Viking '75 Mars Lander Construction, Looking for Viking lander design/construction information |
Viking '75 Mars Lander Construction, Looking for Viking lander design/construction information |
May 17 2012, 12:38 AM
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Member Group: Members Posts: 101 Joined: 3-May 12 From: Massachusetts, USA Member No.: 6392 |
Greetings all! I am searching for detailed construction and design information about the NASA Viking '75 Mars project hardware, particularly for the lander, aeroshell, base cover, and bioshield. Can anyone recommend good sources? I am especially looking for engineering drawings and under-construction photographs.
To set the stage, here is an album of about 100 drawings and photos which I've collected so far. I have already read the "usual" books, such as NASA RP-1027 "Viking '75 Spacecraft Design and Test", the press kits, the scientific papers produced about the mission, a number of industry papers covering various instruments and subsystems, the major Martin Marietta books, etc. I am hoping to find additional sources. Any ideas? Also, does anyone know if there are aeroshell, base cover, or bioshield components lurking in a museum or in storage somewhere? FYI, I have visited three of the best landers still on Earth: The Proof Test Capsule in the Smithsonian NASM, the Flight Capsule 3 (backup) in the Museum of Flight near Seattle, and the Science Test Lander in the Virginia Air and Space Center. I've taken nearly 1,000 photos of the three of them (most of which are publicly available in other Picasa Web albums of mine). I've taken a few measurements, but I would dearly love to find more authoritative drawings of more hardware (interior, exterior, everything). I have begun submitting some Freedom of Information Act requests to NASA/JPL which has started to bear some trivial but kind of fun fruit. --- Update as of March 2017: During the past few years I have been fortunate enough to collect a significant amount of information on the Viking lander hardware. My thanks to a number of organizations for providing me access to their resources:
Flight Capsule 3 in Seattle Museum of Flight (756 photos) Dimensioned diagrams of the FC3 lander PTC Lander at Smithsonian NASM 2013 (466 photos) PTC Lander at Smithsonian NASM 2016 (888 photos) Lander at Virginia Air and Space Center (622 photos) Dimensioned diagrams of the VASC’s lander Lander at California Science Center (456 photos) Dimensioned diagrams of the CSC's lander Misc diagrams, unusual photos (over 350 images) Body assembly blueprints Collector Head Shroud Unit at NASA LaRC (99 photos) Biology instrument at Cleveland MoNH (36 photos) Meteorology Sensor Assembly (60 photos) Meteorology Electronics Assembly (22 photos) Tape Recorder (53 photos) High Gain Antenna photos and measurements (96 images) XRFS Instrument (42 images) Viking lander contractor historic scale model (14 images) My Viking project documents collection The main focus of my efforts during the past few years has been to create an accurate and high-fidelity digital 3D model of the Viking lander. I've chosen to use the SketchUp software to build the model because a near-full-featured free version is available, allowing other people to use my model. The 3D model itself, as a work-in-progress, is available via DropBox. I update that model file periodically as major elements get added. I've created an album containing numerous renderings of digital model components, and I have a YouTube channel with some videos about the modeling project. I have also uploaded the lander core body and the Surface Sampler Collector Head to the SketchUp 3D Warehouse so that other people can easily access those components (the 3D Warehouse can be accessed from within SketchUp, or via web browser). The file on DropBox lister earlier contains those components and others. -- Tom |
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Jun 7 2023, 03:37 PM
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
Great post on the RTGs, Tom! Looking forward to seeing them integrated into the overall model. I've never been sure of exactly where they were, as they are underneath a cover and not shown well in most extent drawings and photos.
It's a little surprising to me that having the RTGs "inside" was the configuration they chose (with a "thermal switch"* to control the conduction between the RTG and the equipment plate). MSL and M2020, of course, have their RTGs outside with a fluid loop to bring in the heat. Seems like it would get pretty hot under the RTG cover. * https://ntrs.nasa.gov/api/citations/1981000...19810001592.pdf page 34. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jun 7 2023, 11:08 PM
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Member Group: Members Posts: 101 Joined: 3-May 12 From: Massachusetts, USA Member No.: 6392 |
Indeed it surely was pretty hot within the lander's wind covers, given that the RTG exterior housings were over 300F continuously. Even so, the conduction and radiation of heat into the lander was not sufficient during cold winter nights, thus the need for thermal switches used to occasionally provide a higher-efficiency conduction path under each RTG's front edge. (An earlier reply above has details of those thermal switches.) I think the rationale for enclosing the Viking lander's RTGs was due to lack of knowledge of Martian surface winds, and to some extent of surface pressure and gas composition. The covers were a strategy to avoid loosing too much heat to worst-case estimated winds; the risk of over-heating was apparently deemed minimal.
Regarding the installation of the RTGs, I have almost completed modeling the associated wind covers and their internal framework and fasteners, the RTG Upper and Lower End Cap Coolers and their plumbing, etc. Here is a sneak peak at the RTGs and wind covers on a partial lander for context: And here is a historic image from Martin Marietta showing the Proof Test Capsule lander (now in the Smithsonian National Air and Space Museum) without the wind cover tops. In this image instead of RTGs there are two ETGs installed - Electrically-heated Thermoelectric Generators: nearly identical to the RTGs but with an electric heater block instead of a Plutonium fuel capsule. The electric cable leading into the ETG reservoir dome is the indication of ETG vs. RTG. In both my 3D model rendering and the historic photo the black conical objects on top of the RTG/ETG (and within which the reservoir dome is situated) are Upper End Cap Coolers. You can see the coolant loop tubing that enters and exits the front edge of the cooler near the top of the RTG/ETG. The Lower End Cap Coolers are not visible due to the angle I chose in the 3D rendering, but one is barely visible under the left ETG in the historic photo. It is a black flat disc with a large cutout to accommodate the giant bulge in the wind cover bottom to avoid the fuel tank. An edge of the LECC is just visible at about the 7 o'clock position between ETG radiator fins. In the historic photo the massive plastic-wrapped hoses that encircle the ETG on the right (and that snake around behind the lander) are providing the coolant to the lander's coolant loop. The internal path of the coolant loop is visible in some of my earlier 3D renderings in posts above. |
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