Space is a whole lot of nothing, at least in terms of solid bodies that a person can set a boot on, until one reaches the moon, which on average lies about 385,000 kilometers from Earth. It's small wonder, then, that humans have since the 19th century envisioned the construction of new moons - space stations - closer to our planet. We have proposed myriad possible functions for these toeholds on the infinite: laboratory, Earth-observation post, astronomical observatory, technology test-bed, hotel, shipyard for assembling spaceships for voyages to the moon and beyond, assembly base for large space structures, propellant depot, communications relay, battle station, geopolitical prestige generator, quarantine facility for arriving samples from Mars, factory, and experiment in international cooperation.
In late 1960, NASA called on U.S. industry to propose designs for an "advanced manned spacecraft" that it named Apollo. The three-person spacecraft, designed mainly for Earth-orbital use, was to follow and replace the single-seater Mercury space capsule, NASA's first piloted orbital spacecraft. Apollo would include an auxiliary pressurized volume, generally dubbed the orbital module, which would provide room for instruments and experiments, as well as extra living space. Astronauts would live in Earth orbit on board Apollo spacecraft for a week or longer, performing space station-type experiments in the orbital module.
NASA expected that its piloted program in the 1960s would proceed down one of two "logical" paths. The first would have the Apollo spacecraft transport crews and supplies to a temporary "orbiting laboratory." The other would see Apollo perform a circumlunar flight. What would come after 1970 was anybody's guess, though NASA proposed that the orbiting laboratory should lead to a permanent Earth-orbiting space station and the Apollo circumlunar flight to a manned moon landing, interplanetary flights, and a planetary (probably Mars) landing.
On 25 May 1961, however, new President John F. Kennedy played havoc with NASA's logical plans when he opted to skip the circumlunar Apollo step and proceed directly to a lunar landing before 1970. Stinging from the humiliation of the Bay of Pigs fiasco in Cuba and the first piloted spaceflight by Soviet cosmonaut Yuri Gagarin (12 April 1961), Kennedy had asked his Vice President and National Space Council chairman Lyndon Johnson to propose a goal in space that the U.S. might reach ahead of the Soviet Union. The apparent Soviet advantage in launch-vehicle capability gave the communist collosus a head-start if the space goal was as modest as the establishment of an Earth-orbiting space station. Landing a man on the moon, on the other hand, was a goal audacious enough that the U.S. and Soviet Union were starting out more or less even.
Despite Kennedy's new high-priority moon landing goal, space station studies within NASA did not cease. In fact, some believed that NASA might launch its first station even before astronauts stepped onto the moon; they expected that lunar landing development costs would peak two or three years before NASA launched its first lunar landing attempt (as in fact they did), freeing up funds for an early station.
Langley Research Center (LaRC) was the early leader in NASA space station studies. A pioneering player in station work at the Hampton, Virginia-based laboratory was engineer Rene Berglund. He often designed stations that took advantage of existing or planned space hardware. In 1960, for example, Berglund designed a one-man space station comprising a metal-walled core, an inflatable fabric torus, a dish-shaped solar array, and a Mercury capsule at one end. At the time, Project Mercury had only recently begun flight testing.
In May 1962, Berglund filed a patent for an "erectable" artificial-gravity space station that would reach orbit on a single two-stage Saturn C-5 (as the planned Saturn V rocket was then known). Folded atop its launch vehicle, Berglund's station would measure just 33 feet across (the diameter of the rocket's second stage, to which the station would joined as it ascended to orbit). The station would unfold in orbit into a hexagon 150 feet wide. Three spokes would link the hexagon to a central hub where piloted Apollo-derived logistics spacecraft would dock. The hexagon would revolve like a merry-go-round to create acceleration, which the crew inside would feel as gravity. "Down" would be away from the hub, toward the hexagon's outer rim.
Meanwhile, in Houston, Texas, Edward Olling at the newly established Manned Spacecraft Center (MSC) was hard at work on a temporary space station program which he called Project Olympus. In April 1962, he circulated a draft planning document for comment; then, on 16 July 1962, he unveiled his Project Olympus "Summary Project Development Plan" to top-level MSC managers.
Olling explained that Project Olympus space stations would for the first time provide NASA with a large usable volume and enough scientific equipment, astronauts, and electrical power to carry out wide-ranging basic and applied research in space. Early station research would seek to answer basic questions about piloted spaceflight; for example, could humans work effectively for long periods in space?
New objectives would be added over time. Beginning even with the first station, the Project Olympus stations would become space-environment research facilities, "national laboratories" for research into meteorology, geophysics, communications systems, navigation systems, and astronomy, and "orbital operations" facilities (that is, sites for assembling spacecraft bound for points beyond space station orbit).
Each 138,600-pound Project Olympus station would comprise a large central hub with three evenly spaced arms. Each arm would include a pressurized crew module of oval cross-section nested between two cylindrical access tunnels. Apollo-derived logistics spacecraft (typical mass, 31,700 pounds), each bearing six astronauts, supplies, and equipment, would dock at the zero-gee central hub.
The 150-foot-wide Project Olympus stations would spin four times per minute to create acceleration in their arms. On each station, the crew deck farthest from the hub would experience the greatest acceleration: the equivalent of one-quarter of Earth's gravitational pull, or about midway between lunar and martian surface gravity. Crew decks closer to the hub would experience less acceleration. Olling hinted that the different levels of acceleration the astronauts would experience on decks at varying distances from the hub might be useful for scientific research, but he provided no specifics.
Like Berglund's erectable station, MSC's Project Olympus station was designed to be launched folded atop a single two-stage Saturn C-5 with its hub on top and its extremities - its three radial arms - folded below. The MSC station's three radial arms would, however, include fewer moving parts and places where structures would need to join together in orbit to form airtight seals than the LaRC design. Less complexity and fewer seals meant less likelihood that something could go wrong during station deployment.
Olling provided other comparisons between the MSC and Berglund designs. The Berglund design's living areas - the six cylindrical segments that would together form its torus - had a total of 33,000 cubic feet of volume, or about 2000 cubic feet less than the MSC design. It had a floor area of 2900 square feet, or about 850 square feet less than the MSC design. The exterior surface area of the Berglund design's living modules would total 13,000 square feet, or about 3400 square feet more than the MSC design; this meant that Berglund's station would provide a larger target for marauding meteroids. Compared with the Berglund design, the Project Olympus station design's zero-gee hub was enormous: 15,000 cubic feet versus just 2500 cubic feet for Berglund's station.
Project Olympus stations would operate in a circular 300-nautical-mile-high orbit inclined 28.5° relative to Earth's equator - what Olling called a "Mercury orbit," apparently because it shared its inclination with the Mercury capsules used to fly four piloted Earth-orbital missions between February 1962 and May 1963 (Scott Carpenter had orbited Earth for nearly five hours on board the Aurora 7 Mercury capsule on 24 May 1962, while Olling prepared his project plan presentation). The orbital inclination would match the latitude of the launch pads at Cape Canaveral, Florida, from which the Project Olympus stations and their piloted logistics vehicles would launch. Olling also mentioned (albeit briefly) the possibility of a polar-orbiting Project Olympus station which over time would pass over all points on Earth.
A Project Olympus-type station could be staffed continuously for up to five years starting immediately after it unfolded in space, Olling wrote. The station's first six-man crew would in fact be launched with it; the astronauts would ride in an Apollo-derived logistics spacecraft mounted atop the station hub. Upon reaching space station orbit, the astronauts would separate their logistics spacecraft from the station, move it away to a safe distance, and turn it so that they could observe station deployment. They would then dock nose-on with the top of the station hub. Once on board, they would fire small rocket motors at the ends of the arms to spin the station.
Olling envisioned frequent crew rotation and resupply flights to the Project Olympus stations. He expected that the first Project Olympus station would reach Earth orbit in late 1966 or early 1967. In its first six months, during which time the station population would be maintained at six men, Apollo-derived six-man logistics spacecraft would arrive and depart every 30 days.
The logistics spacecraft would launch atop expendable Saturn C-IB (as the Apollo Saturn IB was known at this time) or Titan III rockets. Each spacecraft would include a crew module with meager habitable volume for the astronauts during flight to the station and return to Earth, and a logistics module, which would include propulsion and life support systems for the crew module and tanks and storage bays for station supplies.
The logistics module would be discarded during return to Earth and would burn up in the atmosphere. The crew module, on the other hand, might be reused; that is, after it landed and was recovered it might be paired with a new logistics module, stacked atop a new Saturn C-IB or Titan III, and launched to the space station at least one more time.
At the start of its second six months, the population of the first Project Olympus station would expand to 12. NASA, by then confident that a 30-day Earth-orbital sojourn would not harm astronauts, would cautiously extend the crew-rotation interval to 60 days. Spacecraft sufficient to evacuate the entire station crew would remain docked with the Project Olympus station at all times.
Beginning with its third half-year in space, 18 men would inhabit the first Project Olympus space station. NASA would extend crew stays to their maximum duration of 90 days. The Apollo-derived logistics spacecraft might continue in use during this period; alternately, a new-design 12-man station transport might be introduced to reduce the number of spacecraft, launch vehicles, and launches required to maintain Project Olympus space stations.
An important outcome of Olling's project plan was the realization that space station crew rotation and resupply would dominate Project Olympus costs. Staffing and supplying the first station would, Olling calculated, require 47 Saturn C-IB launches over three years. If six-man Apollo-derived logistics spacecraft could not be reused, then the cost per spacecraft would amount to $14.2 million. Each expendable Saturn C-IB rocket and its launch operations would cost $38.7 million. Thus, over three years, the cost of crew rotation and resupply would total $1.819 billion. If each spacecraft could be reused at least once, then the cost would decrease, but not by as much as one might hope; crew rotation and resupply would still cost a total of $1.421 billion over three years.
A five-year artificial-gravity flight program spanning from the start of Fiscal Year (FY) 1966 through the end of FY 1970 would cost a total of $4.050 billion, Olling told MSC managers. Even if four space stations were launched on expendable Saturn C-5 rockets during the program, station cost would account for only $1.273 billion of Project Olympus's total cost. Crew rotation and logistics resupply cost would account for the remaining $2.777 billion. Summing up his findings, Olling wrote that the "launch vehicle is [the] major cost item compared to [the] logistic spacecraft" and that a "reusable launch vehicle could contribute large economies" (that is, large savings).
Olling's Project Olympus presentation marked the beginning of a series of artificial-gravity space station study efforts at MSC that lasted into 1966. Future Beyond Apollo posts will compare the patents Berglund and MSC engineers filed for their respective artificial-gravity station designs and will describe a Lockheed study of the Project Olympus design conducted for MSC.
Reference:
Project Olympus: Proposed Space Station Program, Edward H. Olling, NASA Manned Spacecraft Center, 16 July 1962.