As we flip the calendar to 2012, we get the first blast of space news, and the resurgent relevance of human space exploration. China just announced plans to lead humanity in to the moon and beyond, the tail of their comet a strong defense mindset. The Chinese challenge comes at a time of a dangerous convergence, the international debt crisis and a contentious, highly consequential presidential election. In short, 2012 is an inflection year -- the year we will and must decide whether the U.S. has the will and ability to lead the world in human space exploration. For me, I am betting we do -- and here is how I suggest we begin.
In 1969, Neil Armstrong and I walked on the moon. Shortly thereafter, I participated in work on the "next generation of space transportation systems." Without getting too technical, my strong tendency was to support a two-stage reusable launch system, with crew only in the second stage, allowing a first stage to return to Earth unmanned. This seemed both efficient and safer than the alternatives. I found myself on the minority side of the discussion, and relented. Over the past forty years, I have had multiple of occasions to regret that decision. We are now at another turning point -- and this time, we must resolve to do it right.
In short, to make a real difference -- from an exploration, science, national security and international leadership perspective -- our Nation needs to commit to seeking a permanent presence on Mars. This idea has already been widely supported by leaders in both political parties -- and seems central to the vision many Americans have for the country. While the goal uniquely protects U.S. leadership in space exploration, provides insurance for our national security, uniquely presses the envelope of science, and is certain to trigger a fusillade of economic opportunities here on Earth, there are big questions that loom -- and now compel answers. Specifically, two questions leap off the page: When and how. If China's ambitions help create new urgency, the how becomes central.
Space architectures capable of supporting a permanent human presence on Mars are extraordinarily complex, with many different interdependent systems. It is too much information for one short article. But for now, I want to focus on just one element: crew transportation systems.
From the outside looking in, we have two competing programs to provide Crew transportation to space -- the NASA's MPCV and a variety of possible private Commercial Crew Transport Systems. We only need one. As we crystallize the country's level of commitment -- what we can afford and how we make the move to action from theoretical agreement to go forward, there are big reasons to make the commercial sector an engine of action. The U.S. government would then become a purchaser of crew transportation from the U.S. commercial sector, the same way we are currently purchasing launches today from Russia. The MPCV should evolve to become a dedicated exploration system. Initially, it may work in concert with commercial crew systems.
But NASA is critical to success and always will be. Chris Kraft has pointed out that we already have a fairly robust set of launch vehicles being provided by the commercial sector. So, in this area, we do not need the government competing to develop another launch vehicle. One could -- on another day -- even discuss whether we need a 130 metric ton launch vehicle, but assuming we do, the U.S. launch industry is capable of building a vehicle capable of such lift reasonably soon. After all, only four years were needed for the U.S. space launch industry to develop EELV. Likewise, Falcon 9 was developed in a little more than seven years.
No, NASA's role is more important that simple lift to orbit. NASA needs to focus on the things that are really important, and that we do not know how to do. The agency is a pioneering force, and that is where its competitive advantage lies. While the list is long of what we do not yet know how to do in the private sector, two things stand out as critical path technologies.
Interestingly, both needs are defined by one scientific fact: The vast majority of mass required to get to Mars is contained in propellants. Think about it. The physics of the effort dovetail with common sense. You need propellants to accelerate toward Mars, then to decelerate at Mars, again to re-accelerate from Mars to Earth, and finally to decelerate back at Earth. Accordingly, the mass of these required propellants, in short, drives our need for innovative launch vehicles.
Where do we go from that realization? First, developing in-space crew habitation systems capable of transporting people safely to and from Mars will be needed. Common sense says these vehicles need to be dedicated, single-purpose vehicles. Known requirements for reusable in-space habitation and transportation are quite different from the more basic requirements of delivering people from Earth to orbit.
Notably, the Apollo program provided clear testimony for this factual reality. Von Braun's original concept of using a single, multipurpose spacecraft required two Saturn V launches for a single lunar mission. But the NASA's revised plans properly allocated the functionality of the missions across separate vehicles (e.g. the Command Module, and the Lunar Module). The resulting efficiencies allowed these seminal Apollo missions to be completed in a single launch.
What do we really need right now to migrate from America's commitment to human exploration and eventual permanent presence on Mars -- with all the Earth side advantages in exploration, national security, science and economic activity -- from vision to reality? The vision that comes first to mind is this: In addition to commercially provided Earth-to-orbit crew transportation, I envision two NASA developed, complementary interplanetary transportation systems, one to get people and a small amount of cargo to a second system, a "cycling mother ship," that offers longer range and long-term habitability.
Explore this idea one level deeper with me. This two module exploration system would intercept a larger habitation system which would cycle between Earth and Mars, providing a means for getting crew and cargo to Mars on regular 26 month intervals. Regular, long-term cargo transportation would also support a permanent presence on the Red Planet or its highly attractive inner moon, Phobos.
One of the major problems with long-term deep space human flight is the requirement for radiation shielding. Shielding requires mass, and yet there are well-understood ways for accommodating the need for such mass. For instance, water contained in the outside wall of an inflatable habitat makes for excellent shielding. By keeping all of this mass on a single spaceship which cycles between Earth and Mars, requiring minimal thrust and no high-energy lift and descent from Earth, we strikingly reduce Earth-to-orbit launch costs.
Now, consider one other part of the "how" problem, what we call aero-capture. Put simply, aero-capture is a technique for using the atmosphere to decelerate to orbit, rather than burning precious fuel, be it Mars or a return to Earth. This is the extraterrestrial equivalent of free money. By using the atmosphere to decelerate, we again reduce the amount of propellant required to get to and from outer orbits. Like hunting and finding synergies in other areas of economic and national security, these systems offer hope, opportunity and a challenge that can be embraced by both the private and public sectors. While not simple, they offer real ways for converting our collective ambition -- which in increasingly urgent -- into a multi-generational reality, and commitment to long term U.S. leadership in human space exploration.
In a nutshell, the advantages -- not least for the U.S. economy and permanent leadership in space -- are almost incalculable if we begin from this first step. On the other hand, if we wander aimlessly, pick our way from one short-term goal to another, lose vision, ambition or commitment, we will find ourselves spending the next fifty years the way we have spent the last -- without significant outward movement. We can no longer afford that kind of approach, or an attitude of leisurely investment in the future. Needed now is vision and commitment -- with common sense. There, I have said it. I have spoken up as I did not when last the opportunity presented itself. Now, together, we should reaffirm the value of NASA, private sector engagement in space transportation, and America's leadership in manned space exploration. The sooner we make these commitments, the sooner we all benefit from their extraordinary returns.
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