That is a complicated story with many, many twists and turns. The best I can do here is briefly summarize some key points, but it should be understood this is a simplification.
In the mid 1960s, the Apollo program was at peak effort, preparing to go to the moon. The Command and Service Module was being built. The Lunar Module was being built. The crew and flight controllers were being trained. But Wernher von Braun's team at the Marshall Space Flight Center had almost completed their job. They had built the mighty Saturn V rocket that would take us to the moon. They were in that awkward phase where their primary work was coming to an end but their resources and expertise would still be needed in the event something went wrong with the plan. So, von Braun was looking for work to keep his team active. There was no way Congress was going to authorize a completely new additional program, but he and George Mueller came up with an idea called Apollo Applications. Apollo Applications would find ways to use existing Apollo resources to perform new objectives. One idea was to use the Saturn V to launch a small space station that would itself be constructed out of the second stage of a Saturn rocket. That would make a relatively low cost mission that would have strong science and engineering objectives.
That got people interested in the idea of a space station. NASA had its eyes set on going to Mars after the Moon. But in order to go to Mars we would have to learn how to do long duration spaceflight. We would need to learn how to keep the crew healthy and effective on the long journey to Mars and we would have to learn how to keep equipment healthy and effective on the long journey to Mars. We needed a microgravity environment to do that. A lunar base wouldn't help with that.
But asking for the money to build a space station with the sole purpose of supporting a not yet approved mission to Mars was a formidable challenge because there was very limited funds and a lot of competition for those funds. The space station advocates needed to build a coalition, which meant they needed to find ways in which a space station would be beneficial to other people. A space station, in Earth orbit, becomes an obvious place from which to study Earth. So, incorporating features and instruments to do that would bring support from the people interested in studying the Earth. A space station, in Earth orbit, becomes an obvious place in which to perform experiments that benefit from an absence of gravitational influences. So, incorporating features and instruments to do that would bring support from the people interested in performing such experiments. And so, on. Incorporating all of these features means building a larger space station.
Engineers at NASA's Langley center put out design pitch after design pitch, showing all kinds of space stations from the small three person models like Skylab to giant thirty person stations. Analyzing all of these designs made it obvious that economic construction and operation of a space station would be facilitated by reusable launch vehicles and spacecraft.
And this is where politics comes back into the picture. President Nixon gave a speech in which he said the following:
"We should work to reduce substantially the cost of space operations. Our present rocket technology will provide a reliable launch capability for some time. But as we build for the longer-range future, we must devise less costly and less complicated ways of transporting payloads into space. Such a capability-designed so that it will be suitable for a wide range of scientific, defense and commercial uses-can help us realize important economies in all aspects of our space program. We are currently examining in greater detail the feasibility of re-usable space shuttles as one way of achieving this objective."
With the President's vision clear, NASA and the various contractors interested in building such a vehicle started presenting their options. The idea of a space shuttle was sold well with its advertised reduction in cost because of reusability and the new capabilities it would provide such as being used to launch payloads and to repair orbiting satellites. The Administration decided to go with the Space Shuttle. But, with a tight budget and a limited workforce, beginning a Space Shuttle program meant completely ending the Apollo program, including the Apollo Applications program. Some initiatives, such as Skylab and the Apollo-Soyuz missions had already been funded and would continue, but the plans for an additional Skylab were cancelled.
Once NASA was committed to the Space Shuttle program, it was committed to staying in low Earth orbit. If approval of a space station were to come, it would definitely be a low Earth orbit space station. The 1970s were spent building the Space Shuttle and it flew its first flight in 1981 – nine years after the last moon landing. Three years later, on 25 January 1984, in his State of the Union Address, President Reagan announced the following:
"Our progress in space, taking giant steps for all mankind, is a tribute to American teamwork and excellence. Our finest minds in government, industry and academia have all pulled together. And we can be proud to say: We are first; we are the best; and we are so because we're free.
America has always been greatest when we dared to be great. We can reach for greatness again. We can follow our dreams to distant stars, living and working in space for peaceful, economic, and scientific gain. Tonight, I am directing NASA to develop a permanently manned space station and to do it within a decade.
A space station will permit quantum leaps in our research in science, communications, and in metals and lifesaving medicines which could be manufactured only in space. We want our friends to help us meet these challenges and share in their benefits. NASA will invite other countries to participate so we can strengthen peace, build prosperity, and expand freedom for all who share our goals."
That space station was called Space Station Freedom. While NASA worked away on it for the next decade, it received weak support from Congress, at least once coming just a single vote away from cancelation. President Clinton made changes to the program that strengthened its support. He announced we would bring the Russians in as partners to reduce our costs. This was also a move to help stabilize Russia and prevent their scientists and engineers from going to work for Iran. That gave birth to the International Space Station (ISS), which launched its first module in 1998 and was constructed over the next decade.
In 2004, President Bush gave a speech in which he said:
"Our third goal is to return to the moon by 2020, as the launching point for missions beyond. Beginning no later than 2008, we will send a series of robotic missions to the lunar surface to research and prepare for future human exploration. Using the Crew Exploration Vehicle, we will undertake extended human missions to the moon as early as 2015, with the goal of living and working there for increasingly extended periods. Eugene Cernan, who is with us today — the last man to set foot on the lunar surface — said this as he left: "We leave as we came, and God willing as we shall return, with peace and hope for all mankind." America will make those words come true.
Returning to the moon is an important step for our space program. Establishing an extended human presence on the moon could vastly reduce the costs of further space exploration, making possible ever more ambitious missions. Lifting heavy spacecraft and fuel out of the Earth's gravity is expensive. Spacecraft assembled and provisioned on the moon could escape its far lower gravity using far less energy, and thus, far less cost. Also, the moon is home to abundant resources. Its soil contains raw materials that might be harvested and processed into rocket fuel or breathable air. We can use our time on the moon to develop and test new approaches and technologies and systems that will allow us to function in other, more challenging environments. The moon is a logical step toward further progress and achievement."
This began the Constellation program, and again because of limited funds, resources, and workforce, that meant ending the Space Shuttle program. We would continue to support ISS operations, but would focus on going back to the moon and building that moon base you asked about.
But then, in 2010, President Obama gave a speech in which he announced plans to cancel the Constellation program. He retasked NASA to focus on technology development. In that speech he said:
"Early in the next decade, a set of crewed flights will test and prove the systems required for exploration beyond low Earth orbit. And by 2025, we expect new spacecraft designed for long journeys to allow us to begin the first-ever crewed missions beyond the Moon into deep space. So we’ll start — we’ll start by sending astronauts to an asteroid for the first time in history. By the mid-2030s, I believe we can send humans to orbit Mars and return them safely to Earth. And a landing on Mars will follow. And I expect to be around to see it.
But I want to repeat — I want to repeat this: Critical to deep space exploration will be the development of breakthrough propulsion systems and other advanced technologies. So I’m challenging NASA to break through these barriers. And we’ll give you the resources to break through these barriers. And I know you will, with ingenuity and intensity, because that’s what you’ve always done.
Now, I understand that some believe that we should attempt a return to the surface of the Moon first, as previously planned. But I just have to say pretty bluntly here: We’ve been there before. Buzz has been there. There’s a lot more of space to explore, and a lot more to learn when we do. So I believe it’s more important to ramp up our capabilities to reach — and operate at — a series of increasingly demanding targets, while advancing our technological capabilities with each step forward. And that’s what this strategy does. And that’s how we will ensure that our leadership in space is even stronger in this new century than it was in the last."
Hopefully, if just one thing is learned from this answer, it is that NASA doesn't really decide what it gets to do. While the Space Act of 1958 gave the NASA Administrator the authority to set the agency's mission, it also made him an appointee that serves at the pleasure of the President and it also included a clause that says that while the Administrator controls the agency's funds, he or she cannot buy anything that costs more than $250,000 without it being specifically appropriated by Congress.
xochielt 