Each Mercury spacecraft was configured to the mission assigned, so no two were alike. Externally, two basic types of operational spacecraft were built by McDonnell Aircraft, the major differences were in the type of windows and side hatch. Spacecraft number 7 (Shepard's) was the only example of the early type to be manned. Figure 1 shows the basic dimensions of the Mercury spacecraft and escape tower.
|Figure 1. Mercury Spacecraft Basic Dimensions|
First the escape rocket halves (parts 1 and 2) were glued together. The resulting cylinder needed lots of filling and sanding. Part 1 has a cable raceway of sorts running up the side and a fairing which doubles as a locater tab to fit into the aft cap (part 5). The position and shape of the raceway is wrong. I chose to sand off the raceway but leave the fairing, then I cut a new notch in part 5 next to the tower leg attach point of part 13. The original notch in part 5 was filled with scrap plastic and a bolt-head attached to the top of the area filled. This part was glued to the assembled escape rocket. A new cable raceway and fairing were added to the escape rocket with 0.010" plastic stock built up in two layers. An excellent photograph of the raceway is in Scale Model Rocketry -- Methods and Data for the Historian-Craftsman by Peter Alway. The escape rocket nozzles (parts No. 7) were reduced on the inside to scale thickness and Evergreen 1/8" diameter plastic tube was used to create a stiffening ring at their base. The three nozzles were then glued to the escape rocket assembly.
Next, attention was given to the forward cap (part 10). First the attach points to the tower legs were carefully cut off and saved, then the raised bolts on the side of the cap were sanded off. The attach points are too long and cause the tower legs to sit out too far from the antenna housing (part 9). Also the top of the cap needed to be filed down to a more angular profile. After this was done, I cut down the three attach points to about one-third of their original length and re-attached them (See figure 2). This part was now primed and painted with Testors Model Master Gloss Black. When dry, a liquid masking agent was applied to cover the cap. Next the mold-marks on the three tower support legs (parts 11, 12, and 13) were cleaned up and the place where they are attached to the forward cap was bent to slightly straighten the legs. I used a second kit as a jig to construct the tower and did the following: First, parts 8 and 9 were temporarily glued together with Elmers white glue, after the altered cap was placed on the jig, I took each tower leg and white glued their bottom struts to part 8 of the jig while cementing their attach points to the cap. I didn't worry about the alignment of the top of the tower legs at this time. After the cement had set, extra cabling was added to the base of the legs. Next, I took the escape rocket assembly and white glued it to the top of the three legs. I straightened the tower and measured the distance between each leg where the large cross brace (part 14) should go, then cut Evergreen 0.025" rod to three equal lengths and glued each into place. I repeated this for the small cross brace (part 15), then used 0.025" rod for all the diagonal bracing. When all of the supports were dry, the joints were filled. Testors Contour Putty was used on these areas and the excess was cleaned off with denatured alcohol, leaving very little to sand. I primed and filled as necessary. The third subassembly for the escape tower was to cement the flow generator (part 4) to the forward cap (part 3).
Now all three subassemblies were painted (I used Testors Red No. 1103). The jettison rocket (part 6) was cleaned up and painted Floquil Old Silver. After it was dry and cemented into the bottom of the escape rocket, a piece of paper was wrapped around the jettison rocket and the escape rocket assembly was cemented onto the tower legs. Next I attached the upper cap assembly, filled those seams (again I used the Testors putty and denatured alcohol to minimize the sanding) and painted these areas red. What few decals I used were now applied. After pulling the masking agent off of part 10, the entire unit was sprayed with Micro Scale Satin finish. The paper mask was then removed from around part 6.
|Figure 2. Launch Escape Details|
|Figure 3. Part No. 30 revisions for spacecraft No. 7 details|
|Figure 4. Crew compartment details: Spacecraft No. 7|
|Figure 5. Periscope and External Electrical Interface Details|
|Figure 6. Mercury Spacecraft Instrument Panels|
|Figure 7. Spacecraft Cabin Arrangement|
|Figure 8. General Arrangement of Mercury Spacecraft|
|Full size PDF files of the figures|
You can download these files (each is approximately the size of an 8.5
x 11 inch page and has a resolution of 300 dpi) and print them on your
own printer for cleaner illustrations. The most current version of the Adobe Acrobat software may
be obtained free of charge from the Adobe web site:
Part 2: Redstone ConversionIn 1959 an advanced version of the Army's Medium Range Ballistic Missile (MRBM) Redstone was chosen as America's first manned launch vehicle. Originally called "Jupiter C" this version had sufficient performance to satisfy the mission requirements for the ballistic flight of the Mercury Program. The Jupiter C had lenghtened propellant tanks, lighter structure, and engine modifications to permit longer burning time. Further adaptation, however, was necessary to satisfy the manned mission. The major external modification ws the development of a new instrument section, called the aft unit. This section contained the pressurized instrument compartment, including flight control-sensing and abort systems, booster telemetry antennas and ballast. Attached to the top of the aft unit was a short spacecraft/booster adaptor. Out of a total of eight Mercury Redstone vehicles, five were launched. The first three were unmanned and were called the Qualification Flight Test Program. After the first two manned flights, the rest were cancelled.
The total length of the Mercury Redstone stack was 83.38 feet which I rounded down to 83.333 feet, or 83' 4" for the purpose of building the model. 288 inches (24 feet) is taken up with the Mercury stack: from the tip of the escape tower to the widest point of the heat shield. The Monogram kit scales out very well in this respect. The spacecraft/booster adaptor is a frustum 7 inches long with the diameter tapering from 74.5 inches at the top to 70 inches at its base. The instrument section is 140.5 inches long, propellant tank section is 450 inches, and the propulsion section is 110.75 inches in length. There are two noticeable seams in the stack, the first at 1.25 inches is between the instrument section and the propellant tanks. The second is between the propellant tanks and the propulsion section and is 2.5 inches tall. The diameter of the instrument, propellant and propulsion sections is 70 inches while the maximum diameter at the stabilizing fins is 152 inches.
Because the Jupiter C was shorter than the Mercury Redstone stack, two Glencoe Jupiter C kits were necessary to complete this conversion. I started by taking parts 11 R/L and 12 R/L and glued them all together. Then I measured up from the bottom 450 scale inches and took my razor saw and carefully cut through the cylinder. After sanding the edge square, a styrene strip about 1/4" tall was added around the inside of the cylinder. This gave a solid flange for attaching the instrument section. Then parts 11 R/L from the second kit were glued together, adn cut at 140.5 scale inches from one end to make the instrument section. By the way, the cylinder diameter of the Glencoe kit is two inches over scale (72 inches). The next step was to scribe and cut all external details into the propellant section. The fuel and oxidizer fill and drain and oxidizer vent orifices were drilled and filed out of the propellant section. A backing of sheet and tube styrene was fashioned for the fill and drains while a short piece of 1/8" styrene tube was used to back the oxidizer vent. The instrument section also had all major hatches scribed into it. Because I intended to model the launch pad umbilical masts, the umbilical door was cut out of the instrument section: this was backed by a piece of sheet styrene.
The next area tacked was the propulsion section, including the stabilizing fins and engine exhaust nozzle. This section of the kit has several scale problems. The cylindrical part measures 89 scale inches long, while it should be 94.75 scale inches. This also affects the length of the fins as they start from the top of the section and continue for 110.75 scale inches. The kit fins scale out to 105 inches. The diameter across the fins is also off, while the aerodynamic rudders scale out very nicely, being only one scale inch under in width. The diameber across the fins minus the rudders measures out at 128 scale inches -- it should be 114 scale inches. I decided not to fix any of this in my conversion as it would mean scratch-building a completely new propulsion section with fins and a new launch base.
Parts 13 R/L make up the cylindrical portion of the propulsion section. Part 13L has a hatch scribed into the side about halfway up. I scribed a similar hatch into part 13R so that when the two parts were glued together the hatches were opposite one another. (Adding a 0.005" thick panel around both hatch areas and rescribing the hatches would be more accurate.) The hydrogen peroxide fill valve was then created in the top of part 13L by cutting out the rectangle and building an indented box with 0.010" sheet plastic. The turbine exhaust pipe was added to part 13R by thinning a piece of Evergreen 3/16" styrene tube, drilling a hole in the bottom of the part and inserting the tube. Parts 13R/L were then glued together. Next the fin halves, Parts 21 and 24 were assembled, making four sets. Prior to the fins being fixed to the propulsion section, the leading edge was filed and sanded to scale thickness. The aerodynamic rudders (parts 23) had sink holes that were filled, the upper edge was filed to a fine edge, and the retaining ring removed from the pivot pin. The engine nozzle was used after a new retaining ring was fabricated to fit the bottome of the propulsion section. The nozzle and ring, carbon vanes and aerodynamic rudders were fitter after the final assembly of the booster stack to the launch base.
Next, the Spacecraft/Booster Adaptor was created out of three concentric rings of 0.040" styrene stock glued together and the edges carefully filed to a taper. The ring was constantly test fitted to the instrument section and bottom of the spacecraft. The inside of the ring was filed out to accept the spacecraft heatshield. I ended up with a ring that was 0.040" larger than the heatshield at the top. Enough plastic was left inside the ring to drill three holes for piano wire locator pins to attach the Mercury spacecraft. This was done by gluing the heatshield to the adaptor with white glue, drilling three 0.010" holes down through the heatshield into the adaptor. The heatshield was then removed and piano wire pins were inserted into the adaptor. The reason the adaptor was built 0.040" oversize at the heatshield was to accept a 0.020" by 0.040" band of styrene that encircled the base of the spacecraft, representing the clamp ring. I attached the spacecraft/booster adaptor to the instrument section with a 0.010" concentric ring to represent the flanges that are used to bolt the two elements together.
The last major subassembly was the launch base, steps one through five in the instructions. All four base support legs (part 2) were cleaned up and attached to the base ring (part 1). The blast deflector (part 3) was also cleaned up. The kit had lots of flash and mold marks on most of the parts. I decided to modify the rotating ring (part 4) by removing the gear teeth and replacing them with a 0.010" by 0.060" styrene strip collar. I scratch-built two umbilical mast receptacles. These were made from Plastruct 1/8" ABS round tubing. I cut two pieces 1/4" long and shaped them to look like a collared pivot hinge, retaining enough plastic to support the actual mast. Then I glued these to a base and secured them to the bottom of part 1. Because of the modifications to part 4, I didn't use parts 5 or 6, but glued the upper launch ring to the base ring. Parts 8, 9, and 10 were cleaned up and modified by drilling out holes to accept 0.025" styrene rod and two pound test monofilament. Part 7, the main relay box, was not used: I couldn't find any photos which showed this item attached to this type of Redstone launch base. Some added do-dads were scrounged from the spares box and placed around the outer base of the launch ring. Four pipe conduits were scratch-built out of Plastruct 1/4" ABS round tubing. These would be placed around the edge of the base. The actual umbilical masts were scratch-built from Evergreen 1/8" styrene tube and parts from the spares box. The flexible hose was created with tungsten lamp filament supported by 0.025" styrene rod. I found that I could superglue these items together after carefully bending the rod into its general configuration.
I then took a 6" by 6" plywood base and added a 0.040" styrene top. The major subassemblies of the launch base were painted with Floquil Gunmetal. The sheet styrene base itself was painted Floquil Cement and the the blast deflector was glued to the base. The launch ring assembly ws then attached to the deflector and most of the support equipment was added to the base. I left the umbilical masts themselves off until after the launch vehicle was attached. The launch base was then weathered with pastel chalk and simulated oil stains. The major subassemblies of the launch vehicle were then painted. I used Testors Model Master Med. Gray for the primer coat and Gloss White for the base coat. I masked off the propulsion section for the tracking markings and painted them with Testors Flat Black. The checkerboard markings on the instrument sections were applied with Microscale Black Decal Sheet as was the stripe around the middle of the propellant tanks. The MR 7 at the base of the tanks was pieced together using Micro Scale Sheet No 87-70-2 R.R. Gothic Letters & Numbers Black. (Note: The MR 7 which is seen on all four of the sides at the bottom of the propellant tanks refers to this particular Redstone booster, it being booster number 7. Grissom's flight, designated MR-4 by NASA, had MR 8 on its booster.) The red UNITED STATES on the sides came from Letraset 36 pt. Helvetica Medium Number 2120 Dry Transfer Sheet. The letters are a little small, but were as close as I could find. To apply these I took each letter and rubbed it onto a clear decal sheet. I then cut out each letter from the decal sheet and applied it to the side of the propellant section using Microscale Micro Set sparingly. If too much is used the dry transfer ink will run. The blast shields on the base of the propulsion section sere covered with silver decal sheet. After all these sections were dry a final coat of Microscale Micro Satin was airbrushed onto the model. The booster subassemblies were then glued together and attached to the launch base. The Mercury spacecraft minus the escape tower assembly was attached to the adaptor with epoxy cement. The spacecraft/booster umbilical covers and clamp ring covers were added with superglue, the umbilical covers having been prepainted flat black. The clamp rings were covered with red decal sheet cut to the proper witch and length and set down with lots of Microscale Micro Sol so they would conform to the plastic's shape.
The launch umbilical masts were stiffened with 0.040" piano wire and glued to the launch base. I also used 0.010" piano wire to attach the spacecraft umbilical mast to the booster at the top of the propellant section. The pressurization lines of the booster umbilical mast were then secured in the umbilical door opening that was cut into the instrument section. The last of the conduit lines feeding the umbilical masts were added to the base of the launch base. The final task was to attach the escape tower assembly to the top of the spacecraft. The astronaut figure on the pad was placed to give the model a sense of scale. The figure is a composite of the astronaut head and helment from the Monogram kit, the torso and legs from Monogram's F-15 ground crewman and the arms from one of the figures included in the Glencoe kit.
This conversion took about 230 hours to complete. Most of that time was taken up with modifying the Mercury end of the project and creating the scratch-built areas. As is usual, even more time was spent on research. I made a trip to the Lyndon B. Johnson Manned Spaceflight Center in Houston, Texas, where one of the remaining Mercury Redstone boosters is on display, so I took lots of photos and measurements. Overall, I was very pleased with the outcome of the project and the model took first place in the Real Spacecraft category and Best Spacecraft in Show at the 1992 IPMS/USA Nationals in Seattle.
Reference ListAmerican Rocket Society
Spaceflight Report to the Nation
New York Coliseum October 9-15, 1961
Jerome B. Hammack and Jack Heberic
Langley Air Force Base, Virginia
Avation Week and Space Technology
Sept. 21, 1959, Nov. 28, 1960, Dec. 5, 1960,
Dec. 26, 1960, May 8, 1961, May 15, 1961,
May 22, 1961, June 26, 1961, July 22, 1963
Commemorating The First United States Manned Space Flight
The Launch Operations Directorate
The Encyclopedia of U. S. Spacecraft
By Bill Yenne
Exeter Books 1985
The History of Manned Spaceflight
By David Baker, Ph.D.
Crown Publishers 1981
The Illustrated Encyclopedia of Space Technology
Chief Author Kenneth Glatland
Harmony Books 1981
The Illustrated History of NASA
By Robin Kerrod
Gallery Books 1986
Life in Space
Editor: Robert Grant Mason
Time-Life Books 1983
Vol. 49 No. 14 October 3,1960
Vol. 50 No. 18 May 5,1961
Vol. 50 No. 19 May 12,1961
Vol. 50 No. 20 May 19, 1961
The National Air and Space Museum Volume Two Space
By C. D. B. Bryan
Peacock Press-Bantam Books 1979
National Geographic Magazine
Vol. 119, No. 5 May 1961
Vol. 120, No. 3 September 1961
Petersen's Book of Man in Space Volume One
Editor: Al Hall
Petersen Publishing Co. 1974
Project Mercury-A Chronology NASA SP-4001
Prepared by James M. Grimwood
U.S. Government Printing Office 1963
Scale Model Rocketry-Methods and Data for the Historian-Craftsman
By Peter Alway 1990
This New Ocean-A History of Project Mercury NASA SP-4201
By Loyd S. Swenson, Jr,.James M. Grimwood, Charles C. Alexander
U.S. Government Printing Office 1966
We Seven-By the Astronauts Themselves
M. Scott Carpenter, L. Gordon Cooper, Jr., John H. Glenn, Jr.,
Virgil I.Grissom, Walter M. Schirra, Jr., Alan B. Shepard, Jr.,
Donald K. Slayton
Simon and Schuster 1962