Modeling the Gemini in 1/24 Scale

David Weeks


  • Introduction
  • A Very Short History
  • A Brief Vehicle Description
  • Crew Cabin - External Changes
  • Crew Cabin - Interior Details
  • Gemini 4 Astronaut Figures
  • Crew Cabin - Final Assembly
  • Adapter Modules - Gemini 4 Model
  • Gemini B Adapter - General
  • Gemini B Adapter - Retro Section
  • Gemini B Adapter - Equipment Section
  • Wiring Harnesses
  • Handling Fixtures
  • Gemini B Hardware
  • Reference List

  • Introduction

    After I started modeling again in the 80's, one of the projects I wanted to do was an accurate spacecraft from 1/24 Gemini kit. I've always felt that this kit would lend itself well to super-detailing. My first thought was to do a model of GT-4 with Ed White space walking. I tried to collect reference material, and at that time, the pickings were slim. A little later, after meeting a fellow space enthusiast, some of that started to change. Don Pealer was also into "retro-space", that is, programs of the late 50's and 60's. Don does some modeling, but his real skill is in hunting down hard to find research material. Don was working on a pet project of his, the Manned Orbiting Laboratory program (or MOL for short), and doing other research when I met him. I couldn't believe the amount of documentation he had on MOL as well as other 60's programs. We reached an agreement; I would build him a model and he would share some of his research. Don wanted a Gemini B MOL and that's how this project started. All of the accompanying MOL documentation is from Don and it's only the tip of the iceberg.

    If I was going to do a Gemini B for Don, I figured I'd also create the GT-4 mission model that I wanted. I started looking at the kit and determining what changes were needed. It became obvious that less modification would be required for the GT-4 model than for the Gemini B model. The following article deals mainly with the Gemini B model, but most of the crew cabin work was done for both models at the same time.

    A Very Short History

    The MOL project was first announced on December 10, 1963, by then defense secretary Robert McNamera. At the same press conference he announced the cancellation of the DynaSoar project. On June 10, 1969, the deputy secretary of defense, David Packard, announced the cancellation of the MOL project on grounds of cost savings and "advances in automated techniques for unmanned satellite systems". In the interim a total of 1.4 billion dollars had been spent on the Air Force's Manned Orbital Laboratory space project. On August 25, 1965, President Johnson announced the formal go-ahead of the project. The program as announced was to consist of two unmanned and five manned flights originating from Vandenberg Air Force Base in California. Douglas was to build the laboratory, McDonnell the Gemini B and General Electric was to manage the experiment package. In 1968, fabrication of the first three flight vehicles (two unmanned and the first manned spacecraft) was undertaken. The entire vehicle was to be launched on a variant of the Titan IIIC called the Titan IIIM.

    A Brief Vehicle Description

    The model depicts the McDonnell portion of the project and consists of the Gemini B re-entry vehicle and the spacecraft adapter. The major changes from NASA's Gemini were a thicker and slightly wider heat shield, a 25.8 inch diameter heat shield hatch, a 25 inch diameter Large Pressure Bulkhead (LPB) hatch, modified seats, hatch stowage area and instrument panels. The Gemini B adapter module is completely different from the NASA Gemini adapter module. First, it is only 54.03 inches in height. The forward diameter is the same as the NASA Gemini adapter (88.50 inches) but the base diameter is 118.35 inches. The NASA Gemini adapter is 90.0 inches tall, with a base diameter of 120 inches. Like the NASA Gemini adapter, the B adapter was divided into two sections. However, unlike the NASA Gemini adapter, the longer section is the retro adapter and is 33.32 inches in length. The major internal components include the six retro-rockets and their support structure, crew transfer tunnel and the environmental control system coolant pump module. The 20.17 inch tall equipment adapter includes two equipment beams, which support the main batteries, several "electronic black boxes", the primary oxygen subsystem and the coolant module water tanks. The equipment adapter also houses the pad abort control system separation rockets.

    Crew Cabin - External Changes

    New cove pieces.
    Each of the three parts of the crew compartment (Nos. 12, 13, 14) needed some amount of modification. On the bottom (Part no. 14), the small shingled section that includes the slot for the stand was removed and replaced with a similar section from a second kit. The major change on both the left and right crew compartment parts involved lengthening the coves in front of the hatches. This process started by placing the hatches in their respective openings and, using a French curve, drawing the outline of the lengthened cove. The material within those lines was then removed using an Exacto razor saw and files. The second kit was again used to supply the lengthen cove material. The cove area from the hatch as well as the corresponding crew compartment area was used. After gluing these two areas together, they were then shaped to fit into the vacant space. These lengthened coves are now available from RealSpace Models, if you don't want to tackle this on your own.

    After the outside edges of each new cove were shaped to fit, the hatch-side edge was faired in so that the hatch would fit snugly. This edge was further modified to accommodate a new hatch sill. Other modifications to the crew compartment included the reduction of both hatch sills by a little more than half their original width, the removal of the two umbilical covers just below each hatch opening and the filling of the hatch hinge pin receptacles. The last modification was to the lower portion of the parachute bridle on part 13 to mirror the configuration on part 12. After these modifications, the edges of the three crew compartment parts were lightly sanded and the parts glued together with the inside of each seam reinforced with .040" x .100" strip styrene.

    I feel that one of the hardest things to do on this kit is to take care of the seams between these crew compartment parts. My usual method of dealing with this type of seam (Where there is detail very close that you don't want to eliminate.) is to use Testors Contour Putty. After the putty has dried, the excess is removed with denatured alcohol (not isopropyl rubbing alcohol). However, this is a hit and miss proposition, it can take many applications to get a seam of this length completely filled. On the Gemini B model I decided to try a more conventional approach on the two lower seams. I used Squadron's White Putty and applied it only to the seam being very careful not to get it into the shingles. I then masked along the seam and sanded away the excess. (I can't stress enough the importance of initially fairing the outside surfaces of these seams so that you only need to fill the seam itself and not do any "contour work" as one must do if the seam itself is slightly mis-aligned.)

    Exterior seam.
    I then airbrushed a thin coat of Testors Camoflauge Gray on the seam and checked for flaws. If any were found, the process was repeated. After all looked good, the paint was removed with alcohol. In the sanding process, the only details removed were the tiny washers along the seam line. These were replaced by .005" styrene disks cut with a Waldron Punch and Die set using the smallest (.039") punch. A tiny spot of white glue simulated the missing nut on the new washers. The seam between the hatches was much easier to deal with. I left it alone and cut the parachute bridle cover out of .005" styrene stock, painted it white and glued it on near the end of the assembly process.

    The area forward of the cabin section was now tackled. This includes the Reentry Control Section (RCS Section) and the Rendezvous and Recovery Section (R&R Section), parts 15,16 (Capsule Forward Section, right and left half respectively) and part 17 (Nose Section). I chose two different approaches to replicate the exposed channels on either side of the rectangular washers on these sections. The first, used on the Gemini 4 model, was to scribe out the channels (I used a dental pick). This was completed after replacing the washers on both seams of the R&R Section with a strip of .005" styrene cut to the same width as the molded-on washers.

    While this was adequate, I wasn't totally pleased with the results. So on the Gemini B model, I decided to remove and replace the washers completely and create new channels. For the RCS Section, the locator pins were removed, the seams cleaned up, and the two parts were glued together. Then using some .030" sheet styrene, two circular disks were made to fit inside the section. These were glued in and the area around each washer line was removed until a .125" wide gap was created. A razor saw made quick work of removing most of this material with riffers and needle files used to clean and true up the edges.

    Because the average thickness of the RCS Section was .050", I used the following combination of styrene thickness to allow the new washers to flush up to the outer contour of the section. First, a .020" x .020" strip was glued even to the inside edge on each side of the gaps. This supported a .015" x .125" strip which filled the gap. After all seams were filled (I used the Testors Contour Putty cleaned up with denatured alcohol trick), .010" x .100" strip styrene was cut to length and carefully scribed to indicate each washer. These strips were then glued to each channel. Although this seems like a lot of work (and it is) the resulting channels on each side of the washers looked great! The bolts in the middle of each washer were the last detail added. These were, once again, a drop of white glue applied with the cut end of a toothpick.

    Nose sections.
    After removing the nose fairing, a similar sequence was used on the R&R Section. Four support disks were used, the first at the lower end, the next 5/16" higher, then one at 5/8" from the bottom and the last at the top of the section. Because some of the washers don't run straight up the R&R Section, a different technique was used to remove them. Micro Mark sells a micro saw set. This set has saw blades shaped like Number 11 Xacto blades and, of course, they fit into Xacto Number 1 handles. With one of these saw blades I was able to remove the angled washers. The reason for the two extra interior disks was two-fold; first, to pick up the "V" shaped shingle on the TY axis and second, to allow the R&R Section to be cut into two parts at the step (15/32" up from the lower edge). Using a razor saw, this cut was done after all channels were completed and allowed a .010" x 1-13/32" diameter disk to create a seam at this location. This also looked much better than a scribed line.

    The nose fairing was reconfigured based on the accompanying McDonnell photos. The three rendezvous latch covers were also removed from the side of the R&R Section. These were replaced with styrene "plugs" attached to the nose cap. This allowed the entire nose cap to be painted without the need for masking as well as creating a location for holding on to the completed reentry module for painting.

    Gemini 4 nose.
    For the Gemini 4 model, the nose fairing was also cut off and a 1-9/32" diameter disk was attached to form the base for the drogue covers, their associated cables and the UHF antenna. All of these items were scratch built. The other external additions were the horizon sensors, these were scratch-built and then painted white. Of course, you can now get all of this from Glenn Johnson's RealSpace Models 1/24 Gemini Detail Set.

    Heat shield hatch.
    Modifications to the heat shield (Part No. 5) included removing both attachment flanges for the retro-rocket adapter, filling the circumferential sink hole and scribing the scale 25.8" diameter heat shield hatch.

    Crew Cabin - Interior Details

    Modified Parts 4 and 6.
    Work on detailing the interior began by removing the rear bulkhead detail and seats on part 6 (Interior Bulkhead W/Seats). The edges were filed and sanded to remain flush with the inside edge of part 4 (Crew Compartment Interior). Pieces of styrene were added to the back of part 6 to extend the crew compartment interior to the contour of the heat shield. Also a 1/8" by .040" extension was added to the back edge of part 4. The rationale for this was that I didn't know exactly how much room in the interior the new seats and rails were going to take up and the crew compartment parts allowed this much expansion. Because of this extension, the notches for the front instrument panel ends were cut back by about 1/16".

    Seat rail attachment.
    Attention was now directed to the placement of the seats and seat rails. Numerous photos were scrutinized to get a sense of how the rails and seats interfaced with the hatch openings and other interior parts. Because I had decided to use the heat shield part as the rear bulkhead, the rails would have to be mounted to it. Their locations were determined by dry-fitting the crew compartment outer shell on the heat shield and then finding the center of each hatch opening. The rails needed to sit at a 12 degree angle from the Y axis and center in the hatch opening. The width of the back of the rails was determined and two pieces of .040" x 3/8" x 2" long styrene rectangles were glued on to the rear of the heat shield. This would give the rails a positive attach point.

    Seats rails.
    The rails were a somewhat complicated conglomeration of plastic. Not only did the rear edges have to match the curvature of the heat shield, but when completed they also had to sit in parallel to the instrument panel as well as have a 8 degree forward angle in relation to the vehicles X axis. I also added at the outside bottom of each rail the pivot hinge for the hatch actuator pistons. The only difference between the two sets of rails was that the Gemini B set had slots cut into their inside faces for the Large Pressure Bulkhead (LPB) hatch stowage. At this time I scribed the LPB hatch (A scale 25" diameter hatch) into the inside of the heat shield part. Both the inside and outside hatches were scribed using a compass with two metal points.

    Gemini B seats.
    The seats were based on both the Gemini and Gemini B spacecraft interior diagrams, several basic dimensions taken from the kit seats, and a three-view drawing that I did. This was the only component of the cabin interior for which I did a drawing. All four seat carcasses (as well as the rails) were built at the same time with the commander's seat for the Gemini 4 model being the "pathfinder". Every effort was made to make each pair of seats as identical as possible. After the basic shapes were built, the cushions and ejector handle details were fabricated. Since in the Gemini 4 model, the commander's seat was to be occupied, these details were modified to fit the figure, so the final look of this seat was somewhat different from the others.

    Hatch modifications.
    Next came the hatches. I went round and round about removing the hinge pins and finding some other method of hinging the hatches. I finally decided to remove the pins and use a doll house piano hinge. The major hatch modifications started by removing all of the molded detail from the inside surface. The recesses for the hatch sills were, in part, filled in with .030" x .030" strip styrene to match the smaller sills. The main reason for all of the sill work was to allow the hatch actuator piston hinge web-spars to sit as far back on the hatches as possible, as well as to allow the seats to slide in to the cabin during final assembly. The forward and rear web spars were built in two sets of opposite pairs. These structures were fabricated from .020" stock with .010" strips for the stiffing webs. Special attention was devoted to the rear web spars so they wouldn't interfere with the tops of the seat rails when the hatches were closed. The box-like structure that spans the two web spars was created out of .015" and .020" stock.

    Finished hatch.
    The hatch details were pulled from the proverbial "spares" box. The latches were HO scale diesel parts from Detail Associates Lift Ring Switcher (LR 1105), while the linkages were MU Air Hoses (MU 1508). After these parts were painted they were attached with Aleen's Tacky Glue. I use this product quite a lot in the final assembly of smaller, non load bearing parts. The window frames were created out of .015" and .040" sheet styrene with Grantline # 5098 bolts attached to the top. The windows themselves were .005" clear acetate dipped in Future floor wax. Again, Aleen's was used to attach these parts.

    Main instrument backing.
    After the rails, seats and hatches were basically completed and all fit adjustments were dealt with, attention shifted to the other details within the crew compartment. The centerline beam (Part 10, Upper Interior) was replaced. I originally was going to use the kit part but, as the fit was marginal against the outer compartment parts, a new one was fabricated. On this new part as well as on the rear bulkhead (Part 6), the latch receptacles were drilled out and filed to shape. Two beams were created at the forward portion of the cabin with latch receptacles also drilled and filed. These parts took some doing. The top profile needs to fit under the coves and the instrument panels sit in front of them. Several templates were created out of thin styrene stock to find the correct shape before the actual pieces were made.

    Crew cabin interior.
    The kit instrument panel (Part 11) was also replaced with several different structures. The new instrument panel consisted of an individual main console (center), command pilot and pilot's panels and the lower console (Part 3). Three other circuit breaker panels needed to be fabricated. These were located on the upper centerline beam (Overhead switch/circuit-breaker panel), and the left and right hand sides of the crew compartment interior (Left and right switch/circuit-breaker panel). The basic dimensions of the four main panels were based on the kit parts. First, backing pieces were cut-out, then the actual panels were cut to their respective shapes to be placed on the backing.

    Main instrument panels.
    Although the placement of the panels was the same on both models, the configuration of instruments and switches was entirely different between the two models. I used as much of the surface detail of the kit instrument parts as possible. This ordeal started with sanding the kit parts to an approximate thickness of .005". The individual components were then removed and, in the case of the Gemini 4 model, glued to the new instrument panel. All round gauges were taken from various Waldron Instrument placards. The two prominent Attitude Director Indicators (commonly called the "eight-ball") were created out of the swivel stand pieces (Parts 36 and 159) from the 1/48 scale Mercury and Gemini kit. These parts have raised lines on them, and when painted, have the desired three dimensional look.

    Gemini B panels.
    On the Gemini B vehicle, the commander and pilot's panels have most of the switches and instruments recessed. I suppose this configuration was used to protect the instruments during the transfer of the crews into the laboratory through the LPB and heat shield hatches. Because of the recesses, the construction of these panels was very different from the Gemini 4 model. All switch guards were made out of .020" styrene rod. The guards were located mainly on the switch/circuit breaker panels as well as on the main console.

    Crew cabin interior.
    Various items located on the side walls were also scratch-built. These included the secondary Oxygen Regulators, waste storage containers and miscellaneous storage compartments. The fabric covered containers were made out of A and B Epoxy Putty and sculpted into the appropriate shapes. The Gemini 4 model also had the left and right aft storage containers and the water management center scratch-built, while the centerline storage area was enlarged. The final interior parts were the quilted blankets. I used paper towels embossed with a diamond shaped form for the GT-4 model. For the Gemini B, I used a different product. This was the seal from a yogurt container (I don't know the brand, it was given to me by my Mom and she can't remember!). This thin aluminum had an embossed diamond pattern that was almost to scale. In both cases, the process of creating the blankets was the same; a paper pattern was created for each piece, the pieces were then cut out and painted and the edges were covered with thin strips of paper.

    Gemini 4 Astronaut Figures

    The kit astronauts were used to make both figures. For the commander, only slight modifications were necessary. This included shortening the legs, turning the head and separating the arms slightly from the torso. This last modification required two figures. The changes to the space walking figure were much more extensive. The legs were cut at the torso as well as at the knees and then repositioned to semi-standing attitude. The helmet and arms were also removed and the torso reinforced so that the umbilical could hold up the figure.

    Astronaut figure.
    To make the repositioned arms, two extra figures were required. Each figure supplied an arm. To do this, I glued the two figure halves together and then cut out both the left and right arms. After removing the hands, I used the two arm "halves" to make one complete arm. As an example, to make the right arm, the left arm piece was sanded to fit the right arm piece until a proper proportion was achieved. After sanding the shoulder to fit the torso, the appropriate hands were re-attached. I used A and B Epoxy Putty to fill the joints between cuts, this allowed fabric folds to be sculpted into the joints. The body was painted a light ivory while the helmet was painted white. The fabric folds were shadowed and highlights applied. The chest pack and the hand held maneuvering unit were scratch-built. A piece of copper wire was used for the umbilical line. This was twisted around a pencil and stretched and pulled to approximate that "zero g" look. Gold foil was wrapped around the line and a paper strip attached to the figure and line for the tether.

    Crew Cabin - Final Assembly

    Finished LPB hatch.
    Final assembly began by attaching the crew compartment interior (Part 4) to the rear bulkhead (Part 6) and fairing in that seam. The reworked centerline beam and the instrument backing panels were attached as well as the pedestal backing and its supporting structure. The sides panels for the pedestal were created out of .010" sheet stock. Painting began by airbrushing the interior, including the instrument panel and hatch interiors, with Testors Light Ghost Gray. The seat frames were painted Medium Gray and the cushions Camouflage Gray. The quilted blankets were painted Field Drab with the "tape" edges painted with Testors Metalizer Non-Buffing Aluminum. After detailing, the instrument panels and most of the other interior details were installed. After attaching the LPB hatch latching mechanism (Cal-Scale Freight Air Hoses #190-276 were used for the linkages) and the seat rails, the rear bulkhead/crew compartment interior assembly was attached to the heat shield.

    Finished crew compartment.
    The RCS and R&R sections were attached to the outer crew compartment section. (Note that the RCS section needs to be rotated so that the double row of shingles is in the TY position.) There's a bit of mis-match in diameters between the top of the crew compartment and the RCS section. This was fixed by gluing a .010" by .060" styrene strip at the lower edge of the RCS section. Now the interior and exterior assemblies were glued together. The heat shield was slightly larger in diameter in some areas and needed to be filed and sanded down to fair it up with the bottom edge of the crew compartment. New strap/umbilical fairings were made and then attached in the proper location to match with the adapter fairing housings. The seam between the heat shield and the crew compartment was hidden by a strip of .010" x .060" styrene that had its forward edge rounded off. As one length of this strip would not fit completely around the vehicle, it took two pieces to cover the seam. These were applied between the umbilical fairings and flush to the back edge of the heat shield. These strips not only hid the seam but represent the fiberite edge ring around the heat shield.

    Crew cabin.
    After masking the hatch openings, the process of painting the exterior began. For the Gemini B model, the heat shield was painted first. The main surface was covered with Testors Camouflage Gray with the hatch area Flat White. For the shingles on the main body, I choose a very dark Insignia Blue. I had two bottles of this color and prior to painting, I boxed these together. I didn't use a primer coat because of the darkness of the color and I wanted to decrease the paint build-up on the model. After masking, the fiberite edge ring and strap fairings were painted with Floquil British Crimson. The color selection was a little different for GT-4. The crew cabin exterior was primed and then painted with a mixture of Gloss Black and Ford Engine Blue, about three parts black to two parts blue.

    The decals were taken from Scale-Master USAF Lettering, sheet #2, SM-32B, while the insignias were from the Microscale 72-0084, Current US Navy Insignia sheet. I used the 1/72, 20" lettering and the 30" insignia. Each letter was individually cut out with all carrier film removed and then placed on the model. Even though a lot of work, this helped tremendously in allowing the letters to conform with the shingles. The same technique was used for the insignias, with the blue field cut away.
    Seat details.

    After all of the painting and decaling was finished, the few crew cabin internal details that were not installed before were now attached. This included the seats, the left and right switch/circuit-breaker panels and the hatches. The seats were finished by fabricating the oxygen hoses and restraint harnesses. The hoses were made out of tension springs filled with an annealed wire insert with connectors from Williams Bros. Ho Scale Pipeline and Fittings kit, No. 620. The harnesses were cut from paper, painted and Waldron 1/24th Scale Standard Seat Belt Buckles and Detail Master Racing Harness-Lever type, DM 2260 parts were used for the hardware.

    Adapter Modules - Gemini 4 Model

    To begin the work on the Gemini 4 adapter modules, all exterior details were sanded off and new access hatches were scribed. The two parts (part 27, Retro Module and part 51, Equipment Housing Module) were then glued together. The small lip between the sections was sanded down and then covered with a 1/8" x .020" styrene strip. Placed against this strip were two other styrene strips.

    The first strip, the one facing the crew compartment, was cut out of 010" by .040" stock with 77 notches cut equal distant around the adapter. The back strip was cut out of .010" x .100" styrene. This back strip was further modified with .060" being removed from most of its length. 88 "V" shaped notches were cut into this strip with the exception of the areas were it remained at .100".

    Retro module.
    The front of the retro module had a .020" x .030" strip attached on edge with 76 .015" x .020" x 5/32" stringers applied at a right angle to the edge. The strap and thruster fairings were scratch-built, as were the equipment module thruster housings. I applied 88 strips of black decal material cut to 1/32" width to the equipment module while also applying 77 strips to the retro module. This simulated the thermal control Kapton tape that was applied to adapter exterior.

    Rear thrusters
    The various antennas were also added. For the thermal blanket material that covers the back of the equipment module, I chose a gold colored mylar balloon. The support structure for this was created out of .040" sheet styrene. First, a 1-3/4" diameter ring was fashioned and supported 1-1/8" above the retro blast shield. Ten .040" x .100" strips were cut to length and spaced equal distant between the lower edges of the equipment adapter and the 1-3/4" ring. The gold mylar was cut into the proper shapes based on paper patterns and the mylar was glued in place with cyanoacrylate glue. A thin strip of gold mylar was then applied to each seam between blanket panels. The rear facing thrusters, as well as the other equipment placed in the blanket were scratch built as well.

    Gemini B Adapter - General

    Equipment section.
    As the Gemini B adapter was so different from the kit adapter module, a completely new piece was necessary. A master was turned on a lathe and the new adapter was vacuformed. The entire adapter was pulled in one piece. (The resulting shape looked a lot like a margarine tub.) The first step in transforming this into an acceptable adapter was to cut the shape to length, making sure that the top and bottom edges remained parallel. Both inner and outer surfaces were sanded, with 800 grit wet and dry paper used for the final sanding. Based on the McDonnell adapter shell drawing, the location of the six interior ring frames was determined and drawn onto the inside of the adapter. Using a pair of inside calipers, the outer dimension of each ring was then established. A drawing was then generated for each frame using the dimensions taken from the adapter. The width of each frame was determined, drawn, and for rings with lightening holes, their locations were also drawn. Based on the drawings, the ring frames were cut out of .015" stock while the lightening holes were created with the Waldron Punch and Die set using the .089" size punch. The inside edge of each ring was stiffened with .010" x .030" strip styrene. The frames there then glued into the adapter with Testors liquid cement.

    Next, the spacing for the 104 external hat section stringers was tackled. Yet another drawing was created that laid out the stringer locations as well as the 26 attachment lugs/shields radiating from the centerline of the vehicle. After this information was transferred to the adapter shell, the size and location of the three adapter fairings could be established. At this time the separation plane line between adapter sections was also located and drawn onto the adapter shell.

    Retro section.
    The adapter was then carefully cut into two sections using an Exacto razor saw and a strip of masking tape to guide the cut. The stringers were created out of .030" x .040" strip styrene. The forward edges were beveled to a 50 degree angle while the rear ends were squared off. At first I was going to use the lug shields of the Gemini adapter, but these proved to be too small to fair into the rear ends of the stringers, so the fairings were created out of .080" diameter styrene tubing from Contrail Model Aircraft.

    The final two adapter ring frames, located at the outer ends of each adapter section, were dealt with in two different manners. The front edge of the retro section had a .010" x.015" styrene strip glued on edge to the outside of the shell, flush to the top, while the aft ring of the equipment section was cut from .15" sheet stock with the 26 lugs carefully carved out around the outside of the ring.

    Gemini B Adapter - Retro Section

    Retro section.
    The retro section adapter fairings were constructed out of an extra adapter with enough material laminated together to create .120" thick pieces. These were shaped to fit within the three open areas between stringers and a .010" sheet backing piece was applied. The stiffening ribs came from .060" half round.)
    Retro rockets.

    The equipment contained within the adapter sections was mainly scratch built except for the retro-rockets and the environmental cooling unit (ECU). Several modifications were made to the retro-rockets. First, the outer edge of the nozzles (Parts 26) was thinned and the nozzle lengthened by drilling out the bottom. The locator tab on the casings (Parts 24, 25) was removed and attachment rings were inserted. Two holes were drilled into the ring of the casings that surrounds the nozzle to accept the igniters (Detail Associates, HO scale, "Motorola" Firecracker Radio Antenna RA 1805).

    ECU modifications.
    Support brackets
    The ECU was also modified from the Gemini kit. All three parts (31, 32, 33) were used, but each was modified and several smaller sub-assemblies were added. The retro-rocket support structure was constructed out of .015" sheet styrene. Both the front and back edges were stiffened with .010" x .080" strip stock. The backing panel was cut out of .010" sheet with .010" x.080" stiffeners. The mounting brackets for the retro-rockets were cut out of .015" x .030" strip for the base and .10" x .040" for the uprights. This was cut to length to make two brackets for each retro-rocket and a .025" hole was drilled in the upright to accept the mounting pins. A jig was created to position the brackets so the retro-rocket casings could be tilted to their appropriate angles.

    Transfer tunnel.
    The final major component for the retro section was the crew transfer tunnel. The cylinder for this was vacuformed out of .040" sheet stock from a master turned to a scale 31" diameter. The heat shield hatch cavity was built out of two adjacent sides of .250" x .375" rectangular tube placed on either side of the main tunnel cylinder. The various external stiffening rings were cut out of .015" sheet stock, while the flexible seal ends were taken from .040" sheet. The lower edge of each ring frame was covered with .015" x .020" strip. I elected to attach the tunnel only to the top spar of the retro-rocket support structure. This made installation of the tunnel much easier.

    Gemini B Adapter - Equipment Section

    Equipment section
    For the equipment section, the separation rockets were based on the McDonnell interior profile drawing (Fig. 2). The equipment support beams were constructed out of .015" styrene sheet stiffened by .015" x 3/32" strip with .060" channel used for equipment placement. The .060" channel was also used for the pick-up trusses. One side of this channel was removed to create these "L" shaped supports. The batteries were made out of .250" x .375" rectangular tube as were portions of the encoder and guidance interface adapter while the mulitplexer was created out of .187" x .312" rectangular tube. The tape memory unit was cut out of part 49 (Electronic Equipment Package) from the Gemini kit. The wiring harness connectors for all of these "boxes" were .040 styrene rod topped with Grantline 2-1/4" Nut, 5" Malleable Washers (No. 5093). The primary oxygen subsystem tanks were 1/4" diameter tube with parts 156 and 157 (Pressure Cell Half) from the 1/48 Mercury/Gemini kit used for the hemispherical ends. The cooling water tanks were created out of 7/16" diameter tube for the larger tank and 5/16" diameter tube for the smaller. The elliptical ends were filed out of .120" styrene plugs. I originally thought that the "fins" could be applied with .010" x .020" strip glued on edge to the tanks. This proved to be a mistake, so .010" sheet was used to make oversized disks (17/32" dia. and 13.32" dia. respectively). The tanks were sectioned and nine disks were glued into each tank. When these were dry, the "fins" were sanded down to a diameter just greater than the tanks.

    Wiring Harnesses

    Wiring harness jig.
    The wiring harnesses (There were a total of four.) were created using a "breadboard" for each harness. The breadboards were created from the adapter equipment layout drawings with the location and number of wires needed added to the drawings. "Styrene gates" were attached to the breadboard to constrain the wires and allow portions of the bundle to break-out were necessary. Size "O" Gudebrod Bros. Silk "C" Thru Color Blending Nylon Thread was used for the wire. After all of the wires were threaded into the breadboard, the bundles were tied and paper bands glued on to allow the bundles to be attached to the adapters. The wire bundles were brush painted with thinned Testors Neutral Gray and accented with a dark gray wash. The wiring harness guillotines were made out of .125" x .015" strips with 3/64" rod.

    Adapter interiors.
    The painting of the adapters and equipment began with the interior. A two-to-one mix of Testors Metalizer Non-Buffing Aluminum to Brass was used to paint the interior surfaces including the ring frames. Interior masking included an extra heat shield for the retro section and a disk cut for the equipment section. These were attached using a liquid masking agent while the wider ends of both sections were taped to wooden bases. The exterior was painted Dark Ghost Gray as were the adapter fairings. A coating of Floquil gloss and flat was then mixed and applied. The retro support, equipment beams, ECU frame and crew transfer tunnel were all painted Medium Gray. The Oxygen tanks, water tanks, and the retro-rockets were painted Non-Specular Sea Blue while the batteries were European I Dark Green.

    Handling Fixtures

    Fixture overviews.
    The last elements constructed were the handling fixtures, there were two reasons for this. First, something has to be built last and second, the rest of the model had to be completed before the final dimensions of the fixtures could be determined. The first step was to figure out from the photos what these things looked like and then create a drawing for each one. The base frames were 1/8" diameter styrene tube stiffened with .062" music wire while the uprights were 3/32" diameter tube stiffened with .032" music wire. The caster support plates were .030" thick stock cut into 3/8" x 9/16" rectangles supported by .020" stiffeners.

    Caster detail.
    The casters turned out to be one the hardest elements to find/create. I spent quite a bit of time looking for a ready made product but could not come up with anything until I ran across Grantline's Griffin Denver 26" Dummy Wheel Sets. With a little modification these worked out to be exactly right for the fixtures. I glued two of these wheels together, face to face, and then sanded off the center ridge. The axle was .060" styrene rod, while the yokes were made out of .187" x .312" rectangular tube. The upper plates were pieces of .020" thick styrene sheet cut into 1/4" squares with a .040" thick, .120" diameter plug between the yoke and plate. The fixtures were painted with Testors European I Gray while the casters were painted with Metalizer Titanium.

    The final assembly consisted of a creating a drawing showing a plan view of all of the fixtures and their relative spacing. This was placed on the sheet styrene base and with a pin vice, holes were drilled under the caster locations to accept a .010" thick piece of music wire which attached the castors to the base. The finished modules were then attached to the fixtures and the fixtures attached to the base.

    As mentioned throughout the article, quite a few drawings were perused and created of the assemblies that went into this model. These drawings supplied dimensions and allowed me to check clearances. Without these, I never would have been able to achieve a consistent level of detail and alignment.

    McDonnell Drawings

    McDonnell Photographs

    Finished Gemini-B Model

    Finished Gemini 4 Model

    Gemini B Hardware

    USAF Gemini-B.
    Existing Gemini B hardware is somewhat rare. The man rated re-entry vehicle minus adapter is displayed at the U. S. Air Force Museum at Wright-Patterson AFB in Dayton, Ohio. Although mis-identified on their web site as being used by NASA for thermal qualification testing, this Gemini Spacecraft is the only known example of actual Gemini B hardware.

    The USAF Space and Missile Museum has another piece of Gemini B related hardware. This is the Gemini 2 vehicle, which was the first capsule of its type to be reflown. The Air Force used this vehicle to test the concept of the heat shield hatch on a ballistic flight in November, 1966.

    The one other piece of Gemini B related hardware that I've seen is at the Astronaut Hall of Fame in Titusville, Florida. Their Gemini example is actually a Gemini B procedures trainer. This was, of course, a trainer modified from the NASA Gemini. But if you look closely at it, you'll see it has the LPB hatch, modified seats as well as the modified instrument panels.

    Reference List

    Many resources, other than the ones supplied, were used to create these models. The main one was Mike Mackowski's Space in Miniature Gemini booklet. Others include:

    The History of Manned Spaceflight
    By David Baker Ph.D.

    On the Shoulders of Titans: A History of Project Gemini
    By Berton C. Hacker and James M. Grimwood

    Project Gemini: A Technical Summary
    By P. Malik

    Petersen's Book of Man in Space, Vol. 2: A New Environment
    Editor Al Hall

    History of NASA: America's Voyage to the Stars
    By E. John and Nancy DeWaard

    Entering Space: An Astronaut's Odyssey
    By Joseph P. Allen

    Sightseeing :A Space Panorama 84 Photographs From The NASA Archives
    selected by Barbara Hitchcock

    The Illustrated History of NASA
    By Robin Kerrod

    Gemini Spacecraft Number Eleven Press Reference Book
    Prepared By the External Relations Division
    McDonnell Aircraft Corporation

    NASA Project Gemini Familiarization Manual
    SEDR 300 McDonnell Aircraft Corporation

    For further reading on the U.S. Air Force's MOL project:

    The Illustrated Encyclopedia of Space Technology
    By Kenneth Gatland

    Guardians: Strategic Reconnaissance Satellites
    By Curtis Peebles

    Quest, The History of Spaceflight Magazine
    Vol. 4 No. 3
    Vol. 4 No. 4
    Vol. 5 No. 2
    Manned Orbiting Laboratory (MOL)
    This three-part article is probably the most complete dissertation on the MOL project.

    Back to Scale Models page