Paul Spudis has some guidance for the Augustine Commission to update the 1990 report to the 2009 report, based on what we know about the moon now that we didn’t then:
what do these discoveries mean for lunar return? We now know that sustained human presence on the Moon is possible, largely because we’ve found a source of near-constant power (permanent sunlight) and a source of sustenance and rocket propellant (volatiles, including water). The robotic Clementine and Lunar Prospector missions showed us that the poles, almost completely unknown in 1990, are inviting oases on the lunar desert. There, we can extract hydrogen and oxygen to make air and water for life support and propellant to fuel rockets. The sunlit areas can generate near continuous electrical power, with regenerative fuel cells providing power for the short duration eclipse periods. Locally obtained power and consumables means that continuous human presence is possible, without the enormous expense or unproven technology of large nuclear reactors and the delivery of massive quantities of material from Earth.
The new Augustine committee should be made cognizant of these facts. The more we learn about the true nature of the Moon, the more the goal of learning to live there on a quasi-self sufficient basis appears feasible. This opens up wholly new areas of operations and commerce in space, undreamed of as little as twenty years ago. It has the potential to change the entire paradigm of spaceflight, from a narrow, government-run, science-oriented program, completely dependent upon the caprice Congressional largess to a self-sustaining, free-market program, in which NASA develops and demonstrates new technologies that open up spacefaring by many different passengers and payloads for a wide variety of purposes.
Wouldn’t that be a breath of fresh space policy air?
Sounds good. As to ‘near constant power’ the last numbers I remember hearing was that the peaks at the poles had 70% light and 30% dark. Are those numbers correct? If so, is the 30% continuous or sporadic? If it’s continuous, ~8 days in darkness is still along time to run on batteries.
One other question: How much area is there to build on? Would there have to be a tower with a lot of solar arrays on it, going for height (and getting more continuous sun by doing so)?
Tom,
A peak that we’ve found near the south pole of the Moon is in sunlight 75% of the lunar day in “winter” and is 100% illuminated in “summer.” The winter darkness occurs as several discontinuous periods ranging in length from around 10 hours to almost 65 hours. It’s not regular because local eclipses are caused by local horizon topography. This hill is about 10 km from the rim of Shackleton crater and the irregular sunlit area is several hundred meters across in maximum dimension.
Three areas near the north pole are in 100% sunlight in northern summer. We are still analyzing the northern winter data.
Would laying a few kilometers of power cable on the surface be technically difficult with teleoperated rovers ? If not, you could have 100% power-generation from a couple nearby peaks that individually are less than 100% of time sunlit.
Or use microwave power beaming.
8 days in darkness is still along time to run on batteries.
Only if you use 20th century batteries made of lead and stuff. How about using 21st century “batteries” instead — engineered plants? Solar collector, highly-efficient separator of your H2O into O2 and combustable fuel, and zero-loss dark-time storage unit all rolled up into one. Cheap and self-assembling, too! You only need to transport up a tiny bootstrapping package we call a “seed.”
“Or use microwave power beaming.”
Cables could be laid over the most convenient path from the collector location to the best location for the base (perhaps determined by spacecraft approach/landing/departure requirements) in what could be quite irregular terrain. A path that may not be line of sight…
The important point is water, not power. There’s absolutely no reason not to have a nuclear reactor. Supplement with solar and batteries? Fine. A reactor of a good standardized design can be used everywhere which would justify it’s development in spades.
Thanks Paul, for the succinct summary. Can’t wait for the LRO data. Their ops center is right next to my office.
Ken-I’m with you on the nuclear plant. To me, the talk about ‘constant sunlight’ was to convince people that bases could be just solar, but the long dark periods and limited real estate for development always struck me as a problem. I’d much rather have a ‘hot plug’ 100% of the time, with some solar panels around to convince people it was a ‘green’ base 😉
Goodness, why do we want a green base? Surely there’s no need to preserve the Moon’s delicate (mpf! snrk!) “ecosphere.”
Heck, maybe we can build all our nukes on the Moon, have them beam microwaves Earthside. No need for expensive containment vessels and double super doofproof emergency systems. If Joe the Reactor Operator forgets to close a valve and the core — sitting naked out on the regolith, built of the cheapest, flimsiest materials — starts to melt down, you just evacuate and build another core a kilometer away. Plus, your disposal problem for high-level radioactives goes away. You just throw it in the nearest pit and put a few warning signs around the lip of the pit.
I’d baseline solar power over nuclear just because one is commercially way more accessible technology and can be expanded in-situ gradually ( ISRU-solar cell baking is also in prototype stage ). For nuclear you need red tape, clearances and whatnot.
The biggest incentive for solar, rather than nuclear, power on the Moon is financial, not ecological. An outpost needs 100’s of kW of electrical power. No space reactor exists with those output levels. The SP-100 program cost billions of dollars before it was canceled. Finding permanent sunlight at the poles allowed us to just avoid the whole messy issue by using existing technology to reach the 100 kW level.
One other advantage — the permanently lit areas near the poles are also thermally benign. Because the solar incidence is always around a degree or two, the sunlit areas are always a nice, toasty -50 C. Temperatures on the equator range from +100 C to -150 C. Of course, you can bury the habitat to equalize temperatures; it’s just handy to have a near-constant surface thermal environment.
No space reactor exists with those output levels.
Then isn’t it about time it did? Borrow one from the navy… But seriously, isn’t this an enabling technology? We should get right on it. It give redundancy which is a good thing.
it’s just handy to have a near-constant surface thermal environment.
Sounds reasonable, although the base will likely be buried anyway. It’s an independent issue that happens to correspond to good solar locations. As I already said, solar can supplement nuclear.
It’s time the freaking ‘greens’ go to freaking hell. I want to live in a clean environment but that doesn’t mean I would join the idiots that join a movement they think is about environment when it’s actually about money. Morons.
I have two basic areas of dissatisfaction with the polar base concept.
First, the emphasis on water ignores the elementary point that the hydrogen in the water molecule is only 11% of its mass — the remainder being oxygen, the largest single constituent of lunar minerals, which can be produced from regolith using any of a variety of known processes. Furthermore, any reasonable level of self-sufficiency (not to speak of industrial development) will require a variety of inputs, & the mineralogy of the poles is too monotonous to be favourable in this regard. The Brown University results seem to dictate reconsideration of the hypothesis that Transient Lunar Phenomena are emissions of residual lunar volatiles from subsurface reservoirs, suggesting that mid-latitude sites with more mineralogical diversity & a history of TLP activity, such as Plato or Alphonsus, may be substantially superior in all respects.
Second, the “continuous power” argument disregards the effect of the very low sun angles. Although the extreme atmospheric attenuation experienced at the terrestrial poles does not take place, collectors will have to be substantially vertical to achieve anything like acceptable intensity, & will tend to shadow each other. Combined with the small available area, this means that the polar base will have low peak power output. While a high-output space-rated nuclear reactor is desirable, waiting on its development would seriously extend the waiting period until lunar development was possible, & in the current political climate it may not be possible to launch such a thing. Fairly simple calculations suggest that a power satellite based the technology (now more than a decade old) of the “Deep Space One” probe, launched into a medium Earth orbit by a DELTA IV HEAVY to climb into an L1 halo orbit via ion drive, would be able to provide substantial “keep-alive” power to a mid-latitude near-side base, which would have access to practically unlimited daytime power.
publius,
The mass of hydrogen is irrelevant — you need something to combust with the oxygen you make. Powdered aluminum is a possibility, but it takes high energy to make and produces a low Isp rocket. Hydrogen is the best fuel, but it is a rare element on the Moon, so on the basis of the Willie Sutton principle, you go where the highest concentrations of H2 exist, which as far as we know, are at the poles. We still have no idea what LTP really is, much less that it’s an expression of gas emissions from the lunar interior or that if true, such gas will be a useful resource.
The panels of a solar array farm at the poles can be mounted vertically, with staggered heights and placements to prevent shadows interfering with power collection. I am not against nuclear power on the Moon — I just don’t think it’s affordable right now. The free solar power and excess hydrogen make the poles attractive as a place to “bootstrap” human lunar presence. We can move to other locations and other resource processing feedstocks once we establish a foothold on the Moon at the easiest place to do so.
It’s relatively common to launch nuclear power into space. I’d like to hear a definition of space rated. Low mass? Safe in a crash?
We have nuclear powered ships because we’re serious about it. I guess we’re not serious about non terrestrial bases.
Only 11% by mass is a total red herring. The point is you don’t have to transport water if it’s already there.
Powersats make sense because they allow you to have mobile power.
@ken anthony
There hasn’t been a nuclear reactor (as opposed to an RTG, which is a totally different thing) launched since about 1990 when the Soviet RORSAT programme shut down, & the USA has only ever launched one, back in the 1960s. A space-rated reactor must be able to lose heat to a vacuum by thermal radiation ; in addition, an Earth-launched one must have high power per unit mass, & be proof against disintegrating in case of a launch accident.
@Paul Spudis
If you’re talking about making rocket fuel from lunar sources, oxygen is still by far the dominant mass component. It’s not difficult to show that, for example, if what you want to do is relaunch a lander, refuelling with oxygen alone (i.e., hydrogen for the round trip, obtained ultimately from Earth, is carried on-board) gives almost as much advantage as refuelling with both propellants. Similar results appear when considering, e.g., refuelling a Moon-bound vehicle in low Earth orbit, which is part of why current talk about propellant depots has concentrated mostly on oxygen.
Your underlying assertion appears to be that rocket propellant is the most significant component of the “bootstrapping” process, & therefore should be the first priority in lunar development, but I have seen no convincing case to support this. (Of course, the question is partly a teleological one, i.e., depends upon the intended function & operational characteristics of the base.) Expanding capabilties & reducing costs demands local sourcing for consumables first, & subsequently massive durable goods or “capital” components such as habitat shells, furnishings, tools, &c. The advantage in a polar location in terms of the former is not enormous (gaseous oxygen for breathing & the 89% of oxygen in water together account for more than 80% by mass of basic life-support requirements), & for the latter it is nil, owing to the feedstocks problem. Considering the poor situation with respect to communication with Earth, & the lack of convenient landing areas in the rough terrain, the polar-base argument still fails to convince.