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That's very interesting! I'm going to contact my colleague about this development.
The hormone Calcitonin is implicit in Calcium uptake, and there are several other pituitary hormones which I will not mention here that have been identified in the Osteoblast/Osteoclast system.
Maybe I can again become professionally active and keep my brain from turning into a useless pile of mush.
Thanks for the Heads Up!
Robert-
There is no doubt the Mars Direct plan needs some updating. As you point out, the Nuclear Reactor has lost weight. As for the food supply, there needs to be some mixture of freeze dry and fresh foods, simply for diet variety and mental health of the astronauts. Yes, I too was in pretty damned good shape when I was younger, and could fireman's carry a average weight person a decent distance. However, there are some injuries which require litter transportation--back and neck injuries. I'm standing fast with my triads. The other option of a triad is having one person stay with the injured while the 3rd arranges for additional backup help. Murphy's Law always applies to emergency situations, and Murphy was an optimist. By the way, my Army training was as a combat medic. The other argument for whole foods as opposed to freeze dry is the water content; cannot bring TOO MUCH water along.
Yes we need to keep the mission lightweight and simple, but it also MUST SUCCEED! If having a 5th crew member increases the odds of success significantly, we'd better make things a little bigger. My mission model always had overlap of crewed missions, such that at one point there would be 2 crews. This would require a larger Hab, but that will have to be in the planning. My thoughts were centered around 2 Triads plus a mission commander. a total of 7 astronauts per crew. Projecting that forward, construction of a decent base is going to require a lot of manpower, if only to avoid exhaustion of the crew members. Our hypothetical models are prone to failure due to overestimating the capacity to get tasks finished. There has to be adequate down time for rest and some sort of recreation. Going on a 24/7 schedule will destroy morale.
Your comments about using polyethylene and polypropylene as radiation shielding are right on the mark; these plastics are quite strong and do shield radiation from Solar Flares and van Allen radiation very effectively. Polymer sheeting and preformed injection molded components should definitely be incorporated into the buildable Hab structure, especially doors, airlock structure, roof components, etc. I'm strongly in favor of using regolith to partially bury the Hab into a hillside; that would provide shelter against Solar Flares, and reduce heat losses.
Regardless of which crew size model we work with, food will remain an issue. How much? What type? How much emergency food planning? I'm strongly in favor of a full mission reserve already on Mars before we arrive. Maybe solar activity during a Hohmann window prohibits a manned mission from taking place? We cannot allow a crew to starve to death ala Mark Watney in The Martian.
I'm not in denial of the accomplishments of NASA; historically, they have done great things. What concerns me, moving forward, is the manner in which they spend taxpayer dollars--never accomplish a project in the 8 year time frame of a particular presidential term--which leads to subsequent cancellations and waste of efforts. Example: Project Constellation. There needs be a much more aggressive mind set w/r completion times. Not--Man on Mars "some time in the 2030s." We've done about as much as possible there by robotics; what's needed now is boots on the ground. Maybe a better cooperation between NASA and SpaceX, Orbital ATK, and yes--Boeing and Lockheed Martin. And for goodness sake, stop these wasteful cost-plus contracts. Break the barrier of using nuclear reactors in space applications. The deep space probes to the outer solar system could give a huge return on the investments made if they were to say" we need to fly a small reactor to optimize data return," we'd be seeing 100X the data for these billion dollar missions.
The SLS is a great example as to why NASA should no longer be "building" rockets. Start issuing contracts for defined goals and under non-glacially mandated time lines.
Tom-
In my view, your description was NASA "then," and not "now." NASA has become very conservative and risk adverse, and when an organization is "afraid to lose," they cannot develop strategies to win. Progress on everything has become glacially slow. I was at one time a huge cheerleader for NASA, but that was when Von Braun was still in the loop.
Robert-
I've always argued for a minimum 5 person mission, preferably 7, based on my Triads argument. Any extra habitat mission must always have 3 bodies involved. Yeah, I know--we're never going to fall down a steep slope and break a leg or such, but if we do--2 "rescuers" for the "victim." With all the Hi Tech electronics around, there's also a need for an electronics specialist on the mission. An odd number of crew makes decisions easier. I've been on mountaineering expeditions where the decision making gets tense with an even number--especially if there is no designated "mission commander." Standoffs have occurred in the damndest places--friends went on mountaineering trips and came back enemies.
With regard to foods, Mountain House freeze dried stuff is OK, but it IS pretty thirsty. I'm stating that whole foods OR freeze dried and water combined must equal 2% of body weight to avoid losing weight under stressful activities. Whole foods have a psychological edge, being "comfort foods." They also provide some of the radiation shielding discussed by Zubrin in his books, since they contain masses of water. The freeze dried Beef Stroganoff and Turkey Tetrazinni packages will not provide the same shielding as long shelf life vacuum packed hydrated foods. A lot of food these days is packaged in plastic containers and are irradiated to preserve the foods. Our plant engineer ( a Chem Engineer) quit the company where I was last working and went to work at Mountain House, so yes, I'm familiar with their operations and products. What ever we do---NO MREs! They are OK for short term use and don't taste too bad; they are by design, low bulk and are pretty constipating.
Have I read The Case for Mars? Uhhh...only about 4 or 5 times. I'm using a lot of information provided in Zubrin's second book, Entering Space. I've been involved with Physical Chemistry most of my professional career and have lots of Industrial Scale and Pilot Plant experience. My concern is the tendency to be overly optimistic about the efficiency of robotic operation of a very remote manufacturing facility--exactly what the Sabatier Reaction plant will be. Ditto the Oxygen generation reactor. Yes, I'm aware that electrolysis of H2O requires less energy than direct disproportionation of CO2, but that's an energy issue. There will not be enough H2O available from the initial H2 supply brought from Earth. In a chemical plant operation scheme, there would be 2 independent reactors always working in parallel; one for direct production of O2 from CO2, in parallel with the Sabatier reactor.
Regards your comments above about the stay time on the Martian surface; another argument for that approach involves the consumables; food and water. I think we've got the O2 issues covered. Food and consumables for a 425 day stay would drastically lower the supply logistics tail. I've been figuring on a optimal 7 person crew, but initially will more likely be a 5 person mission. All at the 170 Earth pound weight of FAA average passengers and my 2 % body weight food allowance per day. This means food for Mars residents is now only 7225 pounds of food.
NASA really needs to do some project rationalization. Yes, they are doing some "interesting stuff," but not what the agency was founded to do. And...it's not individuals, but whole research groups. A little belt tightening?
So--we will have the ERV on the surface of Mars for 18 months before the first crew arrives, basing the Mars trip on the most energy conservative flight path. That means ~540 days (and nights) available for O2 and CH4 preparation. Oxygen is needed in a 4:1 mass ratio to methane. As a small "plant scale" process, it would seem feasible to me for ~320 Kg of O2 to be manufactured a day, and easily make 80 Kg of Methane. In the 540 days available before the next Hohmann transfer window, the system could accumulate 43,200 Kg of CH4 and 172,800 Kg of O2. That would seem to be "enough" to boost to escape velocity , make trajectory corrections, and possibly do some retropropulsive braking. This would require the capture and utilization of 1100 kg of CO2 nightly (or nightly and daily). What really needs occur is sending two completely independent SAFE-400 reactors, each with it's own plant; one for O2 and the second for CH4. My concern now is collecting enough atmospheric CO2 in the system.
What's really needed by the chemists in this group is an estimate of the fuel and oxidizer required for the return to Earth flight. So...do we need to accumulate 100 kg, 200 kg, or ...500 kg of solid CO2 per night to make this work? Numbers! The concept is truly elegant, but the devil is in the details.
Here's the chemistry for both needed products:
2 CO2 ---------------------------> 2 CO + O2 At 100% efficiency, we need 88 kg of CO2 to produce 32 kg of O2.
(catalyst + heat)
CO2 +4 H2 ----------------------> CH4 +2 H2O At 100% efficiency, we need 44 kg CO2 and 8 kg H2 to produce 16 kg CH4 and 36 kg
(catalyst + heat to initiate) H2O.
For combustion at the stoichiometric ratio, we need 64 kg of O2 to completely consume 16 kg of CH4.
I just wonder what scale one would have to use in order to collect enough CO2 during a Martian night to collect a meaningful amount. Some pretty large coils in order to get more than just a few kilograms, I'd expect. These questions are essential in order to manufacture the amounts of CH4 to make the refueling system realistic.
Edit. After some additional thought, there would need to be a compressor running during the night in order to get enough CO2 available to condense as dry ice.
As someone on the receiving end of Government Specifications about 55 years ago, I can speak volumes about what the Powers that Be expect a simple grunt infantryman to carry--just because they "might need it." A generation earlier, Guys were so loaded down with packs and weapons and ammunition dropped off the landing craft into deep water at Normandy, and never came back up. Utterly stupid to have guys carrying extra clothing, mess kits, canteens, shelter halves, gas masks, huge amount of ammunition trying to get ashore through deep water from the landing barges. All that's really needed: weapon, double to triple load of ammo, rations for 36 hours, and water. That way they might live long enough to eat the rations.
Same reasoning applies to the Orion capsule which became too heavy to launch into LEO using an Ares I. I have a friend recently retired from Ames/Moffitt Field as a NASA engineer who wrote me saying that the original system would have worked had the capsule not grown to monstrous proportions, forcing him to recommend cancellation. NASA = Overpriced, Overweight, and Overdue.
GW-
One nice thing about some of these reactions is the ability to do them on a continuous flow basis through long tubes packed with the appropriate catalysts; one gas or combination of gasses goes in one end and a product--or mixture of products--come out the other end. That means they run 24/7 continuously. The power requirement for the Sabatier reaction isn't bad at all as it's an exothermic reaction, hence self sustaining. The splitting of CO2 is more energy intensive due to the endothermic nature of the reaction. Bond breaking requires net energy input, but in the Sabatier there are also bond formation reactions in sequence which are always exothermic. Mainly the energy will be needed for compression and liquefaction. Dr. Zubrin has a small nuclear reactor for energy in the Mars Direct model, and specifies a 100 Kw unit as a minimum. Sucking up enough Martian CO2 is an ongoing process requiring some major compressors, intermediate storage tanks, and receiving storage tanks for the prepared gasses. Liquefaction requires more compressors and heat exchangers, hence more energy needed. In the long run, we'll require storage facilities to accept and store these cryogenic fluids. No set of solar panels is ever going to provide the total energy for such a system, so nuke power is the ONLY option. Just for comparison, a normal subdivision home has a 100A main breaker--nowadays probably a 125 A breaker. Run full tilt, that means 27.5 Kw power consumption if everything is 220Vac. But most households have an average rate of power consumption around 5-8 Kw. In reality, a bigger nuclear plant would be required if ISPP and all other applications are fully powered for the Mars Base.
As an addendum: If we DO find ice as a source of water, then we'll be needing a lot more power in order to run the electrolysis reaction AFTER melting the ice!
Here we go again! It appears that the 2020 Mars rover is facing some severe design completion problems, and the engineering drawings are not yet complete for the February 2017 review. The problems center around the sample collection system for future return to Earth, and elimination of the Moxie experiment for production of Oxygen from Martian atmosphere.
http://www.spaceflightinsider.com/organ … al-delays/
This is another result of putting too many unhatched eggs in a single basket. The Moxie experiment is probably the most essential one being (not) flown. This is why we're still in LEO with NASA running the show.
Actually GW, methane is the component of the MethylOX system requiring components brought from Earth, H2. The CO2 atmosphere of Mars does NOT require finding water for O2 production; 2C02 ----> 2 CO + O2. This reaction is definitely energy hungry, being endothermic even though catalyzed. The metal catalyst simply ensures the correct output of molecular Oxygen. Yes, "ice is nice," but not essential. I've seen some suggestions about a modified ISPP that simply brings the methane or RP-1 from Earth and produces 80 % of the Fuel-Oxidizer couple on Mars; instead of the Methane production, only Oxygen is produced.
On the other hand, if ice is available and converted to water, then electrolysis is the way to go for producing Methane in addition to Oxygen.
A much more powerful 2nd stage is within the realm of possibility; if they experiment with a new Raptor engine replacing the Merlin 1-D+, the numbers I've seen figures stating triple the thrust and an increase in Isp(vac) to 383 Seconds. This could be what Musk has in mind for the Red Dragon mission to Mars?
I believe that Elon Musk has had several meetings with Donald Trump. I think the "Old Space" advocates better get ready for the Pork Barbecue represented in the SLS and Orion capsules. Another 4-5 years before they fly? Unreasonable.
Many of us living in the Mountains of the West experience the BP depression already. I live at ~6,000 ' msl. Granted, that's not what you were saying, but using pressure cookers is pretty easy.
The jury is still out on the water available on the Moon. There is some evidence of some water ice deep within the shade of the polar craters, but no indication of how much. Extraction of this super cold ice could be difficult w/o access to adequate power (nuclear). Use of Solar panels will be limited to 50% of the time, requiring enormous battery packs.
The Moon offers "Magnificent Desolation."
GW-
I am in agreement with most if not all of your analysis of the hazards involved. The lack of gravitation is indeed a major problem, and even the early Wernher von Braun publications included the big bicycle wheel space station for producing artificial gravity through centripetal acceleration. The Cosmic Ray hazard is greatly overblown, and the problem attenuates > 50% once on the Martian planetary surface. The psychological issues aren't easily solved for the amount of living space required for sanity; the Navy screens the crews for duty on submarines pretty rigorously because of this problem. I seriously doubt that a nonstop pinochle or bridge tournament will suffice! As you mentioned, there needs to be some private/personal space for each crew member in addition to the community activities and communal living areas. Having artificial gravity will really help the crew members by allowing normal food preparation. God help us if some genius wants to feed the crews MRE rations the entire journey! As you pointed out--frozen foods are the ticket, but would more likely supplement the more concentrated rations. I could go on and on about this, but we are basically on the same wavelength.
When one considers the 14 days of total darkness, followed by 14 days of sunlight, the dark cycle means extremely low temperatures due to rapid radiative heat loss. The space suits are much heavier for both thermal and pressure protection when built for lunar use. Not really much there to support a base, since the O2 availability requires LOTS of energy in order to liberate; no solar panels for 14 days. Mars also has enough atmosphere to slightly attenuate the Cosmic Ray background radiation, as well as a larger gravitational constant which is healthier for the human organism.
So...I must totally disagree with your assessment of using the Moon for a base as a stepping stone to Martian missions.
Then there is Titan, a most unusual moon.
The problem re: Titan is distance and travel time to the objective. In order to get a realistic science return, there would by necessity be a nuclear reactor involved as part of the payload. Power = data return. The Jovian environment is about the furthest we can go without reliance on an exotic onboard propulsion system for the probe. Yes, I agree that Titan is scientifically interesting, but very little has been done in regard to the 4 Galilean moons of Jupiter. They're big enough to be considered planets, were they in orbit about the Sun and not around Jupiter. Ganymede and Callisto are both larger than Mercury, although less dense. There is some evidence of subterranean oceans on both these moons, making them "very interesting" w/r to ongoing manned exploration of our solar system. Ganymede is still within the Jupiter Van Allen belts, but Callisto is NOT, making it suitable for a distant human outpost on our way to the stars.
Just another WAG from me--once Elon gets into the engineering and hardware stages, some things will change. We've all seen the optimism that drives him become moderated over time. Falcon Heavy has slipped time after time, and maybe this year we'll see a launch. Now scheduled for April, followed by several (2 at this juncture) commercial payloads later in the year. We may also see the launch of the Man-Rated Dragon 2 later this year and the abort test. These are all critical steps, moving forward.
In reality, the Moon is simply a distraction due to proximity. As a destination, it's far more hostile than Mars when one considers the diurnal cycle of a 14 day "day," followed by a 14 day "night." The temperatures are more extreme, and other than He-3, not much of economic value to mine. We've had a bunch of "moon rocks" for 50 years, and the few footprints are still there. I view the 1970's Moon voyages as the first exploratory steps off-planet, and ones which after Mars, can be repeated "at leisure."
I'm happy that Elon Musk has "bought in" to Dr. Zubrin's Mars Semi Direct model, but the way forward will not be as easy as he indicated this past September. Some of the earlier SpaceX proposals are looking good to me, especially the Falcon XX and Falcon XX Heavy. Those would seem to offer a possibility of fulfilling my "proof of concept" models incorporating the new Raptor engines. They would also be compatible with a 12 passenger spacecraft.
I believe that elsewhere I mentioned multiple smaller loads to Mars per Hohmann Transfer Window? Maybe as many as 3 to 5 smaller loads in 2020, 2022, and finally a human manned vessel in 2024 or 2026 with multiple cargo ships at the same time, in addition to a bigger Habitat module. There has to be some long-term commitment of these early crews to staying either 3 or 4.5 years in order to get the civilization started. An upgraded Red Dragon could conceivably carry a crew of up to 7 astronauts. The submarine service concept of "hot bunking" could be used, as not everyone sleeps at the same time. This is where my Triad concept comes into play. Always at least 3 crewmembers awake and "doing stuff," while 4 get the necessary rest.
"Doing stuff" translates to monitoring the spacecraft, cleanup and sanitation, meal preparation, or involved in exercise or recreation. The Red Dragon could simply be scaled up and the cargo trunk of the existing Dragons contains the propellant and engines for a landing in addition to some supplies/equipment. This trunk could be landed separately from the Red Dragon crew module, and would be fueled by CH4 and O2. The Red Dragon itself by MMH and NTO. The trunk/descent stage would be reusable and could be mated with the Dragon capsule for a return flight Earthward. I can see a potential upgrade of the Falcon Heavy using the new Raptor engines as possibly being able to handle this . Maybe one of our engineering buds here can crunch the numbers? Additional MMH and NTO could be shipped as cargo, but the ISPP would handle the return boost from Mars and Earthward.
With each crew of 7, at least 4 would need to pre-agree to stay on Mars for at least 3 years instead of 18 months, which would subsequently grow the crew to construction of base size in a matter of only a couple missions.
We've been stuck in LEO for 50 years! Any use of the SLS should be, considering the cost, have much more ambitious goals. We certainly don't need it for the ISS, since both SpaceX and Orbital ATK have that covered. The "planned" asteroid fragment retrieval seems to be an awful waste of capability in contrast to dollars spent; there needs be a more ambitious scientific purpose in mind!