Mariner 5 (Mariner Venus 1967) was a spacecraft of the Mariner program that carried a complement of experiments to probe Venus' atmosphere by radio occultation, measure the hydrogen Lyman-alpha (hard ultraviolet) spectrum, and sample the solar particles and magnetic field fluctuations above the planet. Its goals were to measure interplanetary and Venusian magnetic fields, charged particles, plasma, radio refractivity and UV emissions of the Venusian atmosphere.
![]() Mariner 5 | |
Mission type | Venus flyby |
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Operator | NASA / JPL |
COSPAR ID | 1967-060A ![]() |
SATCAT no. | 2845 |
Mission duration | 1 year, 4 months (launch to last contact) |
Spacecraft properties | |
Manufacturer | Jet Propulsion Laboratory |
Launch mass | 244.9 kilograms (540 lb) |
Power | 170 W |
Start of mission | |
Launch date | June 14, 1967, 06:01:00 (1967-06-14UTC06:01Z) UTC |
Rocket | Atlas-SLV3 Agena-D |
Launch site | Cape Canaveral LC-12 |
End of mission | |
Last contact | Loss of contact December 4, 1967; briefly regained October 14, 1968[1][2] |
Flyby of Venus | |
Closest approach | October 19, 1967 |
Distance | 3,990 kilometers (2,480 miles) |
Instruments | |
Ultraviolet Photometer Two-Frequency Beacon Receiver S-Band Occultation Helium-Vector Magnetometer Solar-Plasma Probe Trapped Radiation Detector | |
Mariner Mariner 6 → |
Mariner 5 was actually built as a backup to Mariner 4, but after the success of the Mariner 4 mission, it was modified to be used for a Venus flyby mission to take place during the 1967 Venus launch window. Mariner 5 omitted several experiments from Mariner 4, including the TV camera, the ionization chamber/geiger counter, the cosmic ray detector, and the cosmic dust detector. It retained the helium-vector magnetometer, solar plasma probe, and trapped radiation detector from Mariner 4. Unlike Mariner 4, Mariner 5 needed to face away from the Sun to keep its high-gain antenna pointed at Earth because of its trajectory. As a result, the solar panels were reversed to be aft facing so they could remain pointed at the Sun. Additionally, since its mission to Venus brought it in closer proximity to the Sun, less solar cells were needed to achieve the necessary power generation and as a result the solar panels were reduced in size to save mass as well as to make room for two 50 MHz dual-frequency receiver (DFR) antennas that were mounted on the frame of two of the solar panels. Since the aft side of the spacecraft faced the Sun, the solar plasma probe was relocated to the aft-facing side of Mariner 5.[3]
The mounting for the high-gain antenna also needed modification. Unlike Mariner 4, where the geometry of the transfer orbit allowed for the high-gain antenna to be inclined at a relatively simple 38 degrees from the bottom plane, Mariner 5's trajectory required the high-gain antenna to be skewed at a more awkward angle. The high-gain antenna also included a single-use mechanism that allowed the high-gain antenna to make a shift in its angle as part of the radio occultation experiment.[3] Mariner 5 also included some additional equipment that was not flown on Mariner 4, such as its Ultraviolet Photometer, two 50 MHz DFR antennas, a 423 MHz DFR antenna mounted on the end of one of the solar panels, and a deployable Sun-shade on the aft of the spacecraft for thermal control. The UV Photometer was originally supposed to fly on Mariner 4 and would have been mounted to its TV Camera scan platform. However, it was removed (allowing it to be flown on Mariner 5) and swapped out for a thermal/inertial mass simulator late in the assembly of Mariner 4 as it was discovered to create electrical arcing problems that would have jeopardized the TV Camera.[3]
Prior to the choice of Venus as the target proposals had been made to send it to either the comet 7P/Pons–Winnecke or 10P/Tempel.[4]
Liftoff took place on June 14, 1967, from Cape Canaveral Air Force Station Launch Complex 12 on Atlas vehicle 5401. Booster performance was normal through the Atlas portion of the launch and the first Agena burn, with all systems operating at the proper level. During the second Agena burn, abnormal fluctuations in the engine chamber pressure occurred, however they did not preclude successful interplanetary injection. There had been several occurrences of this behavior on previous NASA and Air Force launches and a program was initiated to correct it which led to a redesign of the Agena turbopump gearbox.
Mariner 5 flew by Venus on October 19 1967 at an altitude of 3,990 kilometers (2,480 mi). With more sensitive instruments than its predecessor Mariner 2, Mariner 5 was able to shed new light on the hot, cloud-covered planet and on conditions in interplanetary space.
Radio occultation data from Mariner 5 helped to understand the temperature and pressure data returned by the Venera 4 lander, which arrived at Venus shortly before it. The Venera 4 and Mariner 5 data was subsequently analysed together under a combined Soviet–American working group of COSPAR in 1969,[5][6] an organization of early space cooperation.[7] With the data of these missions, it was clear that Venus had a very hot surface and an atmosphere even denser than expected.
The operations of Mariner 5 ended in November 1967 and it is now defunct in a heliocentric orbit.
Further communication attempts were tried, in a joint spacecraft solar wind / solar magnetic fields investigation with Mariner 4, back in communication with Earth after being out of telemetry for about a year or more around superior conjunction. During the experiment, both spacecraft were going to be on the same idealized magnetic field spiral carried out from the sun by the solar wind.
Between April and November 1968 NASA tried to reacquire Mariner 5 to continue probing interplanetary conditions. Attempts to reacquire Mariner 5 during June, July, and early August 1968 yielded no spacecraft signal.
On October 14, the receiver operator at DSS 14 obtained a lock on the Mariner 5 signal. A carrier wave was detected, but outside expected frequency limits and varying in wavelength. Signal strength changes indicated the spacecraft was in a slow roll. Nevertheless, it was possible to lock the spacecraft to an uplink signal, but no response was observed to any commands sent to it. Without telemetry and without any signal change in response to commands, there was no possibility to repair or continue to use the spacecraft. Operations were terminated at the end of the track from DSS 61 at 07:46 GMT on November 5, 1968.
Mariner program | |
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← 1966 · Orbital launches in 1967 · 1968 → | |
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Intelsat II F-2 | OPS 1664 | IDCSP 9 · IDCSP 10 · IDCSP 11 · IDCSP 12 · IDCSP 13 · IDCSP 14 · IDCSP 15 · IDCSP 16 | Kosmos 138 | Kosmos 139 | ESSA-4 | OV3-5 | OPS 4399 | Lunar Orbiter 3 | Kosmos 140 | OPS 6073 | Diadème 1 | Kosmos 141 | Kosmos 142 | Diadème 2 | OPS 4750 | OPS 4204 | Kosmos 143 | Kosmos 144 | Kosmos 145 | OSO 3 | Kosmos 146 | Kosmos 147 | Kosmos 148 | Kosmos 149 | Kosmos 150 · OGCh No.8 | Intelsat II F-3 | Kosmos 151 | Kosmos 152 | OPS 4779 | Kosmos 153 | ATS-2 · RPM-481 | Kosmos 154 | Kosmos 155 | Unnamed | OPS 0100 | Surveyor 3 | ESSA-5 | Soyuz 1 | San Marco 2 | OPS 4243 | Kosmos 156 | OPS 6638 · OPS 6679 · ERS-18 · ERS-20 · ERS-27 | Lunar Orbiter 4 | Ariel 3 | OPS 4696 · OPS 1967 | Kosmos 157 | Kosmos 158 | Kosmos 159 | Kosmos 160 | OPS 7218 | Kosmos 161 | OPS 4321 · OPS 5557 | Explorer 34 | Molniya-1 No.8 | ESRO-2A | NRL PL-151 · NRL PL-152 · NRL PL-153 · NRL PL-154 · NRL-PL 159 · Timation 1 · Calsphere 3 · Calsphere 4 · OPS 5712 | Kosmos 162 | OPS 4360 | Kosmos 163 | Kosmos 164 | Venera 4 | Kosmos 165 | Mariner 5 | Kosmos 166 | OPS 3559 · OPS 1873 | Kosmos 167 | Zenit-4 No.32 | OPS 4286 | Unnamed | SECOR-9 · Aurora | IDCSP 16 · IDCSP 17 · IDCSP 18 · IDCSP 19 · LES-5 · DODGE | Kosmos 168 | Surveyor 4 | Kosmos 169 | Explorer 35 | Zenit-4 No.33 | OPS 1879 | OV1-11 · OV1-12 · OV1-86 | OGO-4 | Kosmos 170 | Lunar Orbiter 5 | OPS 4827 | Kosmos 171 | Kosmos 172 | OPS 4886 | OPS 7202 | Kosmos 173 | Kosmos 174 | Zenit-2 No.51 | Biosatellite 2 | Surveyor 5 | Kosmos 175 | Kosmos 176 | OPS 5089 | Kosmos 177 | Kosmos 178 | OPS 4941 | Kosmos 179 | OPS 4947 | Kosmos 180 | Unnamed | 7K-L1 No.4L | Intelsat II F-4 | Molniya-1 No.9 | OPS 1264 | Kosmos 181 | Kosmos 182 | Kosmos 183 | OSO 4 | Molniya-1 No.12 | Kosmos 184 | OPS 4995 | Kosmos 185 | Kosmos 186 | Kosmos 187 | Kosmos 188 | Kosmos 189 | OPS 0562 · OPS 1587 | Kosmos 190 | ATS-3 | Surveyor 6 | Apollo 4 | ESSA-6 | Kosmos 191 | 7K-L1 No.5L | Kosmos 192 | Kosmos 193 | WRESAT | Kosmos 194 | OV3-6 | OPS 5000 | OPS 1001 | Pioneer 8 · ERS-30 | Kosmos 195 | Kosmos 196 | Kosmos 197 | Kosmos 198 | |
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. |
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Radar |
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Radiometer |
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