910:
971:. The balloon was constructed from a 9 μm (0.00035 in)-thick mylar film sandwiched between and bonded with two layers of 4.5 μm (0.00018 in)-thick aluminum foil. It was inflated to a pressure that caused the metal layers of the laminate to plastically deform slightly, while the polymer was still in the elastic range. This resulted in a rigid and very smooth spherical shell. A beacon telemetry system provided a tracking signal, monitored spacecraft skin temperature between −120 and +16 °C (−184 and 61 °F), and measured the internal pressure of the spacecraft between 0.00005 mm of
792:
1142:
1130:
738:, designed an experiment to observe atmospheric refractive effects using reflective balloon satellites. Believing the experiment would advance research toward transoceanic communications via satellites, the two engineers presented a paper advocating for the launch of balloon satellites to be used as passive communications reflectors to the National Symposium on Extended Range and Space Communication on 6 and 7 October 1958.
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The observed variations of the Echo orbit - due primarily to the effects of the pressure of sunlight - are in excellent agreement with our theoretical results. The perigee altitude has an oscillation of large amplitude (approximately equal to 600 km (370 mi)) and long period (approximately
991:
test vehicle, a three-stage rocket. The first
Shotput flew at 5:40 pm on 27 October 1959. Shotput 1 successfully delivered the Echo prototype to the desired altitude, but a small amount of residual gas in the folds of the balloon violently expanded, bursting the test article. People up and down the
922:
Echo 1 was 30 m (98 ft) in diameter, had a non-rigid skin made of 12.7 μm (0.00050 in)-thick Mylar, and had a total mass of 180 kg (400 lb), weighing 71 kg (157 lb) at launch. During ground inflation tests, 18,000 kg (40,000 lb) of air were needed to
844:
network of stations. The computer would then issue antenna-pointing commands to control the antenna. The third tracking method was a continuous-wave radar subsystem. Radar was not suitable for acquisition of the satellite, but once Echo was acquired by optical, or digital slave, radar signals could
839:
were mounted to the structure of the antenna at each site. The camera images were displayed to a servo operator who would control the position of the antenna to track the satellite. When optical tracking could not be used, a computer system called digital slave could acquire and track Echo. Digital
758:
Project Echo was a pathfinder mission with the objective of testing new technologies and preparing for future missions. Spaceflight engineers used Echo to prove new ideas and test limits in aerodynamics, satellite shape and size, construction materials, temperature control and satellite tracking.
1033:
in
Holmdel, New Jersey, that same day. It was originally expected that Echo 1A would not survive long after its fourth dip into the atmosphere in July 1963, although estimates allowed the possibility that it would continue to orbit until 1964 or beyond. It ended up surviving much longer than
1081:. Because Echo was only a passive system, it was primarily useful in demonstrating the future potential of satellite communications and became obsolete before it deorbited in 1968. Echo was most known to the general public for its visibility as it could be seen at night with the naked eye.
814:
facility located at
Holmdel, New Jersey. Both sites used separate antennas for transmitting and receiving. West-to-east transmissions were sent from Goldstone by a 26 m (85 ft) dish antenna built for Project Echo by JPL. The signals were received at Crawford Hill by a
1072:
Project Echo facilitated the first successful satellite transmission and first two way communications between the JPL Goldstone facility and Bell
Telephone Laboratories facility in Holmdel, New Jersey. Other groups participated in experiments including the
992:
Atlantic coast witnessed what looked like distant fireworks as thousands of pieces of shredded Mylar reflected sunlight in a display that lasted for about 10 minutes. Four more
Shotput tests were flown on 16 January, 27 February, 1 April, and 31 May 1960.
749:
to the new agency. Project Echo, NASA's first communications satellite project, was officially laid out in a 22 January 1959 meeting with representatives from NASA, JPL, and Bell
Telephone Laboratories setting the initial launch for September 1959.
967:. Echo 2's skin was rigidizable, unlike that of Echo 1. Therefore, the balloon was capable of maintaining its shape without a constant internal pressure; a long-term supply of inflation gas was not needed, and it could easily survive strikes from
823:
was selected, as this was the planned frequency band for future satellite experiments. East-to-west transmissions were sent from
Crawford Hill using a 18 m (59 ft) diameter parabolic antenna and received at Goldstone using the existing
853:
The Echo spacecraft (Echo 1, Echo 1A, and Echo 2) were large thin skinned spheres that were inflated in orbit after leaving the atmosphere. These balloon satellites were approximately 30 m (98 ft) in diameter with a thin skin made of
1502:
Harrison M. Jones; I. I. Shapiro; P. E. Zadunaisky (1961). H. C. Van De Hulst, C. De Jager and A. F. Moore (ed.). "Solar
Radiation Pressure Effects, Gas Leakage Rates, and Air Densities Inferred From the Orbit Of Echo I".
782:
All of these objectives were accomplished with
Project Echo. Further experiments used the satellite to engage a two-way telephone conversation on 15 August 1960 and to relay a live television transmission in April 1962.
877:
As its shiny surface was also reflective in the range of visible light, Echo was easily visible to the unaided eye over most of the Earth. The spacecraft was nicknamed a "satelloon" by those involved in the project (a
1029:) was successfully put into an orbit of 944 to 1,048 mi (1,519 to 1,687 km) by another Thor-Delta. A microwave transmission from the JPL Goldstone facility in California, was relayed by the satellite to
1045:. Since it was larger than Echo 1A and orbiting in a near-polar orbit, Echo 2 was conspicuously visible to the unaided eye over all of the Earth. It reentered Earth's atmosphere and burned up on 7 June 1969.
1154:
1056:, solved the problems associated with this by using a grid-sphere design instead of a covered surface. Later yet, NASA abandoned passive communications systems altogether, in favor of active satellites.
831:
Satellite acquisition and tracking were accomplished by three methods: optical, digital slave, and automatic radar. Optical tracking was the easiest method but could only be used at night when the
963:
Echo 2 was a 41.1 m (135 ft)-diameter balloon satellite, the last launched by
Project Echo. A revised inflation system was used for the balloon, to improve its smoothness and
828:
antenna. A transmission frequency of 960.05 megahertz was used for westbound communications because the JPL receiver was already tuned to this frequency from the Pioneer lunar program.
975:
and 0.5 mm of mercury, especially during the initial inflation stages. The system consisted of two beacon assemblies powered by solar cell panels and had a minimum power output of 45
1158:
1156:
2914:
715:
put forth a presentation on passive satellite relay, describing how a reflective orbiting body could be used to bounce transmissions from one point on the Earth to another.
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equal to 300 days), which has a decisive influence on the lifetime of Echo I. Our present best estimate is that the balloon will perish in the summer of 1963.
724:
1041:
launch vehicle. In addition to passive communications experiments, it was used to investigate the dynamics of large spacecraft and for global geometric
1211:
1078:
759:
Echo was designed as an experiment to demonstrate the potential of satellite communications, not to function as a global communications system.
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fill the balloon, but while in orbit, several pounds of gas were all that was required to fill the sphere. To address the problem of
2188:
1865:
1814:
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723:(JPL), also attended the conference and suggested that JPL facilities, specifically a 26 m (85 ft) diameter polar-mounted
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520:
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in 1945. Experiments using the moon as a passive reflecting way station for messages began as early as 1946. With the launching of
987:
Five suborbital ballistic tests to determine whether the launch, deploy, and expansion mechanisms would work were flown using the
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364:
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punctures and keep the sphere inflated, Echo 1 included a 15.12 kg (33.3 lb) make-up gas system using two types of
995:
On 13 May 1960, the first attempt to orbit an Echo satellite was made. The mission, which was also the maiden voyage of the
791:
1088:. This improved accuracy was sought by the U.S. military for the purpose of targeting intercontinental ballistic missiles.
1806:
2909:
2904:
681:
1312:
2934:
2919:
1360:
1329:
516:
59:
1164:
AT&T Bell Labs video about the first voice transmission via satellite and the engineers who conducted the effort.
951:, due to its large area-to-mass ratio. It was held together with Schjelbond, a proprietary adhesive developed by the
940:
1654:
1141:
836:
720:
700:, Earth's first artificial satellite, in 1957, interest quickly developed in orbiting communications satellites.
1505:
Space Research II, Proceedings of the Second International Space Science Symposium, Florence, April 10–14, 1961
692:
The concept of using orbital satellites to relay communications predated space travel, first being advanced by
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246:
124:
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89:
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40:
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1680:
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1084:
The Echo satellite program also provided the astronomical reference points required to accurately locate
1100:
1074:
1015:
863:
673:
684:, on 12 August 1960. The last Echo satellite deorbited and burned up in the atmosphere on 7 June 1969.
988:
2498:
1398:
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effect due to their large size and low mass. Later passive communications satellites, such as OV1-08
1011:
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signals. During the latter portion of its life, it was used to evaluate the technical feasibility of
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658:
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2738:
2731:
2395:
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stage performed properly, but during the coasting phase, the attitude control jets on the unproven
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495:
327:
211:
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Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in
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2696:
2691:
2402:
2165:
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in
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1183:
952:
948:
859:
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mounted on the balloon. The spacecraft was useful to the calculation of atmospheric density and
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2619:
2614:
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2153:
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1990:
1943:
1852:
1842:
693:
580:
290:
33:
1553:"A mind for business: Schjeldahl's ingenuity helps keep bread fresh, hearts safely beating"
653:
experiment. Each of the two American spacecraft, launched in 1960 and 1964, were metalized
2305:
1316:
968:
867:
825:
806:
Two ground stations were used for testing Project Echo. The Goldstone facility located at
735:
590:
535:
300:
1575:
Mechanical And Physical Properties of the Echo II Metal-Polymer Laminate (NASA TN D-3409)
1272:
870:, signals could be sent from a ground station, reflected by its surface, and returned to
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1402:
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2018:
1857:
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63:
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2024:
2011:
1977:
1970:
1964:
1924:
1736:
1699:
1629:
1616:
1584:
1459:
1421:
1346:
1291:
1222:
932:
866:. The satellites functioned as a reflector, not a transceiver; after being placed in
811:
728:
677:
450:
158:
1064:
858:(a trade name for stretched polyethylene terephthalate or BoPET), and were built by
815:
6 × 6 m (20 × 20 ft) aperture horn-reflector antenna.
2141:
2083:
2069:
2057:
1917:
1135:
Scale prototype of the Echo satellites undergoing a skin stress test on 1 May 1960.
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936:
816:
1034:
expected, and finally reentered Earth's atmosphere and burned up on 24 May 1968.
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2853:
2801:
2796:
2786:
2708:
2671:
1473:
1104:
879:
778:
Provide precedent for the overflight of other nations by surveillance satellites
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2524:
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1954:
1438:
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1205:
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1038:
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964:
944:
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17:
1410:
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1937:
1658:
1448:
1306:
1053:
924:
891:
841:
731:, might be used as a ground facility for experiments with such a satellite.
708:
697:
662:
463:
171:
1440:
Spaceflight Revolution: NASA Langley Research Center from Sputnik to Apollo
1335:
819:
were known to have low-noise properties. A transmission frequency of 2390
2868:
2604:
2559:
2377:
2294:
2118:
2005:
1474:"Static Inflation Test of 135 ft Satellite In Weeksville, North Carolina"
1234:
1849:"Space Triumph. Discoverer Capsule Recovered From Orbit, 15 August 1960"
669:
and bounced off the surface of the satellite to another Earth location.
2549:
2544:
2362:
2269:
2106:
2076:
2029:
1995:
1949:
1931:
1237:, a subsequent expandable spacecraft technology project pursued by NASA
1231:– first active, direct relay communications satellite, launched in 1962
1228:
775:
Demonstrate commitment to the development of an American space program
2811:
2656:
2433:
2367:
2244:
1984:
1959:
1216:
1085:
762:
Echo was designed, approved and built with the following objectives:
745:(NASA) was formed, and two months later JPL was transferred from the
665:
signals. Communication signals were transmitted from one location on
2887:. Payloads deployed from other spacecraft are denoted in (brackets).
2173:. Payloads deployed from other spacecraft are denoted in (brackets).
913:
T. Keith Glennan shows LBJ aluminized Mylar film used to make Echo I
835:
illuminated the satellite. Broad and narrow field telescopes with a
1397:. Washington, D.C.: National Aeronautics and Space Administration.
2641:
1195:
1191:
1063:
1002:, failed before deployment of the payload. Echo 1 lifted off from
908:
895:
871:
855:
820:
790:
666:
607:
597:
363:
317:
307:
53:
1735:
This article incorporates text from this source, which is in the
1698:
This article incorporates text from this source, which is in the
1615:
This article incorporates text from this source, which is in the
1583:
This article incorporates text from this source, which is in the
1458:
This article incorporates text from this source, which is in the
1420:
This article incorporates text from this source, which is in the
1345:
This article incorporates text from this source, which is in the
1290:
This article incorporates text from this source, which is in the
890:). It was used to redirect transcontinental and intercontinental
2337:
1095:
constructed by Bell Labs for the Echo project was later used by
976:
399:
99:
2184:
1861:
798:, constructed for Project Echo, and later used to discover the
1202:) – an amateur radio communications satellite launched in 2004
840:
slave worked by receiving primary tracking data from the NASA
832:
1394:
Beyond the Ionosphere: Fifty Years of Satellite communication
1361:"When a Giant Mylar Balloon Was the Coolest Thing in Space"
1208:– world's first active repeater satellite, launched in 1960
939:. It also had 107.9 MHz telemetry beacons, powered by five
32:"Echo project" redirects here. For the music festival, see
1225:– world's first communications satellite, launched in 1958
189:
30.48 m (100.0 ft) diameter sphere when inflated
1803:
Out from Behind the Eight-Ball: A History of Project Echo
1752:
Angle of Attack: Harrison Storms and the Race to the Moon
1472:
NASA/Langley Research Center (NASA-LaRC) (29 June 1965).
1331:
To See the Unseen: A History of Planetary Radar Astronomy
734:
In October 1958, Pierce, along with fellow Bell engineer
1018:
stage failed to ignite, sending the payload into the
473:
41 m (135 ft) diameter sphere when inflated
1805:. AAS History Series. Vol. 16. Univelt for the
1025:
On 12 August 1960, Echo 1A (commonly referred to as
766:
Observe and measure the effects of atmospheric drag
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136:
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105:
95:
85:
71:
672:The first transmissions using Echo were sent from
1114:On 15 December 1960, the U.S. Post Office issued
27:First passive communications satellite experiment
707:sponsored meeting on communications satellites,
1507:. North-Holland Publishing Company-Amsterdam.
2883:. Uncatalogued launch failures are listed in
2196:
2169:. Uncatalogued launch failures are listed in
1873:
1386:
1384:
1382:
1380:
1378:
1241:U.S. space exploration history on U.S. stamps
1037:On 25 January 1964, Echo 2 was launched on a
743:National Aeronautics and Space Administration
39:"Echo 1" redirects here. For other uses, see
8:
2915:Communications satellites in low Earth orbit
1432:
1430:
845:be used to automatically maintain tracking.
769:Passively reflect ground based transmissions
356:
46:
1827:Summer 2007, Volume 23, Number 1, pp. 38–43
1577:", NASA Goddard Space Flight Center (1966)
1524:"Mechanical Development of Antenna Systems"
1497:
1495:
1493:
1491:
2203:
2189:
2181:
1880:
1866:
1858:
355:
45:
810:in the Mojave Desert, California and the
725:antenna installed near Goldstone Dry Lake
1823:Nick D'Alto "The Inflatable Satellite",
1302:
1300:
1256:
1212:List of communications satellite firsts
1125:
1048:Both Echo 1A and Echo 2 experienced a
931:powders – 9.1 kg (20 lb) of
1559:. Fargo, North Dakota. Archived from
1219:– a similar balloon satellite project
1109:cosmic microwave background radiation
800:cosmic microwave background radiation
7:
1551:Gilmour, Gerry (11 September 1999).
1359:Marsh, Allison (12 November 2020).
1755:. W. W. Norton & Co. pp.
772:Demonstrate two-way communications
25:
1573:Staugaitis, C. & Kobren, L. "
1851:is available for viewing at the
1841:is available for viewing at the
1730:
1714:"A Brief History of Solar Sails"
1693:
1610:
1578:
1453:
1415:
1340:
1285:
1176:
1152:
1140:
1128:
935:and 4.6 kg (10 lb) of
362:
58:Echo 1 sits fully inflated at a
52:
1712:Coulter, Dauna (31 July 2008).
1198:51 (also known as Phase 2E, or
1269:Mission and Spacecraft Library
979:at 136.02 MHz and 136.17 MHz.
862:'s G.T. Schjeldahl Company in
508:(Thor 397 / Agena 6301 / TA-2)
418:
126:
1:
1807:American Astronomical Society
1781:"Arno Penzias - Biographical"
1657:. Astronautix. Archived from
1093:large horn antenna at Holmdel
322:1,684 km (1,046 mi)
2930:Spacecraft launched in 1964
2925:Spacecraft launched in 1960
1391:Butrica, Andrew J. (1997).
1328:Butrica, Andrew J. (1996).
709:Bell Telephone Laboratories
612:1,316 km (818 mi)
602:1,029 km (639 mi)
312:1,524 km (947 mi)
2951:
1443:. Washington, D.C.: NASA.
1107:-winning discovery of the
494:25 January 1964, 13:59:04
38:
31:
2877:
2235:
2163:
1912:
1801:Elder, Donald C. (1995).
1437:Hansen, James R. (1995).
1079:Naval Research laboratory
1068:Echo 1 stamp – 1960 issue
721:Jet Propulsion Laboratory
640:
636:
567:
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210:12 August 1960, 03:39:43
197:
193:
181:180 kg (400 lb)
148:
144:
81:
60:Navy hangar in Weeksville
51:
1825:Invention and Technology
943:that were charged by 70
941:nickel-cadmium batteries
651:communications satellite
531:Douglas Aircraft Company
247:Douglas Aircraft Company
1022:instead of into orbit.
904:satellite triangulation
41:Echo I (disambiguation)
1716:. NASA. Archived from
1334:. NASA. Archived from
1271:. NASA. Archived from
1069:
914:
803:
649:was the first passive
1960:Solrad mass simulator
1101:Robert Woodrow Wilson
1075:Collins Radio Company
1067:
912:
864:Northfield, Minnesota
794:
741:That same month, the
674:Goldstone, California
577:Reference system
445:Spacecraft properties
287:Reference system
153:Spacecraft properties
140:7.75 years (achieved)
2219:Orbital launches in
1896:Orbital launches in
1522:Davis and Tanimoto.
796:Holmdel Horn Antenna
717:William H. Pickering
432:5.5 years (achieved)
224:(Thor 270 / Delta 2)
2910:1964 in spaceflight
2905:1960 in spaceflight
2839:Surveyor Mass Model
1749:Gray, Mike (1992).
1661:on 28 December 2016
1634:Gunter's Space Page
1403:1997bify.book.....B
703:In July 1958, at a
682:Holmdel, New Jersey
358:
106:Harvard designation
48:
2935:Balloon satellites
2920:Passive satellites
1720:on 28 January 2010
1476:. Internet Archive
1338:on 23 August 2007.
1315:2008-05-11 at the
1184:Spaceflight portal
1118:depicting Echo 1.
1070:
953:Schjeldahl company
915:
860:Gilmore Schjeldahl
808:Goldstone Dry Lake
804:
747:United States Army
657:acting as passive
655:balloon satellites
572:Orbital parameters
521:LC-75-1-1 (SLC-2E)
282:Orbital parameters
2892:
2891:
2178:
2177:
1839:"Big Bounce, The"
1307:Astronautix.com,
1246:Norman L. Crabill
1159:
1031:Bell Laboratories
837:television camera
644:
643:
354:
353:
16:(Redirected from
2942:
2280:Jupiter Nosecone
2224:
2223:
2222:
2205:
2198:
2191:
2182:
2124:Korabl-Sputnik 3
2047:Korabl-Sputnik 2
1991:Korabl-Sputnik 1
1901:
1900:
1899:
1882:
1875:
1868:
1859:
1853:Internet Archive
1843:Internet Archive
1820:
1789:
1788:
1777:
1771:
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1746:
1740:
1734:
1733:
1729:
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1703:
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1613:
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1607:
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1588:
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1565:
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1563:on 13 July 2011.
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1537:
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1512:
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1280:
1261:
1186:
1181:
1180:
1179:
1161:
1160:
1144:
1132:
694:Arthur C. Clarke
598:Perigee altitude
581:Geocentric orbit
486:Start of mission
429:Mission duration
420:
366:
359:
308:Perigee altitude
291:Geocentric orbit
222:Thor DM-19 Delta
202:Start of mission
137:Mission duration
128:
56:
49:
34:The Echo Project
21:
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2499:Atlas-Centaur 3
2306:Zond 3MV-1 No.2
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1795:Further reading
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1363:. IEEE Spectrum
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1322:
1317:Wayback Machine
1305:
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1265:"Echo 1, 1A, 2"
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1177:
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1148:
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1136:
1133:
1124:
1116:a postage stamp
1062:
985:
969:micrometeoroids
961:
920:
868:low Earth orbit
851:
826:Pioneer program
789:
787:Ground stations
756:
736:Rudolf Kompfner
690:
608:Apogee altitude
591:Low Earth orbit
536:Lockheed Martin
534:
369:
318:Apogee altitude
301:Low Earth orbit
76:
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44:
37:
28:
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2450:Molniya-1 No.2
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2154:Vostok-1K No.4
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2019:Vostok-1K No.1
2015:
2008:
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1998:
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1832:External links
1830:
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1785:nobelprize.org
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1275:on 27 May 2010
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1020:Atlantic Ocean
1004:Cape Canaveral
1000:launch vehicle
984:
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957:
949:solar pressure
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850:
847:
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719:, director of
713:John R. Pierce
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551:End of mission
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18:Echo satellite
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2657:Apollo AS-102
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2396:Transit 5BN-3
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2389:Luna E-6 No.5
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2345:Luna E-6 No.6
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2148:Discoverer 19
2146:
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2130:Explorer S-56
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2100:
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2025:Discoverer 13
2023:
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2012:Discoverer 12
2009:
2007:
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1978:Luna E-3 No.2
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1971:Luna E-3 No.1
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1965:Discoverer 11
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2849:Transit 5E-5
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2697:Dragsphere 2
2692:Dragsphere 1
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2403:Transit 5E-4
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2166:
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2142:Pioneer P-31
2140:
2128:
2111:
2089:
2084:Mars 1M No.2
2082:
2075:
2070:Mars 1M No.1
2068:
2058:Pioneer P-30
2056:
2034:
2017:
2010:
1983:
1976:
1969:
1942:
1930:
1923:
1918:Discoverer 9
1916:
1847:A film clip
1837:A film clip
1824:
1802:
1784:
1775:
1751:
1744:
1722:. Retrieved
1718:the original
1707:
1685:. Retrieved
1675:
1663:. Retrieved
1659:the original
1649:
1637:. Retrieved
1633:
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1602:. Retrieved
1592:
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1569:
1561:the original
1556:
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1534:. Retrieved
1530:
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1508:
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1478:. Retrieved
1467:
1439:
1393:
1365:. Retrieved
1354:
1336:the original
1330:
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1308:
1277:. Retrieved
1273:the original
1268:
1259:
1199:
1113:
1097:Arno Penzias
1090:
1083:
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994:
986:
962:
937:benzoic acid
921:
887:
883:
876:
852:
830:
805:
781:
761:
757:
740:
733:
705:US Air Force
702:
691:
671:
647:Project Echo
646:
645:
506:Thor-Agena B
460:Manufacturer
386:Mission type
168:Manufacturer
86:Mission type
29:
2864:Explorer 26
2854:San Marco 1
2802:Explorer 25
2797:Explorer 24
2787:Explorer 23
2709:Explorer 22
2672:Explorer 21
1665:27 February
1367:10 February
1105:Nobel Prize
945:solar cells
929:sublimating
880:portmanteau
618:Inclination
559:7 June 1969
513:Launch site
491:Launch date
328:Inclination
269:25 May 1968
229:Launch site
207:Launch date
178:Launch mass
2899:Categories
2834:Titan 3A-1
2636:Titan 3A-2
2530:Elektron 4
2525:Elektron 3
2290:Elektron 2
2285:Elektron 1
2113:Transit 3A
2097:Explorer 8
2064:Courier 1B
2036:Courier 1A
2001:Transit 2A
1955:Transit 1B
1724:4 February
1604:30 January
1279:6 February
1252:References
1206:Courier 1B
1103:for their
1050:solar sail
1039:Thor Agena
1010:, and the
997:Thor-Delta
965:sphericity
900:television
882:combining
849:Spacecraft
754:Objectives
688:Background
659:reflectors
556:Decay date
527:Contractor
517:Vandenberg
470:Dimensions
266:Decay date
243:Contractor
186:Dimensions
2881:underline
2829:Kosmos 51
2818:DS-2 No.2
2807:Mariner 4
2782:Mariner 3
2767:Kosmos 50
2762:Kosmos 49
2721:Kosmos 48
2715:Voskhod 1
2682:Kosmos 47
2667:Kosmos 46
2647:Kosmos 45
2630:Kosmos 44
2625:Kosmos 43
2620:Kosmos 42
2615:Kosmos 41
2600:Kosmos 40
2595:Kosmos 39
2590:Kosmos 38
2575:Kosmos 37
2565:Kosmos 36
2540:Kosmos 35
2505:Kosmos 34
2486:Kosmos 33
2476:OPS 4467B
2471:OPS 4467A
2461:Kosmos 32
2456:Kosmos 31
2424:Kosmos 30
2414:Kosmos 29
2373:Kosmos 28
2358:Kosmos 27
2332:Kosmos 26
2312:Kosmos 25
2265:OPS 3367B
2260:OPS 3367A
2250:SOLRAD 7A
2167:underline
1938:Pioneer 5
1687:8 October
1655:"Shotput"
1630:"Shotput"
1557:The Forum
1536:8 January
1411:229170160
1054:PasComSat
925:meteorite
892:telephone
884:satellite
842:Minitrack
821:megahertz
711:engineer
698:Sputnik 1
663:microwave
464:Bell Labs
411:1964-004A
407:COSPAR ID
377:NASA A-12
172:Bell Labs
119:1960-009A
115:COSPAR ID
77:NASA A-11
2869:OPS 3762
2859:OPS 3358
2844:OPS 6582
2824:OPS 4439
2792:OPS 3360
2777:OPS 3062
2772:OPS 5434
2757:OPS 5063
2752:OPS 4384
2726:OPS 3559
2703:OPS 4036
2687:OPS 5798
2677:OPS 3333
2662:OPS 4262
2652:OPS 3497
2610:OPS 2739
2605:Syncom 3
2585:OPS 3216
2580:OPS 3802
2570:OPS 3042
2560:Ranger 7
2535:OPS 3491
2520:OPS 4923
2515:OPS 3684
2510:OPS 3395
2481:OPS 3754
2466:OPS 3236
2444:OPS 3483
2439:OPS 4412
2429:OPS 3592
2419:OPS 2921
2409:OPS 3743
2383:Polyot 2
2378:Gemini 1
2352:OPS 3467
2327:OPS 3435
2322:OPS 3722
2317:OPS 2423
2300:OPS 3444
2295:Ranger 6
2119:SOLRAD 2
2006:SOLRAD 1
1681:"Echo 1"
1639:21 March
1598:"Echo 2"
1531:NASA JPL
1480:15 March
1449:62404314
1313:Archived
1235:TransHab
1194:, AMSAT-
1170:See also
1077:and the
396:Operator
96:Operator
2885:italics
2550:Vela 2B
2545:Vela 2A
2363:Ariel 2
2270:Relay 2
2255:SECOR 1
2240:Poppy 3
2171:italics
2107:TIROS-2
2077:Samos 1
2030:Echo 1A
1996:Midas 2
1950:TIROS-1
1932:Midas 1
1399:Bibcode
1229:Telstar
1122:Gallery
1043:geodesy
989:Shotput
983:Flights
973:mercury
888:balloon
727:in the
538:(Agena)
417:SATCAT
125:SATCAT
47:Echo 1A
2812:Zond 2
2555:ERS-13
2368:Zond 1
2275:Echo 2
2245:GGSE-1
2228:1965 →
2213:← 1963
1985:Echo 1
1905:1961 →
1890:← 1959
1813:
1763:
1683:. NASA
1600:. NASA
1447:
1409:
1217:PAGEOS
1147:Echo 1
1086:Moscow
1060:Legacy
1027:Echo 1
1008:LC-17A
959:Echo 2
918:Echo 1
898:, and
628:Period
587:Regime
533:(Thor)
502:Rocket
368:Echo 2
357:Echo 2
338:Period
297:Regime
237:LC-17A
218:Rocket
75:ECHO 1
2642:OGO-1
1527:(PDF)
1196:OSCAR
1192:AO-51
1016:Delta
896:radio
872:Earth
856:Mylar
676:, to
667:Earth
622:81.5°
424:00740
374:Names
332:47.2°
132:00049
72:Names
2492:ESRS
2338:BE-A
2221:1964
1944:S-46
1898:1960
1811:ISBN
1761:ISBN
1726:2010
1689:2015
1667:2021
1641:2024
1606:2019
1538:2022
1482:2020
1445:OCLC
1407:OCLC
1369:2021
1309:Echo
1281:2010
1200:ECHO
1099:and
1091:The
1012:Thor
886:and
455:ECHO
400:NASA
163:ECHO
100:NASA
1757:5–6
1006:'s
833:Sun
680:in
661:of
496:GMT
451:Bus
419:no.
212:GMT
159:Bus
127:no.
2901::
1809:.
1783:.
1759:.
1632:.
1555:.
1529:.
1490:^
1429:^
1405:.
1377:^
1299:^
1267:.
1111:.
977:mW
955:.
906:.
894:,
874:.
519:,
235:,
62:,
2204:e
2197:t
2190:v
1881:e
1874:t
1867:v
1819:.
1787:.
1769:.
1739:.
1728:.
1702:.
1691:.
1669:.
1643:.
1619:.
1608:.
1587:.
1540:.
1484:.
1462:.
1451:.
1424:.
1413:.
1401::
1371:.
1349:.
1294:.
1283:.
802:.
66:.
43:.
36:.
20:)
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