“In 1966 Gemini 11 did a tether-generated artificial gravity experiment. A several thousand foot long tether system with equal masses on either end generating one gravity is the solution that people have been doing calculations for since the 1930’s (it was not known if humans would remain conscious without gravity so the tether was a solution to this possibility even then). No extensive testing is needed. We just need to build it and use it as it is pretty straightforward.
The ice on the Moon is the source for shielding. 15 feet and several hundreds tons of water for a small capsule. Well over a thousand tons for the very minimal crew space needed on a long duration mission. This is also pretty straightforward as well as how to push such a shield around the solar system- there is only one practical system. All the work to conclusively prove this concept was done in the 60’s and includes over 1000 live tests of the required devices.
-
And as for “living off the land” on Mars, what started the space colonization movement of the 70’s was the singular conclusion that one gravity was a prerequisite to any permanent colony. The less gravity the easier it is to build centrifugal “sleep train” facilities for small crews on small icy moons but for large populations miles in diameter artificial spinning hollow moons constructed of lunar material has always been, and will remain, the best plan.
It goes without saying (but I will say it anyway) that such a public works mega-project is the anti-thesis of the NewSpace scam (retire on Mars!) presently being endlessly hyped to the public.”
I responded to someone who had posted some interesting artificial gravity numbers on a forum. Unfortunately I cannot post those figures here because the moderator of that site has repeatedly banned me and warned me about using any material posted on his blog- or rather, news site, since he does not like it to be called a blog.
To generate one gravity on the inner surface of a sphere about 6000 feet in diameter the sphere would spin a little over 200 miles per hour and complete one revolution in a minute or so. A person living in such a sphere would take about an hour to walk the circumference and arrive back at the starting point.
It is a good example to explain what a Bernal Sphere would be like.







“A reusable Extraterrestrial landing vehicle could operate between the Earth-Moon Lagrange points and LEO and between the Lagrange points and the lunar surface using propellant derived from lunar water. A super heavy lift vehicle is great for deploying heavy cargo within cis-lunar space but its an inefficient crew launch vehicle since it throws away all of its components– every launch. This makes it necessary for the lander to dive 20,000 miles from GEO into LEO to pick up human beings and then boost out of LEO- presumably with propellants taken on at a fuel depot. What a mess. The Super Heavy Lift has to “throw away it’s components” but it can reuse them. And all the humans are on Earth right now so…..
Chemical rockets operating between the Earth-Moon Lagrange points and high Mars orbit would be much more efficient than nuclear rockets operating between LEO and high Mars orbit– because of the substantially lower delta-v requirements when launch vehicles from the Lagrange points. Plus the delta-v requirements to supply water and propellant for interplanetary vehicles launched from the Lagrange points is substantially lower than trying to supply fuel and water from the Earth’s deep gravity well. Nuclear rockets would never be allowed to operate in the magnetosphere, let alone in LEO or GEO.
IVF technology being developed by the ULA will enable us to utilize hydrogen and oxygen very efficiently. That piston engine is no miracle solution and while it might work well maintaining oxygen for an extended mission, hydrogen is a whole different set of problems.
Commercial crew vehicles will been in operation long before the SLS is launching humans into space. Perhaps, but it is meaningless since they are not going anywhere except LEO and that is nowhere.
Marcel