§ 7.2.2 Asteroidal vs. Lunar Materials Utilization
There has been a longstanding debate on whether asteroidal material near Earth is better than lunar material or vice versa.
Both have their advantages and disadvantages, and both will be utilized. Indeed, there is a synergy in using both, and using one will result in expanded use of the other.
However, there are debates and discussions on which one is better, and some people are taking sides, e.g., for establishing a base or embarking on a first mission to retrieve material. It may be premature to take sides at this time, especially as there are continuing discoveries such as ice at a lunar pole and newly found Earth approaching asteroids which are cheaper to get to.
Sometimes, taking sides is motivated by wanting funding for certain projects one has heavily invested oneself in, or for maintaining momentum for a current agenda, e.g., the "Return to the Moon". Other times it's something as simple as preconceived visions and people taking sides quickly without really considering all issues and aspects.
Of those who take sides, more people have taken sides with the Moon, but the basis for their choice is often (but not always) due to financial support by existing government programs focused on the Moon, general conservatism, their immediate peer group and/or not considering all the issues. Some very conservative people tend to choose the Moon and dismiss asteroids out-of-hand. Supporters of asteroids are dominated by research and development people, with few government bureaucrats in that community because asteroids have never been a strongly established interest group in government contracting circles. Much of the government support of the Moon comes from the NASA Johnson Space Center, which carries on the legacy of Apollo, and is full of lunar scientists who have spent much of their career studying the Apollo samples and have interest in furthering lunar science, with little interest in commercial endeavors.
There has been a significant shift over time towards seriously considering asteroids, but the Moon is still a higher profile target politically at this time. It's notable that most of those who have increasingly supported asteroids have been cautious in their statements within their sociopolitical government funding environments, as they often get government funding for research and development related to the "Return to the Moon" and Mars mission initiatives, e.g., how to extract oxygen from Mars atmosphere and soil.
Technically and economically, the main advantages of the Moon are:
The main advantages of asteroids are the following:
Some issues are worth further discussion and hashing out.
The Moon has a fairly strong gravity. Landing and deploying heavy industrial equipment without damaging it takes a careful operation with considerable risk. On an asteroid, the equipment simply docks with the asteroid at nearly zero gravity, entailing little risk. (It could be anchored down, e.g., on a harpoon, and/or tunneled in.) If a rocket or subsystem fails during landing or launching, it would be a disaster on the Moon but of little consequence at an asteroid.
Indeed the entire industrial facility can be assembled and deployed in low Earth orbit with no deployment needed after "docking" with the asteroid.
Except at the poles, the Moon has a two week long, very cold night, followed by a two week long, very hot day. This has two effects:
First, the existence of night means that more power generation and storage equipment must be landed in order to store energy for the nighttime -- to produce extra energy for storage during the day. The only exception is if the mining is done in a certain permanently sunlit spots which may exist at each lunar pole, and hopefully which exist near a lunar ice concentration.
Secondly, it's hard to design equipment to operate in the extreme day-nite temperature range, so any surface operation would probably shut down for long periods of time in any ordinary long day/nite site on the Moon. Underground operations, however, could continue, and other countermeasures may be feasible on the Moon. Mining a frigid, permanently shadowed polar crater also presents some challenges.
Some current analysis is focusing on how to use certain points at the lunar poles which may be permanently sunlit to collect energy and transmit it to mining sites. Such power sites may or may not exist. The vast majority of the lunar poles will have warm sunlit spots next to frigid shadows, a real challenge for equipment.
Asteroids typically rotate several times a day, whereas the moon rotates once per month, hence the extreme differences between shadow and sunlit spots. With no air, the temperature differences are sharp.
Asteroids don't suffer the power challenges of the lunar poles. An unshadowed power satellite can be located above. Also, with the asteroid microgravity, a very large power station can be erected at an asteroid pole if inclined well. Alternatively, a chunk of an asteroid can be broken off and processed in free space without shadows and with a powered factory attached. Some people have proposed that small asteroids be despun by wrapping a cable around them and thrusting, or better yet by the propellantless unwinding of a counterweight, as discussed in the chapter on asteroids. Relying on solar power for both electrical and thermal energy, as well as lighting, is much easier and definitely feasible for small asteroids.
Of industrial significance is the fact that larger solar ovens and power plants can be more easily deployed at asteroids due to the very weak gravity of asteroids. In addition to the feasibility of large solar power systems, the negligible gravity also allows a more lightweight power plant structure than would need to be erected in the Moon's gravity, and hence less weight launched up from Earth (structure plus delivery fuel) -- a less expensive power plant. Since the asteroid is small, continuous electrical energy can be cabled from any permanently sunshined pole if so desired.
To compensate for the two-week-long lunar night and hence conservation of energy during the nighttime, we could polarize/segregate most mining/processing/manufacturing operations on the Moon into tasks that are more energy-intensive and labor-light for performing during dayspan, and those that are comparatively energy-light but labor-intensive for performing during nightspan. Any step, however partial, in this direction, would work to create an up-down wave in power demand that may work with the lunar dayspan-nightspan power cycle and reduce the quantity of energy storage capability we would need on the Moon. (Any nuclear power plants would be excepted from this problem, though it would need to be a large nuclear power plant for mining, transport and manufacturing.) Also, it has been pointed out, hydrogen imported from Earth for use as water, or extracted from the Moon, could be first used in hydrogen-oxygen fuel cells to produce power, with water as a byproduct.
It can be argued (depending on how you analyze the economics) that a disadvantage of near Earth asteroids is that they are "temporary assignment" missions because they can be reached economically at only certain times in their orbit. For example, a given asteroid may be economically attractive in terms of "delta-v" for several months which recurs at seven year intervals. This is similar to a "launch window". Assuming this economic argument is true, several months is still more than enough time to collect all the material we could handle for space industry in the near-term.
However, once we start exploiting asteroids, we're no longer as "delta-v" fuel constrained when it comes to transporting asteroidal material as we are for payloads launched from Earth. Once fuel propellant is abundantly extracted from asteroids rather than launched from Earth, the delta-V (fuel needed, more or less) based economic parameters become less significant. What becomes even more significant in the merit of asteroids relative to each other and to the moon is the delta-T, or time required to go from one point to the other. With more fuel available, we can opt for faster and less efficient trajectories. The economic equations shift when fuel becomes abundantly available in space for cheap.
There is also the emerging use of efficient, low-thrust electric propulsion vehicles which might make interorbital transportation even more economical. Further, the same equipment can be reused by moving it to any of a number of alternative asteroids which are entering their launch window at the time the current asteroid is leaving its launch window. Using fuel propellants extracted from the first asteroid, we could move the equipment to a second asteroid.
Many bureaucrats who promote a lunar base as the next step state that the lunar base would be a necessary stepping stone to asteroids. A base at a lunar pole may well be the next step. However, the opposite might be true. A lower cost, simpler and arguably lower risk First Mission could retrieve asteroidal material to Earth orbit for various uses sooner than delivering lunar material to orbital space, e.g., for experiments and developing technologies. A critical first step in raising support and interest in lunar and asteroidal materials utilization for space industrialization is simply the first mission to bring large quantities of materials back to Earth orbit in any form, and to gain some experience along these lines. This First Mission threshold would be another giant leap for mankind, and may be cheaper with an asteroid mission, which is significant for a private sector venture. Once we establish some space based infrastructure, both the Moon and additional asteroids become more economically accessible.
A few invalid arguments (unless you can make a strong case otherwise):
"The Moon is preferable because it's a planet with gravity, which is a better place to mine." Wrong, it's simply what we've designed equipment for to date on Earth. There are many alternatives for mining in microgravity. There are also advantages of microgravity. If you want gravity for processing, just rotate your facility for the centrifugal (i.e., centripetal) force. I have a lot of confidence in the ability of the private sector to adapt innovative technologies to solve practically any challenge, and this doesn't seem to be as technically difficult as countless other challenges we've solved in short order.
"It's better to manufacture on the Moon's surface than on asteroids or in orbital space." Wrong. More solar power in orbit. Again, if you need gravity, make a centrifuge. Choose any strength of gravity you want, many different ones if you like. Often, zero gravity will be preferable. But in orbit, you've got all the options. I want to emphasize that there are advantages to processing and manufacturing in zero gravity as well as small gravity. In orbital space, you can have whatever gravity you want -- Earth-healthy, heavier or lighter gravity can be easily created by the centrifugal force, e.g., get a couple of tanks, connect them by a cable, and rotate the structure. You can choose whatever gravity you prefer according to the rotational speed and distance from the axis of rotation.
Most of all, I want to caution against Earth biases. Following such a course would be at the risk of wasting money, time and energy unless there were an objective analysis first. As regards private industry competing for the market, you can bet they will do the proper analysis and come to terms with the above issues regardless of peoples' political opinions. Competition will shake out the right from the wrong.
Human ingenuity not only has solutions to problems, it also sees new opportunities. It is hoped that these webpages will help dispel some widespread myths and misunderstandings.
Much of the government money going to people researching the long-term effects of zero gravity on humans can be made irrelevant with a cheap and simple spacecraft. Take two big throwaway fuel tanks, furnish the interior with a nice human design (e.g., with a shipment from an IkeaŽ factory in orbit), put a long cable between them, and rotate the structure. Earth-normal gravity if you like. This simple solution makes a lot of government spending look wasteful, and media coverage look unenlightened, as regards concerns over the long-term effects of zero gravity on humans being a major issue in space colonization. The media can make it an issue, but some of it is based on lame research and public relations campaigns to get government money for studies.
Right now, the majority of the space development community has a lot of intertia towards the Moon as the next step into space. This is largely due to government support. The outlook of much of the government and the public is that Mars is the ultimate target of man's venture into space (again, familiar old planetary chauvenism) and the Moon is a logical steppingstone. Hence the official "Return to the Moon" program that has been circulating through NASA since President George Bush called for this agenda in a speech, set up by people of this political bent. Look at articles in the press as well as the NASA sites and those of their contractors (who they give money to, of course) regarding "In Situ Resources Utilization (ISRU)" with main focus on the Moon and Mars. Planetary chauvenism is still strong, and it takes time to broaden peoples' perspectives. It would take high profile public relations for orbital based settlements as pictured in the PERMANENT home page to become part of the government agenda. Many professionals think the concept of mining asteroids is far out, without having considered it much. At the very least, the government isn't investing much money into research into asteroid materials utilization, but is still handing out lots for lunar and Mars ISRU.
When private money is on the line, that will change, as the values will become cost and profitability.
Look at this, too: NASA is not investing much money into researching potential products and services from lunar and asteroidal materials utilization besides fuel propellants and things to support the Mars and Moon bases. Many people think that the taxpayer is unlikely to fund a large scale lunar or Mars mission that does not give direct economic payback. But a number of long-term government bureaucrats and government contractors get job security from the traditional public Mars push, and have practically no incentive to make their government job profitable at all.
The barriers are not technical but are of committment and proper focus. We have achieved much more difficult technologies than asteroid or Moon mining. Mining and basic processing of asteroidal material is relatively mundane technology, especially compared to achieving space flight and landing on the Moon in roughly a decade ... 30 years ago! Technology has come a long way since then. There are many sectors of product development on Earth that are more technically demanding than asteroidal materials retrieval and processing, and many products currently under development on Earth have readiness goals of several years, not unlike products from asteroidal and/or lunar materials. All by the private sector. The author of this article consults to multinational corporations and consortiums making high tech factories in remote places in the world, and many of these factories and products are of vastly lower payback potential and thinner projected profit margins than an asteroid mission. Some are of the same magnitude in cost as an asteroid mission to retrieve materials, but have many competitors and uncertain markets. The investors are usually not American, and investing in space is outside their range of consideration, for purely psychological and/or cultural reasons. This must change, too. Space development is not a NASA monopoly, if you just consider it.
As for government and much of the space community, many supporters of the "Return to the Moon" think that government will someday fund that project beyond the current low funding effort (currently for paper studies, small scale R&D, and inexpensive little probes) and, despite the current government tight spending times, express the belief that they will gain the political support (against competing interests getting cut to the bone) to spend billions of dollars to establish a lunar base for one reason or another. They perform these studies at taxpayer expense without much regard to sociopolitical realism or economic payback besides "spinoffs" -- no participation by anyone besides the NASA elite and their favorite yes-men contractors, who they surround themselves with, and no vision of specific products and services to benefit people on Earth, unlike PERMANENT.
Journalists generally say this about the Return to the Moon: "Been there, done that". It's a catchy phrase that the Return to the Moon community will need to deal with, regardless of its accuracy. Sure, we are doing some new, different things, technically, just as the space program has been doing in the 25+ post-Apollo years -- lots of technically new and interesting things for techies, but will an expensive lunar base and a Mars flags-and-footprints shot fly sociopolitically in a budgetary era where other important things are being cut?
One longtime supporter of the Return to the Moon scenario responded to this PERMANENT page as follows: "Been there done that[?] NO WE HAVEN'T. No one has so much as slept in a bed on the Moon, or taken a walk without a space suit [in a lunar habitat] (no pressurized environment big enough) or tried to process, manufacture, or build anything. We've only scouted. No one has been in a lunar lavatube (the Moon's relatively benign hidden valleys) and no, their existence is not problematical. We have NOT done the Moon. That's a superficial and ignorant response. That the asteroids are more interesting will wear thin with the very first mission."
This is a common kind of response I get from my website. What do you think, realistically, as regards enough public support for the above?
One hope in this old fixation on government-supported lunar and Mars human bases is that some of the research will establish some of the basic flight hardware and infrastructure needed for private sector lunar and asteroid missions. However, it would be much more efficient to focus on the technology needed to industrialize space rather than focus on Mars technology and hope that space industrialization occurs as a spinoff.
It will certainly become more feasible to send people to Mars after we start to industrialize space using nonterrestrial materials, and almost certainly not before. After we start to industrialize space using asteroidal and lunar materials, a permanent manned base on Mars and permanent human habitation of Mars becomes less expensive and more feasible, for those who want to live on another planet. They can do it in greater style, and permanently, based on richer and commercially self-sufficient space infrastructure, not the political winds.
Apollo was the result of fear during the Cold War. The end of the Cold War marked the end of the big daddy warbucks. Times have changed.
The threat of an asteroid hitting modern, 20th century Earth, is filling some of the void of fear which seems such an integral fixation of the human animal. This is fueling the effort over the past few years to discover Earth-crossing asteroids by putting state of the art sensors on a few telescopes from time to time, which discover many new asteroids every nite, including Earth-crossers from time to time, as discussed in another section of this website. The asteroids so discovered add targets for potential private sector ventures.
Asteroids appeal to the '49er instinct of humans to explore new kinds of places vastly different than the norm, including different from the Moon. Asteroids are the next "Americas", destined to leave America on Earth, as well as the Moon, to history. It's the ultimate outback frontier for freedom and creativity.
One thing is for sure: It would be a big mistake to depend upon the government to take us there, especially as things have changed from the old days when the Western governments were competing with Communist systems. Government bureaucracies suffer from the same fundamental human nature mechanisms as Communism. To get NASA to research potential products from lunar and asteroidal materials utilization that can be sold to consumers, or even to do paper studies into asteroidal materials utilization, would displace other established research programs within NASA. It would take a revolution, and leadership from the President. Change will not come from within entrenched NASA bureaucratic interests. NASA's space program has become just another government program of established fatcat contractors consuming taxpayer money with their fingers traditionally pointed towards Mars. There's little enrichment of our greater economy and wellbeing there, mainly just the bureaucracy and its contractors. Within the latter, you're more likely to find yourself within a political rat's nest. Major new initiatives generally don't come from entrenched bureaucrats who have the old established interests of their own turf and friends to protect from competing new initiatives.
If the PERMANENT pages tend to lean a little towards asteroids near Earth, please understand that this is partly because there are so many government-reliant institutions strongly pushing for the Moon. But there are authorities and assumptions that need to be questioned if we are to consider free enterprise industrialising space, and rapid space colonization.
Free enterprise could embark on a profitable asteroid materials retrieval mission, not only by selling material and products retrieved to Earth orbit (e.g., fuel propellants, radiation shielding, walls, beams, material for scientific and engineering study and experiments, etc.), but moreso by selling television news clips of the trip, perhaps making a movie, enhanced company name recognition, licensing use of trademark names associated with the mission to makers of consumer products, computer games, toys and the like, and of course gaining patents for equipment and processes used to mine and process asteroidal materials, and selling scientific and engineering data. This is covered in the PERMANENT page on a First Mission.
Notably, PERMANENT is currently not dependent on anyone for support, and harbors no financial or national biases. We should be more concerned for the well being of life on Earth and the security of our species (inter-national security) than particular bureaucratic interests.
Please feel free to make any comments. The more inputs, the better we can make well thought out decisions. In any case, it's better to air as many opinions as possible, and everyone is free to decide for themselves. This could also be your chance to get involved in the space program, playing a role to get our species off the planet in our generation, a purpose which will enhance your life in other ways as well.