Viking '75 Mars Lander Construction, Looking for Viking lander design/construction information Options

[Tom Dahl]

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:

• Viking Mars Missions Education and Preservation Project
• The Museum of Flight in Seattle
• NASA Langley Research Center
• California Science Center
• Virginia Air and Space Center
• Smithsonian Air and Space Museum

Here is a list of on-line albums with Viking information that I have gathered. Essentially all the photographs - about 3500 currently - were taken by me (with the notable exception of those in the "Misc diagrams" album, which come from historic sources). The photos have descriptions that explain the major subject of each image. To see the descriptions with the current Google Photos web album interface, click on an image and then click the small letter i in circle (i) icon in the upper right corner. This displays an information panel that includes the description. You can also zoom and pan to see the full resolution image detail. Many images in a number of the albums show the 1000 or so measurements I have been able to capture from actual Viking hardware, thanks to the kind cooperation of the above folks.

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

[Tom Dahl]

Here are exploded views of the wind cover for RTG #2. The two wind covers are nearly-identical mirror images of each other. They differ primarily in small items attached to the front face of the wind cover, and that the top of wind cover #2 has an indentation for clearance of the Low Gain Antenna which is located very close to the wind cover. As can be seen, the wind covers are more complicated than they perhaps appear. Each wind cover has internal stiffening ribs along the side and an internal panel near front-center. Each wind cover has a large circular vent on its bottom face near a front corner (visible left of center in the second exploded view below). The vent allows equalization of pressure during launch from Earth and landing on Mars, and is covered with fine mesh to filter out most Martian atmospheric dust. Each wind cover has a camera Reference Test Chart (RTC) attached to its front face. The RTC itself is exploded in these views. A small skirt surrounds the sides and front of the wind cover bottom edge, to minimize build-up of Mars dust under the wind cover during the mission.


Here are close-up views of RTG 2 within its wind cover, starting with a top view. The large conical Upper End Cap Cooler (ECC) is prominent surrounding the reservoir dome atop the RTG housing. The rear rim of the ECC is clipped for clearance within the sloping top of the wind cover. The curving coolant loop inlet and outlet lines are prominent in the upper right of the image. The flat disc radiator fin of the lower ECC blends into the black interior of the wind cover bottom, but it is quite large and obvious when you know what to look for. The rear edge of the radiator fin is also clipped to clear the wind cover's large spherical inward-bulging rear which in turn provides clearance for the lander's nearby propellant tank. The large red cable in the lower right carries the 4.4 volt DC electric output of the RTG, along with six instrumentation signal lines (two each for an internal pressure transducer, a fin root thermistor which measured the temperature of the interior surface of the RTG housing, and a Resistive Temperature Detector (RTD) which measured the temperature of one of the thermocouple pairs surrounding the RTG's internal heat source). The small cream-colored cable passing through an electrical connector near bottom-center delivers the signal from a hazard monitor thermistor which measured the exterior temperature of the RTG housing.

Here is a side view of RTG and wind cover 2 that is cut away to reveal RTG mounting details. The lower ECC has a flattish gray (I believe cast aluminum) body with a somewhat irregular shape. The coolant loop lines enter and exit from the right portion of the ECC body. Four stout tabs (only one of which is easily visible here below-center of the image) mount the ECC, and thus the RTG and wind cover, to the lander structure. The ECC's two inboard tabs are supported on titanium (for low thermal conductance) U-channel tripods and bipods (with lightening holes) that are in turn mounted to the Equipment Plate within the upper interior of the lander. The green-tinted object between the tripod and bipod and below the RTG front edge is a Thermal Switch for transferring variable amounts of RTG heat into the lander. The ECC's two outboard tabs bolt to small extensions of the lander body side beam structure. The lower ECC's flat disc radiator fin is cut away to better reveal the ECC body below the fin. The disc fin is thin on its outer perimeter, thickening toward its slightly depressed center.

The dark conical upper ECC is easily visible atop the RTG housing, and the coolant loop inlet and outlet lines can be seen passing into the upper ECC base. The larger-diameter striped segments of the coolant loop represent braided flexible hoses used in that area. The remainder of the coolant loop is rigid 0.25 inch tubing.