Stuck in Transit - Unchaining Ourselves from the Rocket Equation
Paul Spudis
The Once and Future Moon
Smithsonian Air & Space
Last fall, after much anticipation, the Augustine Committee presented us with their assessment of the future of space exploration. Its basic conclusion was that at currently envisioned budgets, the Program of Record (a.k.a. ESAS, Project Constellation) would not get us back to the Moon before many decades had passed, if then. This meme has been picked up by many in the space community to the point where is it now cliché to claim that we don’t have enough money to do anything in space. Hence, the direction proposed in the new budget takes NASA out of the space transportation business entirely, freeing up their budget to focus on technology development, and contracting with commercial providers to create access to low Earth orbit (LEO) and the International Space Station (ISS).
How are costs estimated for space systems? The costing exercise for the Augustine Committee was done by The Aerospace Corporation, a non-profit science and engineering company run for the U.S. Air Force. Their costing procedures (described briefly on page 82 of the committee report) includes estimating the time and level of effort it takes to develop a system, informed by data from past projects. The vast bulk of this costing effort deals with launch vehicles and systems.
Looking over cost estimates is a strange experience. Almost anyone can immediately see inflated levels of costing for things they know about, but are uncertain for other items. Bob Zubrin wrote a stinging rejection of the Aerospace Corporation’s costing just before the Augustine Committee released their report. He noted in particular that the estimates included several years of increasing ground operations costs, even while nothing was being launched. Of course, if you pull together a ground crew, you have to pay them to keep them around, even during slack times. But his point is a good one; why should it cost more than Shuttle does now to support a launch system that requires an order of magnitude less preparation than the highly complex Shuttle Orbiter?
Using these estimates of the cost of the existing architecture, the Augustine Committee concluded that it was unaffordable. What did they do then? Rather than fix the problems with the ESAS architecture, they discarded the entire Vision for Space Exploration and came up with the so-called “Flexible Path” (FP). Although cloaked in platitudes about how technology development will give us options to go to many destinations beyond LEO, the real motivation for this idea is revealed by the committee’s words on “public engagement” (e.g., “It (FP) would provide the public and other stakeholders with a series of interesting “firsts” to keep them engaged and supportive.” – Augustine report, p. 15). Thus, the goal of FP is to create Apollo-like spectacles for public consumption, rather than creating steps toward increased space faring capability.
We can wait and hope for the proposed technology development program to provide us with magic beans, or we can begin that process now by returning to the Moon with robots and humans to learn how to harvest and use its material and energy resources. Creating a sustainable system of space faring that can take us anywhere we want to go would be a real accomplishment. By gaining this knowledge and expertise, mankind will be free to choose many space goals, thereby achieving “at will” space destination capability.
Jeff Greason, President and co-founder of XCOR Aerospace and a member of the Augustine Committee, recently spoke at the annual Goddard Memorial Symposium. He asserted that for the near future, we have no path to move people beyond low Earth orbit because the options the Augustine Committee looked at cost more than the United States can afford or is willing to spend. His principal message to Symposium attendees was to “deal with it.”
According to the Augustine Committee, “The cost of exploration is dominated by the costs of launch to low-Earth orbit and of in-space systems.” This outlook is one reason why so much of the costing focus was on building Ares V, the super-heavy lift (188 mT) launcher designed for human Mars missions. For such a mission with chemical propulsion (the only technology currently available) you need about one million pounds in LEO, of which more than 70% is propellant. Going to Mars is expensive because you must lift all of that fuel out of the deep gravity well of Earth. Even with the economies of scale provided by a super heavy lift rocket, it still costs tens of billions of dollars to mount such a mission.
Making propellant on the Moon completely changes these numbers, yet use of lunar resources is discussed in only a few brief paragraphs of the Augustine report. We now know (as the committee did then) that water is present at the lunar poles in significant quantity and that its use to make rocket propellant can create a transportation system that could routinely access all of cislunar space. This should be the objective of lunar return: to create a space “transcontinental railroad” through the use of lunar resources. Once established, we can go to the planets with relative ease.
Is any of this possible under the existing budget? Not if we dissipate our money with pointless and unfocused technology development. Of the many advantages of the Moon, one of the biggest is that it is close enough that preliminary work can be done by robots on the lunar surface – controlled and remotely operated from Earth. By emplacing robotic assets on the Moon before human arrival, we can begin to survey, process and store water for use well in advance of human arrival. Sending robotic assets in advance of people allows us to start creating capability now, without a major increase in budget. It simply requires a sense of clear objectives; we have the technology to work this problem now.
Simply put, our space objectives need to be – arrive, survive and thrive. To do that, the goal must be stated, mapped out and achieved before setting out to the next destination. A sustainable, expandable transportation system in space can be devised by using the resources we find in space. We will learn how (and if) we can do this on our Moon. Once we don’t have to haul everything with us from the Earth, costs become lower. When you don’t have to use 90% of your travel budget just to get out of town, a lot more people can take the trip. Before you know it, you have a space-based economy.
The nation has important strategic and economic interests in cislunar space and it is entirely appropriate for the federal government to develop a sustainable and extensible cislunar transportation system. NASA needs to lead and point the way so that the private sector (not just aerospace companies) can invest in and develop the yet unknown technologies that will improve our lives here on Earth as we move out to explore and ultimately settle the new territory of space.
The Moon is a classroom, a test bed and a supply depot. By using its resources, humanity can create the capability to live, work and travel in and beyond cislunar space. As a nation, we cannot and must not pass on this enterprise.
The central farside crater Bhabha (64 km diameter) was named in honor of the physicist Homi Jehangir Bhabha (1909-1966), a nuclear physics pioneer in his home country of India.
