To develop the hardware needed to go to Mars, both NASA and the Soviet Union decided that the best place to test it and gain experience would be Earth orbit and on the Moon.
The Soviet Union had already taken the lead in some areas of development, like the study of long term habitation in space and the infrastructure needed for a permanently manned station, by launching the first space stations into low earth orbit.
Salyut 1 had been launched in 1971 and had been visited by the crews of Soyuz 10 and 11, before the first successful Soviet landing on the Moon. But just the crew of Soyuz 11 was able to actually man the station, only to be killed during reentry in their capsule. An air valve in the descent module had opened up during reentry and the air in the capsule lost pressure, killing the crew in seconds.
The following station, Salyut 2, was an utter failure when compared to Salyut 1. Salyut 2 had suffered several technical problems, like the unexplained loss of external hardware such as solar panels and was already destroyed before a crew could be launched for it.
Salyut 3 finally was somewhat successful again, being occupied for fifteen days by the crew of Soyuz 16. The crew of Soyuz 17 could not dock to it again, forcing them to return and the station subsequently re-entered the atmosphere and burned, as there was no one inside to keep it at its desired orbit.
Salyut 4 was the last of the Salyut stations and four crews of cosmonauts visited during its existence. Soyuz 20 even docked with the station after returning from a successful lunar landing to remain on the station for 21 days.
The Multipurpose Orbital Complex was a more ambitious project in comparison to Salyut. MOK was a modular station with two main modules launched by the N-1F launch vehicle and four smaller Salyut type modules launched by the UR-500. Each of the main modules was six meters in diameter and thirty meters in length, featuring a docking adaptor with five docking ports on one end and a single docking port on the other.
This was the first time a station would be fully constructed in orbit, without the help of cosmonauts, by using an automated docking system that had initially been developed for the Salyut program. Only after its construction was definitely finished and all conclusive tests were done, the station would be opened up for cosmonauts.
By October 1977 MOK had been finished and the initial visit was done not by one, but by two simultaneously launched crews, one on Soyuz 22 and the second on TKS 1. The Soyuz 22 would also be the last flight of a Soyuz capsule, its job completely taken over by the TKS spacecraft.
MOK was the first space station to become continuously manned and by 1979 it became the staging area for the first Soviet Lunar Base.
For NASA on the other hand, the start in using space stations was a less successful venture when compared to the Soviets in the beginning, as they were plagued by problems, whether they were of technical by nature or caused by human error or external influence.
On May 16th, 1973, a Saturn V lifted off at Cape Kennedy, carrying Skylab into orbit. During ascent the technical problems began, that would eventually mark Skylab as being insufficiently designed.
Constructed from the tankage of the third S-IVB stage of the Saturn V, Skylab had structural problems during lift off and halfway through the ascent the micrometeorite shield of one solar panel was ripped off, destroying the solar panel in question. The second panel proved to be stuck, after Mission Control attempted to open it.
As Skylab 2 launched ten days later on a Saturn IB, the crew hoped that they were equipped with all the things needed to repair the station. Docking with the station was possible and the installation of a parasol to bring the temperature of the station down succeeded according to plan. But that was all that was successful of the mission, as Paul Weitz failed to release the stuck solar panel even after three EVAs.
Skylab 2 was aborted on June 6 and Skylab 3 launched on August 7. Three EVAs were made by Owen Garriott and Jack Lousma, to try and unfold the solar panel, but it remained stuck. The crew was able to reroute the solar panels from the telescope mounted onto the station, but the energy produced by those smaller panels was barely enough to keep the life support system active.
On the ground the Skylab mission was booked as a failure and abandoned. Skylab 4 and 5 were canceled and Skylab 3 aborted on August 21. But NASA used the experience gained with the failed mission and the replacement for Skylab, Skylab B was modified.
Not only were known failure points removed and redesigned, but the common bulkhead between the hydrogen and oxygen tanks of the rebuilt S-IVB stage was opened to create more living space in the station. Additionally Skylab B was equipped with a Common Docking Adaptor developed for the Cislunar Infrastructure Development Plan, making the station a good place to test the new hardware.
After it was renamed to Spacelab, the station was carried into space on top of the second last original Saturn V on April 4, 1975. The launch had its own complications as the launch vehicle experienced pogo oscillations, which were solved in time by turning off the center engine. Other problems were of minor nature.
Spacelab 2, originally intended to be Skylab 4, launched on April 7, docking with Spacelab on April 9. Once inside the station, the crew found that the pogo oscillations had ripped several items and systems from their mountings and damaged others. After cleaning up and taking stock of damages, the crew stayed on the station for 48 days.
Three more Spacelab missions followed using the Apollo capsule, until Spacelab 6 launched on top of a Titan IIID in September 11, 1977. Spacelab 6 used the new Crew Transport Module, CTV, which had been developed for the CID Plan. It was a direct Apollo evolution and had made several successful unmanned test flights. Spacelab 6 docked with Spacelab while Spacelab 5 was still docked, with a new american record of 129 days. It was the first meeting of two crews in orbit able to actually shake hands. Tests of the Crew Transport Vehicle showed that it was doing its intended tasks.
Spacelab 5 and 6 undocked from Spacelab on September 24, returning to Earth and plunged into the water only a hundred kilometer away from each other.
Spacelab 7 was the last crew to launch to Spacelab on January 3, 1978. Two days later the first Saturn CC-31 launched from Cape Canaveral with the first production test modules of the CID Plan. A stack made up of a two deck Manned Command Mission Module Two, a Multi Docking Module, a Solar Power Module and a Consumables Storage Module Two, propelled by a CTV Service Module bus, was launched into an orbit poised for a docking with Spacelab.
The launch happened with minimal problems, but to everyone’s dismay, it missed its intended orbit. The following five days were needed to maneuver the craft to a rendezvous with Spacelab. Two of the Spacelab crew remained inside of Spacelab while the other two had to pilot the CTV away from the station to allow the docking of the two deck MCMM with the station. After undocking the CTV Service Module bus, Spacelab 7 docked with one of the free docking ports of the MDM.
Over the next four weeks the stack was tested by the crew to make sure that everything worked as designed.
Spacelab 7 then saw to the end of Spacelab, as they removed anything of scientific value from the station and moved it to the docked stack as ordered, before closing Spacelab for a final time. The old station was released from the stack to be reentered the atmosphere over the Indian Ocean, where its remains sank beneath the waves. One of the sewage tanks however made it all the way to a beach of Sipora, where it provided additional entertainment for the natives by spraying its contents over a number of tourists.
The crew of Spacelab 7 remained on the stack, which was given the name Space Operations Center Hephaestus, normally shortened to SOC Hephaestus, for two additional weeks, waiting for the arrival of Hephaestus 1.
SOC Hephaestus was the first permanently manned station of the United States and until February 1981 additional modules were launched by three Saturn CC-11 and two Saturn CC-31 to complete the station.
By 1979 the Soviet Union had set its aim for the Moon. A permanently manned base on the closest celestial body had the advantage of testing any hardware to be used on Mars close to Earth and under circumstances pretty much resembling to the red planet.
With the completion of MOK, made its first big steps towards that goal. A single N-1F Sr carried the first module of the Soviet lunar base into orbit on December 13, 1979, where the Block Sr upper stage placed it into a low lunar orbit. Like the Luna probes before, the first of the DLB modules, designed by Vladimir Barmin, landed on its own and without remote commands at Mare Tranquillitatis.
The Station was named Zvezda.
Three more modules followed, landing near the first module, thanks to a radio beacon integrated into that module. Two of the modules were identical to the first one, while the third contained a lunar rover, a small nuclear reactor and prefabricated parts to bring the modules together and link them to each other.
Another N-1F launched a lunar lander to MOK, where it waited for a TKS to dock with it and launch a crew of three cosmonauts to the moon. They touched down near the previously landed lunar base modules and set out to work.
The first module was expanded to its full length and was made habitable, before the cosmonauts took the rover from the last module and moved the other modules close to the first one. Next, the modules were connected to each other and supplied with energy by the nuclear reactor.
The first week saw the completion of the basic baseplan. The following three weeks were then used to bury the base under a thick layer of lunar regolith as protection from micrometeorites, solar flares and cosmic radiation. It involved the extensive use of the rover, accompanied with spades and shovels. In the end only a communication array and one airlock were visible on the surface.
The first crew remained on the Moon for three months before they were replaced by a second crew of three. A second set of four modules was landed by December 1980, followed by a third set late 1981 and a fourth in 1982, increasing the number of modules to twelve habitable modules and a permanent crew of twelve.
Regular supply transports were done by Luna-derived single use landers that were also salvaged by the crew and turned into various useful things.
By 1982 the original landing place had been replaced by a lunar-crete landing pad, created with water and lunar regolith.
Gaining experience with orbital and lunar long term habitation, the Soviet Union decided that they were ready to try for Mars.
That the Soviet Union had beaten the United States with a lunar base was something that Congress absolutely couldn’t approve of and neither did NASA. NASA had to be ready to keep up with the Cislunar Infrastructure Development Plan. Congress felt that the United States could not afford any more disgrace to the eyes of the rest of the world. If the Soviets had beaten them back to the Moon, what would happen if they were the first at Mars?
While the Space Finance Act prohibited an increase of NASA’s budget of already 13 billion US Dollar, or two percent of the Federal budget, until 1983 Congress decided to stretch the percentage to 2.25% to give NASA some leeway. When 1983 rolled around, the Space Development Act, Pub. L. 98-11, increased the budget of NASA to 2.5 percent of the federal budget for the next ten years as planned.
While SOC Hephaestus was in its final stages of assembly, NASA launched the first modules for an orbital propellant depot.
May 17, 1981 the first stack went into space with the first launch of a Saturn CC-32, massing 130 tons, the payload stack included a double deck MCMM, a moon landing module with a small garage for a small rover, and a large CCPM, which would return to Earth once it had dropped its payload into lunar orbit. The module landed in the Copernicus Crater, on safe ground.
A second stack, containing a nuclear reactor module and a Consumables Storage Module launched on June 3, using another Saturn CC-32, and landed only two hundred meter away from the first module.
Both CCPM returned to Earth orbit, where they were refueled at the propellant depot by the crew of SOC Hephaestus. A manned lander using a single deck MCMM and a small CCPM, was launched by a Saturn CC-31 on July 16 and docked with one of the CCPM on July 18, before docking with SOC Hephaestus. The first crew of four arrived on SOC Hephaestus on July 30, after the systems of the manned lander were checked completely.
They left for the Moon on August 1, landing near the two modules on August 4. With the first American arriving at the new base, it needed a name. Moonbase Alpha had been put forward, but NASA decided to keep it close to the landing site, naming it Copernicus Base.
Two more stacks of modules were launched in 1982, followed by four more in 1983.
To ease the transfer between Earth and Moon a single two deck MCMM with a small propellant depot and several Multiple Docking Adaptors was placed in lunar orbit, completing another section of the Cislunar Infrastructure Plan. The station, named Lunar One, was only manned when it was used as a stopover.
By the end of 1984, the development of the Common Advanced Propulsion Module, using a NERVA nuclear engine had been completed and NASA prepared to launch two by mid 1985, to use them as more efficient shuttles to the Moon, compared to the chemical propulsion modules.
By having built up a more complete infrastructure in space and thereby reducing the costs for future space travel in cislunar space, compared to the Soviet Union, NASA was confident that they would be the first to land a man on Mars.
Already 16 astronauts were living on the Moon permanently. And before NASA could think about Mars, Copernicus Base had to be completed by the delivery of two more modules to increase the number of astronauts to 24.