PAGEOS

Passive Geodetic Earth Orbiting Satellite (PAGEOS)

Test inflation of PAGEOS, 5 August 1965

Names| PAGEOS-A
Operator| NASA Office of Space Applications
COSPAR ID| 1966-056A
SATCAT no.| 02253
Spacecraft properties
Launch mass| 56.7 kg (125 lb)
Dimensions| 30.48 m (100.0 ft) diameter[1]
Start of mission
Launch date| 00:14, June 24, 1966 (UTC) (1966-06-24T00:14:00Z)
Rocket| Thrust augmented Thor-Agena D
Launch site| Vandenberg AFB
End of mission
Destroyed| partially disintegrated July 1975 (1975-07)
Orbital parameters
Reference system| Geocentric[2]
Eccentricity| 0.00301
Perigee altitude| 4,207 km (2,614 mi)
Apogee altitude| 4,271 km (2,654 mi)
Inclination| 87.14°
Period| 181.43 min
Epoch| 24 June 1966

PAGEOS (PAssive Geodetic Earth Orbiting Satellite) was a balloon satellite which was launched by NASA in June 1966.[1] It was the first satellite specifically launched for use in geodetic surveying,[3] or measuring the shape of the earth, by serving as a reflective and photographic tracking target. At the time, it improved on terrestrial triangulations of the globe by about an order of magnitude.[4] The satellite, which carried no instrumentation, broke up between 1975 and 1976.[5] One of the largest fragments of the satellite finally deorbited in 2016.[6]

PAGEOS was part of a larger program of inflatable satellites that grew from the original concept by William J. O'Sullivan of a 30-inch diameter inflatable satellite in 1956 to measure air drag at high altitudes, called the Sub-Satellite.[7] While the Sub-Satellite failed, the idea of a visible US satellite became very attractive after Sputnik launched in the Cold War, resulting in a program of similar, larger satellites.[7] These included satellites Echo 1 and Echo 2 under Project Echo, which were also used for experiments in geodetic surveying;[3] several air-density-focused Explorer satellites; and finally PAGEOS.[7]

## Contents

* 1 Design
* 2 Usage
* 3 Orbit
* 4 See also
* 5 References

## Design

PAGEOS had a diameter of exactly 100 feet (30.48 m), consisted of a 0.5 mils (12.7 μm) thick mylar plastic film coated with vapour deposited aluminum enclosing a volume of about 524,000 cubic feet (14,800 m3)[8][9] The metal coating both reflected sunlight and protected the satellite from damaging ultraviolet waves. The satellite was launched in a canister, which explosively separated as it was ejected from the rocket. Then, the balloon was inflated through a combination of residual internal air and a mixture of benzoic acid and anthraquinone placed inside, which turned to gas when the satellite was exposed to the heat of the sun.[9] The satellite carried no instrumentation.[9] The study and construction of PAGEOS was done by the Schjeldahl company, which also made Echo 1.[10]

## Usage

Network of BC4 cameras used to establish the Worldwide Geometric Satellite Triangulation Network A BC4 (Ballistic Camera-4) camera, inside its observing dome, with instrumentation shelter in background.

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PAGEOS was placed into a polar orbit, about 200 nautical miles above the earth, so that the U.S. Coastal and Geodetic Survey could practically apply triangulation techniques developed from experiments with Echo 1. This program was known as the "Worldwide Geometric Satellite Triangulation Program".[11] Because of the satellite's high altitude, the sun illuminated it during the entirety of Earth night, allowing it to be picked out from a background of stars.[4][10] Over five years, 16 groups conducted observations at 45 globally distributed stations, about 3000-4000 km apart from each other.[4][7][12] 12 mobile tracking stations were used, which observed during favorable weather conditions during a few minutes of twilight each evening.[7] [clarification needed] BC4 cameras were used to photograph the satellite.[12] Observations were taken when the satellite was visible simultaneously to multiple stations at the same time.[12] This resulted in the fixing of the precise locations of 38 different points around the world.[4] This could be used to help determine the precise locations of the continents relative to each other, and to help determine the precise shape and size of the earth. Some unclassified data was used by scientists studying continental drift, and more classified data was used by US military planners studying intercontinental ballistic missiles.[7] The observations were done with BC4 (Ballistic Camera-4) cameras, and could last more than a year at each station before satisfactory results were obtained.[11][12] The network reached an accuracy about an order of magnitude better than terrestrial triangulations at the time,[4] and was the first time that a scientific determination had been made with accuracy of a complete global polyhedron.[12]

## Orbit

Thor-SLV2A Agena-D launching PAGEOS

The PAGEOS spacecraft was launched by a Thor-SLV2A Agena-D (Thor 473) on 24 June 1966,[13] and placed into a polar orbit (inclination 85–86°) with an initial height of 4200km,[14] which had gradually lowered during its 9 years of operation. The satellite first partly disintegrated in July 1975,[10] which was followed by a second break-up that occurred in January 1976 resulting in the release of a large number of fragments. Most of these re-entered during the following decade.[5][better source needed] In 2016, one of the largest fragments of PAGEOS de-orbited.[6] The satellite's orbital period was approximately three hours.[2] It was about as bright as Polaris, and appeared as a slow-moving star.[10] Thanks to its high orbit and its polar inclination, it did not pass through the Earth's shadow and was visible any time of night, unlike lower-orbit satellites which had to be viewed exclusively just before sunrise and after sunset.[10] Its high orbit also allowed it to be seen simultaneously by observers 2000-3000 km apart at optimum distances from the zenith.[14]

## See also

* List of passive satellites
* Reference ellipsoid
* World Geodetic System (WGS84)

## References

1. ↑ 1.0 1.1 "PAGEOS 1". https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1966-056A. Retrieved 16 March 2017.
2. ↑ 2.0 2.1 "NSSDCA – PAGEOS 1 – Trajectory Details". NASA. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1966-056A. Retrieved 22 June 2016.
3. ↑ 3.0 3.1 "Modern Surveying" (in en). https://www.britannica.com/technology/surveying/Modern-surveying.
4. ↑ 4.0 4.1 4.2 4.3 4.4 Kleusberg, Alfred (2003). "Satelliten im Dienst der Geodäsie und Geoinformatik". https://www.uni-stuttgart.de/wechselwirkungen/ww2003/Kleusberg.pdf.
5. ↑ 5.0 5.1 Krebs, Gunter D. "PAGEOS 1". http://space.skyrocket.de/doc_sdat/pageos.htm. Retrieved 16 March 2017.
6. ↑ 6.0 6.1 J.-C. Liou (February 1, 2017). "USA Space Debris Environment, Operations, and Research Updates". 54th Session of the Scientific and Technical Subcommittee, Committee on the Peaceful Uses of Outer Space, United Nations, 30 January – 10 February 2017, Vienna. http://www.unoosa.org/documents/pdf/copuos/stsc/2017/tech-15E.pdf.
7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Hansen, James (12 March 2013). Spaceflight Revolution: NASA Langley Research Center from Sputnik to Apollo. Cia Publishing. https://ntrs.nasa.gov/citations/19950021264.
8. ↑ Teichman, L. A. (June 1, 1968). "The fabrication and testing of Pageos 1". NASA Technical Reports Server
9. ↑ 9.0 9.1 9.2 "Pageos Satellite to Girdle Globe for Earth Mapping". 19 June 1966. https://ntrs.nasa.gov/citations/19660022793.
10. ↑ 10.0 10.1 10.2 10.3 10.4 Dicati, Renato (2017-01-10) (in en). Stamping the Earth from Space. Springer. ISBN 978-3-319-20756-8. https://books.google.com/books?id=O4LgDQAAQBAJ&dq=PAGEOS&pg=PA44.
11. ↑ 11.0 11.1 "Entering the Space Age: The Evolution of Satellite Geodesy at the Coast and Geodetic Survey" (in en). National Oceanic and Atmospheric Administration. 2007. https://celebrating200years.noaa.gov/foundations/satellite_geodesy/welcome.html#scene.
12. ↑ 12.0 12.1 12.2 12.3 12.4 Seeber, Günter (2008-08-22) (in en). Satellite Geodesy: Foundations, Methods, and Applications. Walter de Gruyter. ISBN 978-3-11-020008-9. https://books.google.com/books?id=qZTS6OI9NGoC.
13. ↑ Krebs, Gunter D. "Thor-SLV2A Agena-D" (in en). https://space.skyrocket.de/doc_lau_det/thor-slv2a_agena-d.htm.
14. ↑ 14.0 14.1 Henriksen, S. W. (1 January 1977). ﻿National Geodetic Satellite Program, Part 1﻿ (Report). https://ntrs.nasa.gov/citations/19780003602. Retrieved 5 August 2024.

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Orbital launches in 1966

Kosmos 104 | OPS 2394 | OPS 7253 * OPS 3179 | Kosmos 105 | Kosmos 106 | OPS 1593 | Luna 9 | OPS 7291 | ESSA-1 | OPS 1439 | Kosmos 107 | Kosmos 108 | OPS 1184 * OPS 3011 * OPS 3031 | Dipason | Kosmos 109 | DS-K-40 No.2 | Kosmos 110 | ESSA-2 | Kosmos 111 | OPS 3488 | GATV-5003 | Gemini VIII | Kosmos 112 | OPS 0879 * OPS 0974 | Kosmos 113 | N-4 No.3 | OPS 1117 | Molniya-1 No.5 | OV1-4 * OV1-5 | OPS 0340 | Luna 10 | Kosmos 114 | OPS 1612 | Surveyor SD-3 | OAO-1 | OPS 0910 | Kosmos 115 | OV3-1 | Molniya 1-03 | Kosmos 116 | OPS 1508 | Kosmos 117 | Kosmos 118 | OPS 1950 * OPS 6785 | Nimbus 2 | Zenit-4 | GATV-5004 | OPS 0082 | OPS 1788 | Kosmos 119 | Explorer 32 | Surveyor 1 | ATDA | Gemini IX-A | OPS 1577 * OPS 1856 | OGO-3 | Kosmos 120 | OV3-4 | FTV-1351 * Secor 6 * ERS-16 | OPS 9311 * OPS 9312 * OPS 9313 * OPS 9314 * OPS 9315 * OPS 9316 * OPS 9317 * GGTS | Kosmos 121 | OPS 1599 | PAGEOS | Kosmos 122 | Explorer 33 | AS-203 | Proton 3 | Kosmos 123 | OPS 1850 | OV1-7 * OV1-8 | Kosmos 124 | GATV-5005 | Gemini X | Kosmos 125 | Kosmos 126 | OPS 3014 | OV3-3 | Kosmos 127 | OPS 1545 | Lunar Orbiter 1 | OPS 1832 * OPS 6810 | Pioneer 7 | OPS 2366 | FTV-1352 * Secor 7 * ERS-15 | Luna 11 | IDSCP 1 * IDSCP 2 * IDSCP 3 * IDSCP 4 * IDSCP 5 * IDSCP 6 * IDSCP 7 * GGTS | Kosmos 128 | GATV-5006 | Gemini XI | OPS 6026 | OPS 1686 * OPS 6874 | Zenit-2 No.40 | OPS 6026 | OPS 1686 * OPS 6874 | OGCh No.05L | Surveyor 2 | OPS 1703 | Ōsumi 1 | OPS 4096 | ESSA-3 | FTV-1583 * Secor 8 | OPS 2055 * OPS 5345 | Kosmos 129 | Molniya 1-04 | Kosmos 130 | Luna 12 | Surveyor SM-3 | Intelsat II F-1 | OV3-2 | OGCh No.06L | OPS 2070 * OPS 5424 | OPS 0855 * OV4-1R * OV4-1T * OV1-6 | Lunar Orbiter 2 | OPS 1866 | GATV-5001A | Gemini XII | Kosmos 131 | Strela-2 No.1 | Kosmos 132 | Kosmos 133 | Kosmos 134 | OPS 1890 | ATS-1 | OV1-9 * OV1-10 | Kosmos 135 | Soyuz 7K-OK No.1 | OPS 8968 | Biosatellite 1 | Kosmos 136 | Ōsumi 2 | Kosmos 137 | Luna 13 | OPS 1584

Payloads are separated by bullets ( * ), launches by pipes ( | ). Crewed flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets.

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