UMSF space history photo of the month |
UMSF space history photo of the month |
Guest_PhilCo126_* |
Apr 26 2008, 05:27 PM
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#46
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Guests |
The 245 kg Mariner 5 was actually built as a backup for the 1964 Mariner 4 Mars flyby mission but after the success of the Mariner 4 mission, it was modified for a Venus flyby mission.
Mariner V was launched on 14th June 1967 and flew by Venus on 19th October 1967… Radio occultation data from Mariner-5 helped to understand the temperature and pressure data returned by the Soviet-Russian Venera 4 lander which landed a day earlier. Mariner’s close encounter over the night side and subsequent swing across the terminator towards the Sun altered its trajectory, allowing the determination of the planet’s mass at 81.50% of Earth’s. The operations of Mariner 5 ended on 21st November 1967 when the craft was put in hibernation. Between April and November 1968, NASA tried to reacquire Mariner 5 to continue probing interplanetary conditions… without success. |
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Apr 27 2008, 08:12 AM
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#47
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
At or near the end of the planned period of reacquisition attempts, they DID recover the signal from Mariner 5. They detected carrier wave only, no telemetry, WAY outside expected frequency limits, I think varying irregularly in wavelength, and with signal strength variations indicating the spacecraft was in a slow roll. They were able to get the spacecraft to lock on to an uplink signal, I think, but no response whatever was observed to any commands sent to the spacecraft. Without telemetry and without any signal change in response to commands, they had very little to go on for troubleshooting.
Mariner 5 was in some mechanical equivalent of a "Permanently Vegetative State" and they finally just gave up on it. The recovery attempts were part of a dual 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 spacecaft were going to be on the same idealized magnetic field spiral carried out from the sun by the solar wind. Mariner 4 did fine, 5 was useless. Mariner 4's attitude control gas ran out at the end of it's extended mission and the spacecraft transmitter was commanded off. |
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Apr 27 2008, 10:00 AM
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#48
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Phil, was Mariner 5 pretty much a backup bus for Mariner Mars 64? Reason I ask is that of course Mariner 3 was supposed to fly with 4 but was lost; seems odd that there would be a third spacecraft held in reserve, esp. because 5 had no camera.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Apr 27 2008, 07:31 PM
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#49
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Phil, was Mariner 5 pretty much a backup bus for Mariner Mars 64? Reason I ask is that of course Mariner 3 was supposed to fly with 4 but was lost; seems odd that there would be a third spacecraft held in reserve, esp. because 5 had no camera. Mariner 5 would have had a camera as a Mars mission, but it was determined that that camera would have been relatively useless for a Venus mission, so it was removed, which also allowed the scan platform to be removed. To be clear, they didn't think that pictures of Venus were useless, but they didn't feel the Mariner 4 style camera would be able to take useful pictures. Had Mariner 4 failed, it probably would have been launched as a Mars probe. -------------------- |
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Apr 29 2008, 11:42 AM
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#50
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Well, they were probably right in that regard. I'm just a bit amazed that the early Mariner bus was that flexible in terms of mission assignments; good design!
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Apr 30 2008, 07:35 AM
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#51
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
Mariner 5 was an engineering test vehicle for Mariner Mars 1964, but it had not been "abused" during light development and the relevant hardware on it took relatively little effort to refurbish to flight-ready status.
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Guest_PhilCo126_* |
May 1 2008, 08:55 AM
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#52
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The next pair of Mariner spacecraft were the Mariner VI & VII.
Mariner VI was launched on 25th February and flew by Mars on 31st July 1969. Mariner VII was launched on 27th March and flew by Mars on 5th August 1969. Both 413 kg spacecraft ( originally Mariner F & G ) were launched with the more powerful Atlas-Centaur rocket combination which permitted extra weight to the spacecraft. At conception, scientists even suggested an atmospheric entry probe but it was rejected on grounds of time & cost. However, both spacecraft carried a scan platform underneath the main octagonal magnesium body. Among the instruments were wide-angle + narrow-angle television cameras which permitted for the first time to make far-encounter images which were taken with 37 minutes intervals. When these were played back, scientists could see a turning globe with the poles clearly visible. Mariner VI made 50 far-encounter images and 25 flyby surface photos. Mariner VII made 93 far-encounter images and 33 flyby surface photos. However, interesting features weren’t seen until NASA-JPL launched Mariner IX to go in orbit around the red planet in 1971… that’s for next time! the other Phil |
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May 1 2008, 01:48 PM
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#53
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Solar System Cartographer Group: Members Posts: 10198 Joined: 5-April 05 From: Canada Member No.: 227 |
I like the 1960s laptop.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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May 1 2008, 02:17 PM
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#54
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
I like the 1960s laptop. It was known as the MacBook Anvil. -------------------- If Occam had heard my theory, things would be very different now.
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May 1 2008, 04:30 PM
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#55
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Member Group: Members Posts: 753 Joined: 23-October 04 From: Greensboro, NC USA Member No.: 103 |
I miss having knobs to turn and switches to throw. Depressing keys all the time is...depressing.
-------------------- Jonathan Ward
Manning the LCC at http://www.apollolaunchcontrol.com |
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May 1 2008, 04:51 PM
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#56
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Solar System Cartographer Group: Members Posts: 10198 Joined: 5-April 05 From: Canada Member No.: 227 |
I know, I know... I mean, picture it... the bolt of lightning strikes the tower, the Professor gazes expectantly at the *thing* on the slab, and Igor lurches over to the desk to press CTRL-L... it just doesn't work.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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May 2 2008, 02:21 AM
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#57
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Junior Member Group: Members Posts: 55 Joined: 8-November 06 From: Indiana, USA Member No.: 1337 |
Secretly, I admire Mariners 6 and 7. To my untrained eye, their images have the quality of a Viking Era image. Likewise, Mariner 7 was the first spacecraft to provide data about another planetary satellite, Phobos. I have searched for information about the demise of these craft? I know they were occulted by the Sun long after their planetary encounter. Does anyone have any information about the last contact with these great travelers and why they were not heard from again.
Thanks Ken |
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Guest_PhilCo126_* |
May 2 2008, 10:02 AM
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#58
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Guests |
Mariner Mars 1969 in launch configuration ( with thanks to Paolo Ulivi )
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May 2 2008, 10:11 AM
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#59
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
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May 4 2008, 02:45 AM
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#60
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
"...the last contact with these great travelers and why they were not heard from again."
Mariners 6 and 7 did not have any significant cruise science capability. Their entire science package were remote sensing experiments located on the spacecrat's scan platform. After Mars encounter, the primary mission concluded with sufficient tape recorder readouts via different telemetry modes etc until they were sure there was nothing more to recover from the data onboard. So there was very little science to be done during extended missions. There was one engineering experiment done where the midcourse motor was fired and immediately afterwards, the infrared spectrometer was used to examine the spectrum of the dissapating exhaust plume. They did see spectral features, I presume related to hydrazine and ammonia (from hydrazine breakdown). They may have taken some images of black space possibly with a bright star in the camera's view in attempts to diagnoise noise problems with the analog tape recorders (there was oxide crud on the tape heads -- one reason the images are relatively cruddy). Other engineering exercises were performed on the spacecraft. The missions ended maybe a year after Mars encounter when attitude control nitrogen gas was depleted and I presume transmitters were turned off, as was Mariner 4's. Some documentation on this was in the JPL TR series mission reports, others, on the later extended mission, in JPL reports on Deep Space Network avtivities. You may be able to find them in government document repositories in Engineering Libraries on large university campuses. I think thwere was some s |
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