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Of course western media are biased. All media are biased. That’s simply a part of being human. Not recognizing or dealing with that fact of life is insane. The real trick is looking past all the words at what people really do.
There is a definite pattern to these pro-Russian demonstrations, building takeovers, and other operations by pro-Russian “civilian militias” in Ukraine. That pattern suggests both pre-existing organization and outside support. These are simply not civilians looking for governmental change. It’s just too neatly the same in all the incidents taken together. This is orchestrated, and not locally. It’s coming from Putin’s Russia.
As for the argument that got so vitriolic earlier in this thread, WW2 had no one "cause" or "startpoint". No war ever does. It’s always a confluence of a lot of things. So, there is little point being dogmatic about this or that cause. That doesn't match reality. Which gets one nowhere. That’s why being dogmatic is insane.
WW2 in Europe could be said to have started with the Nazi annexations of Czechoslovakia and Austria, circa 1936-1937, just as easily as with the invasion of Poland Sept 1939. Or, just as valid, with the signing of the Treaty of Versailles in 1919, since some consider WW1 and WW2 two phases of the same war with a long pause in between. And, they do have a point about that.
WW2 in the Pacific started long before Dec 7, 1941. Take your pick, either the 1931 or 1937 Japanese invasions of China. Or, almost as valid, the US embargo on sending scrap metal, oil, and other potential war materials to Japan in 1939, which made the Pearl Harbor attack inevitable.
My father-in-law was a US Navy surface sailor, mostly destroyers until after the war was over. Early in 1939, long before the invasion of Poland, his ship was routinely in a “hot” shooting war with Nazi U-boats in the Atlantic, all the way to Dec 7, 1941, after which they sent him to the Pacific. Where he had 3 ships blown out from under him, and did hand to-hand combat in the Aleutians.
And my dad was a B-25 pilot, slated for surface attack duty in the Pacific when the war ended. Their combat lifetime expectations were about like helo pilots in Vietnam, by the way.
As a kid, our next door neighbor had been a WW2 crewman on a B-24, and had survived at least one shoot-down. He later killed himself, so that PTSD/suicide thing is nothing new. And, there's no excuse for anyone "not to have known about it", either. This has been going on for centuries.
Most of my uncles served in WW2, too. And my maternal grandfather was a USN battleship sailor in WW1. He anglicized his name from Wilhelm Friedrich Olsen to William Frederick Olsen, after the sinking of the Lusitania in 1915, even though technically he was more Danish than German. Politics has been a bitch far longer than most of you suspect.
So, yeah, I know personally an awful lot about the history of those times. It's a sort of family affair. Since long before most of you were even born.
GW
So there's some radioactivity in Martian dirt, it's around 0.5 REM annual, and seems to be neutron radiation. And we have no idea how deep it goes. That's not a killer dose, even for lives spent there, but it is rather inconvenient to build a radiation shelter out of slightly-radioactive material. I suppose therefore that determining how deep this goes is crucial data. Another reason to drill meters down....
GW
It'd have to be at least partly custom-designed, because none of the usual prime movers would work on Mars. How about hydraulic drive for locomotion, since you already have hydraulics for the lift/dig bucket? Let the source for the hydraulics be battery electric. Probably some kind of lithium battery.
When close to base, just operate on the solar charger as if the cable were an extension cord. Further out, you can only operate for the battery life without recharging. It does mean the solar charger for this will be fairly large and powerful.
About the only other major design change from Earthly equipment intended to be abused for decades, would replacing some of the steel structure with aluminum. I think the wheels will be different too, but definitely not aluminum tires! That was a horrible design error on Curiosity.
GW
I followed the link in post 1 above. The photo there looked like a ballute with some sort of flexible heat shield panel. I'd guess this is ballute technology combined with the inflatable heat shield technology. Not sure what all the connections are, because I haven't followed this very closely, just observing the occasional news story.
Ballutes can be power-inflated. In fact, the should be. Self inflation from ram-air ports has always been rather uncertain. The blunt shape is the drag, but it also has to "tow" stably, that's the real trick. If you have a flexible heat shield material coated onto your ballute, these things become good candidates for aero decelerators in the regime higher than 2.5 Mach, which is just about the fastest you can open a ribbon or ringsail chute successfully.
By providing better aero deceleration at higher Mach than a parachute, is how ballutes can get an big object slowed at an altitude high enough to do some good on Mars. I noticed that the article said "10 tons". This appears to be aimed at surface probes like Curiosity and a little larger. Doesn't appear to be aimed at the even-larger objects that would carry men to Mars. I still think supersonic retro-propulsion, dispensing with chutes entirely, offers more promise in those sizes.
GW
Seems kinda silly to go to Mars and establish some surface base (temporary or permanent), and NOT take the equivalent of a front-end loader. That's a digging bucket on the front of your rover with the drill rig on the back (that you also need). Take two in case one fails or is needed elsewhere when you want it. Three is even better. They might be around a ton each, if built stout the way we do here on Earth.
GW
I copied the article in the first post this thread. Let me digest it a bit, and see if the ballistics matches what they claim. Easy storables with performance between kerolox and LOX-LH2 might be just the ticket for ventures fueled from home.
GW
US 0.6 REM is a figure that surprises me. I thought the US average background was closer to 0.3 to 0.4 REM, with about a third of that coming from coal plant plumes. It would be up to factor 10 higher at high-altitude locations in the presence of radioactive ores. Yet folks in Denver seem to be about as healthy as the rest of us. So, civilians seem to do mostly fine with lifetime-long annual exposures up to 3 full REM. Maybe more if the 0.6 figure is better than mine.
I'd still set the standard a bit lower, nearer 1 REM max annual, but that 3 would also likely be more or less OK. Nobody really knows for sure. Astronauts are allowed 50 REM max annual, with a career limit that is age and gender dependent. They can only absorb that max a very few times in their lifetimes.
I'd think a standard somewhat like that astronaut standard would work for civilians going on colonization voyages, with a long-term domestic exposure in their new homes nearer 1 (or at most 3) REM annual. And BTW, unshielded GCR exposure in the vicinity of Earth varies sinusoidally with the solar activity cycle from a min of 24 REM annual to a max of 60 REM annual. That's actually just about the same as the astronaut's max allowed dose rate.
The only real risk on a voyage is being hit by an X-class coronal mass ejection, which is about like going outside in the max fallout after a nuclear bomb goes off on or near the surface (100's to 1000's of REM per hour, for several hours). Yet the energy is lower, and shielding is possible. 20+ cm of water is an effective shield for that.
What would the source be for radioactivity in Martian soil? Induced by GCR or solar wind/flare interaction? I know there can be induced radioactivity in Earthly dirt from near-, on-, or sub-surface atomic explosions, but that's the extreme case. It's where most bomb fallout comes from. Air bursts that do not pull dirt up through the fireball are much cleaner: just the bomb fragments.
Lesser sources like reactors, even reactor accidents, seem not to induce much of anything in the basic soil, they just contaminate it. That's different.
If Martian dirt really is radioactive, could that be a sign of abundant nuclear fuel ores there?
GW
You ask why NASA would do nonsensical things? The answer would be too long. Let me shortcut things with two observations about the world which explain much of the nonsense we all see going on all around us. Nonsensical behavior by NASA is just a small part of all the idiocy.
A "law" regarding the behavior of government (and non-government) agencies: the degree of bureaucratic arrogance is inversely proportional to the degree of competence exhibited.
A "law" explaining why nonsensical things happen in any society: HA >>>> H, where H is the number of horses, and HA is the number of horses' asses.
GW
It's not so much the garden you need to protect. It's the gardeners.
GW
As far as dangers from metals go, the really heavy ones cause toxicity effects (lead, etc), and the really light ones seem to have various bad effects (beryllium is not expellable from the lungs leading to death by edema, lithium alters the brain's functioning, etc). The ones in between don't seem to bother folks much, like iron. I remember the scare over aluminum cookware, too, but I've seen no evidence that was anything but fearmongering, at least as far as Alzheimer's disease is concerned.
On the other hand, very small particles do cause problems in the lungs, that's why 2.5 micron and finer carbon soot is now considered a bad actor in air pollution from diesel engines. Aluminum is used in solid propellants, and in paints, in powdered form. I'm not sure how fine in those applications, but the finer, the more risk there is to evaluate. That seems to be the message.
It's just something to be aware of, before jumping in with both feet on something utterly new to human experience, like organo-metallic propellants bearing lithium. Actually, organo-metallic anything compounds the potential danger of metals.
For example, it is a whole lot harder to really get lead poisoning from metallic lead pipes, solder, or pewter utensils than it from minute amounts of lead bound in organic compounds. Same is true of mercury. Busting a mercury thermometer in your mouth is unlikely to hurt you (except as cuts and punctures from the glass fragments), even if you swallow the mercury. Trace amounts of methyl mercury in your drinking water most certainly will hurt you, usually as both toxic poisoning and as birth defects.
On the other hand, there is a well-known historical incident from the start of the industrial revolution involving mercury poisoning. The expression "mad as a hatter" comes from this. People who made hats from felt in steam-heated molds all day long every day for years had severe problems. They used mercury in the hats to force the felt out against the mold, and handled it barehanded. Skin exposure wasn't the problem, it was inhalation. At steam temperatures (NOT at room or body temperature), mercury actually does have a noticeable vapor pressure. The heated mercury vapors got to them, over about a 20 year working career. Symptoms were violent insanity from brain damage done by the metal.
BTW, the "amalgam" in standard tooth fillings has been around the best part of a thousand years now. It's in part mercury and lead. No one has ever, ever, ever had a problem with it. Trust long experience. It usually doesn't lie to us.
GW
So, get out your backhoe, and build a roof up on supports, covered in regolith, with transparent walls. Put reflective stuff around the building to bounce light into the building through the transparent walls. You can even concentrate it to Earth-standard light intensity, especially if you build it in a small depression or crater.
That's a greenhouse that is completely radiation-protected. It would work on Mars or even airless places like the moon, if you stack up your sandbags deep enough. I had one design concept for such a thing posted over at "exrocketman". It was titled "Aboveground Mars Houses", dated 1-26-13. Some sort of concrete substitute would be nice, but you could build the thing entirely with imported steel and glass, and the local regolith. The foundation, since it is buried, could be "icecrete".
Products of hydrazine combustion or decomposition are merely poisons, not other medical effects. Those we have half a century of experience dealing with, and the likelihood of anything unanticipated catching us as an unpleasant surprise is low.
Dosing a nearby population with fallout that has medical effects beyond a dilutable poison is something we probably don't want to do. That speaks against using propellants containing lithium. Aluminum is bad enough, but at least we have experiences with it in solid propellants since WW2. If there's a medical effect, it's a very small one. But, one must always suspect metals, and tiny particles.
Remember the beryllium disaster. And the problems with asbestos. These did sneak up on us. Sometimes the time constant is decades before the damage is evident, as with asbestos.
That being said, using lithium-bearing propellants in space should pose no risks. Not so sure about planetary surfaces, even airless ones, because people could be exposed by surface particles on their suits. The density makes the lithium-bearing propellants easy to launch in smaller packages for the same weight than LOX-LH2. You just have to take the proper precautions and restrict it to uses where you can control the effects, just like we now do with beryllium.
BTW, lithium is used in nuclear weapons. Its effects on the exposed population pale into insignificance compared to the other associated "exposures" from that application. So there is a matter of perspective here.
GW
My take is that these things are extremely-variable in characteristics, and mostly will prove rather fragile with respect to applied forces. This has enormous impact for both mining and deflection of impact threats. Effective planning for either activity is going to require "ground truth" on a whole bunch of these objects, not just one or two. I'd say several hundred of them, all sizes, all spectral types, all different forms and spin rates.
When you think about the implied costs of doing NASA's ARM with hundreds (not one) small objects redirected to cislunar space, vs the costs of simply developing the long distance manned travel capability needed for any destination out to the main belt, the saner choice is clear. Go for long distance manned travel. It's far more bang for the buck. But it ain't minimum-buck.
Doing the redirect with only one object makes no sense at all. It's just PR, not anything useful. And THAT'S what I object to.
GW
So, Tom, what about the US, British, and other troops fighting for the White Russian side against the Bolsheviks, from December 1918 to about 1922? A significant portion of our (plural) expeditionary forces didn't come home from WW1 until then. Don't you think a lot of Russians might have a valid gripe against the west about that? Regardless of how they might feel about White vs Bolshevik, it was still a foreign invasion trying to set up and impose a government on them.
It was exactly that incident that I often heard quoted by the Soviet Communists as to why they so paranoidally distrusted the west, back in the 50's and early 60's. Whether it's really justified makes no real difference. We're talking feelings and perceptions here. Point is, they knew we invaded to impose the government we wanted on them: Kerensky's White Russians, the real October Revolution in 1917 that overthrew the Tsar. The Bolshevik Revolution that overthrew the Kerensky government (not the Tsar) was in November 1917.
The Commies actually rewrote their history books to eliminate Kerensky's October Revolution. Not many real Russians know about it today.
So all of this distorted history, including what I just described, is a part of what bothers us all in Ukraine today.
As I said in an earlier post above, there is plenty of fault on all sides to go around, here. The real question is what the hell do we all really do now? A very serious question for all sides concerned. This is one time when it would really help if nations behaved better than spoiled 5-year-olds.
But I have no hope down that path.
GW
Lithium has medical effects which can be dangerous. Has anybody thought to monitor the guys handling it to make the aluminum-lithium metal tanks that seem to be such a savior today? Decades ago there was a medical disaster with people handling beryllium.
GW
Robert Dyck -- "Working together to achieve great things is far better than shooting each other or dropping bombs."
True enough, friend. Would that nations would behave in an adult fashion, the way individuals can.
But they don't. In most international dealings, nations look exactly like 5-year-olds squabbling on the playground.
I have no answer for that problem, either.
GW
Gas core NTR does not offer Isp as high as explosion propulsion: 200-2500 sec at higher thrust, 6000 sec at low thrust, vs about 10,000 sec at 10,000 tons with acceleration 2-4 gees for explosion propulsion (and nearer 12K to 20K sec Isp at 20,000 tons and up). Explosion propulsion offers super-high Isp at super-high thrust, unique among the ideas I've seen. It was flight tested successfully as a one-meter long model propelled by pulses of high-explosive (dynamite or something similar) back about 1959, so we have known for half a century it will work.
A lot of thinking went into the survivability of the pusher plate. Some of the structural damage observed in Nagasaki and Hiroshima went into the design, as did observations from the surface nuclear tests in Nevada, and in some of the underground tests since. The verdict was "yes, it'll work, and for a long time". All of that was well-defined by the time work ceased in 1965. In part this is because there is no physical blast wave in the vacuum of space, there is only the super-bright "light" of the radiation blast. The blast wave risk is only while in the atmosphere during surface launch. You only do that once, she stays in space from then on.
A piece not well known or remembered from those times is that the charges were actually shaped-charge nuclear fission devices, with a "working mass" material as part of the package. You need a spindle-shaped distribution of EM radiation blast, with the working material in one radiation blast spindle. The radiation and working material plasma strike the pusher plate. Key is to intercept all that spike, so you cannot design small, or else you cannot get tens of 1000's of sec of Isp. (Done in really large ships with fusion devices should be almost an order of magnitude more efficient yet.)
Designing too small and getting too low an Isp to attractive is officially why NASA killed old "Project Orion", which was originally a USAF program. NASA really killed it because they viewed it as a competitor to the NERVA solid core NTR they had in development, instead of the complement that it really was. All of USAF's space programs were given to NASA in 1965 by presidential order, save only the orbital spying programs.
Old "Project Orion" was done at General Atomics in San Diego 1959-1965 with USAF as the sponsoring agency, based on company R&D done in the prior 5 years. Their baseline design ship was 10,000 tons, 280 feet long, 185 ft in diameter, carried a crew of about a hundred, surface-launched from Earth (at the fallout "cost" equivalent to one 9-MT test), with a 3-year design mission. It spun about the long axis like a rifle bullet for artificial gravity. It was to go to Saturn on its maiden voyage, stopping off at the moon and Mars on the way. They were pretty sure it would work just fine and do exactly that. Remarkable for 1959.
And NASA killed it.
Sad history, ain't it?
GW
None of you will like this, but here's how you mine the smaller dry rubble-pile asteroids:
You approach it at one of the rotation poles, match spin, and touch down. You grab on by means yet-to-be-defined (stakes driven in will not work, described in an earlier post). Drill in and take your deep (10's to 100's of m) core sample (again by means yet-to-be-defined, since if a stake won't work, why expect a drill to work?). If there's nothing there of interest, then forget it. Otherwise you must de-spin the thing to proceed.
To de-spin, I suggest the same kind of light pressure that spins them up in the first place. It needs to be less intense than the gravitational binding, so it can only be a few sun's worth. This will require a robot spacecraft shining this light on the approaching limb of the asteroid, while flying station-keeping alongside for many years. Yep, I said years! There had better be something valuable inside this space junk, because station-keeping for years will be expensive, no matter how you do it. The "years" part is what will drive up costs.
Once de-spun, if it's a small one, enclose it in some kind of net or bag (of material yet to be determined, and probably an "unobtainium" to us right now). Then push on it harder than gravity, probably with a laser and beam-spreader. It will simply fly apart very gradually inside your bag. Tow the bag to your processing plant. You just mined an asteroid.
The ones bound with icy volatiles will be a lot easier. You can push on them much harder to de-spin, in weeks perhaps with intense lasers, or if strong enough, only days with rockets placed strategically. Stakes and drills will likely work much better. No need for a bag around it. Just dig away more-or-less conventionally (as if working in near-zero-gee can be "conventional"). I think these will be larger than the dry loose ones, so a bag would be too big anyway.
Dwarf worlds like Ceres will be the only ones where mining will look it does here at home.
Can't offer any suggestions as to potential spray coatings. There are none that work in vacuum right now. So that's another "unobtainium" material to us at present. But it surely could help with mining these things, if we should ever invent one.
As to the stake and drill technologies that also don't yet exist for the rubble-pile objects, some sort of rocket thrust-balance insertion of a giant hypodermic needle might work. As a stake you inject steam and freeze it to ice, probably with a shot of liquid nitrogen. As a core sample, just close the end and rocket thrust-withdraw it.
For the bag or net, that might be a good application for in-situ-produced basalt fiber. Not sure if it will be very strong, so you have to avoid impact and collision forces of chunks moving around inside. They must be moving very slowly, period.
Absolutely none of these issues and technologies are being addressed in NASA's proposed Asteroid Redirect Mission, by the way. If we can come up with this, how come the supposed experts cannot? Tough question, ain't it?
GW
I may be wrong, but there is a shape issue with aerocapture, entry, even just plain hypersonic flight. You cannot have one module's shock wave impinging upon an adjacent module. That causes extreme shock-impingement heating, and is what nearly cut the tail off one of the X-15's on its Mach 6.7 flight decades ago. That bird was carrying an experimental scramjet nacelle on its ventral fin stub, instead of a nice "clean" fin. The compression spike shock angled right up through the tail section in a beautiful Mach 6 conical shock pattern. Cut away Inconel-X superalloy structure, it did.
To do aerocapture (or entry, or hypersonic flight) you want one single very clean shape exposed to the hypersonic wind blast, such that none of the shock waves it inevitably sheds can directly impinge upon adjacent surfaces. For small space probes, this is easy to do as a single heat shield panel of some kind, behind which you can hide pretty much whatever you want. For a big cluster, I have doubts this can be done. At least in any practical way.
GW
I've got no numbers, but somehow this tripropellant scheme should work. I really like how easy it is to ship water-as-ice. Kerosene is not much harder to ship. Makes good practical sense to me. Especially if you are not flying very fast, so that electrolysis rates are not required to be very high.
But, if you add solar electric propulsion and fly much faster, the production rate problem requires a really good solution. It's a bit outside my areas of expertise to suggest that we have such a solution. But, I'd bet someone out there does know.
GW
Well, the real problem is not reported openly here in the west. When the Soviet Union broke up, and Ukraine went independent, Ukraine had a significant portion of the Soviet nuclear ICBM's.
We here in the west (NATO) promised to militarily defend Ukraine from Russian invasion, if they would agree to give up and destroy that ICBM fleet in their possession. And they did. That was a signed agreement.
Now Russia has invaded and annexed Crimea, and there now appears to be a credible invasion threat to much of eastern Ukraine. So, we the west are either liars not to be trusted in geopolitics, or else we the west defend a region that we really have no strategic interest in.
Rock and a hard place.
If we live up to the agreement we signed (NATO, not just the US), then this threat to eastern Ukraine requires a military response, not just sanctions and diplomacy.
Oh how the sins of the past catch up to you!
GW
Real colonization needs bigger ships than we usually contemplate.
We have known since the late 1950's how to build one version of such a thing: nuclear pulse (explosion) propulsion. Those ships are quite large (must be immense to have good Isp), something like 10,000+ tons at launch.
Think 20,000+ tons, Isp 12,000+ sec, vehicle acceleration 2 to 4 gees during burns. Made out of 1 or 2 inch steel plate, like a marine ship, so there's a lot of shielding effect there. Big enough to spin about any axis you want, for artificial gravity. With modern nuke device technologies, performance should be even better, and the nuke "side effects" less.
In ships like that, you can ship any crops and farm animals you could possibly imagine, along with hundreds to thousands of colonists. But, NOBODY is working on this idea. Not since 1965.
GW
The problem is that they're already spinning. You need to de-spin them to mine them, enclosure-or-not.
GW
How about splitting the water at 9:1 oxygen:hydrogen, then diverting some of the oxygen to life support. That plus a little kerosene would get better propellant ratios, perhaps, for a tripropellant engine.
GW
The invasion excuse is wannabee-Russians living in Ukraine. That suggests deporting the wannabee-Russians to Russia. But with troops massed on the border to invade, it's already too late to head off the invasion with such deportations.
This is real rock-and-a-hard-place stuff. It's a cold war with a potential to go hot that is higher than I have seen since the Cuban missile crisis.
GW