By looking at the entire network, it was possible to determine the flight path and direction. Using the experience of twelve shuttle landings and one SR-71 flight, Mori concluded:
On three of the four days, the records showed two events, which means that there were two planes. They flew about one minute apart as they traveled across the seismic net from south to north. The planes traveled at about two to four times the speed of sound, at an altitude of 10,000 to 40,000 feet. From the frequency of the event on the seismogram, we think that the aircraft is smaller than the Shuttle. It appears that they did not land at Edwards Air Force Base, but kept going north to southern Nevada. The last time the planes flew, on January 30, they passed over the Los Angeles area about one-half hour before the Space Shuttle was due.[756]
Because the top end of the speed range was above that of conventional aircraft and because its flight path would take it toward Groom Lake, many assumed the mystery plane was Aurora. A fifth "rumble" occurred on April 16, 1992, (again a Thursday) at about 7:00 A.M. A public affairs director for the Tournament of Roses described it as "kind of a rumble — very short." A restaurant manager said, "It rattled the glass door. And there was a roar, a slight roar." By November 1993, a total of eight such rumbles had been heard.[757]
On April 20, 1992, the NBC Nightly News carried a feature on Aurora.
This included details on the rumbles and on the aircrafts' flight path. There was a brief film clip taken from a site near Groom Lake of a light hovering in the night sky. This light was described as being an extremely maneuverable Black airplane.[758]
As Mori noted, "If they were really trying to keep this secret they wouldn't fly it over downtown L.A., over and over again." The seeming public display of Aurora indicated to some that a disclosure was imminent. The believers detected a "subtle language shift" in the air force denials. One spokesman said, "I have nothing for you on that." Steven Aftergood, an analyst with the Federation of American Scientists — which had long opposed new U.S. weapons programs — said about the air force statement, "it's a non-denial denial. Coming from the air force, it amounts to a confirmation." Aftergood continued, "I would say the triggering of earthquake sensors is a leak from the air force. This is a form of signaling to the people who watch these things that (they've) arrived." Just when the "unveiling" of Aurora would come was unclear to observers. Some thought it would occur in the spring of 1992, recalling Lyndon Johnson's A-ll and SR-71 announcements during the 1964 presidential campaign. (1992 was also an election year.) Others thought it would be within a year. (The F-117A was unveiled shortly after the 1988 election.) Others thought it still might be several years away.[759]
Another reason for the belief in an imminent disclosure was reports of an Aurora sighting in Scotland. It was claimed that in November 1991, a Royal Air Force air traffic controller had picked up a radar target leaving a NATO-RAF base at Machrihanish, Scotland. He tracked it at a speed of Mach 3.
When he telephoned the base to ask what the plane was, he was told to for-get what he had seen. Another witness reported hearing an extremely loud roar at the same time as the radar sighting.[760]
A number of English newspapers and magazines carried the story. It was claimed that Aurora took off from Groom Lake and headed west to a landing at Kwajalein Atoll in the Pacific. It then continued west and overflew Iraq, using "high-powered cameras and infrared radar" before continuing on to Machrihanish. After taking off, Aurora was refueled with liquid methane by tankers based in England. It then flew back to the United States. To hide the landings, an F-lll flew in close formation to confuse civilian radar. As the reports spread, Defence Minister Archie Hamilton told Parliament that the existence and operation of Aurora was a "matter for the American authorities." When the air force was asked, they did not confirm or deny its existence.[761]
The story crossed the Atlantic and the Antelope Valley Press carried a story on March 6, 1992. It included an estimate that the development cost ran into the tens of billions, with each Aurora in a twenty-plane fleet costing $1 billion apiece.[762] An editorial published on March 12 expressed the hope that the Aurora would produce high-paying jobs in an area hard hit by defense cutbacks.[763] The May 25, 1992, issue of Time picked up the Machrihanish story and carried a brief report in its "Grapevine" column. (Another item was a poll on the question of which presidential candidate had the best haircut.) It said the code name for Aurora was "Senior Citizen."[764]
Nor were sightings limited to the wilds of Scotland. On February 25, 26, and 27, 1992, there were nighttime sightings of an unknown aircraft with a "diamond-pattern" of lights at Beale Air Force Base (the former SR-71 base). On the first two nights, a KC-135Q took off at about 6:15 P.M., followed by the aircraft. It had a red light near the nose, two "whitish" lights at the wingtips, and an amber light at the tail. The aircraft had a distinctive engine noise, described as "a very, very low rumble, like air rushing through a big tube." The plane then joined the tankers in a close formation and extinguished its lights.
On one of these nights, at 9:30 P.M., two T-38 trainers took off with an unknown aircraft between them. The third aircraft did not turn on its lights until it was about three miles from the runway. It also showed a diamond pattern.
Finally, on February 27, a formation of a KC-135Q, two F-117As, and the unknown aircraft took off. The wing lights were described as about twice as far apart as those on the F-117s, and the length was about 50 percent longer than the F-117s.[765]
What was thought by some to be a ground test of the Aurora's engine was also reported. Late on the night of February 26 (the second night of the sightings) a series of "booms" was heard coming from the base. These occurred every two to three seconds and continued for around thirty minutes.
They were described as "like artillery fire," and "deep bass notes, not like sonic booms." It was thought these might be "light-off" tests of the engine.
It was speculated the plane used a pulse detonation wave engine (PDWE).
The noise and low frequency would, it was said, be consistent with a PDWE. The "light-off" was thought to be the most difficult phase to control, and the sound may have been from technicians "trimming" an engine.[766]
Three months later, photos were published of a "doughnut-on-a-rope" contrail seen over Amarillo, Texas. It had long been reported that Aurora left such contrails, but this was the first time it had been photographed. The sighting took place at 8:30 A.M. on March 23, 1992. The person who took the photographs stated that he had heard a "strange, loud, pulsating roar… unique… a deep pulsating rumble that vibrated the house and made the windows vibrate." He added that the sound was "similar to rocket engine noise, but deeper, with evenly timed pulses."[767] It has been reported that the pulse rate was three hertz.[768] The photographer later said he talked with an engineer at Convair Fort Worth, who said the contrails were formed only when the PWDE was operating outside its design parameters. Another theory was that they became visible only when the aircraft descended out of the thin air of high altitudes and into the thicker air of low altitudes.[769] This powerplant was also referred to as an "impulse motor."[770]
756
Betsy Woodford, "Phantom of the air tracked by Caltech's seismo-graphic network,"
757
Edmund Newton, "Secret Is Out on 'Quakes': It's a Spy Plane,"
760
Bill Sweetman, "Mystery contact may be Aurora,"
761
Christy Campbell, "Secret US spy plane is Kintyre's dark visitor,"
762
Bill Sweetman, "Clues hint of phantom spy
763
Editoriaclass="underline" "Aurora may be going 'boom' in the
765
"Possible 'Black' Aircraft Seen Flying in Formation with F-117s,
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William B. Scott, "New Evidence Bolsters Reports of Secret, High-Speed Aircraft,"
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Computer Message, Subject: Contrails, From: Steve 1957, America Online, 93-09-19, 17:39:11 EOT.
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Industry Observer, "Combined Cycle Powerplant,"