Re-entry Sightings and Debris Recovery of 1979-072B

Bolivia - 1979 August 10 UTC

Ted Molczan - 2014 July 30

 

Major Revisions

2014 Jul 30 First published
2014 Aug 13 Addendum 1: discovery of sighting from Chile
2014 Sep 18 Addendum 2: discovery of four newspaper articles
2014 Oct 26 Re-written to merge addenda into report
2015 Feb 21 Re-organized and consolidated 2.1 and 2.2; rewrote 3.2

1. Summary
2. Reports on Bolivian and Chilean Events
3. Prime Suspect is Re-entry of 1979-072B
4. Estimated Orbital Elements of 1979-072B
5. Orbital Decay Analysis of 1979-072B
6. Conclusions
7. Research Suggestions
8. Acknowledgments

1. Summary

The re-entry of Delta rocket second stage 1979-072B has been found to correlate with two large metallic spheres found in Bolivia on 1979 August 10 UTC, hours after sightings of a fireball from Bolivia and Chile. Newspaper reports at the time focused on the re-entry of a satellite or rocket stage as the possible cause, suggested by the director of the Bolivian Air Force Academy. The Defense Attaché of the U.S. Embassy in La Paz promptly informed the U.S. DIA (Defense Intelligence Agency) via telexed Moon Dust reports, which included translations of two Bolivian newspaper reports. Moon Dust was the unclassified name of a cold war USAF program to obtain Soviet space hardware that survived re-entry.

Public knowledge of the case appears to have been confined to South America until the mid-1980s, when two Moon Dust telexes came to light as a result of FOIA requests filed by UFO researchers, some of whom suspected that the scope of Moon Dust may have included crashed extraterrestrial spacecraft. Most reports from those circles have tended to emphasize what may seem to be mysterious aspects of the case. This report presents strong circumstantial evidence that identifies the re-entry of 1979-072B as the source of the observed aerial phenomena and both spheres.

The precipitating event was the launch of Westar 3 from Cape Canaveral, on 1979 August 10 at 00:20 UTC, aboard Delta 149. The second stage of the Delta rocket was discarded in a rapidly decaying orbit. It bore the international designation 1979-072B. USSTRATCOM (U.S. Strategic Command) assigned it catalogue number 11490, and reported that it decayed on the same day it was launched.

1979-072B was a model DSV-3P-4 Delta second stage, which contained two helium pressurant spheres, made of titanium, similar in size to the pair that fell in Bolivia. The spheres of some earlier and later model Delta second stages are known to have survived re-entry and been recovered. The two Bolivian spheres were found soon after sightings of a fireball in the early hours of August 10, 1979, and showed signs of exposure to extreme heat. The orbit of 1979-072B passed close to the site of both sphere discoveries in the early hours of 1979 August 10 UTC. If it was re-entering at that time, then it could account for the fireball sightings and both spheres.

Complete orbital elements of 1979-072B from official sources have yet to be found; however, partial elements from authoritative sources enabled their accurate reconstruction. Orbit propagation analysis of a large sample of other re-entered Delta DSV-3P-4 second stages confirms that 1979-072B could have re-entered over Bolivia at the relevant time and place. There is also strong temporal and spatial correlation with the Chilean fireball sighting. The result is highly sensitive to the perigee height, which is not precisely known, so is considered borderline; however, when examined in the context of the other evidence, it may reasonably be concluded that the re-entry of 1979-072B caused the aerial phenomena and was the source of the spheres.

The evidence is not in perfect agreement. The mass of only one sphere was reported, which was much lighter than expected given its size and the mass of other known Delta helium spheres. One of the two reported fireball sighting times was a couple hours earlier than the time of 1979-072B's passage. Unless strong corroborating evidence emerges, these single-source discrepancies should not be given too much weight.

Section 2 documents existing reports relevant to the Bolivian and Chilean events, which form much of the evidence of the case. Section 3 examines this evidence in relation to the 1979-072B re-entry hypothesis. Section 4 reports the orbital elements derived from the partial orbital elements. Section 5 reports the orbital decay analysis. Section 6 states the conclusions. Section 7 suggests further lines of research that could improve understanding of the incident. Section 8 acknowledges those who assisted this study.

2. Reports on Bolivian and Chilean Events

This section documents existing reports relevant to the Bolivian and Chilean events. Links to complete source documents are presented, from which the information most relevant to the re-entry hypothesis is extracted and discussed. The four main sub-sections respectively cover the source documents, extracted evidence, reports by Luis Ruiz Nóguez, and the recently discovered fireball sighting reports from Chile. The analysis in this section is intended to aid in understanding the evidence. In-depth analysis begins in Section 3.

2.1 Source Documents

The documentary evidence considered in this report is found in two Moon Dust reports and four newspaper articles.

2.1.1 Moon Dust Reports

The Defense Attaché of the U.S. Embassy in La Paz, Harold T. Hamilton, Col. USAF, informed the U.S. DIA (Defense Intelligence Agency) of the spheres via telexed Moon Dust reports, which included translations of two Bolivian newspaper reports. Moon Dust was the unclassified name of a cold war USAF program to obtain Soviet space hardware that survived re-entry. The telexes came to light in the mid-1980's, as a result of FOIA requests filed by UFO researchers.

The telex of Friday, August 17 reported the discovery of the first sphere, based on information received from an unidentified informant late on the afternoon of Thursday, August 16, and a front page article published by El Deber on the on the morning of August 17. El Deber is based in Santa Cruz de la Sierra, which is the capital city of Santa Cruz Department - one of the nine primary administrative divisions of Bolivia. Both spheres fell in Santa Cruz Department. The major portion of the telex is devoted to the embassy's "unofficial translation" of El Deber's report.

El Deber described the fall of "part of what could be a satellite" as a "phenomenon that could focus the attention of the world on Bolivia", a likely reference to the infamous Skylab re-entry one month earlier, that showered southwestern Australia with a large quantity of debris, and had been a huge international news story.

The telex of Tuesday, August 21 reported the discovery of the second sphere, based on a front page article published on Sunday, August 19, by El Diario, "one of the leading daily newspapers of La Paz." The embassy translated the headline as New sphere fell from space in Santa Cruz. The reference was to Santa Cruz Department. The major portion of the telex is devoted to the embassy's "unofficial translation" of El Diario's report.

2.1.2 Newspaper Articles

In September 2014, subsequent to the initial publication of this report, Vicente-Juan Ballester Olmos discovered clippings of four articles on the spheres that fell in Bolivia on August 10, 1979, reported by three different news wire services, published by three newspapers based in Buenos Aires, Argentina. The files tabulated below contain the scanned original, followed by the reproduced Spanish text, presented side-by-side with an English translation provided by Allen and Zaida Thomson.

Source Dateline Title Published
Associated Press Aug 17, Santa Cruz Cayó en Santa Cruz de la Sierra un extraño artefacto espacial Aug 18, Clarín
Associated Press Aug 21, Santa Cruz Bolivia: Aparecio Otra Extraña Esfera Metalica Aug 21, Cronica
France Press Aug 22, Santa Cruz de la Sierra Nuevo OVNI Cae en Bolivia Aug 22, Cronica
United Press Aug 24, La Paz Cayeron en Bolivia otros dos artefactos espaciales Aug 25, La Prensa

2.2 Extracted Evidence

This section presents the evidence found in the documents presented in Section 2.1 that may be relevant to the re-entry hypothesis.

2.2.1 Spheres Fell on August 10, 1979

Careful reading of the two news reports translated in the Moon Dust telexes revealed that both spheres fell on August 10, 1979. Two of the recently discovered articles explicitly reported that date.

The Associated Press (AP) article datelined August 17, 1979 quoted the discoverer of the first sphere (referred to here as the south sphere), Benigno Roca: "It fell on the morning of August 10 and scared the animals".

The Associated Press (AP) article datelined August 21, 1979 largely quoted newspaper El Mundo, based in Santa Cruz, Bolivia: "The "twin sphere" would have fallen on the 10th day of this month, the same day as the first one."

2.2.2 South Sphere Fell Near Enconada

The "El Deber" article datelined August 17, 1979, as translated in the Moon Dust telex of the same day, reported that the south sphere fell "on a farm located 15 km from Cotoca". The Associated Press (AP) article datelined August 17, 1979 included the following statements that narrow the location to the nearby village of Enconada:

The unit fell 25 kilometers from this capital on a rural farm and had been hidden by Benigno Roca and his wife, until one of their relatives convinced them that they should acknowledge the fact to the press and the authorities.

According to the official report, based on statements from the Roca couple, in the early morning of August 10 a noise that alarmed pets was heard in the area called La Enconada.

The Associated Press (AP) article datelined August 21, 1979 reported similar information:
The first sphere was found 27 kilometers from this city and is located at the Military College.
Enconada (17.732 S, 62.935 W) is 26.6 km from the centre of Santa Cruz de la Sierra (17.784 S, 63.181 W), in close agreement with the AP reports.

Enconada is 6.5 km from the town of Cotoca (17.751 S, 62.993 W), significantly less than the 15 km reported by El Deber. This discrepancy apparently resulted from confusion regarding the coordinates of Cotoca, which the Moon Dust telex noted incorrectly as "17-49S, 63-03W" or 17.817 S, 63.050 W, which is in the middle of farmland. Enconada happens to be 15.4 km from those false coordinates. Interestingly, the identical false coordinates of Cotoca are still sometimes used today. They can be seen on a few web pages unrelated to the Bolivian spheres. The exact cause of the error may never be known, but with the recently discovered AP reports, the point of impact of the south sphere can now be narrowed to Enconada or its immediate vicinity.

2.2.3 North Sphere Fell Near Buen Retiro

The El Diario article datelined August 19, 1979, as translated in the second Moon Dust telex, reported that the existence of the second sphere came to light after a friend of its finder learned of the discovery of the first one, presumably from news reports. The discoverer had taken it home, but soon after its existence was disclosed, radio news reporters moved it to their station at Santa Cruz de la Sierra, where it was publicly displayed for an afternoon. El Diario based its report on information provided by the radio station's reporters.

El Diario reported that Mr. Gonzalo Menacho Viveras found the second sphere on the farm of his employer, Mr. Juan Saavedra, "in the area of Buen Retiro near the Yapacani River." The article incorrectly described the location as 200 km north of Santa Cruz de la Sierra. Buen Retiro is about 80 km to the northwest. Section 3.3 shows that the locations of the spheres relative one another narrows the range of inclination of an orbiting parent object; therefore, in this report the one found near Enconada is referred to as the south sphere and the one found near Buen Retiro as the north sphere.

2.2.4 Appearance and Physical Properties of the Spheres

Size and Mass

According to the first Moon Dust telex, late on the afternoon of Thursday, August 16, Col. Hamilton's informant described the south sphere as "about 70 centimeters in diameter and two meters in circumference" with a "metal skin covering of approx one-half inch thickness." The two metre circumference corresponds to a diameter of about 64 cm. The use of English units for the thickness seems out of place, perhaps the result of a mistranslation or misunderstanding of one-half centimetre as one-half inch.

Col. Hamilton also reported that later the object was described as "about three times the size of a basketball", which implies about 72 cm dia and 2.2 m circumference.

The Associated Press (AP) article datelined August 17, 1979 reported the following information about the mass and size of the south sphere:

The material seemed to be an aluminum or iron alloy, about 6,800 grams and a diameter of 80 centimeters.

According to the second Moon Dust telex, on Sunday, August 19, El Diario reported that the north sphere, "weighs about six kilograms with a diameter of about 80 centimeters". It is odd for the AP and El Diario to have reported substantially the same mass and size for both spheres - especially since it is now known that both values are inaccurate (Sections 3.1 and 3.2).

As of the AP article's dateline, the existence of the north sphere was still known only to its discoverer and his friends; therefore, there is no doubt that the reported mass and diameter applied to the south sphere. This raises the question of how El Diario came to attribute substantially the same properties to the north sphere. Since it would have been improbable for independent sources to have reported substantially the same erroneous physical properties for both spheres, it seems most likely that El Diario or its sources assumed that the previously reported properties of the south sphere applied to both. It appears that all of the currently available information on sphere diameter and mass is of the south sphere, sometimes misapplied to the north sphere.

Construction

On Friday, August 17, El Deber reported that the director of the Air Force Academy, Col. Ariel Coca, described the sphere as, "made of a special light alloy but very resistant, possibly a fuel tank or a part of a satellite." El Diario reported that the north sphere "is made by two pieces put together without any rivets"; the (AP) article datelined August 21, 1979 agreed: "The sphere is divided into two perfectly joined hemispheres, but no clear signs of welds could be seen."

Appearance

Col. Hamilton described "an accompanying picture in the newspaper [that] shows Col Coca, Commander of the Bolivian Air Force Academy, examining a round object which reaches above his knees and appears to be perfectly round except for a hole (missing portion of outer skin) which is about nine inches in diameter."

El Deber reported that the south sphere, "does not have any signs or marks that could identify its origin nor the country to which it belongs."

The August 17 AP article described the south sphere:

The interior of the sphere shows melted materials, apparently due to the high temperature the device endured on its re-entry into Earth's atmosphere.

The sphere is visibly charred and has three holes which, the military authorities speculate, "might have been for screws to attach this object to a larger piece.”

El Diario noted that the two spheres were "exactly alike", with the following similarities:
The material of the spheres is kind of fragile, but they are not damaged (by impact) and in both cases they only show a hole (in outer skin) with melted edges and an explosion (apparently) destroyed the contents of the interior.

In both, the material is melted. At the other end of the sphere there is a round area that looks like a cork in a bottle held in place by three semi-melted screws.

El Diario reported that "the outside metal of the north sphere is similar to copper, is kind of dark with light spots, and has apparently been exposed to very high temperatures," and that "on the top of the sphere you can see a hole of irregular shape and next to it another small round hole."

2.2.5 Audible and Visual Phenomena

El Deber reported an apparent correlation between the sphere found at Enconada and luminous phenomena observed by, "the people who live in the area where this ball of fire (as they called it) fell", who "delayed in telling the authorities about the event because they were afraid that no one would listen".

El Diario reported that the "second fire ball fell from the sky early in the morning of the same day that the first one was found". The discoverer, Gonzalo Menacho Viveras, reported that, "around 12:30 AM on Friday last week he heard a loud whistling sound and saw a fire ball followed by an explosion", and that he found the sphere after dawn the same day.

The Associated Press (AP) article datelined August 21, 1979 reported:

According to "El Mundo", at the dawn of that day a piercing whistle was heard in Buen Retiro "followed by some explosions." Hours later, a farmer found the sphere and took it home.

2.2.6 Discovery of a Third Sphere Reported

The discovery of a third, much smaller sphere was reported by the France Presse article datelined August 22, 1979, published the same day in the evening edition of Cronica:

A third unidentified metallic object fell on Santa Cruz and, it was reported, gave rise to a variety of interpretations. The fall of this third object from the sky led to further discussions between its potential owners because the ownership of the land where it fell is disputed.

Additional information appears in the United Press (UP) article datelined La Paz, August 24, 1979, published the next day by La Prensa:

Another mysterious sphere, this time of just 10 centimeters in diameter, was found in the area where peasants discovered two other much larger ones a few days ago, press sources reported today.

Newspapers of Santa Cruz, city of 300,000 inhabitants, about 900 kilometers southeast of La Paz, said the third sphere found in less than ten days, on the outskirts of the provincial capital, can fit in the palm of your hand.

It is tightly sealed and a kind of screw appears to be its only opening, according to photographs published by newspapers in Santa Cruz.

The small sphere was x-rayed and its internal structure appears to contain a liquid heavier than water and lighter than mercury, media reports said, which added that the material of the third device appears to be plastic fiber, of unusual hardness.

Whether this sphere was related to the first two is impossible to assess without precise information on its construction, contents, mass and diameter, also the location where it was discovered. It would also be important to know whether Delta DSV-3P-4 second stages contained such a sphere, given the strong circumstantial evidence that the two large spheres belonged to a stage of that model.

The need for caution regarding the relevance of the third sphere is made clear by the following report on the effect of the discovery of the second one on the city of Santa Cruz de la Sierra, which appeared in the Associated Press (AP) article datelined August 21, 1979:

The appearance of a second object has created a state of psychosis in this city of 300,000 inhabitants, the second in Bolivia. Radio stations and newspapers are constantly receiving phone calls from people who say that they have seen "spheres".

2.2.7 Non-Mysteries

According to the second Moon Dust telex, El Diario commented on what seemed to be mysterious aspects of the spheres:

The mystery of finding these two spheres, exactly alike, is that according to the witnesses they were fire balls. That is to say that these spheres became real balls of fire when they entered the atmosphere because of the friction and after high speed fall they hit the ground. However, in the area where they've been found, there were no signs of the impact and looks as though the spheres landed smoothly.
The non-intuitive reality is that objects can and do survive the heat of re-entry and high-speed impact of the Earth. Prime examples are the numerous titanium pressurant spheres - essential components of rocket and satellite propulsion systems - that have been found largely intact, which match the general description of the Bolivian spheres. This is not common knowledge even today, but is readily discoverable on the web, for example, at the Center for Orbital and Reentry Debris Studies (COORDS) and on Paul Maley's Space Debris Page - resources that did not exist in 1979.

El Diario mentioned that the discoverer of the north sphere, Mr. Gonzalo Menacho Viveras, saw an aircraft:

He said that the next evening a silent aircraft that had three lights was flying over the explosion area.
There were too few details to judge its relevance to the spheres. Flying aircraft are ubiquitous. They are not always audible. They may have multiple lights. There was no further mention in the El Diario report, and none at all in the other two known newspaper reports that covered the second sphere.

2.3 Reports by Luis Ruiz Nóguez

Mexican engineer and skeptic, Luis Ruiz Nóguez, has presented several reports on fallen rocket and spacecraft pressurant spheres, and he has long recognized that the two that fell in Bolivia in August 1979 were of this class. A slide presentation he made in 2003 includes a photograph of the south sphere (at 9m8s), reproduced below. The caption states that the photo appeared in Presencia, a major Bolivian newspaper. It also appears in the recently discovered Associated Press (AP) article datelined August 17, 1979. Standing behind the sphere are its discoverer, Benigno Roca, with his wife and granddaughter. This photograph is the best evidence of the size of the spheres; the analysis is in Section 3.1.

[Roca Family with South Sphere.]
Fig. 1.  Roca family with south sphere.

Mr. Nóguez has also reported that the spheres were sent to the U.S. embassy in La Paz, which he attributed to United Press, dateline La Paz, August 23, 1979.

2.4 Fireball Sighting Reports

2.4.1 Fireball Sighting from Chile

In August 2014, subsequent to the initial publication of this report, evidence was discovered of a sighting of the re-entry fireball of 1979-072B from a location in Chile, 600 km west of the sites of the Bolivian spheres. In the hamlet of Caquena, in the northern region of Arica y Parinacota, more than one hundred military personnel observed a phenomenon consistent with a re-entry fireball, that correlates temporally and spatially with the estimated re-entry trajectory of 1979-072B. This little-known UFO case is the first apparent fireball sighting of 1979-072B sufficiently detailed to provide a meaningful test of the re-entry hypothesis.

The earliest reference found to-date is on the CD-ROM Informe OVNI - Enciclopedia Interactiva, a large compendium of UFO sightings from antiquity to the late twentieth century, authored by Enrique De Vicente, published in 1996 by Realidad Alternativa Ltd. The Caquena sighting appears in the CD-ROM's South American database case file, SUDAMERI.DBF, without attribution:

FECHA: 10 Agosto 1979
HORA: 2:30
LOCALIDAD: Caquena, Arica
PAIS: Chile
CASO: Más de un centenar de militares vieron una gran luz de forma ovalada que se desplazaba de norte a este a una velocidad constante y siguiendo una trayectoria recta. Justo detrás de ese objeto iban otras siete naves más pequeñas de colores azul y rojo. La observación duró 20 ó 30 segundos.

Accurate English translation provided by Allen and Zaida Thomson:

DATE: August 10, 1979
TIME: 2:30
LOCATION: Caquena, Arica
COUNTRY: Chile
CASE: More than 100 military personnel saw a big light of oval form that moved from north to east at a constant velocity and followed a straight trajectory. Just behind that object went another seven smaller ships/craft/vessels of red and blue colors. The sighting lasted 20 or 30 seconds.

A similar, but more detailed report on the incident is MUFON Case #49574, submitted on 2013 August 7, by a witness whose identity has not been disclosed. The reported time of the sighting was 1979 August 10 at 2:30 AM (06:30 UTC). The short description was "Big yellow light followed by 7 Lights blue and red colors". MUFON's questions and the witness's responses are available here. The key testimony is summarized below:

  • "[seen] for 20 seconds before it was lost"
  • "saw a very large light yellow oval 2400 feet long by 600 feet high moving from the north to the northeast without noise"
  • trailed by 7 smaller blue and red lights, also without noise
  • "I was about 8-10 kilometers away"
  • witness coordinates: -18.053844 LAT, -69.201639 LON, 4400 m ASL
  • "the objects followed a straight path and got lost in the mountains to the East"
  • If you have additional information on the Caquena incident or know where it can be found, please contact me.

    The description of the phenomenon: a bright light followed by a number of dimmer lights, moving on a straight trajectory, passing in silence, is typical of either a meteoritic or re-entry fireball. The reported time of the sighting, 06:30 UTC, and motion from the north or northeast toward the east, agrees closely with the estimated re-entry trajectory of 1979-072B from the vantage of Caquena, presented in Section 5.4.

    3. Prime Suspect is Re-entry of 1979-072B

    The reports on the fireball sightings and subsequent sphere discoveries contain the following evidence that may be relevant to deciding whether they resulted from a re-entry and correlating them with a specific object:

  • spheres fell in Bolivia on 1979 August 10 (2.2.1
  • south sphere fell near Enconada (2.2.2)
  • north sphere fell near Buen Retiro (2.2.3)
  • identical metallic spheres (2.2.4)
  • diameter of south sphere 0.6 m - 0.8 m dia. 2.2.4)
  • thickness of south sphere wall "approx one-half inch" 2.2.4)
  • mass of south sphere reported as 6,800 g (6.8 kg) (2.2.4)
  • construction of north sphere described as "made by two pieces put together without any rivets" (2.2.4)
  • both showed signs of exposure to extreme heat (melted portions, charred, areas of burn-through, discolouration) (2.2.4)
  • Buen Retiro, Bolivia fireball sighting about 12:30 AM local time (04:30 UTC) (2.2.5)
  • Caquena, Chile fireball sighting about 2:30 AM local time (06:30 UTC) (2.4.1)
  • The existence of reports of fireball sightings is consistent with a re-entry or meteor. The Bolivian reports are insufficiently detailed for analysis, but the Chilean ones include useful descriptions of the fireball's appearance and its track across the sky.

    The two spheres found in Bolivia were by far the strongest evidence, since they were seen either personally or in photos by officials of the Bolivian Air Force and the U.S. embassy, and by newspaper and radio reporters.

    USSTRATCOM's satellite catalogue lists a re-entry on 1979 August 10 UTC that appears to correlate with the fireball sightings and the spheres: 1979-072B / 11490, the second stage of Delta 149, that launched Westar 3 on the same day. This was a Delta 2914 model, which employed the DSV-3P-4 second stage. It contained two helium pressurant spheres, made of titanium, similar in size to the pair that fell in Bolivia, but probably considerably more massive than the reported 6.8 kg. The standard construction is two hemispheres welded together at their equator, consistent with the description of the north sphere. The spheres of some earlier and later Delta second stages are known to have survived re-entry and been recovered; the Bolivian spheres showed signs of exposure to extreme heat.

    The relative locations of the Bolivian spheres are consistent with the ground track of an orbit of low inclination, like that of 1979-072B. The orbit of 1979-072B passed very close to both sphere locations in the early hours of 1979 August 10 UTC, close to the time of the Caquena, Chile sighting, but a couple of hours later than the Buen Retiro, Bolivia sighting time.

    The evidence is examined more closely in the following sub-sections.

    3.1 Number and Size of Spheres Consistent with a Delta 2nd Stage

    An archived copy of Aerospace Corporation's list of recovered space debris, includes the following helium pressurant spheres from two models of Delta second stage:

          Table 1: Recovered Delta 2nd Stage Helium Spheres
    Delta                    Dia   Mass
    Launch  Stage 2 Model     m     kg      Found    Num  Location
     043    DSV-3E-3         0.58   15.8   Jan 1967   1   Peru
     050    DSV-3E-3         0.6           Jul 1967   1   Saudi Arabia
     051    DSV-3E-3         0.6    29     Apr 1968   1   Australia
     235    SSPS AJ10-118K   0.60   30.6   Jan 1997   1   Texas
     234    SSPS AJ10-118K   0.58   32     Apr 2000   1   South Africa
     299    SSPS AJ10-118K  ~0.5   ~30     Jul 2004   1   Brazil
     344    SSPS AJ10-118K   0.6    30     Feb 2010   2   Mongolia
    
    The typical diameter was about 0.6 m. 1979-072B was a different model - the DSV-3P-4 - but its helium spheres were about the same size. According to the 1989 NASA/GSFC paper, Current Operational Practice for the Delta Second Stage (A. A. Gray Jr.), the Delta 3910 stage (which was the model DSV-3P-4), stored its helium in "two-24-in. titanium spheres at 4350 psi (design burst, 5500 psi)". That is almost exactly 0.61 m diameter. If that was the inside diameter, and assuming a mass of 30 kg, then at the density of the Ti-6Al-4V alloy commonly used in this application (4.43 g/cm3), the tank wall would have been 5.7 mm thick, and the outside diameter would have been just over 0.62 m. The diameter can also be scaled from drawings, like the one in Figure 1 of the above-referenced paper, which also yields a value of about 0.62 m, roughly the same as those in the table, and a close match to the reported size of those that fell in Bolivia.

    The Moon Dust telexes stated or implied various estimates of the sphere diameter, ranging between about 64 cm and 80 cm, none of which were accompanied by estimates of their precision. One estimate of the south sphere size was "about 70 centimeters in diameter and two meters in circumference". The most reliable way to determine the diameter of a sphere is to calculate it from its measured circumference; two metres implies a diameter of about 64 cm. But it is not known whether the circumference was measured or merely estimated from the diameter. The only report of the size of the north sphere, about 80 cm, probably was a misapplied estimate of the south sphere, as discussed in Section 2.2.4.

    The best currently available evidence of the size of the south sphere is the photo in Section 2.3, reproduced below. Its diameter can be estimated by scaling with respect to the length of Mrs. Roca's out-stretched arm. The Bolivian adult female mean height is 142 cm. Standard deviation is 6.9 cm. The standard human arm to height ratio is 0.44. Therefore, the length of Mrs. Roca's arm is 62 cm +/- 9 cm (3 sigma). The diameter of the sphere appears to be about the same as the length of her arm (red lines on photo below); therefore, probably close to 62 cm, similar to the size reported in the Moon Dust telex of August 17.

    [Comparable dimensions of the south sphere.]
    Fig. 2.  Comparable dimensions of the south sphere.

    The telex also noted the presence of "a hole (missing portion of outer skin) which is about nine inches in diameter", which may be the black, comma-shaped area on the right side of the sphere, that appears to be an area of burn-through. Its largest dimension (yellow line on above photo) is about 35 percent the diameter of the sphere. Assuming sphere diameter of 62 cm, the hole is roughly 22 cm (8.5 in.) across, in reasonable agreement with the telexed report.

    3.2 Reported Sphere Mass Is Erroneous

    Section 2.2.4 concluded that the only sphere mass known to have been reported was that of the south sphere, found in the Associated Press (AP) article datelined August 17, 1979:

    The material seemed to be an aluminum or iron alloy, about 6,800 grams and a diameter of 80 centimeters.
    Also noted in Section 2.2.4 was the wall thickness of "approx one-half inch" (possibly one-half centimetre), reported by Col. Hamilton's informant. An aluminum or iron sphere of those dimensions would have far exceeded the reported mass of 6.8 kg. Below are examples based on the more realistic diameter of 62 cm, determined in the previous section. Even a one-half centimetre beryllium wall would have exceeded the reported mass by 60 percent. Given the inconsistency between mass and dimensions, the most reasonable conclusion is that the reported 6.8 kg is erroneous.

    Density 0.5 in. 0.5 cm
    Material

    g/cm3

     kg

    kg

    Beryllium

    1.86

     27

    11

    Aluminum

    2.70

     40

    16

    Titanium

    4.43

     65

    26

    Iron

    7.87

    116

    47

    An intriguing speculation is that the reported mass of "6,800 grams" might have been the volume of the sphere's metal wall in cubic centimetres, garbled in the reporting as its mass. The statement appears in a section of the above news report that quotes the commander of the Bolivian Air Force Academy, which had taken custody of the sphere. The report also claimed that, "the high command of the Air Force received a detailed report of the circumstances in which the sphere was found and its possible composition."

    One method to gain information on its composition would have been to measure its density, which would have involved measuring the mass and volume of its wall. Dividing mass by volume yields density. Mass would have been straightforward to measure using a scale. Since the object had a regular shape, its volume could easily have been estimated with sufficient accuracy by multiplying its surface area by its thickness. Alternatively, it could have been measured using the water displacement method. The existence of the sphere came to light on August 16 and was made public by the Bolivian Air Force the following day. There was sufficient time in the interim to have performed this simple test.

    If the volume of the sphere wall was 6,800 cm3, then at the density of the Ti-6Al-4V alloy commonly used in this application (4.43 g/cm3), its mass was 30.1 kg, which falls within the range of the few recovered Delta second stage helium spheres listed in Table 1, most of which were between 29 kg and 32 kg. Comparable spheres of other rockets would have been of similar mass. For example, in NASA SP-8088: Space Vehicle Design Criteria (Chemical Propulsion), Table II lists Atlas and Centaur propulsion system helium spheres made of 6Al-4V, almost identical in size and design pressure to those of the DSV-3P-4, with masses of 65 lbm (29 kg) and 79 lbm (36 kg), respectively.

    All that can be stated with confidence is that the reported mass of 6.8 kg was erroneous. The only way to be certain of the mass of the spheres is to locate them or authoritative reports about them.

    3.3 Sphere Locations Imply Low Inclination Orbit

    Figure 3 (below) shows the approximate locations where the spheres were discovered.

    [Approximate Sphere Discovery Locations]
    Fig. 3.  Approximate sphere discovery locations

    The south sphere was the first to be reported. As discussed in Section 2.2.2, the best evidence is that it was found on a farm near Enconada.

    The north sphere was the second to be reported. It was found on the farm of Juan Saavedra, "in the area of Buen Retiro near the Yapacani River." The author's guess of the approximate location is depicted in Figure 3 by the green rectangle. The Rio Yapacani forms the western boundary of a region that extends somewhat east of Buen Retiro and to its north and south. Knowing the location of the Juan Saavedra farm could help to greatly narrow the size of this zone. Web searches were unsuccessful, but off-line records may exist in Bolivia.

    Re-entry debris that survives to reach the surface of the Earth falls into a zone commonly called the debris footprint, that closely parallels the ground track of the parent object. Typically, the footprints are hundreds of kilometres long, but only about 30 km wide. The densest debris falls well within about 10 km to either side of the ground track. How far, and on which side, depends on the wind speed and direction and the ballistic coefficient of the debris. The narrowness of footprints compared to their length is a useful property, that enables the trajectory of parent objects to be deduced from the locations of their debris on the ground.

    The locations of the Bolivian spheres are not precisely known, but they are sufficiently far apart - about 100 km - to significantly narrow down the probable trajectory of their parent object. It could not have passed between the two locations, whether travelling north to south or south to north, because the footprint required to encompass both spheres would have been impossibly wide. The parent must have travelled on a roughly NW to SE track that passed through or parallel to both zones in Figure 3. (Theoretically, it could have travelled in the reverse direction, SE to NW, but few satellites have been launched into such extremely retrograde orbits.)

    The inclination can be roughly estimated from the azimuth pointing from the centre of the region of the north sphere (17.31 S, 63.75 W) toward that of the south sphere (17.732 S, 62.935 W), which is about 119 deg. That yields an inclination of about 33° [cos-1(sin(119) * cos(-17.31)], but with a large uncertainty, say, +/- 15°, given the uncertainty of the sphere locations, especially the north sphere.

    The second stage of Delta 149 re-entered from a 31.47° inclination orbit, which falls within the range that could potentially account for both spheres. That it is known to have carried two spheres of the approximate size found in Bolivia, strengthens the circumstantial case that it was the source of the spheres. But it is necessary to determine whether it could have re-entered on a trajectory that passed close to both spheres at about the reported time, which is addressed in Sections 4 and 5.

    3.4 Time of Chilean Sighting Correlates With 1979-072B

    Normally, it would be easy to check whether 1979-072B passed over the area at the time of the sightings, by generating an ephemeris from its orbital elements; however, there is no official record of its complete orbital elements. Fortunately, there have been other Delta launches into similar orbits, which can serve as proxies for 1979-072B. They reveal that the orbit passed very close to the debris locations about 6 hours and 25 minutes after launch, which in the case of 1979-072B would have been 2:45 AM local time, 06:45 UTC.

    Both Caquena, Chile sighting reports agree on 2:30 AM local time, 06:30 UTC, reasonably close to the time of passage of 1979-072B (2.4.1). The single reported Bolvian sighting time is two hours earlier. Section 2.2.5 quotes El Diario, which reported that Mr. Gonzalo Menacho Viveras, who discovered the second sphere near Buen Retiro, Bolivia, reported seeing a fireball and hearing a whistle and an explosion at 12:30 AM local time, 04:30 UTC. El Diario described the time as "early in the morning" and reported that the sphere was found after dawn. The Associated Press did not mention the fireball, but reported the audible phenomena, which it placed at dawn, followed hours later by the discovery of the sphere. The sun rose at 6:36 AM. The Chilean and Bolvian times cannot both be correct; neither one may be correct.

    This discrepancy would be easy to resolve if there were a reasonable number of observations clustered closely together in time. Absent that, some weight should be given to the Caquena sighting report because it describes strong characteristics of a re-entry, as well as correlating temporally and spatially with 1979-072B. In contrast, there is little known of Mr. Viveras' sighting beyond the claim that it happened and the time.

    Large outliers are not unusual, and can occur for many reasons. Mr. Viveras reported his sighting one week after the fact, long enough to forget the exact time. The time could have become garbled as the story passed verbally from one person to another. For example, in Spanish, 12:30 is doce y media and 2:30 is dos y media. They are pronounced almost alike (dohseh ee media vs dohs ee media), so could easily be mistaken one for the other. Without corroboration, this single-source discrepancy does not deserve much weight.

    The evidence that 1979-072B passed close to the area at the same general time of day as the sightings, i.e. in the first few hours after midnight local time, is sufficient to proceed with a detailed orbital analysis.

    4. Estimated Orbital Elements of 1979-072B

    The orbital analysis of 1979-072B / 11490 was complicated by the lack of any complete orbital element sets from official sources. Fortunately, partial element sets have been published by USSTRATCOM, NASA-NSSDC, and The RAE Table of Earth Satellites, 1957-1980, that could be used to reconstruct the orbital elements and estimate the decay trajectory. The data from these sources are summarized below:

    Table 2: Partial Elements of 1979-072B
    Source

    Epoch

    Perigee Apogee

    a

    Period

    i

    e

    ω

    Author's Comments

    yyddd.d

    km

    km

    km

    min.

    type

    deg

    -

    deg
    USSTRATCOM   198 230   88.8 apsidal 28.7     Probably the parking orbit.
    NASA - NSSDC   129.9 238.7   88.2 apsidal 31.5 0.00828   Apparent result of a final, experimental burn.
    RAE Table of Earth Satellites 79222.1 130 239 6562 88.18 apsidal 31.47 0.008 294 Same as above.

    4.1 Parking Orbit

    USSTRATCOM's partial elements appear to be of the parking orbit. Whether they are actual values or pre-launch estimates is unknown. Those elements provided the basis to estimate the inclination, mean motion and eccentricity of the following TLE (two-line elements), based on knowledge of the relationship between USSTRATCOM's partial elements and the TLEs from which they are normally derived.

    00:44:30 UTC                                             201 X 237 km
    1 70001U          79222.03090280  .02000000  00000-0  76279-3 0    01
    2 70001  28.7000 142.3390 0027100 359.0484 179.9262 16.21865000    07
    
    The argument of perigee derives from the initial elements of a similar Delta 2914 launch (1977-029B / 9932). The RAAN, epoch and mean anomaly are as required for the orbit to intersect with that of the third stage of Westar 3 (1979-072C / 13940) immediately before its GTO burn. Elset #10 (epoch 79236.71983477) was chosen for the intersection, because it appeared to have been based on an observational span of sufficient duration to have yielded accurate elements, but not so long after the manoeuvre to have introduced errors due to unmodelled variations in the rate of decay. The result is believed to be accurate in plane (RAAN) to about 1°, and along-track (time) to about 1 min. The decay term is arbitrary, but typical of similar Delta 2nd stages in similar orbits, sufficiently accurate for the ~56 min. spent in this orbit.

    4.2 Final Orbit

    The partial elements reported by NASA-NSSDC and the RAE Table of Earth Satellites are nearly identical to each other, and appear to be the result of an experimental burn conducted after the second stage had separated from the third stage and payload. Whether they are actual values or pre-launch estimates is unknown.

    Experimental test firings of the 2nd stage were performed on many Delta launches of the 1970s and early 1980s. On GTO launches, they typically occurred either immediately after the GTO burn, within range of Ascension Island, or 78-82 min. after launch, within range of Hawaii. The epoch, and especially the argument of perigee, of 1979-072B's partial elements (Table 2, RAE version only), constrain its experimental burn to the latter variety.

    The estimated final TLE intersects with that of the parking orbit at the estimated time of the burn, 1979 August 10 at 01:40:00 UTC (80 min. after launch). It was obtained by propagating the parking orbit TLE to that time, and changing the inclination, argument of perigee and mean motion to match the partial elements. There was some question regarding the type of mean motion. NSSDC was silent on the matter; RAE stated that the period was nodal; however, it clearly was apsidal based on the stated semi-major axis and perigee and apogee heights.

    01:40:00 UTC                                             128 X 249 km
    1 70002U          79222.06944445  .00000000  00000-0  00000-0 0    00
    2 70002  31.4700 147.1010 0092000 294.0000 105.3750 16.33073365    04
    
    RAAN, eccentricity and mean anomaly are as required for the orbits to intersect. The manoeuvre produced a plane change (3.75°) and did not occur at a node; therefore, both the inclination and RAAN changed. The eccentricity is a bit greater than that of the partial elements; however, the resulting perigee and apogee heights with respect to the geoid are fairly close to the values of the partial elements. It is not unusual for perigee and apogee to be stated on that basis, so the proposed TLE value may not be unrealistic.

    The delta-V of the experimental burn is estimated to have been 513 m/s. If it was a burn to depletion, then the final second stage mass would have been approximately 950 kg. Given its TRW TR-201 engine's Isp of 302 s and thrust of 42.9 kN, approximately 180 kg of fuel and oxidizer would have been consumed during a burn of about 12.4 s. If 100 kg of unspent propellant remained, then the corresponding values would have been 199 kg and 13.7 s. Experimental burn durations in excess of 10 s were common.

    The above TLE confirms that about 5 hours after its final manoeuvre, 1979-072B would have passed close to both areas in Bolivia where spheres were found. The proximity is sufficiently close to proceed with the orbital decay analysis, to determine whether it continued on past Bolivia, or could have made its final descent there.

    5. Orbital Decay Analysis of 1979-072B

    Whether 1979-072B could have re-entered over Bolivia just over five hours after it entered its final orbit, depends on its area to mass ratio (A/m), coefficient of drag (Cd), and the atmospheric density it encountered, none of which can be precisely known, but can be estimated. This question has been addressed as follows. To provide a basis for comparison, the A/m of typical Delta DSV-3P-4 second stages has been determined from their physical properties and by analysis of the ballistics of a sample of stages that have been in orbit. Finally, the A/m required for 1979-072B to have re-entered at the time and place in question was estimated and compared with this data.

    5.1 Area to Mass Ratio

    The area to mass ratio (A/m) of the Delta DSV-3P-4 second stage has been determined from its physical properties and by analysis of the ballistics of a sample of stages that have been in orbit.

    5.1.1 A/m Based on Physical Properties

    The Delta DSV-3P-4 second stage was about 6.2 m long overall, including the engine bell. Its main body was 1.52 m in diameter and about 4.3 m long. The combustion chamber and engine bell were significantly narrower. Suspended from a truss attached near the near top of the stage, was a 0.28 m wide "mini-skirt", which extended the diameter to 2.44 m, as shown in the drawing below (extracted from Fig. 2-15 of an unrelated technical report available from NASA):

    Delta 2nd Stage Model DSV-3P-4
    Fig. 4.  Delta 2nd Stage Model DSV-3P-4

    When oriented with the end facing the direction of motion, the drag area was about 4 m2. When oriented with the side facing the direction of motion, the drag area was about 8.3 m2. When oriented with the long axis pointing in the direction of motion and rotating about its transverse axis, i.e. tumbling end over end, the mean drag area was about 7.0 m2. The mean of the latter two values, about 7.7 m2, is a reasonable value for drag estimates.

    The mass of a typical spent stage would not have been much less than 950 kg. This consists of the 823 kg dry stage, the 97 kg spin table present on most launches, and an allowance for trapped propellants and unused pressurant.

    Based on the above extremes of drag area and the minimum mass, the A/m could have ranged between 0.0042 m2/kg and 0.0087 m2/kg. The mean area for drag (7.7 m2) yields mean A/m of 0.0081 m2/kg. For stages that retained unspent propellant, these values would be too high.

    Depletion burns were not yet standard practice; however, experimental burns were conducted on many missions to obtain engineering data. These varied in duration from 1 s to more than 15 s; some went to depletion. Many stages retained significant unspent propellant - in some cases hundreds of kilograms - while others were nearly dry. Precise information on remaining fuel mass is not readily available. Insight into the actual range of A/m was gained through empirical data estimated from propagation analyses.

    5.1.2 Empirical A/m

    The area to mass ratio (A/m) of 25 Delta DSV-3P-4 second stages has been estimated using GMAT R2013a (General Mission Analysis Tool), "developed by a team of NASA, private industry, public, and private contributors".

    The analysis was performed using GMAT's Dormand-Prince 78 numerical integrator, with a four degree, four order gravity field, and the MSISE90 atmosphere model, with actual space weather data entered manually. Orbital elements in TLE format were converted for GMAT propagation using TLE Analyzer 2.11.

    To maximize comparability with 1979-072B, the analysis was limited to flights that were known or almost certain to have carried a spin table. For the same reason, the analysis spanned the few days prior to re-entry. The coefficient of drag (Cd) was assumed to have been 2.2. GMAT was used to propagate the orbit of one TLE to the epoch of a later TLE. Typical spans were 2 to 3 days. The A/m was adjusted by trial and error to obtain the closest match between predicted and actual perigee and apogee height above the geoid of the later TLE. The results are summarized below:

                                                Final Burn Orbit  Exp Burns
                                                Per    Apo   Inc    Total      A/m
     Mission     Cospar      SSN    Re-entry    km     km    deg      s       m2/kg
    Delta  92   1972-090B    6279	07-May-73   203   1678   28.6    Dep     9.36E-03
    Delta  94   1973-023B    6438   18-Oct-75   215   2783   29.5     14     8.95E-03
    Delta 101   1974-022B    7251   25-May-74   227    454   28.6      1     9.03E-03
    Delta 103   1974-075B    7467   23-Dec-78   230   3454   27.3    Dep     9.33E-03
    Delta 105   1974-094D    7550   23-Nov-74   311   3341   28.2    ~12     8.79E-03
    Delta 108   1975-011B    7650   06-Feb-75   277   3241   27.6     16     1.05E-02
    Delta 110   1975-038B    7791   07-May-75   220   2185   28.4     15     1.04E-02
    Delta 112   1975-057B    7971   21-Jun-75   541    555   32.9      0     4.87E-03
    Delta 114   1975-077B    8133   14-Jul-13   407   2016   25.3    Dep     1.02E-02
    Delta 116   1975-100B    8367   16-Oct-75   187    930   28.3     ~5     6.53E-03
    Delta 118   1975-117B    8478   13-Dec-75   190   1880   28.4      0     7.83E-03
    Delta 119   1976-004B    8586   17-Jan-76   177    547   28.6      0     6.75E-03
    Delta 120   1976-017B    8698   19-Feb-76   178    542   28.5     ~2     7.19E-03
    Delta 121   1976-029B    8775   26-Mar-76   191   1966   28.4      0     5.80E-03
    Delta 122   1976-035B    8809   22-Apr-76   179    717   28.2      0     5.96E-03
    Delta 124   1976-053B    8883   10-Jun-76   273    643   28.5      1     7.63E-03
    Delta 127   1976-101B    9479   14-Oct-76   182    618   28.6      1     5.95E-03
    Delta 135   1977-102C   10424   22-Oct-77   277    840   28.7      0     4.90E-03
    Delta 138   1978-012B   10638   26-Jan-78   164   1024   28.7      0     6.35E-03
    Delta 143   1978-071B   10982   14-Jul-78   165   3543   28.1    ~19     6.43E-03
    Delta 146   1978-106B   11116   19-Nov-78   174    732   28.2      0     8.10E-03
    Delta 147   1978-116B   11154   16-Dec-78   183   2069   28.3      0     6.43E-03
    Delta 148   1979-007B   11258   30-Jan-79   189    869   28.6      0     7.00E-03
    Delta 152   1980-074B   11965   09-Sep-80   164   2559   28.1      0     4.60E-03
    Delta 155   1981-070C   12626   23-Nov-88   377    959   90.0     ~2     7.10E-03
                                                                       Min   4.60E-03
                                                                       Max   1.05E-02
                                                                    Median   7.10E-03
                                                                      Mean   7.44E-03
                                                                 Std. Dev.   1.75E-03
    
    The results are in reasonable agreement with the values estimated earlier from the physical properties of Delta DSV-3P-4 second stages, but with the considerable variance inherent in this type of analysis. The assumed value of coefficient of drag (Cd) and modelled atmospheric density can easily be off by 10 to 20 percent. Errors of even a few kilometres in the perigee height derived from the source TLEs would strongly affect the estimated atmospheric density, to which the derived A/m is inversely proportional. The object's drag area depended on its orientation, which was unknown. The aforementioned uncertainty in mass is a significant factor.

    The stages which performed experimental burns might be expected to have been lighter than those that did not. In the hope of gaining insight into their possible influence on the above results, the total duration of any experimental burns has been included under column Exp Burns. The information has been compiled from information shared by Jonathan McDowell, augmented by various other sources. Estimated durations are my mine. Any errors or misunderstandings are my fault. Burns to depletion are denoted by "Dep". Zero values indicate that an experimental burn did not occur. Visual inspection suggests that stages that performed the longest experimental burns, or that burned to depletion, tended to have somewhat greater A/m than those not known to have done so. That may seem to validate intuition; however, there is considerable overlap between the two groups, with missions 101, 143 and 146 among the more extreme examples. The concept appears to have merit, but probably should not be given too much weight.

    The final step in the analysis was to use GMAT to estimate the A/m required for 1979-072B to have re-entered at the time and place in question, and compare it with the above data.

    5.2 Estimated A/m of 1979-072B

    An area to mass ratio (A/m) of 0.0114 m2/kg, with assumed coefficient of drag (Cd) of 2.2, was found to be sufficient for GMAT to propagate the estimated final orbit of 1979-072B to re-entry over Bolivia on 1979 August 10, with passage closest to the sphere locations shortly after 06:45 UTC. The A/m is just outside the range of the values of 25 other Delta DSV-3P-4 second stages determined using GMAT (0.0046 - 0.0105 m2/kg), but within 2.3 standard deviations of the mean (0.00744 m2/kg).

    The A/m required for re-entry to occur within a given time from epoch is inversely proportional to atmospheric density, which is highly sensitive to perigee height, which for 1979-072B is uncertain by at least several kilometres. The atmospheric density scale height (H) near the estimated perigee altitude (~128 km above geoid), probably was between 10 km and 15 km; assume H = 13 km for discussion. Had the perigee height been 3 km lower, the atmospheric density would have been a factor of approximately 1.26 greater, and the required A/m would have decreased to 0.00905 m2/kg, comfortably within the range of the empirical data. Had the perigee been 3 km higher, the atmospheric density would have been a factor of approximately 0.794 lower, and the required A/m would have increased to 0.0144 m2/kg, far outside the range of the empirical data, about 4 sigma from the mean.

    This analysis shows that 1979-072B could very well have re-entered over Bolivia in the early hours of August 10, but not to a certainty. When considered in the context of the other evidence - reports of fireball sightings, and the recovery of spheres with signs of exposure to extreme heat, consistent in number and size with those carried by 1979-072B - the circumstantial case points strongly to the re-entry of 1979-072B as the cause.

    5.3 Re-entry Passed Close to Sphere Locations

    The GMAT-propagated re-entry fireball would have passed close to both areas where sightings were reported and spheres fell, shortly after 06:45 UTC (2:45 AM local time), moving from NW to SE, depicted by the line in Figure 5, below. The alternating red and white segments span 10 seconds of flight. The significantly shorter length of successive segments is due to the rapid deceleration at this late stage of the re-entry. The end of the line corresponds to the toe of the debris footprint, which lay about 45 km to the southeast of the area of the south sphere, near 17.83 S, 62.52 W. It is where surviving fragments greatest in areal density would have fallen.

    [Approximate re-entry track of 1979-072B]
    Fig. 5.  Approximate re-entry track of 1979-072B relative fireball sighting and sphere locations.

    The estimated track is slightly east of both sighting/debris zones - excellent agreement, given the uncertainty in the sphere locations and in the orbital elements. Delaying the pass about one minute or moving the orbital plane west about 0.2° would shift the track close to Enconada and the centre of the zone around Buen Retiro, within the margin of uncertainty of the estimated orbital elements.

    Depending on the wind direction and speed, the spheres could have landed up to about 10 km either side of the ground track. The prevailing winds in this region blow toward the northwest, more or less opposite the bearing of the re-entry trajectory; therefore, the spheres may have fallen more or less on the re-entry ground track.

    As a matter of interest, a global perspective on 1979-072B's few hours in space is provided in Figure 6, which depicts its estimated ground track from final manoeuvre to re-entry.

    [Estimated ground track of 1979-072B from final manoeuvre to re-entry]
    Fig. 6.  Estimated ground track of 1979-072B from final manoeuvre (M) to re-entry (R).

    5.4 Re-entry Strongly Correlates with Chilean Sighting

    The sighting reports from Caquena, Chile are documented in Section 2.4.1. The description of the phenomenon: a bright light followed by a number of dimmer lights, moving on a straight trajectory, passing in silence, is typical of either a meteoritic or re-entry fireball. The reported time of the sighting, 06:30 UTC, and motion from the north or northeast toward the east, agrees closely with the GMAT-estimated re-entry trajectory of 1979-072B from the vantage of Caquena:

    06:42:20 NNW rose above local terrain
    06:44:00 NNE culminated at 12 deg elevation
    06:44:50 ENE set below local terrain

    The time and duration of unexpected events typically are reconstructed after the fact, which tends to reduce accuracy, and may have been a contributing factor to the discrepancies in this case. The 13-15 min. difference between observed and predicted time of the event is well within the typical range of reporting error, which can exceed one hour. The fireball was predicted to be above the horizon for 2m30s - much longer than the reported 20-30 s duration of the sighting; however, the MUFON witness reportedly began observing only after having been alerted by others, so probably missed some portion of the event.

    Considered together, the appearance, trajectory and time of the Caquena, Chile sighting correlate sufficiently with the re-entry of 1979-072B to identify it as the probable cause.

    The Bolivian fireball sightings were impossible to evaluate due to the lack of any descriptions of their appearance, path across the sky and/or direction of travel relative the ground. The Caquena, Chile sighting is the first evidence that a fireball actually was seen at about the predicted time, on about the predicted trajectory of 1979-072B, which increases confidence in the already strong circumstantial case.

    The following ground-level views from Caquena have been generated using a Google Earth kml file containing the GMAT-estimated re-entry trajectory of 1979-072B over South America. (It could also be used to evaluate any other suspected South American sightings that may come to light.)

    Figure 7 (below) depicts the re-entry trajectory rising above mountains in the NNW (azimuth 326 deg) at 06:42:20 UTC. The fireball was 90 km above the Earth and 849 km from Caquena. The alternating red and white segments each span 10 seconds of time.

    [1979-072B rises over Chile]
    Fig. 7.  1979-072B rises above horizon of Caquena, Chile.

    Figure 8 (below) depicts the re-entry trajectory at culmination, 12 deg above the NNE horizon (azimuth 22 deg) at 06:44:00 UTC. The fireball had descended below 80 km altitude, near where the main breakup of re-entering objects typically occurs (78 km +/- 5 km), consistent with the report of multiple lights, which were fragments of the disintegrating rocket stage.

    [1979-072B culminates over Chile]
    Fig. 8.  1979-072B culminates 12 degrees above horizon of Caquena, Chile.

    At culmination, the fireball was at its closest approach to Caquena, a distance of about 378 km - far greater than the 8-10 km reported by MUFON's witness, and a good example of the common tendency to severely under-estimate the distance of unknown lights in a dark sky. At the perceived distance, the reported length of the UFO, 2400 ft. (730 m), subtended 4-5 deg of arc. Projecting this to the actual minimum distance of 378 km, yields an estimated minimum true length of about 30 km, typical for a re-entry fireball. The trail of bright fragments probably extended several tens of kilometres behind the fireball.

    Figure 9 (below) depicts the re-entry trajectory setting behind mountains about 8 deg above the horizon in the ENE (azimuth 66 deg) at 06:44:50 UTC. The fireball was 71 km above the Earth and 459 km from Caquena. This is in excellent agreement with the MUFON witness's response to question #6, regarding the circumstances of the end of the sighting: "got lost in the mountains to the East". Those mountains are just over 8 km from Caquena. If this was known to the witness, then seeing the UFO disappear behind them may have influenced the estimate that it was 8-10 km distant.

    [1979-072B sets below mountains]
    Fig. 9.  1979-072B sets behind mountains east of Caquena, Chile.

    As the re-entry fireball passed out of range of Caquena, it rose above the horizon of Buen Retiro and Enconada, in Bolivia's Santa Cruz Department, the scene of fireball reports and the recovery of a pair of large metallic spheres, now known to have belonged to 1979-072B. Figure 10 (below) depicts the re-entry trajectory of 1979-072B relative the Chilean and Bolivian sighting locations. The alternating red and white segments span 10 seconds of flight.

    [Approximate track of 1979-072B relative Chilean and Bolivian sightings]
    Fig. 10.   Approximate track of 1979-072B relative Chilean and Bolivian sightings.

    6. Conclusions

    Virtually all identifications of suspected sightings of re-entry fireballs and debris recoveries are circumstantial. Authoritative records of known re-entries are consulted to identify potential suspects. Their final orbital elements before re-entry reveal whether they happened to be passing within range of the sightings or close to the location of any debris at the relevant time, and whether they might have descended low enough to have been burning and breaking up. Even with accurate orbital data, it is seldom possible to precisely estimate the time and place of the final descent. Confidence in the circumstantial case depends on the quantity and quality of the sighting and debris reports, and the strength of correlation with the trajectory.

    In the Bolivian case of August 1979, the two recovered spheres were by far the strongest evidence. They matched the number and approximate size of helium pressurant spheres carried on the DSV-3P-4 second stages of Delta rockets. They showed signs of exposure to extreme heat. They were found soon after sightings of a fireball seen in the early hours of August 10, 1979. If they fell from space, then their relative locations were consistent with an orbit of low inclination. The Delta DSV-3P-4 second stage known as 1979-072B / 11490, was in such an orbit, and was reported by authoritative sources to have re-entered on the same day as the fireball sightings.

    The analysis is complicated by the lack of any public record of 1979-072B's complete orbital elements. It's approximate orbit has been reconstructed from partial elements published by authoritative sources, and information from other Delta 2914 launches to similar orbits. That orbit passed close to the location of both spheres in the early hours of August 10, 1979, and correlates temporally and spatially with the Caquena, Chile sighting, which increases confidence in the already strong circumstantial case.

    The area to mass ratio (A/m) required for that orbit to have been in its final descent over Bolivia, falls just within the statistical range of the empirical data from a sample of 25 other DSV-3P-4 second stages that have re-entered. This result is highly sensitive to the accuracy of the estimated orbit, in particular the perigee height, which is uncertain by at least several kilometres. It it were 3 km lower, the required A/m would fall comfortably within the empirical data; 3 km higher would put it far outside the range of the data.

    The orbital re-entry analysis alone does not prove that 1979-072B re-entered at the relevant time, but when examined in the context of the other evidence, it may reasonably be concluded that its re-entry caused the aerial phenomena and was the source of the spheres.

    Additional information is sought, that could strengthen or weaken the circumstantial case, including:

  • authoritative information on the mass and diameter of the spheres
  • photographs - especially of the second and third spheres found, for which none are currently available
  • the precise location of discovery of the spheres, especially of the second and third found
  • additional sighting reports at least as detailed as those of Caquena, Chile
  • confirmation of the experimental engine firing of 1979-072B, and its precise final orbital elements
  • It would also be of interest to learn the history of the spheres subsequent to their discovery, including their present location.

    The following section suggests additional avenues of research and possible sources of information.

    7. Research Suggestions

    The public record of this case consists almost entirely of second and third hand reports. Likewise, none of the NASA pre-launch or post-launch press-kits and technical reports that could confirm the experimental burn and provide detailed information are on the web. Below are some suggestions for further research that could improve the evidentiary record, against which the re-entry hypothesis may be further tested. If you have copies of reports you can share or know where they exist, please contact me.

    Bolivia

    Depending on the weather, the re-entry fireball would have been visible from a wide area of Bolivia, including the major cities La Paz and Santa Cruz de la Sierra. The latter was in close proximity to the spheres. The local time of the re-entry, 2:45 AM, would have greatly reduced the potential number of sightings; however, the newspaper El Deber, based in Santa Cruz de la Sierra, mentioned sightings of a fireball in its report of August 17, 1979, as did La Paz-based El Diario on August 19. Both referred to sightings in Santa Cruz Department. The portions quoted in the Moon Dust telexes mentioned the fireballs, but included scant details.

    Archives of the above and other major papers of the time should be checked from the date of the re-entry, August 10, until at least the end of the month. The earliest reports would have been of the fireball sightings. The key missing information is the accurate time of the sightings and description of the trajectory through the sky and relative the Earth. Detailed descriptions of its appearance and any sounds heard also are of great importance.

    The spheres came to light about a week after the re-entry. Later reports may have clarified the somewhat sketchy details on the locations where the spheres were found, their size and mass, and what became of them. Mr. Luis Ruiz Nóguez has published a photograph believed to be of the sphere found near Enconada, attributed to the major newspaper Presencia. He also reported that the spheres were sent to the U.S. embassy in La Paz, which he attributed to United Press, dateline La Paz, August 23, 1979. Copies of those and any other relevant reports would be valuable.

    Neighbouring Countries

    The estimated trajectory of the 1979-072B re-entry fireball passed within sight of six neighbouring countries of Bolivia over a several minute period. Below are the approximate local times of culmination, taking into account time zones and daylight saving time rules of the day.
    1:40 AM southern Ecuador
    1:42 AM Peru
    3:43 AM northwestern Brazil
    2:44 AM northern Chile
    2:45 AM Bolivia
    3:45 AM northern Argentina
    2:46 AM northwestern Paraguay
    
    Due to the wide area of visibility, at any given time the re-entry would have been visible from one or more of the above. A single Chilean sighting came to light after the initial publication of this report. Additional sighting reports from the region may exist in newspaper archives. The Google Earth kml file of the trajectory presented in Section 5.4 can be used to determine whether the re-entry was visible from the location of a suspected sighting.

    NASA

    The web record of official, detailed technical data on launches of unpiloted spacecraft of the 1970's is spotty at best, and no such data has been found for Delta 149. Below are descriptions of the types of reports known or likely to have been produced, that may have contained details of any experimental second stage burns. Pre-launch reports likely referred to the name of the payload as Westar C; post-launch as Westar III or Westar 3.

    Almost certainly the most useful report, if it exists, is the "Post Flight Analyses," that might have been prepared by MDAC (McDonnell Douglas Astronautics Company) within six months or so of the launch. The only example on the web is for the Delta 113 (COS-B) launch. A FOIA request to NASA/GSFC brought the swift response that if a Delta 149 version exists, it is in the national archives (NARA).

    Judging by other Delta launches of the 1970s, there is a good chance that the MET (mission elapsed time) and duration of any planned experimental second stage burns were reported in the pre-launch press-kit, typically issued from NASA HQ in Washington, D.C. One negative example is the press-kit of Delta 113, which launched COS-B; it did not mention the planned 25 s experimental burn documented in the above-referenced "Post Flight Analyses" report.

    A "Launch Mission Summary And Sequence Of Events" report issued pre-launch by KSC would be well worth obtaining.

    The following two standard reports are known to have been issued, which may contain useful information, but are not currently on the web:

    Mission Operation Report, MOR No. M-492-203-79-03, August 7, 1979.
    Mission Operation Report, MOR No. M-492-203-79-03, October 25, 1979.

    The one dated August was the pre-launch report, which may have included the MET time and duration of any experimental burns. The one dated October was the post-launch report. Based on very limited examples from other launches, the pre-launch report may be more likely to contain useful details on the launch than the post-launch version.

    8. Acknowledgments

    I am grateful to everyone who responded to my requests for information and assistance with this study.

    Bob Christy, Pierre Neirinck and Mike Waterman checked their personal archives of S.O.N. (Satellite Observation Notes) for orbital elements of 1979-072B that might have been published. None were.

    Jonathan McDowell informed me of the experimental burns conducted of Delta second stages in the 1970s and early 1980s, which was essential to understanding the two different partial orbital element sets of 1979-072B that exist. He also shared with me data he has collected on numerous relevant Delta launches that provided valuable insight. Jonathan's satellite catalogue and launch history table were indispensable.

    Allen and Zaida Thomson translated the four newspaper reports presented in Section 2.1.2; the verbal commentary by Luis Ruiz Nóguez of his slide containing a photo of one of the spheres; and one of the Caquena, Chile sighting reports of Section 2.4.1. They also advised on the possibility of mistaking 12:30 and 2:30, one for the other, when heard in Spanish, discussed in Section 3.4.

    Vicente-Juan Ballester Olmos assisted with the follow-up of certain reports on the Bolivian spheres. After the initial publication of this report, he continued to search for additional reports, which led him to unearth the four news reports presented in Section 2.1.2, which added greatly to the evidentiary record. He has provided invaluable information on numerous other re-entry sighting and space debris recovery cases.

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