Environmental Research Satellite

Last updated

The Environmental Research Satellite (ERS, alternatively Earth Resources Satellite) program was a series of small satellites initially operated by the United States Air Force Office of Aerospace Research. Designed to be launched "piggyback" to other satellites during launch, detaching once in orbit, they were the smallest satellites launched to date—what would today be classified as microsatellites. 33 ERS satellites in six different series were launched between 1962 and 1971, [1] conducting scientific research and serving as test beds to investigate the reliability of new spacecraft components. [2]

Contents

The TRS and ORS families. From left to right: TRS Mk. 3, TRS Mk. 2, TRS Mk.1, an OV3 bus, ORS Mk. 1, ORS Mk. 2, ORS Mk. 3 TRS and ORS families (enhanced).jpg
The TRS and ORS families. From left to right: TRS Mk. 3, TRS Mk. 2, TRS Mk.1, an OV3 bus, ORS Mk. 1, ORS Mk. 2, ORS Mk. 3

Summary of launches

SeriesFirst launchLast launchBuiltConfirmed launchedFailed
TRS Mk. 11962-09-071963-07-1910107
TRS Mk. 21963-10-171964-10-7420
ORS Mk.21966-06-191966-08-09520
ORS Mk.31965-07-201967-04-28220
OV51967-04-281969-05-23981
TTS, TETR, TATS1967-12-131971-09-29443

TRS Mk. 1

The TRS (Tetrahedral Research Satellite) Mk. 1 was developed by Space Technology Laboratories, a subdivision of TRW Inc., as an inexpensive, miniaturized "off-the-shelf" satellite that customers could use to perform simple experiments in orbit. The Mk. 1 was a regular tetrahedron measuring 16 cm (6.3 in) on a side, each face mounted with sufficient solar cells to operate the experiments and the telemetry system when the satellite was in the sun. Transmission of data was constant at that time as the spacecraft included neither internal battery nor command system. [3] A transistor-based system provided eight channels of data: five for experiments, two for telemetry calibration, and one for the spacecraft temperature. A 40 in (1.0 m) antenna transmitted data. [4] on 136.771 Mhz. [5]

Each TRS satellite was estimated to cost only $25,000 (equivalent to $213,888.89in 2020) to build, excluding development, launch and mission operations costs. [3]

The Air Force Space Systems Division (AFSSD), then headed by Col. T. O. Wear, was the first and only customer for STL's TRS Mk. 1 satellites, initially purchasing six for its Environmental Research Satellite (ERS) program. [3] Ten TRS Mk. 1 satellites were ultimately produced, designed to research radiation and micrometeoroid flux in Earth orbit. All were launched from Vandenberg Air Force Base attached to primary payloads. [1]

NameMassCOSPAR IDLaunchReentryPrimary satellitesMissionOutcome
ERS 1.7 kg (1.5 lb) [6] 1962 βπ1962-11-111962-11-12 [7] Samos 11 (Samos-E6 5) Radiation studiesFailed to separate
ERS 2 (TRS 1) [5] .6 kg (1.3 lb)1962 αχ1962-09-171962-10-17 [7] KH-4 12 Radiation, natural and from Starfish Prime Failed to separate
ERS 31962-F091962-12-17 MIDAS 6, ERS 4Radiation and micrometeorite studies; carried a cosmic ray experiment and an infrared plume experimentFailed to launch
ERS 41962-F091962-12-17 MIDAS 6, ERS 3Radiation and micrometeorite studies; carried a cosmic ray experiment and an infrared plume experimentFailed to launch
ERS 5 (TRS 2) [5] .7 kg (1.5 lb)1963-014B1963-09-051963-11-11 [7] MIDAS 7, DASH 1, West Ford 2, ERS 6 Van Allen Belts radiation and radiation damage to solar cellsSuccessful
ERS 6 (TRS 3) [5] .7 kg (1.5 lb)1963-014C1963-09-051964-03-17 [7] MIDAS 7, DASH 1, West Ford 2, ERS 5Van Allen Belts radiation and radiation damage to solar cellsSuccessful
ERS 71963-F091963-06-12 MIDAS 8, TRS 8Radiation and micrometeorite studiesFailed to launch
ERS 81963-F091963-06-12 MIDAS 8, TRS 7Radiation and micrometeorite studiesFailed to launch
ERS 9 (TRS 4) [5] 1.5 kg (3.3 lb)1963-030B1963-07-191963-08-11 [7] MIDAS 9, DASH 2, ERS 10Radiation damage to solar cellsSuccessful
ERS 101.5 kg (3.3 lb)1963-030A1963-07-191964-09-24 [7] MIDAS 9, DASH 2, ERS 09Radiation damage to solar cellsFailed to separate

[1]

Significant flights

ERS 2 (TRS 1)

At the time it was launched, TRS 1 was the smallest satellite ever placed into orbit. The aluminum spacecraft carried 140 solar cells, producing 600 milliwatts of power, and five radiation-detecting cells. [4] Though the satellite did not separate from its primary satellite, [1] it returned eight minutes of data per orbit to tracking stations below. It was designed to turn off after 90 days of operation. [4] TRS 1 circled the Earth in a Low Earth orbit. [8]

ERS 5, 6, and 9 (TRS 2-4)

Data returned from these three fully successful TRS satellites, circling the Earth in Medium Earth orbits [9] [10] [11] (within the Van Allen Belts), returned valuable data on the effects of orbital radiation on solar cells. Of significance, it was determined that p-on-n silicon cells deteriorated five times more quickly than n-on-p cells. While protective covers did not affect n-on-p degradation, they were shown to be helpful for the more sensitive p-on-n cells. An unexpected result of the solar cell experiment was that, while it had been observed in ground tests that exposure to radiation of the cells' quartz covers and the epoxy adhesive that held them to the cells reduced the light they transmitted (and thus the power generated) to the cells by 15%, such was not observed in orbit. [12]

TRS 2 and 3 marked the first time two satellites were deployed into orbit simultaneously. [3] Data was obtained by NASA's Minitrack communications network in cooperation with the USAF. [13]

TRS Mk. 2

ERS-11, an unflown TRS Mk. 2 prototype, on display at the Steven F. Udvar-Hazy Center ERS-11, Udvar-Hazy Center.jpg
ERS-11, an unflown TRS Mk. 2 prototype, on display at the Steven F. Udvar-Hazy Center

The TRS Mk. 2 design was a tetrahedron measuring 21 cm on a side. Four were produced: ERS-11 through ERS-14, though only two were launched, both pick-a-back with primary USAF payloads. [14] They were designed to operate for one year, at which point, an onboard timer would shut the satellites off. [5]

NameMassCOSPAR IDLaunchReentryPrimary satellitesMissionOutcome
ERS 112.1 kg (4.6 lb) [15] [16] Prototype satelliteNot launched
ERS 12 (TRS 5) [5] 2.1 kg (4.6 lb) [15] 1963-039B1963-10-17 Vela 1A, Vela 1B Charged particle research in the magnetosphere Successful
ERS 13 (TRS 6) [5] 2.1 kg (4.6 lb) [17] 1964-040C1964-07-17 Vela 2A, Vela 2B Charged particle research in the magnetosphere Successful
ERS 14Not launched

[14]

Flights

ERS 12 (TRS 5)

Launched into a highly elliptical orbit that took the satellite as high as 103,500 km (64,300 mi) above the Earth and as close as 220 km (140 mi) at perigee, [15] ERS 12 measured the intensity of charged particles in the magnetosphere. Its experiment package detected radiation from all directions, measuring electrons at levels greater than 0.5 and 5 MeV and protons between 10 and 20 eV and 50 to 100 eV. [14] The spacecraft returned data until 1963-10-30. [5]

ERS 13 (TRS 6, "Pygmy" [18] )

ERS 13's orbit was similar to that of ERS 12, with a perigee of 250 km (160 mi), but an even higher apogee: 120,317 km (74,762 mi). Spinning once every six seconds, the satellite measured electron and proton levels in the Van Allen Belts with omni-directional radiation detectors—a scintillation counter and a solid-state detector. [17] [14] [a] The onboard transmitter, with a power of 100 mW could only reach ground stations when ERS 13 was within 40,280 km (25,030 mi) of Earth. The satellite functioned normally until 1964-10-20, when transmission became erratic. [17] The satellite went silent on 1965-01-25. [5]

a (it is possible that ERS 12 and ERS 13 had the same experiments in their packages)

ORS Mk. 1

There is no evidence that any Octahedral Research Satellite Mark 1 ever flew.

ORS Mk. 2

The ORS Mk. 2 design was an octahedron measuring 23 cm on a side. Five were produced: ORS-1 and ORS-2 (ERS-15 through ERS-16), which carried out cold welding experiments in space on a variety of metal samples, and ERS-23 through ERS-25, classified satellites whose flights may have been cancelled.

Both ERS 15 and 16 used actuators for their cold welding experiments, the first (16) making five metal to metal tests, and the second (15) making eight. [19]

NameMassCOSPAR IDLaunchReentryPrimary satellitesMissionOutcome
ERS 15 (ORS 1)4.5 kg (9.9 lb) [20] 1966-077C1966-08-19 Midas 10, [21] SECOR 7 Cold weldingSuccessful
ERS 16 (ORS 2)4.5 kg (9.9 lb) [22] 1966-051C1966-06-091967-03-12 [22] Midas 11, [21] SECOR 6 Cold weldingSuccessful
ERS 23Mission cancelled
ERS 24Mission cancelled
ERS 25Mission cancelled

[19]

ORS Mk. 3

ERS-17, an ORS Mk. 3 satellite ERS-17.jpg
ERS-17, an ORS Mk. 3 satellite

The ORS Mk. 3 design was an octahedron measuring 28 cm on a side. Two were produced: ORS-3 and ORS-4 (ERS-17 and ERS-18). [23]

NameMassCOSPAR IDLaunchReentryPrimary satelliteMissionOutcome
ERS 17 (ORS 3)5.5 kg (12 lb) [24] 1965-058C1965-7-201968-07-01 Vela 5, Vela 6 [23] Radiation detectionSuccessful
ERS 18 (ORS 4)9.1 kg (20 lb) [25] 1967-040C1967-04-28 Vela 7, Vela 7, OV5-1, OV5-3 [23] Gamma ray and X ray observationSuccessful

Flights

ERS 17 (ORS 3)

Taking advantage of the high-apogee, eccentric orbit of the Vela 3A and Vela 3B satellites, ERS 17 was attached as a "pigmy" satellite, adding negligibly to the payload compared to the Velas launched 20 July 1965 to monitor the Earth for nuclear tests. ERS 17's 112,012 km (69,601 mi) apogee and 207 km (129 mi) perigee orbit took it through Earth's Van Allen Belts, which the satellite was designed to investigate, measuring charged particles, X rays, gamma rays, and cosmic rays in the near-earth environment. Approximately 1500 hours of data were collected by the ERS 17's five radiation detectors until November 3, 1965, when the transmitter ceased. [24] [26] Though this was much shorter than the planned lifespan of one year, [27] the satellite had collected a useful data set within the first four weeks of operation. [24] In addition to returning basic scientific data, as well as helping to refine the Vela design by a better understanding of the radiation hazard the satellite series would endure, ERS 17 also monitored for the telltale increase of electron fluxes in the event of nuclear detonations in near space. [27] ERS reentered 1 July 1967. [24]

ERS 18 (ORS 4)

The heavier ERS 18, [25] launched with the next set of Vela satellites with the same mission as ERS 17, [27] operated successfully from launch until thirteen months later, on June 3, 1968, when its transmitter was turned off by the onboard timer, as planned. [25] Analysis of returned data indicated that the intensity of gamma rays of energy greater than 1 MeV were higher than would be expected by simply extrapolating from the intensity of gamma rays of less than 1 MeV energy. This suggested an additional, as yet undetermined source of high intensity gamma rays. [28]

As of 8 June 2022, ERS 18 is still in orbit, and its position can be tracked on-line. [29]

OV5

OV5-1 satellite Ov5-1.jpg
OV5-1 satellite

The design of the OV5 (Orbiting Vehicle 5) series was based on the ORS Mk. 3 design and its vehicles were also given ERS numbers. Nine were produced: OV5-1 through OV5-9. [30] These were very small satellites launched pick-a-back with primary payloads since 1962—a natural fit under the Orbiting Vehicle umbrella. The primary innovation over the earlier ERS series was a command receiver, allowing instructions to be sent from the ground, and a Pulse-code modulation digital telemetry system, [31] : 425  versus the analog transmitters used on prior ERS missions. [24] Like prior ERS, the OV5s were spin-stabilized and heat was passively controlled. All of the OV5 series were built by TRW with the exception of OV5-6, built by AFCRL, and OV5-9, built by Northrop Corporation. [31] : 425 

OV5 Missions

NameMassCOSPAR IDLaunchReentryPrimary satellitesMissionOutcome
OV5-1 (ERS-27)6 kg (13 lb)1967 040E28 Apr 1967Materials sciences researchSuccessful
OV5-2 (ERS-28)10 kg (22 lb)1968 081B26 Sep 196815 Feb 1971Radiation studiesSuccessful
OV5-3 (ERS-20)8.6 kg (19 lb)1967 040D28 Apr 1967Radiation studiesSuccessful
OV5-4 (ERS-21)12 kg (26 lb)1968 081C26 Sep 1968Heat transfer studiesSuccessful
OV5-5 (ERS-29)11 kg (24 lb)1969 046A23-May-1969Radiation studiesSuccessful
OV5-6 (ERS-26)11 kg (24 lb)1969 046B23-May-1969Solar flare studiesSuccessful
OV5-7Solar studiesCancelled
OV5-8 9 kg (20 lb)16 Aug 1968Materials sciences research – materials friction experimentFailed to orbit
OV5-913 kg (29 lb)1969 046C23 May 1969Radiation studies – carried low-energy proton detectors, a dE/dx telescope, a Cerenkov counter, a VLF radiation detector, a solar X-ray monitor and a solar flare electron detector to provide further basic research data on solar radiation and its effects on the magnetosphereSuccessful

[32]

TETR

Test and Training Satellite (TTS) Test train sat c.jpg
Test and Training Satellite (TTS)

TETR (also known as TTR and TATS, all standing for "Test and Training Satellite") was a series of octahedral ERS satellites which were built to train Apollo program ground station crews for the Manned Space Flight Network. [33] Four were produced: TTR-1 through TTR-4 (ERS-30 through ERS-33) [34] TETR 2 supported training for Apollo missions 8 through 13 despite a faulty battery pack. TETR C failed to orbit due to a failure in the launch vehicle. [35]

NameMassCOSPAR IDLaunchReentryPrimary satelliteMissionOutcome
ERS 30 (TTS 1, TETR 1)20 kg (44 lb) [36] 1967-123B1967-12-131968-04-28 Pioneer 8 CommunicationsSuccessful
ERS 31 (TTS 2, TETR 2)40 kg (88 lb) [37] 1968-100B1968-11-081979-09-19 Pioneer 9 CommunicationsSuccessful
ERS 32 (TTS 3, TETR 3)TETR-C1969-08-27 [38] Pioneer E CommunicationsLaunch failure
ERS 33 (TTS 4, TETR 4)20.4 kg (45 lb) [39] 1971-083B1971-09-291978-09-19 OSO 7 CommunicationsSuccessful

[34]

Related Research Articles

<span class="mw-page-title-main">Mars 4</span> Soviet spacecraft

Mars 4, also known as 3MS No.52S was a Soviet spacecraft intended to explore Mars. A 3MS spacecraft launched as part of the Mars programme, it was intended to enter orbit around Mars in 1974. However, computer problems prevented orbital insertion from occurring.

<span class="mw-page-title-main">European Remote-Sensing Satellite</span> European Space Agency Earth-observing satellite program

European Remote Sensing satellite (ERS) was the European Space Agency's first Earth-observing satellite programme using a polar orbit. It consisted of two satellites, ERS-1 and ERS-2, with ERS-1 being launched in 1991.

The Space Test Program (STP) is the primary provider of spaceflight for the United States Department of Defense (DoD) space science and technology community. STP is managed by a group within the Advanced Systems and Development Directorate, a directorate of the Space and Missile Systems Center of the United States Space Force. STP provides spaceflight via the International Space Station (ISS), piggybacks, secondary payloads and dedicated launch services.

<span class="mw-page-title-main">Orbiting Vehicle</span> American satellite family

Orbiting Vehicle or OV, originally designated SATAR, comprised five disparate series of standardized American satellites operated by the US Air Force, launched between 1965 and 1971. Forty seven satellites were built, of which forty three were launched and thirty seven reached orbit. With the exception of the OV3 series and OV4-3, they were launched as secondary payloads, using excess space on other missions. This resulted in extremely low launch costs and short proposal-to-orbit times. Typically, OV satellites carried scientific and/or technological experiments, 184 being successfully orbited through the lifespan of the program.

<span class="mw-page-title-main">TDRS-3</span> American communications satellite

TDRS-3, known before launch as TDRS-C, is an American communications satellite, of first generation, which is operated by NASA as part of the Tracking and Data Relay Satellite System. It was constructed by TRW, and is based on a custom satellite bus which was used for all seven first generation TDRS satellites.

Lewis was an American satellite which was to have been operated by NASA as part of the Small Satellite Technology Initiative. It carried two experimental Earth imaging instruments, and an ultraviolet astronomy payload. Due to a design flaw it failed within three days of reaching orbit, before it became operational.

<span class="mw-page-title-main">Discoverer 17</span> Reconnaissance satellite

Discoverer 17, also known as Corona 9012, was an American optical reconnaissance satellite launched on 12 November 1960 at 20:38:00 GMT. It was the second of ten Corona KH-2 satellites, based on the Agena-B.

<span class="mw-page-title-main">Discoverer 18</span> Reconnaissance satellite

Discoverer 18, also known as Corona 9013, was an American optical reconnaissance satellite launched on 7 December 1960 at 20:24:00 GMT. It was the first successful, and the third of ten total Corona KH-2 satellites, based on the Agena-B.

Hermes was an American satellite which was to have been operated by the Colorado Space Grant Consortium. Intended to perform technology demonstration experiments in low Earth orbit, it was lost during launch in March 2011 when the rocket that was carrying it failed to achieve orbit.

<span class="mw-page-title-main">TD-1A</span>

TD-1A, or Thor-Delta 1A, was a European astrophysical research satellite which was launched in 1972. Operated by the European Space Research Organisation, TD-1A made astronomical surveys primarily in the ultraviolet, but also using x-ray and gamma ray detectors.

<span class="mw-page-title-main">BioSentinel</span> US experimental astrobiology research satellite

BioSentinel is a lowcost CubeSat spacecraft on a astrobiology mission that will use budding yeast to detect, measure, and compare the impact of deep space radiation on DNA repair over long time beyond low Earth orbit.

Vela 4A was an American reconnaissance satellite to detect explosions and nuclear tests on land and in space. It was released together with Vela 4B, ERS 18, OV5 1 and OV5 3.

Vela 4B was an American reconnaissance satellite to detect explosions and nuclear tests on land and in space. It was released together with Vela 4A, ERS 18, OV5 1 and OV5 3.

<span class="mw-page-title-main">OV1-1</span> US Air Force satellite

Orbiting Vehicle 1-1, was the first satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-1 was an American Earth science research satellite designed to measure radiation, micrometeoroid density, and magnetic fields in orbit. Launched 21 January 1965, the mission resulted in failure when, after a successful launch of its Atlas booster, OV1-1's onboard Altair motor failed to fire.

<span class="mw-page-title-main">OV1-2</span> US Air Force satellite

Orbiting Vehicle 1-2, launched 5 October 1965, was the third, and first successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. A radiation measuring satellite designed to conduct research for the planned Manned Orbital Laboratory project, OV1-2 was the first American spacecraft to be placed into orbit on a western trajectory. The satellite stopped functioning in April 1967 after a series of technical problems starting two months after launch.

<span class="mw-page-title-main">OV2-3</span> US Air Force satellite

Orbiting Vehicle 2-3, the second satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American solar astronomy, geomagnetic and particle science research satellite. Launched 22 December 1965 along with three other satellites, the mission resulted in failure when the spacecraft failed to separate from the upper stage of its Titan IIIC.

<span class="mw-page-title-main">OV2-5</span> US Air Force satellite

Orbiting Vehicle 2-5, the third and last satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American particle science and ionosphere research satellite. Launched 26 September 1968 along with three other satellites, OV2-5 became the first scientific satellite to operate at geosynchronous altitude.

<span class="mw-page-title-main">OV5-1</span> US Air Force satellite

Orbiting Vehicle 5-1, was an X-ray measuring microsatellite launched in support of the United States Air Force's space weather prediction program. Launched on 28 April 1967, it was the first satellite in the OV5 series of the United States Air Force's Orbiting Vehicle program. Data was collected until November 1967, and the satellite turned itself off in June 1967. OV5-1 is still in orbit as of 11 February 2023.

<span class="mw-page-title-main">OV5-3</span> US Air Force satellite

Orbiting Vehicle 5-3, was a materials science microsatellite launched on 28 April 1967 and still in orbit as of 2020. Carrying a variety of metal and plastic samples, it conducted friction tests on them in the vacuum of space to help determine their usability in space equipment. OV5-3 was the second satellite in the OV5 series of the United States Air Force's Orbiting Vehicle program.

<span class="mw-page-title-main">OV5-8</span> US Air Force satellite

Orbiting Vehicle 5-8, was a materials science microsatellite launched, along with 12 other satellites in the biggest multi-satellite launch to date, on 18 August 1968 on the first Atlas Burner 2 rocket. The rocket and all payloads were lost when the second stage (Burner) shroud collapsed after first stage (Atlas) cutoff. OV5-8 was the third satellite in the OV5 series of the United States Air Force's Orbiting Vehicle program.

References

  1. 1 2 3 4 Krebs, Gunter D. "TRS Mk. 1 (ERS)". Gunter's Space Page. Retrieved 25 October 2021.
  2. ↑ Wade, Mark. "ERS". www.astronautix.com. Archived from the original on December 27, 2016. Retrieved 8 November 2021.
  3. 1 2 3 4 Andrew LePage (2014-05-18). "Vintage Micro The Original Picosatellite". Drew ex Machina. Retrieved 2022-03-12.
  4. 1 2 3 Thomas L. Branigan, ed. (December 1962). TRW Space Log. Vol. 2. Redondo Beach, CA: TRW. p. 45.
  5. 1 2 3 4 5 6 7 8 9 10 William R. Corliss (1967). Scientific Satellites. Washington D.C.: Science and Technical Information Division, Office of Technology Utilization, NASA. p. 714. Retrieved 2022-03-12.
  6. ↑ "Astronautical and Aeronautical Events of 1962" (PDF). NASA. 1963. p. 236. Archived from the original (PDF) on 2013-03-04. Retrieved 2022-04-11.
  7. 1 2 3 4 5 6 McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved 2022-03-12.
  8. ↑ "ERS 2". NASA. Retrieved 2022-03-12.
  9. ↑ "ERS 5". NASA. Retrieved 2022-03-12.
  10. ↑ "ERS 6". NASA. Retrieved 2022-03-12.
  11. ↑ "ERS 9". NASA. Retrieved 2022-03-12.
  12. ↑ John B. Rittenhouse (January 1966). Space Materials Handbook: Space Materials Experience. Supplement 1, to the 2d. ed. NASA. pp. s-67–s-68.
  13. ↑ "Astronautical and Aeronatical Events of 1963" (PDF). NASA. 1964. p. 346.
  14. 1 2 3 4 Krebs, Gunter D. "TRS Mk. 2 (ERS)". Gunter's Space Page. Retrieved 25 October 2021.
  15. 1 2 3 "ERS 12". NASA. Retrieved 2022-03-31.
  16. ↑ Rogerio Atem de Carvalho; Jaime Estela; Martin Langer, eds. (2020). "1.3". Nanosatellites: Space and Ground Technologies, Operations and Economics. Hoboken, NJ: Wiley. ISBN   9781119042068. OCLC   1126347525.
  17. 1 2 3 "ERS 13". NASA. Retrieved 2022-03-31.
  18. ↑ "Astronautical and Aeronautical Events of 1964" (PDF). nasa. 1965. p. 252.
  19. 1 2 Krebs, Gunter D. "ORS Mk.2 (ERS)". Gunter's Space Page. Retrieved 25 October 2021.
  20. ↑ "ERS 15". NASA. Retrieved 2022-04-30.
  21. 1 2 Wade, Mark, Encyclopedia Astronautica Midas Archived 2010-11-20 at the Wayback Machine
  22. 1 2 "ERS 16". NASA. Retrieved 2022-04-30.
  23. 1 2 3 Krebs, Gunter D. "ORS Mk.3 (ERS)". Gunter's Space Page. Retrieved 25 October 2021.
  24. 1 2 3 4 5 "ERS 17". NASA. Retrieved 2022-06-08.
  25. 1 2 3 "ERS 18". NASA. Retrieved 2022-06-08.
  26. ↑ "U.S. Sends Three Satellites into Orbit". Dayton Daily News. 1965-07-20.
  27. 1 2 3 "ERS 17 & 18". UCSD High Energy Astrophysics group. Retrieved 2022-06-08.
  28. ↑ "A New Component of Gamma Rays Above One MEV Observed By The ERS-18 Satellite". Scientific and Technical Aerospace Reports. NASA. 8 (13): 2473–2474. 1968. Retrieved 2022-06-08.
  29. ↑ "ERS 18" . Retrieved 8 June 2022.
  30. ↑ Krebs, Gunter D. "OV5 (ERS)". Gunter's Space Page. Retrieved 25 October 2021.
  31. 1 2 Powell, Joel W.; Richards, G.R. (1987). "The Orbiting Vehicle Series of Satellites". Journal of the British Interplanetary Society. Vol. 40. London: British Interplanetary Society.
  32. ↑ Heyman, Jos (2005-04-12). "OV". Directory of U.S. Military Rockets and Missiles. Designation Systems. Retrieved February 15, 2020.
  33. ↑ Ezell, Linda Neuman (1988). NASA Historical Data Book: Programs and projects, 1969-1978. Scientific and Technical Information Division, National Aeronautics and Space Administration. p. 402.
  34. 1 2 Krebs, Gunter D. "TTS, TETR (ERS)". Gunter's Space Page. Retrieved 26 October 2021.
  35. ↑ "TETR-2 Is Successful Despite Faulty Battery Pack" (PDF). Technical Information Bulletin: The Manned Spaceflight Network. 8 (3). 26 February 1971. Retrieved 13 December 2021.
  36. ↑ "TETR 1". NASA. Retrieved 2022-06-08.
  37. ↑ "TETR 2". NASA. Retrieved 2022-06-08.
  38. ↑ "TETR-C". NASA. Retrieved 2022-06-08.
  39. ↑ "TETR 4". NASA. Retrieved 2022-06-08.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.