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Louis-
Let me say "welcome home." We've had more points of agreement than disagreement during our exchanges, and I've restrained myself from lashing out at times.
But your ideas have been very beneficial to this website.
After additional consideration of the concept proposed in post #1 of this topic, it would possibly make sense to return the power module on a slow-boat trajectory to Earth after slowing the landing Starship in Mars orbit. The earliest Starships landing on Mars will probably NOT be returning to Earth, as they will be cargo ships and will be one-way vessels. In this way, the next Hohman transfer window would already have a flight-proven deep space booster in Earth orbit and with plenty of time for refilling the tanks with cryogens, so the number of power modules would be far less than Starships. Only after 2 flights, would one be used to return a crewed Starship back to Earth on it's 2nd return journey.
Back in 2017 as a new member of this forum, I was suggesting a "modular approach" for getting to Mars--using at the time, "throwaway modules," that were fueled by hypergolics of MMH and NTO. Then Elon came along with the news of the Raptor using liquid Methane and LOX, and a fully reusable system in what was then being called the BFR.
Listening to Eon this past Thursday evening and his talk about the now properly named "Starship," and his talk ending with a concept of exploration of the outer Solar System and beyond, I decided to revise my modular scheme to something even more exotic and probably more useful in the long run.
This is borrowing another concept from Buzz Aldrin, that of a "cycler," but only as a module in my modular system: a nuclear thermal powered interplanetary stage, one that is only a power provider or "tug" to get a vehicle boosted into Hohman orbits using nukes, and then slowing and parking the landing vehicle into an orbit around Mars. The the stage separates and goes dormant until needed again. This way we get the additional boost provided from a high Isp power source and avoid all the radioactive products in a planetary landing or planetary departure into orbit. The orbiting "power module" is simply waiting to be used again--provided the propulsive media of liquified gasses isn't needing replenishment. But since the patiently waiting power module is parked in a stable orbit--it can also be refueled robotically by planetary tanker rockets, and periodically be "topped off."
By not using the Starship onboard methane and LOX for generating the Earth departure delta V, and not being used to do a braking into Mars (or other planetary body) orbit, the fuel is available for a safer propulsive landing and retaining some fuel for planetary departure.
At this point in time, we're looking at an absolute requirement for ISRU in order to return to Earth, and worries about the gee forces on the bodies of returning astronauts coming in at high velocities with massive deceleration gee forces playing roles. Using a slower deceleration into an Earth orbit an easier time would obtain for returnees from deep space journeys.
Elon was also a bit more restrained about his timelines--maybe no more "Elon Time?" It also was evident that he has a fallback, contingency plan in case the FAA approval process drags on. The approval for Starship launches is already in place at Cape Canaveral, and work has undoubtedly moved ahead on conversion of the two oil rigs that were purchased for conversion to launch and landing platforms. Elon is definitely determined to make Starship "work."
I really enjoy his live presentations, and his halting speech isn't that of a polished presenter--which makes him all the more believable.
The Raptor 2 is still a "work in progress" and will undoubtedly be later upgraded by a Raptor 3, but he's reaching the physical limits of performance for a chemical powered rocket motor. The next step will need to be a Nuclear Thermal system, if Starship is to also be used for exploration in the outer Solar System, such as the Asteroid belt and moons of Jupiter.
Heavy Booster and Starship are stacked!! In preparation for Elon's presentation tonight!!
I suspect that Elon Musk may have a more viable option up his sleeves...
kbd512-
Your post #615 was a marvelous and well written summary of the shortcomings of Solar Power for use as the primary energy source on Mars--as well as here on Earth.
Robert Zubrin came to the same conclusion nearly 35 years ago, and he included a small nuke reactor in his Mars Direct proposal as a consequence.
I'll become more enthusiastic about BO after they deliver the BE-4 engines for ULA and they perform in flight, as advertised.
We would need lots of other components. Better to buy a Rolls-Royce megawatt self contained powerplant. Starship has plenty of weight carrying capacity for it.
Although I'm neither a "Green Freak," nor a fan of Bill Gates, this to me represents a step towards better energy independence for the USA. My late friend and Professor, Victor A Ryan, the Nuclear Chemistry Professor at the University of Wyoming would be very pleased at this development. I was his Teaching Assistant for Physical Chemistry Laboratory while a Graduate student in 1971, and he was a superb intellect, although not a really great lecturer. Nice gentleman and was the Democrat Party candidate for the US Senate in 1986 (could be a different year). He lost badly to Malcom Wallop, the incumbent Republican. It was under his supervision that I was able to use the Thorium based critical mass nuclear reactor for a Physical Chemistry experiment.
GW-
I think he has left the forum over some sort of tiff he had with an Administrator or Moderator.
Well, Louis should be happier about Nuclear reactors now that Rolls-Royce is building these small Megawatt units. That's a fantastic company to see building units that could be transported to Moon and Mars.
Vanguard was the Civil Service Rocket for the Aerospace Engineering students at CU, Boulder in 1957. "It won't work, and you can't fire it."
th-
Yes, there really needs to be SOME effort expended to study the physiological effects of reduced gravity, and not simply ignoring it and hope the problem will "go away."
This will become a major factor in the long term, because once we inhabit/populate Mars, the call of the unexplored Asteroid belt and outer 2 Galilean moons of Jupiter are beckoning to the explorers in mankind, as well as Ceres.
As an interjected aside here, I would find that Ceres and Callisto are particularly appealing in the next 50 years of outward expansion of mankind from Earth. Ganymede would be more appealing were it not still somewhat in the Jupiter version of the Van Allen belts. It would be possible to survive there by limiting the time spent outside of a radiation sheltered environment to just a few hours per day and per week.
Re: Gravity centrifuge testing. I really don't believe that an onboard centrifuge system is what we need; it should be a smaller, free floating subsidiary satellite of the von Braun "bicycle wheel" design, completely independent of the ISS structurally. It could be entirely robotic but accessible from the ISS via a spacewalk.
When I say "smaller," I simply am referring relative to the ISS proper.
Getting with the kbd512 counterotational gravity plan, I would again suggest something I mentioned earlier in a post that I haven't looked for, but there should towards the end of the voyage to Mars--be a slow decrease on the gravity could be implemented so that once there, the astronauts would be accustomed to the exact gravity of the planet. It could also work in reverse, and on a return trip start at Mars gravity and over the 5-6 month return, restore a full 1 g onboard.
I am getting a clearer understanding of where this thread topic is heading, and it's a very constructive direction. My contribution has been something else--trying to facilitate the first "baby steps," so to speak. Trying to get there (Mars!) in one massive step is a commendable concept, but I'm a conservative and cautious planner. I would like to see some groundwork for landing and building ISRU facilities before making a high stakes throw of the dice, gambling on everything working all at one time.
The previously proposed--and subsequently cancelled--Red Dragon missions were not ambitious enough, but the concept is still viable on an enlarged scale, large enough to incorporate a decent sized nuclear reactor in one, and a rotary drilling rig in a second vehicle. These could be sent to a proposed first base camp landing zone to have immediately available power and some concept of whether or not any useable subsurface ice is at hand. I'm also a believer that solid experimental/exploratory data is necessary before landing Starships ANYWHERE other than back here on Earth or on the Lunar surface.
Both kdb512 and Rob are thinking even LARGER than Elon. I'm striking out here as a pragmatic minimalist. Don't get me wrong,; what I'm suggesting is still bigger than anything other than Starship/Super Heavy Booster. I view the problems at hand kinda like eating an Elephant. We have to do it one bite at a time, but other's think it takes a bigger mouth and fewer bites.
I thought Elon had some great ideas earlier about Red Dragon, but abandoned those in favor of the Bigger is Better approach.
The primary flaw in Elon Musk's plan for Mars was failure to work on an intermediary size system for the pioneering explorations of the landing zones. He needed to be doing this concurrently with Starship, and using a scaled up center core for Falcon Heavy. Falcon "Super Heavy" with a 17 foot diameter (5 meters) and using the expertise gained in the Falcon Heavy engineering work would have been feasible. This model would have used 4 Falcon 9 side boosters and a 15-17 Merlin engine central core. I recall suggesting something similar to this back in about 2016. This was to have been a bare bones, "survival and explore mission" flight vehicle, and a squadron of 4 of these for the mission. This would have enabled some significant progress on the ISRU fuel production facility and preparation of a larger and boulder free landing site for larger Starship missions. Even a Bobcat style tracked skid-steer unit could clear away some big boulders and use of explosives can render the large rocks to smaller rocks.
But hindsight is always better than 20-20. Just sayin'.
The adjustments they are making are analogous to the collimation process that owners of Newtonian/Dobsonian telescopes contend with constantly. All telescopes require periodic collimation, except for high grade refractors. Each of the mirrors will require careful alignment to bring them to a single focal plane and focal point. The Keck telescopes in Hawaii are a similar problem, as they are composed of many smaller mirrors requiring alignment to function. The Large Binocular Telescope on Mt. Graham in Arizona is just 2 mirrors, but it's still the same set of problems on a drastically smaller scale.
Let's all hope that the optics are working properly--unlike Hubble on the first go-around!!
I'm still in absolute agreement with Robert Zubrin, who referred to it as a "Lunar Tollbooth."
"Ya ain't goin' to the Moon, unless ya pay Old Space a hefty toll."
OK, guys-
Here's my final "take" on vaccines and their usefulness in society:
I didn't take the vaccine, even though it was widely available and recommended for my particular age group and for those with previous heart ailments. I subsequently contracted the "COVID-19" disease and was hospitalized for 4 nights, never on a ventilator.
I have attended various medical and veterinary conferences and discussed the efficacy of vaccination utilization with professionals who regarded me as a peer. The consensus was that vaccinations seem to generally be 35 % effective in prevention of diseases--other than Jenner's original Smallpox vaccines which seem to have wiped out the disease.
After sufficient time after asking my efficacy question had elapsed--I also asked about the relative "natural immunity" to diseases, and the response was always "around 25-35%" of a given population, and varying slightly from disease to disease.
I would normally point out afterwards over evening drinks that in my estimation, vaccines were a placebo for the masses. I then used the numbers discussed earlier as my basis for my conclusions.
I don't want the "jab," and neither does anyone who regards injecting a potential toxic material into their perfectly healthy body as a bad idea.
I strongly oppose these Draconian measures as being carried out by the totalitarian members of Government.
The main purpose of the Gateway is generation of jobs for "Old Space."
The radiation protection from Solar Flare emissions in the designs I've seen is totally non-existent. No provision for any artificial gravity--which is absent all NASA designs. No provision for any Cosmic Ray shielding, either, which is the least of the worries for the inhabitants.
Back in Ancient Times, when I was still an Undergraduate at University of Colorado in Boulder (1957), and still an Aerospace Engineering student, the Government funded space program was floundering and many of the rockets were jokingly referred to by students and faculty members as "Civil Service Rockets," based on the then prevalent view of "They don't work and they can't be fired." Only after the first satellite launch was given to Redstone Arsenal and Wernher von Braun to fix, did the program start moving forward in more than inchworm steps.
This appellation seems kind of appropriate for the current SLS. The first launch has been postponed numerous times for more testing and interminable delays. I am sad that the main contractor, Boeing, has become something other that our nation's top military and launch vehicle contractor.