OSCAR 3 (a.k.a. OSCAR III) is the third amateur radio satellite launched by Project OSCAR into Low Earth Orbit. OSCAR 3 was launched March 9, 1965 by a Thor-DM21 Agena D launcher from Vandenberg Air Force Base, Lompoc, California. The satellite, massing 15 kg (33 lb), was launched piggyback with seven United States Air Force satellites. Though the satellite's active life was limited to sixteen days due to battery failure, OSCAR 3 relayed 176 messages from 98 stations in North America and Europe during its 274 orbit life-time -- the first amateur satellite to relay signals from Earth. As of 2022, it is still in orbit.
Mission type | Communications |
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Operator | Project OSCAR / DoD |
COSPAR ID | 1965-016F |
SATCAT no. | 1293 |
Mission duration | 57 years, 6 months and 17 days (in orbit) |
Spacecraft properties | |
Launch mass | 15 kilograms (33 lb) |
Dimensions | 7 in × 12 in × 7 in (18 cm × 30 cm × 18 cm) |
Start of mission | |
Launch date | 9 March 1965, 18:29:47 UTC |
Rocket | Thor SLV-2 Agena-D |
Launch site | LC-75-1-2 |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth |
Eccentricity | 0.00227 |
Perigee altitude | 884 kilometers (549 mi) |
Apogee altitude | 917 kilometers (570 mi) |
Inclination | 70.1 degrees |
Period | 103.1 minutes |
Epoch | 9 March 1965 |
OSCAR |
Project OSCAR Inc. was started in 1960 by members of the TRW Radio Club of Redondo Beach, California as well as persons associated with Foothill College to investigate the possibility of putting an amateur satellite in orbit. Project OSCAR was responsible for the construction of the first Amateur Radio Satellites: OSCAR 1,[1] launched from Vandenberg AFB in California on 12 December 1961, which transmitted a “HI” greeting in Morse Code for three weeks,[2] the similar OSCAR 2, OSCAR 3, and OSCAR 4.[1]
OSCAR 3 was a 15 kg (33 lb) rectangular-prism-shaped satellite, 7 in × 12 in × 17 in (18 cm × 30 cm × 43 cm) in dimension. Unlike its predecessors, which could only transmit a morse code "HI" signal through their beacons, OSCAR 3 was a true communications satellite. Equipped with a translator, when the satellite received signals broadcast to it at 144.1 MHz, its translator converted them to 30 MHz for amplification, and then reconverted them to 145.9 MHz for further amplification and retransmission. A watt of power was available for transmission; if more than one signal were received simultaneously, they shared the power in proportion to their signal strengths when received. OSCAR 3 also carried a beacon like OSCARs 1 and 2, though of lower power.[3]
Four quarter-wave antennas (two for input/output to the translator, one for the beacon, and one for telemetry to the ground) were mounted on the sides of the lightweight magnesium-lithium alloy satellite. The hull was covered with shiny aluminum foil tape to reflect the heat of the sun, and lack stripes were painted over the shiny aluminum to radiate heat away from OSCAR 3 during the times it orbited in the shadow of the earth. A large 18-volt battery powered the satellite, though the beacon was designed to continue functioning, supplied by power from solar cells and a rechargeable battery.[3]
OSCAR 3 flew on the NRL Composite 5 mission, which lofted an unprecedented[4] eight satellites on a single Thor Augmented Delta-Agena D rocket (including POPPY 4, an electronic signals intelligence (ELINT) surveillance package, GGSE-2, GGSE-3, Surcal 2B, SECOR 3, SOLRAD 7B, and Dodedcapole 1) on 9 March 1965 from Vandenberg Air Force Base Space Launch Complex 1, Pad 2.[5][6]
Though the satellite's active life was limited to sixteen days due to battery failure,[7] OSCAR 3 relayed 176 messages from 98 stations in North America and Europe during its 274 orbit life-time.[8] The two beacon transmitters continued operating for several months.[9][10] OSCAR 3 was thus the first amateur communications satellite to relay voice contacts in the VHF 2 meter band, the first amateur satellite to operate from solar power and relay signals from Earth, and the first satellite to use beacon transmitters separate from the main communications system.[11]
As of 2022, OSCAR 3 is still in orbit, and its position can be tracked online.[12]
← 1964 · Orbital launches in 1965 · 1966 → | |
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Kosmos 52 | OPS 3928 | OPS 7040 | OV1-1 | TIROS-9 | OPS 4703 | Kosmos 53 | OSO-2 | LES-1 | DS-P1-Yu No.2 | Apollo AS-103 · Pegasus 1 | Ranger 8 | DS-A1 No.6 | Kosmos 54 · Kosmos 55 · Kosmos 56 | Kosmos 57 | OPS 4782 | Kosmos 58 | Surveyor SD-1 | Kosmos 59 | NRL PL142 · GGSE-2 · GGSE-3 · SECOR 3 · Solrad 7B · Surcal 4 · Dodecapole 1 · OSCAR 3 | OPS 7087 · SECOR 2 | Kosmos 60 | OPS 4920 | Kosmos 61 · Kosmos 62 · Kosmos 63 | OPS 7353 | Voskhod 2 | Ranger 9 | Gemini III | Kosmos 64 | OPS 4803 | OPS 4682 · SECOR 4 | Intelsat I F1 | Luna E-6 No.8 | Kosmos 65 | Molniya 1-01 | OPS 4983 · OPS 6717 | Explorer 27 | OPS 5023 | LES-2 · LCS-1 | Kosmos 66 | Luna 5 | OPS 8431 | OPS 8386 | Apollo AS-104 · Pegasus 2 | Kosmos 67 | OPS 5236 | OV1-3 | Explorer 28 | Gemini IV | Luna 6 | OPS 8425 | Kosmos 68 | Titan 3C-7 | OPS 8480 | Kosmos 69 | OPS 5501 · OPS 6749 | TIROS-10 | Kosmos 70 | OPS 5810 | Zenit-2 No.28 | Kosmos 71 · Kosmos 72 · Kosmos 73 · Kosmos 74 · Kosmos 75 | Proton 1 | OPS 8411 | Zond 3 | OPS 5543 | OPS 6577 · OPS 6564 · ERS-17 | Kosmos 76 | Apollo AS-105 · Pegasus 3 | Kosmos 77 | OPS 5698 · OPS 6761 | SEV · SECOR 5 | Surveyor SD-2 | OPS 8464 · Dodecapole 2 · Tempsat-1 · Long Rod · Calsphere 4A · Surcal 5 | Kosmos 78 | OPS 7208 | Gemini V (REP) | Kosmos 79 | OSO-C | OPS 3373 | Kosmos 80 · Kosmos 81 · Kosmos 82 · Kosmos 83 · Kosmos 84 | Kosmos 85 | OPS 8068 | Kosmos 86 · Kosmos 87 · Kosmos 88 · Kosmos 89 · Kosmos 90 | OPS 7221 | Kosmos 91 | OPS 7208 | Luna 7 | OV1-2 | OPS 5325 | OGO-2 | Molniya 1-02 | OV2-1 · LCS-2 | Kosmos 92 | Kosmos 93 | GATV 5002 | Kosmos 94 | OPS 2155 | Proton 2 | Kosmos 95 | Explorer 29 | OPS 8293 · OPS 6232 | Venera 2 | Venera 3 | Solrad 8 | Kosmos 96 | Kosmos 97 | Astérix | Kosmos 98 | Alouette 2 · Explorer 31 | Luna 8 | Gemini VII | FR-1 | OPS 7249 | Kosmos 99 | Gemini VIA | Pioneer 6 | Kosmos 100 | Kosmos 101 | OV2-3 · LES-3 · LES-4 · OSCAR 4 | OPS 1509 | OPS 4639 | Kosmos 102 | Kosmos 103 | DS-K-40 No.1 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets. |
OSCAR satellites | ||
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Satellites |
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