- VirgilSamms January 30, 2011 at 3:41 pm
- “There are proposed technologies that have been demonstrated in the lab that totally remove this shielding requirement.”This is the same smokescreen that has been thrown up for years to confuse the poorly informed. Let me state the facts one…more…time;The heavy nuclei component of galactic cosmic radiation, over 300 times more damaging than lighter particles, is the prime radiation hazard and showstopper for long duration missions. Not solar events, not the other types of radiation or the lighter particles in GCR; heavy nuclei.
- Heavy nuclei
- Got it? Nothing in the way of an active shield will stop this stuff except maybe a magnetic field so powerful it will collapse steel and require hundreds of megawatts of power; totally impractical. Light shielding rich in hydrogen mitigates the secondary radiation caused when the heavy nuclei hit shielding and spray even more harmful radiation; but to completely stop the heavy nuclei takes about 500 tons of shielding- enough to simulate the earths air column, which works out to about 14 feet of water. In addition to radiation is zero G debilitation, which will cause so many problems on long missions besides just permanent damage to the human body that artificial gravity is a must have. And a tether is by far the most practical engineering solution- a “centrifuge” is probably the worst. This nonsense about solar storms and solar energetic particles being the big problem has got to stop; the real problem is the heavy stuff and if you protect against that it completely protects against everything else. As for Gary Church; listen to the message and don’t worry about the messenger. You can check my facts and that is all you need to do unless you want to play the ad hominem junior high name calling game that is so popular on this site with its so many space industry “experts.”
- VirgilSammsJanuary 30, 2011 at 3:51 pm
- “Sidemount, old Project Orion nukes, megaton spaceships with heavy water shielding are dead give aways. Also less DoD and more NASA funding are tells.
Nice dreams actually, but not politically real.” Dreams? No, the only way to get into space actually. If you think politics are only what determine the future then you have no future at all. Politicians are puppets and the strings get pulled in so many unpredictable ways that politicians are about as useful as economists in shaping the future. It is you and me that make the future. You can drag someone kicking and screaming to the right solution but if they just turn their back on it then there is nothing else to be done.
I have been fighting these NewSpace idiots for over ten years! Amazing. Banned over and over again as they dogpiled me with insults and emailed to the editor into oblivion a dozen or so times. But I kept coming back. The comments advocating a better path than NewSpace keep irritating the Musk fanboys:
“I have no problem with a couple Starship 2.0’s spinning around each other on a mile long tether system. With a near sea level radiation 1G environment the crew can go on long missions, even multi-year missions depending on what kind of living space they have, with zero ill effects. What needs to be understood is the shielding mass inside those two Starship 2.0’s, the mass of water, would total tens of thousands of tons. That mass of water would also be part of a closed loop life support system so using propellent as shielding is not really an option. Chemical energy is completely impractical for that much mass.”
“If you have an industrial infrastructure on the Moon, like a giant factory complex, then it will employ thousands of people and I would guess it would be more economical for those workers to just go up to large shielded rotating space stations and work on those for the necessary 1G time. It all depends on how long they can stay in Lunar gravity before permanent damage is incurred. If they can work on the Moon for several weeks, maybe up to a month, before they have to go into 1G then I would say just rotating them up to a different job in Lunar orbit would be the way to go. I envision the sleeper train concept for use on icy bodies way out there like Ceres but if that is what will be required on the Moon then so be it.”
“Your terminology is all messed up. You acclimate to high altitude. You saturate when you dive. There is no “adapting” to long duration zero gravity and space radiation- there is only debilitation and dosing. I would say there is no “memory” in the muscles, just gravity making it all work the way it is supposed to and the less gravity the less that will work. Muscle and bone decondition if not put under regular stress. Gravity is the number one regular stressor which is why no matter how much you exercise and pound your body in space it still wastes away. Half and half may not even work that well. Humans may only be able to tolerate zero G without that wasting damage for 8 hours a day, or even 6 hours a day, or even 4 hours a day. We do not know. I seriously doubt an hour or two strapped into a centrifuge is going to stop it. I do not believe there is going to be any success at all playing this game of partial gravity and partial shielding, Near sea level radiation and 1 gravity is what is going to allow humans to work and thrive in space because that is not going to permanently damage them while less gravity and more radiation certainly will.”
“It is not about “adapting.” The body is adapted to 1 G by evolution. If you want to evolve as a 1/6 gravity species that is going to take several thousand years at least. I will not argue with you and say it is not possible that sleeping in a centrifuge or even a few hours of exercise or both might keep a person healthy and able to go back to living a normal life on Earth without lengthy rehab.
I would guess that will not be the case and it will be a half and half proposition at best. Half the time living in 1G and half in zero. 1/6 G might bump that down a little. That is the best case scenario. It may be that 1/6 G is nearly as bad as zero gravity in regards to muscle and bone debilitation since no amount of exercise stops that from happening in just a few months to the point of permanent damage. And it is damage when you lose that muscle and bone mass permanently.
If it is a matter of half and half then you have to agree those toys are obviously not going to work. I think I read somewhere that zero G has measurable effects after 11 days but I cannot find it anywhere. If so then a Moon worker might get away with a month “down” and then have to go “up” for at least a couple weeks. No way of knowing yet.”
Two multi-thousand ton shielded habitats spinning at opposite ends of a several thousand foot tether system is the fundamental starting point and, as I stated, orders of magnitude beyond what is being considered. I saw a rendering of Starship 2.0 and it caught my eye. The diameter is about right for the minimum size where you could have the structure for a shielded crew compartment inside.
You are absolutely correct that docking modules to each of the existing ones and connecting more tethers would eventually result in an arc at either end and finally in a complete wheel with the tethers resembling bicycle spokes. Add structure and you have a von Braun wheel. A very large wheel. Stack the wheels and eventually you have a cylinder. Gradually convert the inner structure to outer skin and end caps and the final step is to pressurize the interior, or the interior could be gradually pressurized with end caps added to the cylinder sections as it gets longer.
“I am not a fan of this path to a space colony though, and believe really large habitats would be constructed as such and not gradually. I think the bola configuration is the optimum because the tether system can be reeled in to join the two habitats and then a nuclear propulsion module makes it a spaceship. It might actually work out to have the several thousand ton habitat at one end and everything else necessary for an interplanetary mission as an equal mass at the other end. The spaceship would accelerate to cruise speed and then the tether system would unreel and “split the ship” for the transit.”
“When I compare the Starship and the SLS to the Saturn V, it is for me the ultimate exercise in what could have been. The Shuttle, which I watched from start to finish, was the lesson to be learned and sadly, we, as a nation, continue to flail the water instead of swimming like Tarzan.
In hindsight, the first stage of the Saturn V could have been landed back, like the delta clipper demonstrated in the 90’s (Phil Bono was proposing VTVL designs in the early 60’s). The escape tower and capsule could have also been reusable. Meeting the challenge of the second stage landing back might have been what made the Shuttle a success, if that program had been supported and more focused.
If the Shuttle SRB’s had been instead some form of pressure-fed ocean recovered reusables (as originally specified) and the SSME’s recovered separately (as was later proposed for a cargo shuttle version), instead of mounted on the abomination that was the Orbiter, then the STS could have been stacked vertically. And with a different design to transport crew (with an escape system) it would have looked like the SLS. And it would likely never have killed anybody and still be flying.
The central idea of the Shuttle was a Saturn V class launch vehicle that recovered everything except the second stage propellent tankage. That structure was to be sacrificed on the altar of the rocket equation and it was an excellent concept then and now. Designed to be within budget and to satisfy the multiple agendas in play, the Shuttle cost about as much as the Saturn V per launch but went nowhere except LEO. It is a prime example of the government buying into a very bad design.
Now we have a private entity with this own pet project. In my opinion it is not much different than the Shuttle.”
“Thank you for the article Ms. Grieco.
International cooperation requires a goal to cooperate with each other about. If the goal is to solve common problems faced by the entire planet then space has plenty to choose from.
1. With large human crewed GEO space platforms as essentially embassies in space, any acts against these platforms would be very unlikely. “Testing” anti-satellite systems against them would be acts of war. This would be an insurance policy for civilization in that such platforms, with massive radiation shielding immune to even a Carrington level event, would always be able to guarantee no false warnings of nuclear attack.
2. Militarily, space offers the opportunity to move the entire nuclear arsenals of the superpowers off-world. By utilizing human-crewed spaceships as the equivalent of nuclear missile submarines, these “space boomers” can be kept months away in deep space. This would end the present hair-trigger launch-on-warning situation that has put civilization at risk for over half a century.
3. These Space Boomers would also be able to intercept asteroid and comet impact threats and deflect them, thus filling a joint planetary protection function. Another insurance plan for civilization attracting international cooperation.
4. Since these spaceships would have to enable long tours (possibly multi-year) of duty without permanently damaging crew they, and the GEO platforms, would require massive cosmic ray water shielding and artificial gravity systems. The shielding and the structure able to contain the shielding would require nuclear pulse propulsion, which follows since they are already carrying nuclear weapons, and such devices are ideal for deflecting comets and asteroids.
5. The only place to acquire hundreds of thousands of tons of water shielding for fleets of GEO platforms, Lunar Cyclers, and space boomers, and to assemble, test, and launch nuclear missions, is the Moon. The program to make Earth nuclear weapon-free and protect the world from another dinosaur killer would thus depend on an international project to set up a lunar industrial infrastructure.
6. With the Moon able to undertake industrial activity the expansion of this infrastructure to include Space Solar Power satellite components would be yet another insurance policy for civilization as the ultimate solution to providing a western standard of living for the 10 billion people of planet Earth near the end of this century. “A Green New Space Deal.”
7. And lastly, with a large enough population living off-world, this multi-national component of humankind would at some point become independent of Earth and that would be the ultimate insurance policy- the ultimate defense goal.”
“You can build a circular train tube a mile or so in diameter but that is not going to provide for any large population and would likely only be practical on icy very low gravity bodies. The less ice and the more gravity the more expensive and the Moon is not a good candidate. Putting people in a small centrifuge has always been a non-starter for many reasons.”
“We know Humans evolved over millions of years to thrive in 1G and the effects of no gravity are very bad. The effect of very little gravity is going to be bad. Saying “Maybe not” is the same game that has been played for decades concerning radiation. We know humans will not suffer permanent damage in a near sea level radiation one gravity environment.”
“For lunar factory workers that would be my best guess; they would send them up to shielded 1G space stations whatever percentage of the time required to prevent permanent damage. The problem with wheels is that what data there is indicates anything over 3 RPM is going have bad effects and to spin one at a conservative 1 RPM and generate 1G the wheel will have to be 6000 ft in diameter, which is not very practical. A tether system that long, however, is very practical. With likely over 10,000 tons at either end, the tether system loads would not be much different than a suspension bridge.”
“All the data is in on Humans on LEO platforms with no shielding or artificial gravity and it is all bad news. We can put humans in underground bases on the Moon but then they will still debilitate due to the low gravity. Humans have to have gravity and be shielded from radiation and that will require constructs on a scale an “order of magnitude” larger than anybody is funding.”
“Starship 2.0 is big enough to have a double hull with a five meter envelope between the inner and outer hulls. Bringing up water from the Moon would allow that envelope to be filled and used as a cosmic ray shield. Connect two of these together with several thousand feet of tethers and spin them and you have the first true space station providing a near-terrestrial radiation and gravity habitat. Astronauts could do year-long tours of duty with zero ill effects. The tens of thousands of tons of water would make the station invulnerable to even a Carrington level solar event. With the appropriate nuclear propulsion system this first true space station would become the first true spaceship.
And that is what is needed…a fleet of such space stations, lunar cyclers, and spaceships.”
“Marking the edge of Orbital “Space” as where that parking orbit is viable at 100 miles would be a good start. What would be the difference between “Outer Space” and “Deep Space” is an interesting question. There is the magnetosphere and lunar orbital plane to include L2 to consider. Perhaps Outer Space could be considered outside GEO, the magnetosphere, and vicinity of the Moon out to L2. “Cislunar Space” would be everything inside the magnetosphere and a sphere around the Moon encompassing L2. Everything outside a very large sphere around the Earth-Moon system whose surface is at L2 would be Deep Space.”
“GEO is not “Deep Space.” That term is generally accepted as being beyond the cislunar Earth-Moon system, or at least, beyond GEO. Much like the whole reclassification of launch vehicles from the previous Heavy Lift category of 100 tons set by the Saturn V. Earth Orbit should be demarcated at the altitude where a temporary parking orbit is viable, also like the Saturn V used, at around 100 miles. Earth Orbit, Cislunar Space, and Deep Space.”
“Some of us believe in what is good for everyone and some of us believe in what is good for our self. The trouble is that when you only believe in what is good for yourself it is almost always bad for everyone else. What little good competition does is vastly outweighed by the bad and cooperation, while it deprives the greedy predators of their prize, works better. What is good for everyone is good. No man is an island. Most of the “community” here believe in Neoliberalism James. Nothing you say is going to remove them from that universe they exist in. In that universe there is nothing good for anyone else.”
“Elon don’t like Space Solar, says it’s stupid. I think it is the other way around. I notice many other people are thinking the same thing also on youtube channels like the pressure-fed astronaut and common sense skeptic. Hopefully the popular culture tide is finally turning against the Musk cult.”
“What everybody seems to miss is that he might have made more money just dropping those stages in the ocean. The reusability angle was mostly P.R. They might be making a little more than breaking even but not much.”