Previous human mission to a near-Earth asteroid, Willamette Valley, Oregon, 1902.
A much-publicized congressional divide has developed over the administration’s proposed asteroid retrieval mission (ARM). ARM features a robotic capture of a small (few meters across) asteroid and its return to near-Earth (cislunar) space for human examination. Although there are mutterings that (predominantly) Republican opposition developed because a Democratic president proposed it, I believe that this “dust-up” comes from legitimate concerns over how this asteroid mission, without any serious thought or study, was adopted.
The idea to capture an asteroid and return it to cislunar space for examination came out of a 2012 Keck Institute of Space Studies workshop. Although NASA maintains a variety of advisory groups to analyze mission proposals and concepts, inexplicably few in the science or engineering community were given an opportunity to examine and comment on this scheme. While NASA claims that significant benefits will come from the asteroid retrieval mission, attendees considering the idea during a recent meeting of the Small Bodies Assessment Group (SBAG) expressed serious reservations about its feasibility and scientific value.
Many in the space community believe that the asteroid retrieval mission was proposed to paper over the embarrassing and expanding void left after the administration abandoned the Vision for Space Exploration effort to return to the Moon (a program with a history of strong bipartisan Congressional support). They believe that the new Orion/SLS spaceflight system under development currently lacks long-term, sustainable direction and a strategic goal. Confusion over what the administration sees as our national role in space has fanned the divide in space circles and left American space leadership in serious doubt.
After six decades of intense research of meteorites (hands-on study of small asteroids already captured by the Earth), we’ve acquired a comprehensive understanding of the accretion and evolution of the early Solar System. In addition, robotic missions have been sent to several asteroids and small bodies. From these studies, we’ve learned a great deal about the properties and characteristics of these objects. Some asteroids are rubble piles of loosely aggregated debris, while others appear to be largely intact solid rocks. All have experienced impact and are cratered, with landscapes similar to those observed on the Moon and most other planets. When contemplating the possible return of samples from a captured asteroid by the ARM, consider that in the meteorite collections of the world’s museums, we already possess more than 45,000 small samples of these near-Earth objects.
For years, both NASA and the National Science Foundation have been funding asteroid detection programs and observations. The result has been a multi-fold increase in our knowledge of the number and orbits of asteroids, particularly those that encounter Earth’s orbit around the Sun. Because of this long established effort, we possess a good catalog of the biggest (and most potentially dangerous) near-Earth objects. The idea that we can identify potentially hazardous objects and alter their trajectories in space, causing them to miss hitting the Earth, has been under consideration for some time. Several strategies to interdict asteroids have been studied, but to my knowledge, none involve bagging the asteroid and then moving it with solar electric rocket engines. Hazardous asteroids are simply too big (many kilometers across) for such an approach. Thus, as currently configured, the asteroid retrieval mission is not relevant to the problem of asteroid interdiction and the protection of the Earth from catastrophic impacts.
A variety of other alleged benefits from the asteroid retrieval mission likewise do not hold up to scrutiny. The claim that this mission will provide “deep space” flight experience is not unique to ARM – any flight to a destination beyond low Earth orbit gives us this experience. Someday we hope to be able to use the material resources of space, which includes asteroids, but the configuration and limitations of the Orion spacecraft prevent serious resource utilization experiments during the course of the ARM mission. The Orion has no laboratory or processing facilities nor sufficient electrical power to conduct resource extraction and processing experiments. The spacecraft cannot loiter in the vicinity of the retrieved asteroid for any significant length of time. These limitations preclude experimentation with different approaches to resource processing. The ARM mission will not establish or extend our permanent space faring infrastructure nor develop new technology. We’ve been using solar electric propulsion (SEP) for over two decades; the current Dawn mission to the asteroids Vesta and Ceres utilizes SEP.
Perhaps the most disturbing rationale for this manned mission is that in an era of increasingly limited federal funds, we have to “do something.” Such an attitude is amusing coming from those who supported the conclusions of the 2009 Augustine Report; that report outlined something called the “Flexible Path,” whereby we would not aim for a destination but rather, “develop technology” and choose where to go later. The argument that we must “do something” negates that strategy in a particularly indefensible way. Doing nothing is infinitely preferable to doing something when the “something” is a mission so transparently worthless as to bring the entire space effort into disrepute.
But there is another and more pertinent aspect against this rationale. I reject the idea that we cannot afford to go to the Moon. How you go is more important than how much money you spend. Several architecture studies published over the past few years have outlined affordable ways to return to the Moon. A renowned statement made during the presentation of the Augustine study was that America could afford to build the Orion CEV or a lunar lander, but not both simultaneously. As the lunar return effort already was an international partnership, perhaps the Europeans or Japanese would have been interested in building (and more importantly, funding) the lunar lander. This option (and several others designed to lower the cost of lunar return) was presented to (but ignored by) the Augustine committee.
On close examination, none of the claimed benefits of the proposed asteroid mission are valid. There is no rationale for this mission, beyond “flying a mission.” ARM is being sold as an “affordable” choice, however, estimates of low mission costs fly in the face of decades of experience with complex spacecraft and missions. The administration is working to sell this asteroid diversion mission as a new space accomplishment, though in truth, what they’re attempting to divert is public notice of their systematic dismantling of our civil space program. Given this mindset, we will remain Earth-bound indefinitely. Instead of capturing and retrieving an asteroid, we should establish a sustainable presence in cislunar space through resource utilization of the Moon’s known resources, thereby creating a permanent, national spaceflight capability. The next giant leap for mankind requires one small step by the Congress: a return to bipartisan political leadership for space through the re-adoption of the goals endorsed by the three previous Congresses – a return to the Moon.
“-what they’re attempting to divert is public notice of their systematic dismantling of our civil space program.”
Yes! And that needs to be exposed and made center stage as a national disgrace. The public MUST be made aware of what is happening. Right now they do not have a clue.
“As the lunar return effort already was an international partnership, perhaps the Europeans or Japanese would have been interested in building (and more importantly, funding) the lunar lander.”
The lander is the only missing piece of hardware- we have everything else in the pipeline. The Europeans or the Japanese or the Chinese or even the South Koreans could probably build us one. By flying the lander by itself as a single payload on the SLS and putting it in orbit around the Moon, we avoid the extreme weight saving that was necessary with Apollo. And we could also fly it as a one way landing only cargo vehicle a couple times first to position stuff at the pole near the ice.
The President needs to abandon the commercial crew and ISS dead end and go after asteroid interdiction with a vengeance- and that means a Moon base to assemble, test, and launch nuclear missions. If SpaceX thinks they can fly tourists and make a profit then let them support the ISS with their paying customers and spend my tax dollars on a real space program.
“-a permanent, national spaceflight capability.”
Nuclear propelled and equipped with a massive water shield and artificial gravity, a true spaceship can only be operated from the Moon. This is the only path and it is not flexible.
Paul
Concerning Garvers’s comments about not being able to afford a lunar return (from the link in the main article).
She is “all over the map” on the subject.
“Garver said today that asteroid exploration and lunar exploration should not be viewed as an either/or choice, but as complementary targets for future human and robotic spaceflight. But new lunar exploration missions should aim for a sustained presence on the moon, and not just be a repeat of NASA’s Apollo lunar landings, she added. “We truly have an increased focus on sustainable lunar activity,” Garver said.
http://www.space.com/22135-nasa-asteroid-exploration-ideas.html
Seems to almost be reading from your Proposal (not to mention implying that we can simultaneously afford both). I guess that kind of inconsistency is what to expect when you get no leadership from the top.
Has anyone ask the question. “After we do this asteroid mission what do we do next?” or is this one of those ‘we’ll do this and worry about what come next later’ things. There need to be a multimission plan for space exploration not just a bunch of one shot missions…. Better results would be gotten by a lunar based laboratory, then just smack a small asteroid into the moon for study.
This blog is basically about answering the question of “what do we do next?”:
Using the Moon to Create New Spaceflight Capabilities (at the top of the page on the right).
In my opinion the Moon has three critical resources- solar energy, water, and material resources that can be processed with solar energy into spaceship components. As I commented in another post, refine several thousand tons of titanium ore and pour it into the shape of a disk and you have the largest part of a nuclear pulse propulsion engine. An engine efficient enough to push a multi-thousand ton spaceship around the solar system for years at a time. Along with titanium is water derived from lunar ice that provides the other thousand plus ton component; shielding against cosmic radiation on said multi-year missions.
Ships with such an engine and shielding can be assembled, tested, and launched from the Moon. But these thousands of tons of metal and water will never come from Earth and the nuclear materials to power and propel such a ship will also never be used anywhere near Earth. And the public does not know the technology exists right now to do this.
The Moon is the key to the solar system.
Agreed – the whole “idea” begs the question “& now ?” A pointless exercise either politically inept, conceptually challenged, self serving or plain dumb – worse, perhaps all of the above !
Dr Spudis,
I am a geologist with an enthusiastic & long term interest in planetary geology. I have been an avid follower of the human & robotic exploration of the planets/minor bodies/comets/asteroids etc in ” our” solar system.
I am really sincerely disillusioned with the complete lack of vision displayed by the US Govt when capitalising on the legacy of Apollo.
Please continue with your excellent blog/comments. I am a firm believer that the Moon should be the first primary goal of any human endeavour to progress beyond low earth orbit
Thank you, Mike. Have a look through my previous posts — and don’t lose hope! Eventually, the rational path will win out.
Amen….
Consider also, that on the Moon itself, are inevitably going to be meteorites to be found & scientifically analyzed. All those impact craters were formed by meteoric, cometary, & asteroidal matter. If new manned landing missions went there, geologists would have a veritable field day, scoping out the rock characteristics, of extra-cislunar-space-originating meteors. The proposed Asteroid Retrieval Mission is a gross waste of technological resources! Notice how the Flexible Path people avoid the idea of just hauling the captured meteoroid to LEO? What, are they too afraid that some guidance error might crash-land their retrieved sample onto the Earth? (Not to mention moving the “acheivement’s” finish line, right back to LEO distance.) I personally, think that the plan would still stink, even if it actually got off the ground. Can you imagine our astronauts being sent all the way out to Lunar orbit/ Lunar-vicinity space, merely to reach next to some artificially-positioned charcoal lug, while the vast & majestic Lunar surface, replete with hills, rilles, mountains, valleys, craters & even crater peaks——remains a forbidden place for spacemen to ever re-visit?!
“-a forbidden place for spacemen to ever re-visit?!”
Visiting is not the point, establishing a permanent base it the only possible goal. Considering the Space Shuttle was a heavy lift vehicle that wasted most of it’s payload lifting wings and landing gear, we could have been going to the Moon for the last 30 years instead of LEO. Going cheap threw away the space age. The only excuse was we did not know the ice was there and that is not really valid because it would have been found soon enough if we had kept going.
We have a new heavy lifter slowly, oh so slowly, coming into service- and there is no reason we cannot fly it 6 times a year for the NEXT 30 years in support of a Moon base. It would cost no more than the shuttle program and by learning from past mistakes it would turn the failure of the shuttle into a success and make every penny spent on that monstrosity worthwhile.
The real space age would finally begin.
@billgamesh;….True. The Space Shuttle launch stack could’ve long since had been reconfigured into the proposed-but-never-done Sidemount launcher. THIS rocket would’ve used the same industrial resources as STS, and could’ve led to some viable manned deep space program, if it had been seriously considered, for completion. I heavily lament all that has been going on with NASA, since Obama & his people eliminated the human lunar return goal. If the Moon is blotted out, as a future destination, then any plan for a Heavy-Lift rocket will eventually collapse like a house-of-cards, because there’s no compelling purpose for its construction.
If the LEO merry-go-round is just to continue, and a space station is the only “place” for our astronauts to go, then it is only small & medium-small launchers that you’d need. Building a Heavy-Lift vehicle now, without any fixed purpose in mind, is a potential grand mistake-in-the-making. Remember when the Soviets built the Energia? They had no real game plan for its use, hence it flew once or twice and that was it: total decommision. The Ares 5, as part of the Constellation project, was specifically envisioned to launch an earth-escape-stage & a lunar lander, initially unmanned, to a parking orbit; [subsequently to be reached by a human crew in another space-craft.] THIS flight plan alloted the cargo-module parameters, which would’ve drove the multi-stage rocket’s development. From what I now see, the so-called SLS appears to be being built blindly, without any real regard for what its eventual cargo complement will be. It’s like they’re building it to satisfy any possible & imaginable future use for it, to satisfy anyone’s needs for their own pet projects. This is NOT the correct way for a Heavy-Lift rocket to enter the picture. The SLS will likely go the way of the Energia, if no specific mission is lined up with its use.
“From what I now see, the so-called SLS appears to be being built blindly, without any real regard for what its eventual cargo complement will be. It’s like they’re building it to satisfy any possible & imaginable future use for it, to satisfy anyone’s needs for their own pet projects.”
I thought the configuration for Constellation was excellent in that it separated crew and cargo vehicles but SLS could work out to be a better deal. IMO one of the critical issues that is not even being addressed right now is how to transport fissionable material to the Moon where it can be assembled and tested in various power and propulsion systems. The SLS can send “pits” of packaged-to-survive plutonium or uranium directly to the Moon in the Orion capsule which has a powerful escape system.
That is as safe as it is going to get. It is most likely the only way this ultimate hazardous material is going to get to the place where it can be used to effect Human Space Flight Beyond Earth and Lunar Orbit- and be used used for asteroid deflection.
Excellently phrased.
Bob Clark
@Robert Clark;…..Thanks for saying so. I would find it indeed ghoulish for America to send a manned cislunar spacecraft on a mission, that far out, into deep space, just to have nearby Luna be ignored, because the powers-that-be consider it dulls-ville, and are only going close to it to visit some asteroidal boulder. As if THAT would be the sole motivator & draw-factor, behind our ever launching out of LEO with astronauts ever again, after half-a-century.
A planet or planetoid shouldn’t be declared borings-town, just because it received human visitors some four or five decades ago! THIS kind of attitude in the space interest community is the main thing that’s holding us back, from commencing all of those grand space-faring dreams that we’ve all had! By THAT kind of mindset, no further astronauts should ever be sent to LEO, on any more station visits, because: “we’ve already been there!”/ “we’ve already done that!” Exploration has always meant going back to the same places that you’ve previously been. If it didn’t, Antarctica would not now have any bases on it. We would’ve long since been satisfied with the fact that our explorers already had made landfalls there; hence the great IGY base-building exploits of the 1950’s would never’ve come to pass. (IGY: International Geophysical Year).
The attitude by the powers that be seem to focus on “anywhere but the moon”.
Billgamesh says it best in that the public needs to be made aware of the folly behind this thinking.
@Grand Lunar;….Folly-way-of-thinking, indeed. The Heavy-Lift rocket we ought to now be building is the full-up Ares 5! Not some substandard, less-powerful, all-things-to-all-people type of launcher. The Orion craft would require merely a small launcher rocket. (If not an Ares 1, then perhaps something else along those lines.) Nobody has adequately explained the basic SLS launch plan idea, for beyond-LEO missions. [a.] Are all of the cargo-modules & earth departure stage going to be sent up during a single launch, as during the Apollo/Saturn 5 launches? [b.] Will the crew fly to an LEO parking orbit on this same single launch, or do they reach the lunar transport stack separately, on another capsule? [c.] Does the cis-lunar flight plan call for a revival of the transposition & docking procedures, to re-align the lunar orbiter & lander crafts? [d.] Are the two basic types of craft, planned to be much smaller in size, as compared to the former Constellation concepts, due to the different Heavy-Lift rocket being somewhat smaller & less-powerful? [e.] Or will the module elements be sent up on two or three separate launches, to be assembled in space, (for the deep-space flight-phase), afterwards? [f.] Would a multi-vehicle type of expedition, like a new manned Lunar flight, be even possible, utilizing such an alternate booster? These are questions that certainly could use answers, by the NASA bureaucrats & planners, as we fall down the drain-pipe of a possibly Moonless space future, for the next few decades. (Note, while I may’ve used many familiar lunar flight concepts here, all this discussion could still apply to any supposed crewed NEO/ Martian moon/ Mars-reaching mission, with other analogous elements.)
Hi Chris,
A couple of points about the Block One SLS (70 metric ton version).
The reason the Ares 5 had to be as large as it did was because of the “one and a half” launch concept selected for Constellation Systems. In that scenario the Ares 5 launched first carrying the Altair Lunar Lander and the Earth Departure Stage (EDS). That complex then needed to be able to await the arrival of the Orion on a separate Ares 1 launch. The loiter time to assure mission success was set at 90 days and the EDS had to be designed to allow for boil off of the cryogenic propellants for that 90 day period. Additionally the Altair had to be much more massive to allow the design of the docking adaptor (which would hold the Orion in place on the nose of the Altair) to withstand the loads of the Trans Lunar Injection Burn. All this required a much larger payload capacity for the Ares 5.
There was an alternative launch architecture called “dual launch”. In this scenario the Lunar lander would be launched and placed in lunar orbit with no loiter time required. Then using an identical booster the Orion would be launched to lunar orbit to meet with the Lunar Lander (thus allowing a much lighter docking adaptor). The common booster would have been the Side Mount Configuration SDHLV (LEO payload capacity approximately 70 Metric Tons). That architecture was evaluated by a team led by John Shannon (then the head of the Shuttle Program) and found to be practical and in fact highly competitive (in operations terms) with the “one and a half” launch concept.
The Block One SLS has the same approximate LEO payload capacity as the Side Mount Configuration SDHLV and it is therefore applicable to a HSF Lunar Base Program.
I am not saying that the whole process was well thought out (it clearly was not), but the Block One SLS (however it came to be) still has the potential to be very useful.
Thanks for explaining that Joe. It does seem to be the way to do it; send a lander to orbit the Moon while the second launch sends the crew.
I would think the best way to build a base is to find a suitable small crater near the ice and assemble a plastic double roof over it and fill the void with water from the ice to provide radiation shielding.
So the first unmanned cargo lander (UCL?) with the roof kit would land outside this as-small-as-possible crater. The second lander with an inflatable habitat would actually land inside the crater. The third lander with equipment to process and transport the water to the crater would land near the ice. The fourth lander would land with a small nuclear power plant. The fifth lander would carry a crew (launched on a sixth SLS) to as quickly as possible assemble the roof and fill it with water and then inflate the habitat in the crater. With an SLS mission every two months this semi-permanent Moon base could be in operation in just over one year. Then larger bases would follow quickly with this protected sanctuary as a base of operations.
If no suitable natural formation is available then the first mission would be to excavate a hole explosively near the ice. This would require seven launches. Of course there are endless variations on this theme. The water roof is just my own idea and may not be a very good one; it might be easier to excavate a radiation sanctuary with conventional explosives. This might be done using a natural formation to start with or by blasting a large crater to start with a kinetic nuclear device (bunker buster).
Of course my favorite idea in regards to building a lunar colony was illustrated in the book “Beyond Tomorrow” by Dandridge MacFarlan Cole in 1965.
http://en.wikipedia.org/wiki/Dandridge_MacFarlan_Cole
I must have read this book when I was in elementary school because when I read it again several years ago I realized I had been thinking about everything in the book for the last 40 years.
Cole’s book showed lunar colonies built by exploding nuclear devices underground to form huge caverns, as in the gnome blast that took place during project plowshare.
http://en.wikipedia.org/wiki/Operation_Plowshare
You can view a picture of the gnome cavern on the wiki page and also the pic at the top right shows the Sedan crater, which looks to be close to the right size crater for a possible “water roof” site.
Sorry, after looking at it a second time that Sedan crater is way too big for a water roof carried by a single lander. But I am sure you get the idea.
Good ideas. The most detailed design concepts with which I am familiar come from the Space Exploration Initiative (SEI) and Constellation Systems. Both used double hulled structures to position the shielding.
Both those activities also used Lunar Regolith as the shielding material rather than water. Undoubtedly part of the reason for that was that the substantial availability of Lunar Water had not yet been confirmed.
I would suggest, however, that there are at least three other reasons to use regolith rather than water:
(1) If a suitable substitute is available, there are better things to do with the water.
(2) The regolith does not involve the possible leakage problems involved with water. In fact regolith shielding could also provide a micrometeoroid shield, as opposed to a micrometeoroid target.
(3) Handling of water will be relatively complex and (at least in my opinion) require on site human supervision. Collecting and positioning of regolith, on the other hand, should be a “bulldozer” like operation readily adaptable to tele-robotic control from Earth, minimizing the time the first Lunar Base Crews will have to spend without shielding.
Just a few things to consider.
Yes. If NASA could get away from this mental block that: Return to the Moon = Constellation program = $100 billion, we could have an affordable lunar base using the SLS.
Bob Clark
http://www.bbc.co.uk/news/science-environment-23408073
Anyone who thinks this planet does not have the resources to establish a cislunar infrastructure need only look at another fabulous project that has far less chance of ever becoming reality.
Building a Moon base and cislunar highway in space is child’s play compared to the Fusion boondoggle.
http://www.sciencedaily.com/releases/2013/08/130809010232.htm
Mining asteroids; the commercial angle is what ARM is all about. Greasing the tracks for tax dollars to find their way into entrepreneur’s pockets- and for political contributions to find their way into campaign funds. What a tangled web they are weaving and it will all be exposed some day. Or maybe not.
There is the option of using the lava tubes on the moon to house inflatable habitats. Instead of using nukes to blast caverns which requires a significant amount of drilling gear.
Dr. Spudis has said in a previous post there are no known lava tube formations near the polar ice deposits. There may be the option of using space as the “drill.” A bunker buster type device can penetrate hundreds of feet and explode a shaped nuclear explosion that behaves in a precise way to form a cavern. Precisely controlling plasma and blast effects are also used in pulse propulsion.
After untold trillions of dollars and decades of computer and supercomputer time studying weapon effects we might as well use some of that cold war knowledge. The non-nuclear option is to use a TBM- and transporting such a monster or building one on site is not going to happen for awhile.
http://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/6114/Designer-Edge-Image-of-the-Day-Bertha-The-Worlds-Largest-Tunneling-Machine.aspx
“there are at least three other reasons to use regolith rather than water:”
I can think of three reasons why water might be preferable:
(1) No bulldozer is needed, just a way to melt the ice. The water will flow into and fill a void all by itself. Water does most of the work by itself while regolith will do nothing but wear machinery out.
(2) Water is the reason the base will be near the ice. Since processing ice is the main activity then millions of tons will eventually be turned into water. Keeping the first several thousand tons is simply economical in terms of activity as regolith moving is an entirely different operation.
(3) Water is transparent and so is clear plastic. Living underground is not how humans evolved. Seeing up through a roof and also using the water to grow things in is IMO well worth the trouble of repairing micrometeorite damage. Plastic can be made to self seal to a certain degree; the plastic targets I fired thousands of rounds at in the military were self-sealing. I do not know if that property can be incorporated into clear materials.
But water does have drawbacks as Joe points out- it leaks and must be defended against micrometeorites. So perhaps a combination. I am drawn to water because it would allow people to look out (through 14 feet of it) on the lunar landscape at least in some parts of their habitat and I think this may be extremely important in regards to mental health. No one is going to be going outside very much. Of course a really big underground sports arena sized cavern would be different but that would not happen immediately.
Or Joe is right and it is just not a good idea. It is still the way to go for a spaceship radiation shield and that is what the water will be used for eventually.
Thoughtful response. I will address your three points as below.
(1) “No bulldozer is needed, just a way to melt the ice. The water will flow into and fill a void all by itself. Water does most of the work by itself while regolith will do nothing but wear machinery out.”
Some system will be needed to harvest the ice and cut it into segments that can be fed into the device that will melt it. Additionally that melting device will have to be able to maintain an atmospheric pressure as the ice is being melted (or alternatively capture the gases released into a low pressure environment) so that the water can be allowed to flow. That will, of course, have to be done for any use of the ice. My point was that I believe that direct human supervision of such a multi-step process will be required. On the other hand digging a trench and essentially burying the initial habitat modules will be much simpler and much more amenable to tele-robotics, thus reducing the time that the initial crews will have to go without shielding.
(2) “Water is the reason the base will be near the ice. Since processing ice is the main activity then millions of tons will eventually be turned into water. Keeping the first several thousand tons is simply economical in terms of activity as regolith moving is an entirely different operation.”
Two points here. Some degree of regolith moving will be required to harvest the ice. Also, if the lunar base activities are to expand to manufacturing activities then harvesting the metals from the regolith will be required for that purpose. While “regolith moving is an entirely different operation” it is not an unneeded one.
(3) “Water is transparent and so is clear plastic. Living underground is not how humans evolved. Seeing up through a roof and also using the water to grow things in is IMO well worth the trouble of repairing micrometeorite damage. Plastic can be made to self seal to a certain degree; the plastic targets I fired thousands of rounds at in the military were self-sealing. I do not know if that property can be incorporated into clear materials.”
Here we have no debate. I am in one hundred percent agreement with you looking out through a window (even a double pained one filled by 2 meters of water) is much more esthetically pleasing than being surrounded by what amounts to two meters of dirt. I also agree that these esthetics are important when talking about long term habitation by large numbers of people.
As – hopefully – the number of people required on the moon grows the financial incentive to get those people to do longer “Tours of Duty” will also grow and you can only incentivize people so much by what amounts to hardship pay. By that time the industrial capability available on the Moon should be up to building larger habitats with shielded windows and even skylights (I like skylights).
I meant my regolith comments to apply to the initial outposts not to more elaborate later bases/settlements. If I failed to make that clear that was my error.
“If I failed to make that clear -”
No failure or error, just a difference of opinion. Digging appears to require so much mechanical energy to me that melting ice is a more efficient alternative. Just exactly what are we going to be excavating? Is it solid rock after the first couple inches or what? “Digging trenches” may not be practical.
In terms of a first outpost, I am thinking now you are right Joe about digging and filling. Simply blasting a hole in the landscape with an empty stage and value added explosive may be the way to start. This would excavate a crater in which expandable structures could be set up with inflatable habitats inside- then some small earth movers could push the debris back inside on top.
Or if there is a suitable crater and it is easy enough to just scrape surrounding surface material into and on top of the the modules then that would work.
You are right- this could be done with robots and would allow for a base to be waiting for the first crew to walk into instead of my much more human intensive water roof concept. Maybe skylights later.
Of course, despite Garver’s statement concerning the Moon, this discussion of how to build a base is fun but meaningless. We do not have a lander- and that detail is a big problem because it is going to take years to get one built.
This is very frustrating because even though we have an HLV and a capsule on the way they have no place to go and nothing to do without that lander.
“Is it solid rock after the first couple inches or what?”
My understanding is that the Lunar Regolith layer is several meters thick. If that is incorrect I hope Dr. Spuds will correct me and educate both of us (no sarcasm intended).
Yes, that’s correct. The regolith thickness is proportional to the age of the bedrock. It is about 2-8 meters thick in the maria, the relatively young (~3 to 3.8 billion year) rocks, and 10-20 meters thick in the highlands regions (> 3.9 billion years).
“As – hopefully – the number of people required on the moon grows the financial incentive to get those people to do longer “Tours of Duty” will also grow and you can only incentivize people so much by what amounts to hardship pay. By that time the industrial capability available on the Moon should be up to building larger habitats with shielded windows and even skylights (I like skylights).”
My take on living off-world is that a rule of thumb might be that one gravity for half the day will be required to maintain fitness. Yes, I am guessing.
On very low gravity bodies like the icy moons of the gas giants (and Ceres) my idea is to have under ice “sleeper trains” that go in big circles providing centrifugal gravity and small apartment living. The more gravity and the less ice the more difficult this becomes. Setting up these facilities on the Moon would be extremely expensive and is not going to happen for a long time. So the length of a tour on the Moon may not be much longer than the ISS- and I consider the debilitation and permanent damage those people suffer (let alone their cumulative radiation dose) to be unacceptable anyway.
This was all considered long ago by Gerard K. O’Neill in 1976. His well known solution is to create artificial worlds using raw material from the Moon. I agree and think permanent residency on other bodies will not be common at all- most of the human race may eventually leave Earth and be living in habitats. He took into account incentives and financial motivations. The only thing I am concerned with is not going extinct.
For once I get to play the optimist.
While I am an Orbital Habitat proponent myself, some results from the Apollo 14 Mission may indicate that the Moons 1/6 G gravity may a much friendlier to human conditioning. While they were indeed getting a lot of exercise the two crewmembers on the lunar surface returned with no degradation to their muscle tone, cardiovascular capability, or bone density.
Only longer missions will tell for sure, but it is a reason for hope.
@Joe,….Indeed it would appear, even from the very limited data & spaceflight experience——all from 40-plus years ago, mind you——-that a light amount of gravity is better than having no gravity at all. How the human body will react to a long duration surface stay on Luna, would set the stage & script for how we deal with spacemen voyaging to other similar-gravity worlds.
The madcap folly that is Flexible Path, becomes readily apparent, when you realize the importance of building landing vehicles. Lunar landing crafts, will be major engineering laboratories, in & of themselves, teaching us virtually anything that we could ask to know, about planetary surface habitation. The first earthian nation that sends its spacemen to the Moon, in the 21st century, will reap brilliant engineering rewards in the effort. From the get-go, dust-management systems & procedures will need devising; [even on sortie-length missions]. Once you get to the stage of outpost-type missions, some kind of radiation-protection that could withstand solar flare hits, will also need devising. (Perhaps some smaller area of the lunar lander’s cabin, can be fitted out with a protective-material walling, on the regular crew-transporting ones, in case a sun flare struck during an expedition without nearby access to a base module, which undoubtedly would be built with an even more durable protective shielding, in some part or even most of its hull & walls.) In brief, any Lunar landing mission, lasting a fortnight and further, is just the kind of technological challenge that we need, to actually develop all of these things. These technological capabilities are never going to come to pass, until we actually send an expedition beyond-LEO/beyond the ionosphere.
By the way, playing Mars-astronaut in the high Arctic, in an oversized tuna-can tent, won’t yield any of this new technology either. The Mars enthusiasts do a great disservice to the cause of spacefaring, when they call for ignoring the Moon, as an intermediate destination.
I notice Joe mentions two meters of regolith as the thickness of shielding. In his 2006 article in Scientific American Magazine Eugene Parker specifies five meters of water;
“A large mass around the astronauts absorbs incoming radiation and the secondary particles it produces. A spherical shell of water five meters thick provides the same protection that Earth’s atmosphere offers at an altitude of 5,500 meters (18,000 feet).”
I have been quoting 14 feet but I was wrong: I just checked and 5 meters is almost 16 and a half feet. This is such a monstrous amount of shielding that most people cannot wrap their heads around it and simply reject it as completely impractical for a spaceship. I have come to believe if that much shielding is the minimum then that is what must be and no amount of dancing around the problem and wallowing in denial is going to solve it. Heavy nuclei is square one for human spaceflight outside of LEO. If I am not mistaken regolith is not as effective as water so any base would have to be buried probably 20 feet below the surface.
I drew my 2 meter number from the data used in the Space Exploration Initiative and Constellation Systems. I believe the number was also used by Gerard O’Neill (who you mentioned) in his work
As for Dr. Parker’s dissertation, you will have to forgive me if I am a little skeptical of a supposedly neutral scientific paper that contains such phrases as:
– Perils of cosmic rays pose severe, perhaps insurmountable, hurdles to human spaceflight to Mars and beyond.
– What are Astronauts getting themselves into?
– It (meaning spaceflight) is not quite as bad as venturing inside a nuclear reactor, but …
Then referring to the 15 foot shielding he says: “Even so, the required mass would be at least 400 tons—still not feasible.”
He then goes on to “prove” why any active shielding will not work. Thus shooting down a series of straw men of his own creation.
Then just to keep the Mars advocates happy he throws in: “MARS’S PITIFUL ATMOSPHERE is scant protection against cosmic rays”. A word like pitiful used in a supposed scientific paper, really?
I would submit that the good Doctor (due respect to his standing in the Physics community) just might have a political agenda.
I am not (nor do I pretend to be) a radiation expert, but I could tell you “war stories” (do not worry I won’t) about the development of the pre-breath protocols for doing EVA’s from the ISS and the agenda driven experts from the diving industry who attempted to convince management that it just could not be done.
In regards to Parker’s writing, it was not a scientific paper, it was a magazine article and meant to entertain the popular science culture audience to a certain degree as well as enlighten.
He IS a world recognized radiation scientist by the way. He writes that a massive shield is impractical and I happen to disagree with that due to the availability of water in the shallower gravity well of the Moon.
I am of the opinion that our natural environment is a baseline that cannot be violated without eventually paying a price. I strongly believe one gravity and Earth radiation is the requirement for human beings to stay healthy on long duration space missions. While the ISS is often used as an example of how well people can adapt to space it is actually the opposite- the debilitation and permanent bone and bone marrow loss are irrefutable.
It is interesting that at one time it was thought possible that humans beings would not be able to stay conscious without gravity and people like Willy Ley, writing under the pseudonym Robert Willey, proposed solutions like tether generated artificial gravity. If you click on the February 1937 cover you will see this is so.
http://www.sfcovers.net/Magazines/ASF/
And before the Van Allen belts were known it was assumed space stations would be orbiting at all those altitudes where there is deadly radiation and spaceships could slowly spiral up and away from the Earth.
We want to believe that we can keep going farther into space using the same unshielded chemically propelled spacecraft- but the resulting damage to the human body is just too severe for this path to be considered practical. It is the dirty secret of space exploration.
I strongly believe that going with recreating the environment in which we evolved is the best course and will certainly succeed. The solutions are straight forward in the form of nuclear pulse propulsion, artificial gravity, and massive shielding. Going with chemical propulsion and unshielded spacecraft is IMO doomed to failure.
Nuclear energy and the prerequisite shielding in the form of lunar ice is the path to successful interplanetary missions and obviously must originate from a Moon base. The radiation issue continues to be the key determinant in spaceship design and is invariably addressed with varying degrees of simple denial.
That is not going to work. The damage done by heavy nuclei is real, and for long duration missions lasting several years- whether in deep space or on the Moon- it is simply unacceptable. The only solution is a massive shield.
We are probably going to have to agree to disagree about Dr. Parker’s article. I do not doubt he has all the proper credentials, but (to me at least) the article is not “meant to entertain the popular science culture audience to a certain degree as well as enlighten” it is propaganda intended to persuade. In this case to persuade casual readers that HSF is just too difficult and should be abandoned.
Academic “experts” using their status to try to stop work in HSF is not by any means new. You point to a particularly entertaining one with your link about Willy Ley. The idea that the human body could not stand even very short periods (seconds) of weightlessness (free fall) was ridiculous even in the 1930’s. Parachutes were already in use. Even with the old canopy chutes some seconds of free fall are experienced before the chute is deployed. As anyone who has ever “jumped out of a perfectly good airplane” can tell you it you pass out it will not be because of the weightlessness. Yet that myth was used not just in the 1930’s (and by many “experts” with great reputations) but all the way to Yuri Gagarin’s flight in the 1960’s. Then, of course, it became inoperative; and none of the “experts” could remember ever having used it.
You are essentially correct that there is an issue with the appropriate amount of shielding required for long duration spaceflight/settlement. The sad thing is that pieces of agit-prop like Dr. Parker’s article make resolving the issue all the more difficult.
“-Dr. Parker’s article make resolving the issue all the more difficult.”
It made it very simple for me- not difficult. I believe him and am not confusing the facts with any hidden agenda; the DNA damage caused by heavy nuclei and secondary radiation is real.
I have no knowledge of Dr. Parker having any reason to “persuade casual readers that HSF is just too difficult and should be abandoned.” Do you?
It does not read like propaganda to me; it appears to be the truth and everyone else seems to be dancing around it and trying to find some way to deny or ignore it because it is so disruptive to all the other agendas in play.
I am just accepting and not denying, working the problem as it is presented, and going with the best solution.
I find this indeed to be a terrific & much-needed discussion: the detail of designing radiation sheilding on the surface of another world. The Moon is a very challenging environment, from which to conduct manned surface activities: and that’s a good thing! The need to develop an effective radiation storm shelter, in the event of a solar flare, will resolve one of the pieces of the puzzle, of doing viable interplanetary space flight, in the future. The Mars zealots really don’t get this! Once longer-than-sortie expeditions are started on Luna, lasting multi-weeks or multi-months, all of the problems that would be encountered on a Red Planet mission will automatically arise. The dust-management issue, and the radiation-protection issue, just to name two. Imagine if you will, that China in fact commences with a manned Lunar program. It gets past the first few sorties, in order to prove the viability of both its lunar orbiter craft & its lunar lander craft. Then, they launch an unmanned variant of their lander, and guide it to an automated land-fall, on a pre-chosen site. This variant lander does not need to launch back to lunar orbit, hence the usual ascent rocketry can be deleted. Afterwards, a taikonaut crew will arive, on a different lander, making a pinpoint landing at the same site.
Thanks to a bigger supply of provisions, on board the outpost module, this crew will remain on the Moon for a fortnight span of time. (Their orbiter craft would presumably be left unmanned & untended during this time, to be reached later.) On board one of the lunar modules is a section-room walled with special material and/or designed for the on-site emplacement of regolith soil or lunar ice liquid to be positioned into segmented parts of the walls. (Perhaps even the entire hull of the cabin or much of it, can be built to have these segmented/portioned walls, for putting in protective material and/or substance-matter, in the case of ice or liquid.) In short, the Chinese now would have a means of surviving a possible solar flare event, on another planet; and will possess the first scientific data on how well such a radiation protection system would work. When they get this taikonaut crew safely back to Earth, after enduring the first multi-week stay on another world, they’ll be technologically ahead of us, in terms of radiation sheilding work.
Meanwhile, at the exact same time, here comes an American manned cislunar craft, the very first launched to deep space since 1972, which enters into a high lunar orbit, NOT to investigate the Moon, but merely to fly up-close to an asteroidal body—-maybe a boulder-sized rock, that had been transported over there by the ARM plan. America has NO lunar landing craft at all, even at this point, because of its Flexible Path/No Moon space policy. I ask you: Which spacefaring nation will have accomplished more, in the space arena??! China or the U.S., in this hypothetical future sequence-of-events?
Actually Chris, the discussion me and Joe are having is not about solar flares, it is about heavy nuclei, which is a small component of Galactic Cosmic Radiation (GCR). When these nuclei hit other atoms they cause large amounts of very damaging secondary radiation. The DNA damage is massive.
Long duration missions, as in years, are unavoidable if human beings are going to explore the solar system in person. The present paradigm is to use unshielded chemically propelled spacecraft that do not even have artificial gravity systems. Just the added structural weight of a tether system to generate artificial gravity makes chemical propulsion a much more difficult proposition. Massive shielding completely changes the whole outlook for human travel in deep space.
Shielding massing in the hundreds and thousands of tons requires a massively powerful propulsion system and the only candidate for the last half century and for the foreseeable future is nuclear pulse propulsion. This seems to be impossible for space advocates to accept.
I have yet to read anything in the mainstream media about this. Maybe I am wrong but no one has ever been able to convince me otherwise. They just ignore the cosmic ray gorilla and nay say. The basic argument against massive shielding that requires pulse propulsion is, “radiation is not a big problem.”
Because humans have not been irradiated for years at a time on space missions this seems to be the proof for many people that it will not be a problem. Uh-huh.
While cosmic radiation on a mission lasting a few months will not be an issue a solar event certainly is. I am curious what kind of radiation sanctuary the astronauts on the ARM are going to have. How much will it lower the dose they receive from a solar event and how much will it mass?
Does anybody have any info on this?
There are several studies being conducted into Active radiation shielding. A quick Google search on ‘active radiation shielding for space travel’ show up several studies
http://www.thayer.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf
is one.
The basic idea is to mimic earths magnetic field to provide a radiation shield. There is a long way to go, but at least they have started addressing the problem.
Travel times with chemical rockets are much to long, the use of electric engines such as the VASIMR should significantly decrease travel times and thus the radiation received during travel.
billgamesh says: August 13, 2013 at 3:26 pm
“It made it very simple for me- not difficult. I believe him and am not confusing the facts with any hidden agenda; the DNA damage caused by heavy nuclei and secondary radiation is real.”
And you have the right to believe anyone you want about anything you want
“I have no knowledge of Dr. Parker having any reason to “persuade casual readers that HSF is just too difficult and should be abandoned.” Do you?”
I have the use of his own (in my opinion extremely unprofessional) words:
– Perils of cosmic rays pose severe, perhaps insurmountable, hurdles to human spaceflight to Mars and beyond.
– What are Astronauts getting themselves into?
– It (meaning spaceflight) is not quite as bad as venturing inside a nuclear reactor, but …
– Even so, the required mass would be at least 400 tons—still not feasible
– MARS’S PITIFUL ATMOSPHERE (and the all caps are his).
“It does not read like propaganda to me; it appears to be the truth and everyone else seems to be dancing around it and trying to find some way to deny or ignore it because it is so disruptive to all the other agendas in play.”
If the above does not read like propaganda to you , that is again your privilege.
It is also my privilege to say I find no further use in continuing this discussion.
Let me end this discussion (which has certainly drifted off topic — my fault) by concluding that several challenges to human Mars missions exist and while exposure to high energy cosmic rays is one of them, it is not the only — and possibly not even the most critical — one.
In any event, we cannot go to Mars today or in the near future. That is why the current agency is floundering around with silly ideas for stunt missions, like the haul asteroid proposal.
Propulsion is certainly the most critical issue for human spaceflight. If you can go fast you do not need long missions and radiation exposure and zero G debilitation become less of a problem.
In my amateur survey of propulsion technology I can find only three candidates for high speed space travel. They are all three extremely expensive. There is no cheap.
The first is beam propulsion. It is the dream come true for all space advocates because it is non-nuclear and holds the promise of an airliner to space. A microwave launch vehicle could take a payload up through the atmosphere with a much higher Isp than a conventional rocket because pure hydrogen has a much higher exhaust velocity than hydrogen and oxygen- and microwaves can generate much higher temperatures. If an orbital array can beam energy down into the atmosphere to take over from the surface array then a single stage to orbit vehicle becomes possible. Also an outward bound beam propelled spaceship could be launched from the Moon or lunar orbit at very high speeds. But then slowing down at the other end becomes a problem because of the lack of solar energy resources to power a system at the destination to decelerate the spaceship.
The problem with beam propulsion is the technology is not yet mature and a huge infrastructure would be necessary to beam the necessary power.
The second possibility is an atomic engine using Americium 242. This transuranic element has a unique property that makes it fairly easy to use in a fission fragment propulsion system. In this system a rocket similar to conventional engines would have an Isp in the hundreds of thousands and would allow travel anywhere in the solar system. The engineering is fairly straightforward so such engines could be developed fairly quickly. This path seems too good to be true and of course it is.
The problem with Americium that makes it too good to be true is that it is unobtanium; there is very little of the stuff to be had and it would take a huge investment in an entirely new nuclear industry to make it available. And because the exhaust is highly radioactive it could not be used anywhere near the Earth’s magnetosphere so it still relies on chemical rockets to get into deep space.
The third possibility is nuclear pulse. This has the same disadvantage of fission fragment in that it cannot be used anywhere near the Earth’s magnetosphere. It has the added disadvantage that while a fission fragment propulsion system would resemble conventional rocket engines in size a pulse engine would necessarily need to be either an immense parachute type device several miles in diameter or a smaller disc a few hundred feet in diameter massing several thousand tons.
Nuclear pulse is the most practical of the three because of the availability of fissionable material for pulse units. There is a couple hundred tons of plutonium and a couple hundred more of enriched uranium in storage at this time- enough for several hundred deep space missions using pulse propulsion. So unlike beam propulsion and fission fragment- the infrastructure has been built and the material is available.
Nuclear pulse requires the very large or very heavy engine to be either transported beyond Earth orbit or manufactured in space and the Moon seems to be the only place to assemble, test, and launch such missions. The Moon is also the place to build a beam propulsion infrastructure for future fast missions that may utilized nuclear pulse to decelerate spaceships at destinations in the outer system after high speed transits.
So before any missions to Mars or the outer system can be considered a Moon base is IMO a prerequisite.
http://blog.al.com/breaking/2013/08/report_nasa_boss_says_asteroid.html
From a Huntsville times blog:
“When I weigh the cost benefit of going back to the lunar surface in a limited budget environment, and going to Mars, I would rather take what little money I have upfront and advance the technologies we’re going to need” to do Mars missions, the website quotes Bolden saying.”
What technologies? The only technology that is going to make a Mars mission possible is nuclear propulsion IMO. The only place to assemble, test, and launch a nuclear mission is the Moon. And if a nuclear propulsion system is required then Mars becomes a second best destination compared to the low gravity icy bodies. And the closest one of those is Ceres.
Ceres becomes the logical manned mission after a Moon base to support such a launch. The ARM mission is all smoke and mirrors. Our space program is dead in the water.
Recent comments by the NASA administrator about the ARM as discussed on Spacepolitics.com engenders even less enthusiasm for the idea.
Bob Clark