It was the year 1960; the U.S. entered the Vietnam War, President Dwight Eisenhower signed the Civil Rights Act of 1960, John F. Kennedy and Richard Nixon participated in the first televised presidential debate, and Chubby Checker released "The Twist." Meanwhile, McDonnell Aircraft, the makers of NASA's Mercury spacecraft, proposed a modification to their soon-to-be iconic capsule: Create a one-man space station using Mercury hardware.
Mercury-Atlas 9 at Launch-Complex 14 (NASA)
The idea was presented to the Space Task Group at NASA's Langley Research Center in Virginia on August 24, 1960. The group's job was to accomplish Project Mercury and its goal of putting a man into space. President Eisenhower, however, was not particularly fond of the idea of manned spaceflight and saw the act itself as having the technical and scientific value of a circus stunt. He also wanted the program to be strictly civilian as to not interfere with the more serious matters the military was attending to.
The design consisted of a standard Mercury capsule mounted atop a laboratory, or station. The station would have been cylindrical with dome-shaped ends and would have been 10 feet long and 6 feet in diameter (3 meters long and 1.8 meters in diameter). It would have enclosed 282 cubic feet of volume, 182 of which would have constituted living and working in space. 40 cubic feet would have been taken up by "laboratory test payload" with another 60 cubic feet of support equipment at the bottom end of the space station.
It was to launch on an Atlas D rocket, the same rocket that was later used to launch the Mercury program's manned orbital missions, and sit between the Mercury capsule and an Agena B restartable upper stage. Once in orbit, the Agena B would have enough propellant to maneuver itself, the station, and the capsule. It would also remove the need for the standard 24-pound posigrade motor set that normal flights would ignite to separate the capsule from its booster. The station was meant to be used for 14 days by a single astronaut and then permanently abandoned in place after the astronaut and capsule separated to return to Earth. In a sense, the station was more of a mission module for long-duration Mercury missions rather than a space station in the term's modern connotation.
Mercury Laboratory model manufactured by New Ware (Allen Ury via fantastic-plastic.com)
There was one critical problem it faced: With the capsule mounted on top of the lab, how will the astronaut exit one and enter the other? For those of you familiar with the Air Force's Manned Orbiting Laboratory program, the answer might be clear; cut a re-sealable hatch in the heat shield. There were two issues with this method, though. First, the concept would not even be thought of for at least 5 years. Second, the Mercury spacecraft's solid motors were located on its heat shield. Three solutions were proposed: The astronaut would perform an EVA and access the lab from the outside; an inflatable tunnel would connect the two craft; and the Mercury spacecraft would be on a hinge that would allow it to dock with the side of the module rather than the top.
The first option was out of the question— it was not yet known for sure that men could even survive in space concealed in a capsule, nonetheless outside. In fact, the first EVA would not take place for another 5 years. The tunnel access proposal would have used an inflatable tunnel launched under a metal faring. Once in orbit, the astronaut would inflate it and it would have linked the 24-inch hatch of the Mercury capsule to the 24-inch hatch on the side of the space station. The metal cover would actually have remained attached to provide structural support and some shielding from meteoroids. When it was time to return to Earth, the astronaut would have gotten back inside the capsule and fired explosive bolts to sever the tunnel. The hinge lab design had the Mercury capsule pivot on a hinge to link a modified Mercury side hatch to the side hatch on the space station. Afterwards, the astronaut would pilot the capsule back to its original position relative to the lab and fire explosive bolts to separate the two. This was the design that received the most support.
The tunnel and hinge proposals (McDonnell Douglas)
McDonnell estimated that the Atlas D and Agena B could put roughly 6,076 pounds into orbit. This payload capacity minus the combined weight of the capsule and space station left between 1,342 and 1,234 pounds for other things (depending on the spacecraft configuration). The company also said their One-Man Space Station could carry out a number of research projects such as the study of human adaptation to 14-day weightless spaceflights; the study of "long-time equipment performance" on spacecraft; "lunar probe navigation equipment" testing; radiation exposure, geophysical, and astrophysical measurements; and the development of space rendezvous technology. It could also carry out specialized missions for communication research, astronomical or Earth weather observation, and of course, Earth-surface reconnaissance (after all, it was mere months after Francis Gary Powers's U-2 spy plane was shot down by Soviet missiles). It was also emphasized that the astronaut onboard would not be wearing his pressure suit while working but rather a flight suit or regular civilian attire like the astronauts onboard the International Space Station wear.
McDonnell also proposed a number of other modifications to their spacecraft to accommodate whichever missions and configurations NASA chose. New hatch designs added more weight to both the tunnel and hinge systems but were necessary for the hinge to function properly. The astronaut-monitoring camera from the telemetry and recording systems would be taken out, reducing weight, while an additional seven pounds of water would be added for the Mercury's environmental control system. Plans for returning to Earth with the results of the science experiments performed in the lab would have been figured out later. Furthermore, a new adapter for linking the Mercury capsule with the "top" of the space station significantly increased the weight of the spacecraft. In all, the tunnel proposal would have weighed only 35 pounds more than the hinge proposal because it included an extra piece of hardware, the tunnel and its faring, and more attitude-control propellant. But the tunnel would have made the spacecraft lopsided.
It is no surprise that NASA did not go through with McDonnell's proposal for their One-Man Space Station, although it is interesting to know about a feasible civilian space station concept this early in the Space Race. In the coming years, McDonnell would propose a number of modifications to their Gemini capsule in an effort known as Advanced Gemini.
(clockwise from top left) Schirra, Cooper, Carpenter, Shepard, Grissom, Slayton, and Glenn— the potential Mercury Laboratory astronauts (NASA)
Author's note: I first learned of this a few months ago while looking at models on fantastic-plastic.com . I really couldn't believe it at first but here it is. Thanks for reading and remember to like, comment, and share!
Drye, Paul. “Sidebar: The Mercury Space Station.” False Steps, 25 Nov. 2012, falsesteps.wordpress.com/2012/11/22/sidebar-the-mercury-space-station/.
Grimwood, James M, et al. “Project Gemini - A Chronology. Part 1 (A).” NASA, NASA, history.nasa.gov/SP-4002/p1a.htm.
Portree, David S. F. “One-Man Space Station (1960).” Wired, Conde Nast, 28 Sept. 2014, www.wired.com/2014/09/one-man-space-station-1960/.