet.

The warrant officer picked up the phone and asked the filter center to connect him with the spotter. They did, and the two people compared notes on the UFO's position for several minutes. But right in the middle of a sentence the lady suddenly stopped and excitedly said, "It's starting to move--it's moving southwest toward Rapid."

The controller looked down at his scope and the target was beginning to pick up speed and move southwest. He yelled at two of his men to run outside and take a look. In a second or two one of them shouted back that they could both see a large bluish-white light moving toward Rapid City. The controller looked down at his scope--the target was moving toward Rapid City. As all three parties watched the light and kept up a steady cross conversation of the description, the UFO swiftly made a wide sweep around Rapid City and returned to its original position in the sky.

A master sergeant who had seen and heard the happenings told me that in all his years of duty--combat radar operations in both Europe and Korea--he'd never been so completely awed by anything. When the warrant officer had yelled down at him and asked him what he thought they should do, he'd just stood there. "After all," he told me, "what in hell could we do--they're bigger than all of us."

But the warrant officer did do something. He called to the F-84 pilot he had on combat air patrol west of the base and told him to get ready for an intercept. He brought the pilot around south of the base and gave him a course correction that would take him right into the light, which was still at 16,000 feet. By this time the pilot had it spotted. He made the turn, and when he closed to within about 3 miles of the target, it began to move. The controller saw it begin to move, the spotter saw it begin to move and the pilot saw it begin to move--all at the same time. There was now no doubt that all of them were watching the same object.

Once it began to move, the UFO picked up speed fast and started to climb, heading north, but the F-84 was right on its tail. The pilot would notice that the light was getting brighter, and he'd call the controller to tell him about it. But the controller's answer would always be the same, "Roger, we can see it on the scope."

There was always a limit as to how near the jet could get, however. The controller told me that it was just as if the UFO had some kind of an automatic warning radar linked to its power supply. When something got too close to it, it would automatically pick up speed and pull away. The separation distance always remained about 3 miles.

The chase continued on north--out of sight of the lights of Rapid City and the base--into some very black night.

When the UFO and the F-84 got about 120 miles to the north, the pilot checked his fuel; he had to come back. And when I talked to him, he said he was damn glad that he was running out of fuel because being out over some mighty desolate country alone with a UFO can cause some worry.

Both the UFO and the F-84 had gone off the scope, but in a few minutes the jet was back on, heading for home. Then 10 or 15 miles behind it was the UFO target also coming back.

While the UFO and the F-84 were returning to the base--the F-84 was planning to land--the controller received a call from the jet interceptor squadron on the base. The alert pilots at the squadron had heard the conversations on their radio and didn't believe it. "Who's nuts up there?" was the comment that passed over the wire from the pilots to the radar people. There was an F-84 on the line ready to scramble, the man on the phone said, and one of the pilots, a World War II and Korean veteran, wanted to go up and see a flying saucer. The controller said, "O.K., go."

In a minute or two the F-84 was airborne and the controller was working him toward the light. The pilot saw it right away and closed in. Again the light began to climb out, this time more toward the northeast. The pilot also began to climb, and before long the light, which at first had been about 30 degrees above his horizontal line of sight, was now below him. He nosed the '84 down to pick up speed, but it was the same old story--as soon as he'd get within 3 miles of the UFO, it would put on a burst of speed and stay out ahead.

Even though the pilot could see the light and hear the ground controller telling him that he was above it, and alternately gaining on it or dropping back, he still couldn't believe it--there must be a simple explanation. He turned off all of his lights--it wasn't a reflection from any of the airplane's lights because there it was. A reflection from a ground light, maybe. He rolled the airplane--the position of the light didn't change. A star--he picked out three bright stars near the light and watched carefully. The UFO moved in relation to the three stars. Well, he thought to himself, if it's a real object out there, my radar should pick it up too; so he flipped on his radar-ranging gunsight. In a few seconds the red light on his sight blinked on--something real and solid was in front of him. Then he was scared. When I talked to him, he readily admitted that he'd been scared. He'd met MD 109's, FW 190's and ME 262's over Germany and he'd met MIG-15's over Korea but the large, bright, bluish-white light had scared him--he asked the controller if he could break off the intercept.

This time the light didn't come back.

When the UFO went off the scope it was headed toward Fargo, North Dakota, so the controller called the Fargo filter center. "Had they had any reports of unidentified lights?" he asked. They hadn't.

But in a few minutes a call came back. Spotter posts on a southwest- northeast line a few miles west of Fargo had reported a fast-moving, bright bluish-white light.

This was an unknown--the best.

The sighting was thoroughly investigated, and I could devote pages of detail on how we looked into every facet of the incident; but it will suffice to say that in every facet we looked into we saw nothing. Nothing but a big question mark asking what was it.

The initial incident in this chain of UFO sightings was the sighting by a GOC (Ground Observers Corps) observer of a stationary "red glowing light" at 2005 LST near Blackhawk, S. Dak. This light soon began to move some 30° to the right, "shot straight up," and moved to the left, returning to its original position. A companion thought it was "just the red tower light" (a warning light on an FM transmitter tower normally just visible from their location). The report was relayed to the Rapid City Filter Center, and three airmen from the radar site were sent outside to look for the UFO. They saw what was undoubtedly a meteor, judging from their description. The radar operator when informed of the new sighting began to search for unidentified targets. He found many.

Over the course of the next four hours a large number of unidentified blips appeared on the Rapid City radar. Many of those were transitory, moving blips with a fairly short lifetime, usually being "lost in the ground clutter." An F-84 fighter was vectored in to a stationary blip near Blackhawk, and the pilot "chased" a UFO which he found at the location on a heading of 320 ° M. without gaining on it. The F-84 was probably chasing a star, in this case Pollux (mag. 1.2) which was in the correct location (335° true azimuth, near the horizon).

When the Blackhawk GOC post called in that the original object had returned for a third time, another F-84 was vectored in on the visual report. as no radar contact could be made. The pilot made a visual contact" and headed out on a 360 ° magnetic (~15° true) vector. At this point the radar picked up what apparently was ghost echo, that is, one that "paced" the aircraft, always on the far side from the radar. The fighter in this instance was probably chasing another star, the image of which may have been somewhat distorted. The pilot's report that the visual UFO was "pacing" him appears to have strengthened the radar operator's belief that he was actually tracking the UFO, and not a ghost echo. The star in this instance may well have been Mirfak (mag. 1.9), which, at 2040 LST, was at azimuth 15 ° and about 5 ° to 7 ° elevation angle. The second pilot, upon being interviewed by Dr. Hynek, stated that he felt he had been chasing a star, although there were some aspects of the appearance of the object that disturbed him. He also stated that the radar gunlock. which he had reported by radio during the chase, was due to equipment malfunction, and that the radar gunsight continued to malfunction on his way back to the base. This equipment was never subsequently checked for malfunctioning (i.e., not before or during the official AF investigation of the incident).

The Bismarck, N. Dak. sightings began when the Bismarck Filter Center was alerted to the "presence of UFO's" by Rapid City. At 2342 LST the sergeant on duty there and several volunteer observers went out on the roof and shortly spotted four objects. The descriptions of these objects by the various observers were consistent with the hypothesis that they were stars, although some apparent discrepancies caused early AF investigators to deduce by crude triangulations that the sighted objects must have been nearby. It now appears that all four objects were stars viewed through a temperature inversion layer. The observers stated that the objects resembled stars, but that their apparent motion and color changes seemed to rule out this possibility.

Dr. Hynek's summary of the probable nature of the four Bismarck objects is enlightening:

Object #1, which was low on the horizon in the west and disappeared between midnight and 0100 hr. was the star Arcturus observed through a surface inversion. Arcturus was low on the horizon in the west and set at approximately 1220 (LST) at 289 ° azimuth.

Object #2 -- was the star Capella observed through a surface inversion. At 0011 CST Capella was at 40° azimuth and 15 ° elevation ... [and] at 0200 CST [it] was at 53° azimuth and 30 ° elevation, which agrees with the positions given by [the two witnesses].

Objects #3 and #4 were, with a high degree of probability, the planet Jupiter and the star Betelgeuse, observed through a surface inversion. Jupiter's ... stellar magnitude was -1.7 [and it] was low on the eastern horizon at approximately 92° azimuth. Betelgeuse ... was also low on the eastern horizon at approximately 81 ° azimuth.

... they appeared much brighter than most of the stars and at times appeared to take ona rather dull bluish tint.

They appeared to move in the heavens, but at a rather slow rate and unless a person braced his head against some stationary object to eliminate head movement it would be hard to tell that they were moving.

The one in the west eventually disappeared below the horizon and the one in the northeast gradually seemed to blend in with the rest of the stars until it was no longer visible.

The meteorological conditions were generally favorable for anomalous propagation at both locations. The refractivity profile for Rapid City 2000 LST 5 August shows a 0.5 ° C temperature inversion over a layer 109 m. thick, although the resulting refractivity gradient is only -77 km-1 (Fig. 5). The 0800 LST profile (Fig. 6) shows a pronounced elevated duct between 833 and 1,007 m. with a gradient of -297 km-1; a 3.2 ° elevated inversion is reported through this layer. A strong inversion layer evidently formed during the night and was "lifted" to the 833 m. level by solar heating after sunrise at about 0500 LST.

The Bismarck profile for 2100 LST 5 August (Fig. 4) shows a 1.2°C temperature inversion between the surface and the 109 m. level, the resulting layer forming a radio duct with a refractivity gradient -182 km-1. It is noteworthy that the Bismarck sightings show more evidence of optical inversion-layer effects than the Rapid City sightings.

In summary, the Rapid City-Bismarck sightings appear to have been caused by a combination of:

- stars seen through an inversion layer,

- at least one meteor,

- AP echoes on a GCI radar, and

- possible ghost echoes on the GCI radar and malfunction of an airborne radar gunsight (although the commanding officer of the Rapid City detachment was later skeptical that there had in fact ever been even a ghost echo present on the GCI radar).

Google map of this location.