MOL’s 1966 test launch
At 8:50 on the morning of November 3, 1966, a Titan III C missile lifted off from launch complex 40 at Cape Canaveral. It carried a spacecraft, the refurbished Gemini 2 spacecraft now called Gemini B, and a simulated laboratory module made form a Titan II stage one oxidizer tank. Gemini B followed it’s planned suborbital trajectory, splashing down 39 minutes after launch near Ascension Island in the South Atlantic. The Titan’s upper transtage, meanwhile, sent the simulated lab and its satellite payload into a nearly circular orbit roughly 191 miles above the Earth. The lab’s orbit quickly decayed, and on January 9, 1967, the only mission of the U.S. Air Force’s Manned Orbiting Laboratory space station program ended with its last vestiges burning up in the Earth’s atmosphere.
Edging into Hypersonics
In 1952, Bell Aircraft’s chief engineer Bob Woods sent a memo to the National Advisory Committee for Aeronautics (NACA) calling for a hypersonic research program. Rocket engines were routinely pushing planes supersonic. It was only a matter of time before a powerful enough engine would send an aircraft hypersonic, rocketing through the sky faster than Mach 5, more than five times the speed of sound. In Woods’ opinion, the time was right to build a hypersonic research aircraft to start figuring out how to keep a pilot alive flying at these breakneck speeds.
Two years later, Woods’ proposed hypersonic research aircraft came to life as the X-15. It was a small, rocket-powered aircraft designed to fly as fast as Mach 7 at altitudes as high as 250,000. When it fell back to Earth towards its runway landing, it would be akin to a spacecraft returning from orbit. It was clear space was on the horizon, and the vehicle that would make the leap from aircraft to spaceplane was already under development before the X-15 even left the ground. It was a glider designed to launch into orbit vertically on a rocket. After orbiting the Earth it would return through the atmosphere at speeds up to Mach 20 before landing, unpowered but controlled, on a runway.
The X-15 in Flight
In the mid-1950s, this hypersonic glider took on many forms. BoMi, short for Bomber Missile, and ROBO, short for Rocket Bomber, were two weaponized versions. Both would have a pilot bomb an enemy nation as he flew through the upper atmosphere. On the other end of the spectrum was Brass Bell, a non-weaponized reconnaissance vehicle designed to gather intelligence from orbit. In 1956, the glider concept was folded into Project HYWARDS, an acronym for hypersonic weapon and research and development system. The system was alternatively known as weapons system 464L before it was nicknamed Dyna-Soar in reference to its dynamic soaring landing profile.
Progress on Dyna-Soar was slow. Then the Soviet Union launched Sputnik on October 4, 1957 and the sudden national need to get a man in space pushed Dyna-Soar to the forefront; it was the only project under development capable of taking a pilot into orbit. The project was endorsed by the Department of Defense (DOD) as America’s next step towards spaceflight that same month, and by January of 1958 the USAF and the National Advisory Committee for Aeronautics (NACA) were working together to bring the Dyna-Soar to life.
But Dyna-Soar’s move from concept to reality wasn’t a smooth one. The program survived the NACA’s transition into the National Aeronautics and Space Administration (NASA), but the new space agency’s focus on its own Mercury Program left Dyna-Soar without full support. In February 1959, the glider program was defined primarily as a weapons program. In April, it was recast as a suborbital hypersonic research program. In May, it was again redefined as a weapons system; engineering questions were dropped in favour of determining the system’s true military potential. The project risked failing not for any technical reason but because it lacked a clear direction.
By mid-1960, Boeing was beginning to build Dyna-Soar hardware, the Air Force had determined it was suited for manned spaceflight, and the DOD had backed the program with the promise of funding thoughout its orbital flight phase. Attempts were even made to fast track the whole program by cancelling unmanned missions. The Air Force wanted Dyna-Soar to launch manned orbital flights right away.
The Dyna-Soar Mockup
Military Use for a Civilian Spacecraft
Two years later, Dyna-Soar wasn’t much closer to reaching orbit and NASA was giving the Air Force a run for its money where space was concerned. The agency had launched successful orbital Mercury missions, and its next program, Gemini, was already under development. And it was going to be a huge step for the agency. A far more advanced spacecraft, Gemini was designed to support two astronauts for up to two weeks in space and land on a runway using a paraglider system.
Gemini’s sophistication intrigued the Air Force, and during congressional hearings in February of 1962 a military program using this spacecraft started to take shape. By June, a concept had developed wherein a Gemini spacecraft would ferry military astronauts to and from a four-man space station called the Manned Orbital Development System. The MODS would explore the challenges of long-duration spaceflight, house laboratory equipment for experiments, and carry its own supply module and propulsion system. In August, this military Gemini was named “Blue Gemini,” and a proposal surfaced calling for six Air Force Gemini missions as the early training phase of the MODS program.
Secretary of Defence Robert McNamara quickly dropped Blue Gemini and MODS because it was more or less duplicating NASA’s program. NASA Administrator James Webb was also not keen on the program, worried that would blur the line between civilian space exploration and the militarization of low Earth orbit. But military interest in Gemini remained. The Air Force began soliciting concept studies from a handful of aerospace firms in September of 1963, the result of which was a spacecraft called Gemini B that would orbit docked to a 25-foot long cylindrical laboratory module that could sustain a crew for up to a month. Even McNamara was still thinking about Gemini’s potential.
Gemini 6 seen from Gemini 7
Death of the Dyna-Soar
For years, Dyna-Soar’s main selling point had been its manoeuvrable reentry and landing, but McNamara realized no one had given much thought to what it would actually do in orbit. And now here was Gemini, an equivalent Earth orbital program with a controlled reentry that was backed by NASA’s years of experience. Dyna-Soar had lost its advantage, and the question for McNamara became what the USAF stood to gain from pursuing the Dyna-Soar track over a Gemini-style track.
Unsure of Dyna-Soar’s future, McNamara ordered a comparison study between the hypersonic glider and Gemini. The results varied. Many maintained that Dyna-Soar was the best option for America’s military space program, but McNamara ultimately sided with those who saw the benefit of leveraging NASA’s experience into an Air Force Gemini spin-off.
On December 10, 1963, McNamara announced the cancellation of Dyna-Soar and the creation of the Manned Orbiting Laboratory program. To move the program forward faster, keep costs down, and most importantly avoid duplication, NASA entered into a working agreement with the DOD to bring this project to fruition.
The Manned Orbiting Laboratory
MOL immediately entered a review phase; McNamara knew that getting White House and DOD support hinged on proving that it was a military necessity. In January of 1964, the basic goals and guidelines for MOL were set, positioning the program as one that would focus on developing the technology to extend and improve military space capability and also demonstrate assembly of a space station in orbit. Proposed experiments that would be done on board that station related to military goals, including early warning systems, ballistic missile defence, detection and inspection of orbiting satellites, and reconnaissance and surveillance of potential land-based nuclear testing.
Artist’s concept of MOL in orbit
The basic mission structure emerged around this time, too. Astronauts would launch inside a Gemini B spacecraft atop a Titan III C missile. Mated to the spacecraft below the heat shield when the whole stack was vertical on a launch pad would be the 2,000 cubic foot Mission Test Module, later renamed the Laboratory Module. This would house all experiments and give the crew ample working space. When a mission ended, the crew would return to Earth in the Gemini B. The laboratory, meanwhile, would remain in orbit where it could either host a second crew or follow remote commands to reenter and burn up in the Earth’s atmosphere.
The total weight of the payload was roughly 20,500 pounds — 6,000 pounds for the Gemini B, 8,000 pounds for the laboratory, 4,500 pounds for the experiment payload, and 2,000 pounds leeway for any late additions. This put MOL well within the Titan III C’s 25,000-pound payload capability.
With the basic mission set MOL was expected to fly a series of unmanned missions in 1966 with manned flights beginning in 1967 or early 1968. The total cost, including six laboratories, three back up spacecraft, and one ground test unit, was expected to be between $1.5 to $2.5 billion dollars. What remained now were the details.
Four MOL crew transfer options
Defining and Refining
1964 began with Air Force interest in incorporating some Apollo hardware into MOL, but the idea was short lived. The Moon was too high a national priority meaning any secondary uses of the lunar mission hardware would have to wait until after 1970. MOL would be limited to Gemini hardware.
The restriction to Gemini hardware didn’t necessarily crate new problems where Apollo hardware would have solved them. One problem was crew transfer. The laboratory launched docked behind the Gemini B’s heat shield meaning crew transfer was one major technical hurdle mission planners had to address.
There was brief discussion of having the crew spacewalk between Gemini B and the lab, but this untested method was too risky. The idea was dropped, though EVAs were retained as an emergency measure. Transfer by an extendable tunnel connecting the Gemini B’s hatch to the hatch on the laboratory module was feasible but ultimately passed over because of the significant structural modifications it demanded. The idea of physically lining up the two spacecraft hatches by swinging the Gemini B around on hinges was passed over for the same reasons. The last option was to cut a hole in the Gemini B’s heat shield and have the crew use an internal tunnel to transfer between spacecraft. This solution was incredibly simple, and though it raised serious concerns about a cut heat shield’s integrity during reentry it nevertheless won as the crew transfer method.
Other considerations ended up keeping MOL very much in line with NASA’S Gemini program. The Air Force decided that the laboratory module would have its own autonomous inertial guidance system. A sophisticated onboard digital computer would need programming capable of solving complex orbital mechanics problems, an interface for the crew, and the ability to talk to the Gemini B and Titan III C. And of course, this computer would need power. Mission planners rejected batteries because of their weight and power limitation, rejected auxiliary power units because they had limited lifetimes, and rejected solar cells because they were unwieldy and cumbersome on a small station like MOL. This left fuel cells, the same kind NASA was planning to use on later Gemini and Apollo missions. It was a technology that wasn’t entirely flight ready, but MOL planners were confident they would be reliable by the time the station was ready to launch. Also like Gemini, these fuel cells would power a very high frequency (VHF) directional radio assembly with a similar space-to-ground relay system so missions could be tracked by stations on Earth.
MOL before the test launch
Another similarity to Gemini was MOL’s launch escape system. NASA used ejection seats in its Gemini spacecraft rather than an escape tower like it used in Mercury and Apollo just to save weight; anticipating future applications for this spacecraft, its designers hoped to kept the base weight down. These ejection seats were powerful enough to get astronauts free from an exploding Titan II missile, but the Air Force was using the larger Titan III C. In addition to the liquid fuel first stage and upper transtage, this Titan had two solid rocket motors that would ignite seconds before the first stage; they were considered stage zero. If this rocket exploded, there was a lot more fuel to feed a fireball. NASA’s ejection seats wouldn’t save a Gemini B crew, but the weight of a launch escape tower was similarly detrimental to the program. The solution was a compromise. Gemini B would use ejection seats in conjunction with rockets mounted in the spacecraft adaptor section.
MOL was slowly getting more complicated, but it was also becoming more sophisticated, something that would solidify the Air Force’s position in space. But there were external challenges to the program that would be harder to solve than questions of crew transfer methods and power sources.
When MOL was first conceived, NASA was singularly focused on the Apollo lunar landing program. But by late in 1964, the agency’s leaders were beginning to realize that its future was uncertain beyond the Moon. Seeking to extend its central role in space beyond Apollo, NASA began planning a followup program called the Apollo Extension Support (AES) Program or Apollo X, and one of its goals was to build a space station using its advanced Gemini and Apollo hardware.
MOL was suddenly under fire from Congress. With NASA steadily accumulating successes, it seemed MOL was now offering a less capable version of what the space agency had in mind. Pushback also starting coming from President Lyndon Johnson, who was seeking reelection for a second term in office. During the 1964 election season, Johnson’s Republican challenger Barry Goldwater argued that more energy should be spent on military space programs. This prompted Johnson to move away from away from MOL in favour of NASA’s strictly civilian programHe approved only limited funding for MOL, and even after winning the election promised McNamara that he would only support MOL as an advanced concept study to develop experimental hardware. The president would not back MOL as a fully-fledged program.
Undaunted, McNamara stood by MOL, approving continued development in spite of missing funds. In early 1965, the DOD and NASA announced a further collaboration on MOL, stressing a unified approach that would see both organisations making the most of available technology without duplicating missions. But duplication seemed inevitable, and the DOD soon started looking at ways to expand MOL’s capabilities in an attempt to justify the program’s ongoing development. With substantial modifications, DOD officials determined that MOL could sustain a crew in orbit for as long as four months, could rendezvous with Gemini or Apollo to resupply or change crews on a mission, and increase workspace by docking several modules together. For the DOD, there was clearly a need for MOL.
Apollo X space station concepts
Death of the Space Station
President Johnson eventually came around to MOL. He formally approved the program in early 1965 under the assumption was that it would meet all of the DOD’s requirements in space and support NASA’s ongoing endeavours. Congressional support soon followed. Some members of congress went so far as to call for MOL to get the same support and seemingly-limitless funding as Apollo, arguing that the nation’s military space program should be on par with its civilian one.
This change in political attitudes was bolstered by the Gemini 4 and 5 missions. Both returned images that not only showed stunning views of the Earth, they resolved roads and launchpads. It was confirmation that a military space station with high-resolution imaging capabilities would be a stunning spy platform. The Air Force would be able to gather invaluable reconnaissance on enemy nations’ military instalments and better measure the true power of their weapons systems.
Finally, feasibility studies began on March 1, 1965, and MOL was taking shape as an operational manned reconnaissance program that would go beyond the initial plan of six launches. And bringing it one step closer to readiness was NASA’s clearing the Air Force to use the flown Gemini 2 spacecraft for a test flight that would prove cutting a hole for the transfer tunnel wouldn’t compromise the heat shield during reentry. The push towards flight readiness also saw construction of a launch site at the Vandenburg Air Fore Base in California.
MOL being prepped for its test launch
But every step forward raised MOL’s price tag and budget overruns started taking their toll. Manned launches were pushed back, first to 1970 and then to 1971. And successful reconnaissance satellites weren’t helping MOL either. Unmanned missions were finding evidence of Soviet missile installations just like MOL photography was expected to do, which raised the question of why the Air Force should risk men on missions that machines were doing successfully. Eventually the Central Intelligence Agency (CIA) stepped in. It offered the opinion that any reconnaissance returned from MOL wouldn’t justify the cost whatever the DOD might think, and that there was no reason to duplicate existing satellite programs. And all the while the war in Vietnam was escalating, consuming national defence spending.
The Air Force fought to save an increasingly unpopular MOL. Unmanned test flights were cut altogether to save money, and even NASA’s Deputy Administrator Robert Seamans spoke to the value of the Air Force space station program. But nothing could convince the Bureau of the Budget that MOL was worth retaining. By May 17, 1969, the program had cost $1.3 billion and would need an additional $1.9 billion to see it leave the ground on a real mission. With a thriving civilian space program closing in on a lunar landing and planning a space station, a military version had no place. President Nixon cancelled MOL in June of 1969.
This is in no way the full story of MOL. There are a LOT of details I didn’t get into this piece, like MOL astronauts, the one MOL test flight, and what happened to MOL hardware after the program was canceled (hint — this stuff is coming up!). Eventually I’ll get through the hundreds of recently declassified documents and tease out the story!
Sources: History of the Manned Orbiting Laboratory by Carl Berger; MOL Part I Manned Orbiting Laboratory by Donald Pealer, Quest Magazine v4 n3; NASA Office of Defense Affairs: The First Five Years; Vintage Space.
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