62 thoughts on “The Age Of Discovery 2.0”

  1. Scanning their episodes, this looks like quite the departure from their usual content but also thematically relevant. Their YouTube channel hasn’t been kept up to date this last year.

    Rand, if I could make one small suggestion. See if you can get them to post on YouTube again and as the episodes of this series roll out, tweet links to the various space nerd channels and see if they find it interesting enough to cover on their channels. Sometimes these channels pick up articles but I haven’t seen them reference podcasts that aren’t on YouTube. Just getting these other channels to mention the podcast would help but not being on YouTube limits the audience (although the native audience is large) and there are a lot of people who consume space content on YouTube who could benefit from being exposed to what y’all have to say.

    A second small suggestion, all long form podcasts benefit from pulling out some shorter 10-15 minute clips. This can get people to watch the longer version but also reaches an audience who have limited time or who are unfamiliar with the topic and need a taste to see what it is all about. It looks like they used to do this or their podcasts were shorter.

    Looks like there are a lot of good content there. Subbed to the podcast.

  2. Also looking forward to this. The one constant between Age Of Discovery 1.0 and 2.0 are the travel times and duration of missions. Seems like those remain the same. Distances and harshness of the environments vastly greater tho. Until we get the equivalent of jet travel for the solar system.

  3. It seems Venus orbit will be important to Mars settlements.
    And Venus orbit is where you will go, to get beyond Mars to mine space rocks and will return the resources of space rocks to Venus orbit.
    What Venus orbit needs the most is water. What Venus has is solar energy. Venus also has more launch windows to anywhere.
    It’s solar escape trajectory gets faster to anywhere.
    It has atmosphere to aerobrake, anything.
    And one can even have people living in sky of Venus, and still aerobrake, anything. And it seems to me, the planet of Venus is a military fortress.
    And with such aspects, Venus L-1, could provide low income housing for trillions of people. Not that it’s going to have trillions of people at time soon.
    It seems to me, the most population in space for next few centuries, will probably live in Earth orbit.
    People like Earth, and being a few mins away from Earth surface would be an important aspect.
    But in term near, one could send a lot water from Mars to Venus orbit, one should get the best price for Mars water in Venus orbit.
    And in near term exporting water from Mars it could be more business than exporting Mars food.
    One would use cannon/mass driver to ship water to Venus, and other bulk material {including food}could also use same transportation system. Or Mars water export could lead to more stuff exported from Mars.
    For Mars settlements, one needs cheap water. Or Mars water can’t more than 1000 times the price of water on Earth. Cheap Venus orbit water is $100 {or more} per kg. Cheap lunar water is less than $500 per kg. Cheap Mars water is $1 per kg or less. People living on Mars will all ways need much more Mars water than Mars could export, but at some point Mars could export more than 1 million tons of Mars water per year. And some day, when water in space is cheap enough, Mars could import water. Our Moon will export some lunar water, and very likely in more distance future, import a fair amount of water from Space, but Venus orbit will always be importing water from somewhere. And Venus orbit will probably always be largest and most constant water importer.
    The other thing Mars needs for town on Mars is a low cost of electrical power. One could argue it will need to use nuclear power to get the lower costs. And if Mars has lots of cheap water, the nuclear energy can use water for coolant, thereby lowering cost of nuclear powerplant, and waste heat water can used for heating.
    Solar energy on Mars surface is not as bad as solar energy use in Germany, but solar energy on any planetary surface is not very good {but lunar polar region with sites with 80% of time with sunlight is pretty good}.
    Anyhow as said before, traveling to Mars via Venus orbit, doubles Mars launch windows, to and from Earth. So anyway one get water to Venus orbit, and make rocket fuel would be in Mars interests.

    1. I largely agree with the importance of a Venus transfer for chemical rockets. Not so much for Nuclear Thermal or Nuclear Electric. But those are for the belt and gas giant moons.

      If not too OT can you comment on the desirability of Venusian transfer vs the Hohmann Transfer?

      1. Yeah, I agree. Let’s hear some more.

        What about going to Mars one way and returning the other? Like Earth to Mars but Mars to Venus to Earth or the other way around?

        1. You’re talking about a flyby, not a stopover, right?

          Anyway, E-V-M makes a fair amount of sense, M-V-E doesn’t make much that I can see. M-E-V is more reasonable, but that assumes you want to stop at Venus for some reason.

          1. –Daver
            November 2, 2021 At 3:30 PM
            You’re talking about a flyby, not a stopover, right?–

            One can do both, but stopover and refueling gives more delta-v.
            So, with stopover it’s “possible” to go faster Earth to Venus to Mars than Earth to Mars. {or the other way around}.
            If you talking less or same amount rocket fuel used doing, Earth-Venus- Mars vs Earth directly to Mars. I would say that a more complicated question- possible, maybe.
            But on “average” I assume, it takes more time and more rocket fuel doing Earth-Venus-Mars, but point is you get another window, waiting for next window, of Earth to Mars, requires more time to get to Mars {or other way].
            The only reason to take more time to get to Mars, is if you want to visit Venus for some reason.

          2. More time, and more time spent in deep space (more radiation). That doesn’t matter much for cargo, I suppose, but maybe bad on crew and passengers. I suppose you could have a shielded wheel in Venus orbit that the passengers could kick around in until it’s time to launch into Mars transfer, but now you need to do resupply and maintenance on the wheel.

            I’m not sure how much difference opening a second corridor is going to make. You get more launch opportunities from Earth, but if it ties the rocket up for longer periods of time and the transits are more costly, is there really any savings? Why not just launch more rockets when the planets are favorable?

            If we’re talking round-trip (E-M-E) circuits, I get (on the average) .71 years E-M, 1.24 years stayover on Mars (waiting for the M-E Hohmann), .71 years M-E, 1.61 years wait on earth for the next E-M Hohmann. That’s about 4.27 years for a complete circuit, and 2.85 years of that has the rocket sitting on the ground (of course, it wouldn’t just be sitting and being maintained–it’d be launching stuff (like fuel) into orbit. So maybe the 1.42 years on the Hohmann orbit is costlier).

            I haven’t run the numbers for non-Hohmann orbits. Taking higher-energy paths cuts down the travel time, but more importantly might be able to make a round trip in less than 2.1 years (the time it takes for favorable configurations to recur).

          3. –Daver
            November 4, 2021 At 2:19 PM
            More time, and more time spent in deep space (more radiation). That doesn’t matter much for cargo, I suppose, but maybe bad on crew and passengers. I suppose you could have a shielded wheel in Venus orbit that the passengers could kick around in until it’s time to launch into Mars transfer, but now you need to do resupply and maintenance on the wheel.–

            I would use tall cylinder or “stick” artificial gravity station, rather than a wheel.
            What think is simple and cheap is to make the second stage falcon 9 taller {by about 20 meter}
            The second stage 12.6 meter [41.33 feet] and 3.66 meters {12 feet] in diameter with dry weight of about 4.1 tons so add 20 meter with same diameter of 12 feet and give floors- or the top floor when spinning would have most artificial gravity and lower floors having less.
            And one make so weighs less than 10 tons.
            This is pretty small radius for artificial gravity station, but NASA testing much smaller radius artificial devices, and seeing if people can “get use to” the dizzy effect from such short radius and high gees of 3.
            And I am thinking one would design this for Mars gravity see if crew can likewise adapt it’s short radius. And could start with 1/10th of gee and crew go to lower floors and even less, and then later increase until artificial gravity of Mars.
            Another thing one could do, is tie rope to it, and spin a Dragon capsule. If only doing 1/3 of gee, the rope needs strong enough lift a 1/3 weight of dragon when on Earth.
            or if turn out it’s too short, one make radius even longer- in terms testing it.
            Or launch it and figure out how to make and operate [or drive] an artificial gravity station.
            Anyhow, idea was to put in in LEO, but if you refuel the second stage, it could go anywhere. It could be put in Venus orbit or one simply take out of LEO, so not adding more traffic to the LEO orbit. Or you don’t need to deorbit
            The cost of this station is hardly anything, or sending dragon capsules with crews to it, doing all the testing would or should cost more.
            One could put a couple miles ahead or behind ISS, and do such testing could done by the crew of ISS. Or then don’t need to send crew it, a parked dragon, could undock, and go over to it, and then return to ISS. Or do it with EVAs

        2. Yes, one can go one way and return the other.
          I looked at Hop’s cosmic train schedule- which is just simple hohmann:
          Oh here’s some notes:
          –Mars is a lot harder, “because Earth and Mars only align every 26 months,” Musk wrote, limiting Starship’s capacity for reusability.
          Earth to Mars
          Leave Month Day Year Arrive Month Day Year
          2026.8741 11 15 2026 2027.5828 7 30 2027
          2029.0095 1 3 2029 2029.7182 9 19 2029
          2031.1449 2 22 2031 2031.8536 11 7 2031
          2033.2803 4 11 2033 2033.9890 12 26 2033
          2035.4156 5 30 2035 2036.1244 2 15 2036
          2037.5510 7 18 2037 2038.2597 4 4 2038

          Earth to Venus
          Leave Month Day Year Arrive Month Day Year
          2024.9766 12 22 2024 2025.3765 5 16 2025
          2026.5753 7 27 2026 2026.9752 12 21 2026
          2028.1739 3 3 2028 2028.5738 7 27 2028
          2029.7726 10 8 2029 2030.1725 3 2 2030
          Venus to Mars
          Leave Month Day Year Arrive Month Day Year
          2026.7853 10 13 2026 2027.3808 5 17 2027
          2027.6996 9 12 2027 2028.2950 4 16 2028
          2028.6138 8 11 2028 2029.2092 3 15 2029
          2029.5280 7 10 2029 2030.1234 2 14 2030
          2030.4422 6 9 2030 2031.0377 1 14 2031

          Mars to Venus
          Leave Month Day Year Arrive Month Day Year
          2027.4395 6 8 2027 2028.0349 1 13 2028
          2028.3537 5 7 2028 2028.9492 12 12 2028
          2029.2680 4 6 2029 2029.8634 11 11 2029
          2030.1822 3 6 2030 2030.7776 10 10 2030

          Leave Earth to Venus Dec to Jan 2024 arrive May 2025
          Leave Earth to Venus July 2026 arrive Dec 2026

          Leave Earth to Mars Nov 2026 Arrive Mars July 30 2027
          **could abort to Venus, though leave time from Mars is June 6 2027 to arrive Jan 13 2028, but if abort is decided before even reaching Mars, it could be possible, but not as likely if after landing on Mars. Next Venus window is May 7 2028, less than 1 year after arriving on Mars from Earth.
          If arrive at Venus from in Jan 2028 and leave Venus april 2028 and return to Earth Aug 2028.
          Could fly two Starships, land one on Mars uncrewed, crewed could have option of Mars flyby, then to Venus and get crew back to Earth in less than 2 years**
          Starting Nov to Dec 2026 from Earth, to Mars june to July at Mars, to arrive dec to Jan 2028, at Venus. Stay in Venus orbit to March to April, return to Earth Aug to sept of 2028. Would want artifical gravity space station at Venus before Feb 2028.

          Before Earth To Mars, Nov 2026, could send crew to Mars to Venus in July 2026. then leave Venus to Mars sept 2027 and get to Mars April 2028 – slower way to Mars, but can get return Earth Sept 2028, get back Earth July 2029. So leave earth Nov to Dec 2026, return to Earth June-July 2029

          Or 2028 March get Venus in 2028 July and leave for Mars in August 2028 and arrive at Mars 2029 march. And leaving from Mars to Earth Dec 2030, arrive
          to Earth 2031 Feb.
          Next Earth to Mars is 2029 Jan, arrive Mars sept 2029- with first return option 2030 March to Venus. For going directly to Earth, 2030 Dec
          Earth to Venus is 2029 Oct, arrive at Venus 2030 March which go to Mars, 2030 June arrive at Mars 2031 Jan.

          Mars to Earth
          Leave Month Day Year Arrive Month Day Year
          2028.8268 10 28 2028 2029.5355 7 13 2029
          2030.9622 12 16 2030 2031.6709 9 2 2031
          2033.0976 2 5 2033 2033.8063 10 20 2033
          2035.2330 3 24 2035 2035.9417 12 9 2035
          Venus to Earth
          Leave Month Day Year Arrive Month Day Year
          2028.2539 4 1 2028 2028.6538 8 25 2028
          2029.8525 11 7 2029 2030.2525 4 1 2030
          2031.4512 6 12 2031 2031.8511 11 6 2031
          2033.0499 1 18 2033 2033.4498 6 12 2033–

          Hmm, I thought also did over longer period. Anyhow these dates are just simple hohmann trajectories.
          And my argument was should put depot and artificial gravity station as part of NASA Mars exploration program- as to allow more flexibility and abort options.
          But Musk indicated it was commercial problem related to Mars settlements- and it seems to double the launch times both ways.
          OR for NASA, crew safety issue, and for Musk, more use, trips for Starships {commercial value}. But it seems even better for Martians as general thing {make Mars settlements more viable}.

      2. I wrote some programs years ago; I won’t swear as to their accuracy. Mars’ orbit is fairly eccentric, so there’s a lot more variability there than my program accounts for. My program also doesn’t account for plane changes, so actual delta V could be significantly higher. These assume one short burn (chemical rocket). Total delta V is smaller from a direct launch from the ground, but I’m assuming orbital assembly and fueling.

        How much delta V is required depends on your starting point. My routine gives the delta V from a 200 km earth orbit to a Venus Hohmann as 3.5 km/sec, and says that Earth/Venus Hohmanns occur every 1.6 years.

        Delta V from a 200 km earth orbit to a Mars Hohmann is given as 3.6 km/sec every 2.1 years.

        Delta V from a 200 km Mars orbit to a Venus xfer is 3.37 km/sec, every .9 years.

        Delta V from a 200 km Mars orbit to an Earth xfer is 2.1 km/sec every 2.1 years.

        Earth/Venus is a marginally cheaper than Earth/Mars if you aerobrake (or lithobrake) at Mars, but you need to make a burn at Venus and you need to have Earth, Venus, and Mars all in proper positions. That’s way too hard for me to figure–I’d guess that maybe 20% of the E-V Hohmanns would be suitable for a Venus/Mars transfer. You can always use multiple-bounce orbits, but that’s getting silly for commercial business.

        As far as I can tell, E-V-M orbits don’t seem to have much (if any) delta-V savings until you start doing multiple bounces. They could be handy to get payloads in away from E-M Hohmanns.

        Of course, there’s nothing limiting you to Hohmanns, but I imagine that reasonably low-cost transfers that take less than a couple years are going to be pretty close to a Hohmann on at least the initial leg.

        1. The big advantage of Starship and Mars is, Mars has all the resources necessary to make Methane and LOX on the ground, and you can aerobrake to landing at both Earth and Mars (Venus too, but then you’ll never see home again). Earth-Mars-Earth works with fast transfer if you have a fully fuelled Starship (via tankers) in LEO and then fill it back up on the surface of Mars from ISRU. And several people here have noted you can avoid tankers if you launch Starship with a SuperHeavy Heavy Trimaran. None of that supports cyclers, nuclear engines, or Venus depots when it comes to Mars. Part of the Venus problem is the need to transport fuel to the Venus depot, if you want to continue fast transits, or spend time waiting around for a window to open, if not.

          1. Trimaran? Is that essentially Super Heavy with two strap-on side boosters? Such that a Mars bound Starship uses almost 0 fuel to reach LEO?

          2. Partial aerobrake at Venus could make sense–dip into the atmosphere enough to get down to orbital velocity, then circularize. If you dip too far you’re a goner, of course.

          3. Trimaran is a SuperHeavy core with two SuperHeavy strap-on. Basically the core reaches orbit empty with a fully fuelled Starship on top. The problem would be getting that core back to the ground, of course.

            As for the other, you can do aerocapture to orbit anywhere with an atmosphere. In the movie “2010” they did it at Jupiter.

        2. “How much delta V is required depends on your starting point. My routine gives the delta V from a 200 km earth orbit to a Venus Hohmann as 3.5 km/sec, and says that Earth/Venus Hohmanns occur every 1.6 years.”

          With Venus there no sense going to low orbit. So one would space station at a highly elliptical orbit , of something like 200 km to 100,000 km. Therefore when near Venus you have higher velocity as compared to 200 by 200 km orbit. One also change the inclination of trajectory with less delta-v when further from Venus, in your highly elliptical orbit. And Venus also doesn’t have van allen belts like Earth does.
          The higher velocity will give you an increased Oberth effect.

          It seems better despite Earth van allen belts to do something similar with Earth departures and arrival. And one do this if mining lunar water and making rocket fuel. But even without getting rocket fuel from Moon, it makes sense to start from higher Earth orbit. And of course Mars also lacks van allen belt, and one should do likewise with Mars.
          Anyhow your numbers agree with:
          Though didn’t include trip time: 0.3999 Years
          OR in days 145.9 days
          Of course with crew one use more delta-v and hohmann + patched conic and travel quicker between Earth and Venus
          Or travel times between Earth and Venus are much quicker than Earth and Mars. And travel times between Venus and Mars are also much quicker than Earth to Mars.
          The “same kind of patched conic” used with Venus to Mars “works better” as compare to patched conic of Earth to Mars.
          Though not this kind of “improvement or the difference” with Venus to Earth transfer.
          So to put number on it
          Simple of Venus to Mars is travel time of .5954 years.
          Or in days: 217.3 days or divide 30 day a month: 7.24 months
          As compared to Earth to Mars of .7087 years.
          And with patched conic you lessen it by 2 or 3 months
          And roughly from Venus to Mars one lessen it with patched by about 3 months {or perhaps more}.
          Or by more, I mean a higher fraction of total time-and perhaps also less in terms of less months. But if you use a bit more delta-v, I would say definitely less months are removed from the simple hohmann travel time.

          “Earth/Venus is a marginally cheaper than Earth/Mars if you aerobrake (or lithobrake) at Mars, but you need to make a burn at Venus ”
          What do you mean?
          You need more burn from Venus to Mars, and compared to Venus to Earth.
          But as said, above you should be at high orbit at Venus, so leaving Venus from high orbit {highly elliptical orbit] to get to Earth or Mars. require less delta- V.

          1. I suppose I could check just how much delta-V we’re talking about, but there’s a limit as to how far away from a Hohmann orbit you can get with a chemical rocket and still have a payload. That broadens the launch window for an E-M orbit, maybe by several weeks, but isn’t going to make them occur any more frequently (E-M launch seasons start every 2.1 years). Having a broad launch window could help a bit with transit times (more energy for somewhat faster transits, which might be important for some purposes), but isn’t going to help (much) with the number of rockets that can be in transit (maybe it could help in getting the round trip time to less than 2.1 years, which would effectively double the number of rockets available).

            I’d have to run some real simulations (or look at web pages of people who did) to see what adding Venus to the mix does. I can see how, if the planets are properly aligned, it could add another practical route, but I don’t know how frequently the three planets would be in a these favorable positions.

          2. The main point of Musk’s propellant-rich system is to minimize crewed transit times (keeping it down to 2 – 3 months) and see to it that each Starship round trip is kept to one synod (so hardware won’t be stuck on Mars or Earth for years, waiting for a launch window). I also don’t see how waiting aboard a rotating station in Venus orbit helps with radiation.

            I’m not opposed to artificial gravity stations in principle. But part of the problem is providing radiation protection that doesn’t involve kilotons of regolith or water. That’s the main issue with the Kalpana One design. Stability of a free-floating disk or cylinder is the other.

            I personally think the first step in that direction should be spun off (sorry!) from the NautilusX design. Double it in size, use two counter-rotating habitats, make provision for carrying several years of suppies for six crew, add nuclear or solar epectric propulsion (depending), build two and send them off exploring together (for safety). I’d like to know how much radiation protection you could get with polyethylene, food, and water. The last two are permanent, with merely a state change. Water can be mostly recycled. That leaves the question how much radiation protection you’d get from dried poop…

    2. Mars has lots of water, an ocean worth frozen under the dust. A team of former SpaceX engineers has started a company to make nuclear power plants for use in space.

  4. I believe you are underestimating the effect of this new age of exploration. Our single point of failure for the human race has always been Earth. Soon it will be the solar system. Unless I have mis-read it, all necessary minerals and chemicals for sustainable human life are available in several places in the solar system. The possibilities for expansion and growth cannot be over-stated. No longer will one group of people be able to control the future of the human race. A solar Silk Road will not be limited to one route from point to point. Buzz Aldrin’s lunar cycler is a good example of what freedom from opression distributed routes space will allow us.

    1. A lot of this depends on just how hard it is to live in space. Do we need full 1-g essentially all of the time? If so, the moon and Mars are out (sure we could build centrifuges, but moon dust and Mars dust aren’t good on moving parts). How about radiation protection? That makes wheels in space hard (not impossible, but hard). It also means that Moon and Mars colonies might need to be buried under several feet of rock.

      The most inhospitable spots on the surface of the earth (and a good portion of the sea bed of earth) are going to be cheaper and safer to live on than space for a long time to come.

      That said, Apollo-style missions couldn’t have been done by machines in the 60’s. There are lots of jobs now that can’t be done by robots, but that number is decreasing. I can imagine that there would be profitable space-based jobs that wouldn’t be able to be performed by robots in 60 years, but I wonder how many.

      Of course, colonization doesn’t need to be driven by economics, but it’s a lot easier.

      1. I don’t see why it is so hard for space policy folks to understand the need for an artificial gravity lab as part of a space station or to be the station itself. Its need is self-evident.

        1. I agree. Starship will make it cheaper to launch a wheel into LEO so maybe we can finally get some data on this. We could and should do small animal experiments, but we’d eventually want to do some long-term (30 years) human experiments, and that’s going to be rough from a number of standpoints.

  5. At the rate we’re going, we’ll find out when people start suffering from strange symptoms. As with most adaptive illness the symptoms and their severity will differ from person to person. It will be hard to diagnose it as low g related I suspect. For moon we might be able to get people back in time to treat. For Mars who knows? Worst case is they die prematurely on Mars or die even faster once back in 1g. Maybe gravity lab could become a mandatory way-point to and from or at least from, where g’s can be increased gradually, like deep sea divers put in pressure chambers on return to surface to avoid the bends.

  6. –William Barton
    November 4, 2021 At 7:35 AM
    G, I still think the main problem with your idea is Hohmanns. The whole point of Musk’s fuel-rich idea is avoiding them.–

    Well non hohmanns I regard as idea which I talked about for years.
    With chemical rocket I don’t think you do them from 200 by 200 km earth orbit, rather I think one needs highly elliptical orbit or one is starting from high earth orbit.
    Or from LEO they are about 9 to 11 km/sec of delta-v in which the thrust needs to applied when near earth.
    Or you are “wasting a lot delta” changing Earth’s orbital velocity vector.
    Or you are “doing” a Venus distance to Mars hohmann transfer trajectory, but starting from earth distance, and arriving at Mars as though you started from Venus using hohmann [you arrive at Mars at slower velocity relative to the 24 km/sec Mars orbital speed around the sun].
    As compared to hohmann type from earth in which there is high velocity difference when you reach Mars distance.
    Now in terms of Musk, I guess he thinks he can manage this high different of velocity at Mars by using Mars atmosphere, and maybe that is possible.

    But in terms using Venus to get from Earth to Venus to Mars I am talking different planetary trajectories windows to getting to Mars.

    And whether do a bigger hohmann, and do lots of braking at Mars, or non hohmann this a widening the 2.1 year window of Earth to Mars as compare to other earth to Mars trajectory: ie simple hohmann and hohmann + patched conic. And using trajectories not using chemical rocket power, such ion or nuclear rockets {which are not hohmann- they more of the spiraling out {constantly changing the vector- or non hohmann}

    Or from Venus one could also do non hohman- you leave Venus as though you did a hohmann from Mercury to Mars. Though you “waste more delta-v” by altering Venus 35 km/sec around the sun, vector. Or can do the faster/bigger hohmann in arrive at Mars requiring a lot braking.

    Or from only Earth to Mars doing 3 month travel time to Mars, you can only do this same trajectory every 2.1 year. And using Earth to Venus to Mars. It varies but amounts of about 1/2 the time of using “same” trajectories to about 1 year.

    1. I think you’re basis some of this on misinformation. Look, the entire Starship/City on Mars concept is based on a chain of requirements. Opponents of the idea break one link in the chain to “prove” it’s impossible, and then talk about their own favorite idea (whether it’s Aldrin Cyclers, some old NASA DRM, or what have you). But the chain is as follows:

      1. Full reusability. OldSpace is committing suicide over this one.

      2. LEO refueling. A high eliptical orbit is not necessary for Mars, only the Moon, for which aerobraking is obviously impossible.

      3. Aerobraking at Mars and Earth (which counts as free fuel).

      4. ISRU-based refueling on Mars.

      5. Fast transits for crewed spacecraft, which also means single synod reuse. You do get different results for opposition vs. conjunction class transits, but Hohmann orbits are unnecessary because you simply collide with Mars when you get there, and then collide with Earth when you get home. That makes an enormous difference.

      1. At various times I’ve argued why Cyclers and Venus stations either don’t help or arre impractical. Foremost among these is getting them in place and then using them. How do you rendezvous with a cycler? Ans: with an interplanetary spacecraft. How do you build a Venus orbital station? Build it in situ? The scale of that operation would likely be prohibitive. Etc. Etc.

        The rest of any discussion is simply, what else do you want to do in outer space besides colonize Mars? There are lots of answers, but I suspect loitering in Venus orbit while waiting for the next launch window to roll around is low on the list.

        1. “How do you rendezvous with a cycler? Ans: with an interplanetary spacecraft.”
          But cycler would have artificial gravity and /or lots of radiation shield.
          Also this interplanetary spacecraft would need to do a non hohmann transfer to get to the cycler, and leave it.
          So the interplanetary spacecraft requires a lot delta-v, but it’s low mass spacecraft,
          But a cycler doesn’t fit very well with Musk starship, but one tie two starship together and call it a cycler.
          One also tie two starships together and call it, a Venus space station. With Musk idea of huge fleet of starships going to Mars, I don’t he is excluding idea using artificial gravity {tie two or more starships and have them spin].

          “The rest of any discussion is simply, what else do you want to do in outer space besides colonize Mars? There are lots of answers, but I suspect loitering in Venus orbit while waiting for the next launch window to roll around is low on the list.”
          I view colonizing Mars as a good beginning to becoming a spacefaring civilization.
          Both lunar industrialization and Mars colony is just the beginning. Neither involve NASA much, but allow NASA to do some significant solar system exploration. But mostly it’s about or leads to Space Power Satellites for Earth surface.
          [and ocean settlement on earth}

      2. –William Barton
        November 6, 2021 At 11:49 AM
        I think you’re basis some of this on misinformation–
        In what regard?

        “Look, the entire Starship/City on Mars concept is based on a chain of requirements. Opponents of the idea break one link in the chain to “prove” it’s impossible, and then talk about their own favorite idea (whether it’s Aldrin Cyclers, some old NASA DRM, or what have you). But the chain is as follows:”

        I don’t know anyone {who knows anything about space] who are “opponents of idea”.
        But will I make list of my favorite ideas.
        I like my idea of what I call a pipelauncher.
        In terms space exploration, something I always talk about
        is NASA should not make lunar rocket fuel and NASA should just explore the Moon to find lunar water deposit. But don’t get “bogged down with the Moon”. Allow or encourage other countries space agencies to get bogged down on the Moon. Instead focus on exploring Mars, and not keen on idea of NASA forming partnership with other nations with Mars exploration, at least not within say first 10 years of Mars exploration.
        NASA should do something with ISS, so they don’t have to do ISS program and Mars program at same time.
        Whereas one can have overlap with ISS and lunar exploration programs.
        Normally, in past, I would not favor NASA trying to do a Mars exploration and some major kind involvement Venus orbital “program”. But NASA will have the starship it can use and NASA wants crew mars abort, options. Though if NASA wants to partner with other space agencies regarding Venus, that seems like ok thing to do. Also with Mars, NASA as same 2.1 year window and in terms NASA PR, it’s involvement with Venus can fill in the 2.1 year “news gap”.
        Or without SpaceX, Starship, NASA Mars exploration program could be more or less be like Mars Direct type thing.
        Which remind of another of favorite ideas, I think Mars exploration should have a lot robotic mission in addition crewed exploration. And I tend to think Mars surface crew are mostly confined to their base, rather crew spending much time driving around in rovers. Have robotic rovers [and helicopters and/or hoppers}.
        Or I think Lunar development, would have some people on Moon, but a lot things done on Moon can be robotic activity- and same “rule” applies to Mars exploration.
        It seems NASA Mars exploration should have lot deep drilling operations {and with crew involvement, but as robotically done as possible}
        I don’t know what this means: “old NASA DRM”

        1. Regarding misinformation, I’ll just cite the requirement for eccentric high earth orbit refueling as an example. It’s Moon only, not Mars, and maybe not even Moon, since Musk has suggested the Starship lunar lander may work with only 600 tons of fuel and oxydizer in LEO (meaning they can shorten the tanks too).

          I admit I sometimes have trouble disentangling your long posts, each with many subtopics. I’m sure my many confusing typos don’t help anything in return.

          As far as old NASA DRM goes, it refers to the habit of many OldSpace types (usually employees) of circling back to especially DRM (Design Reference Mission) 5.0 and talking about trips to Mars taking years, rather than months, with some to all of that time spent either in transit or in Mars orbit. It’s just an example of what I was talking about.

          A lot of the misinformation comes out of discussions where the many people opposed to Starship invent figures to “prove” it won’t work. Other people then take these untruths as factual. For example, I recently read a discussion where it was asserted an entirely expendable Starship can only put 41 tons through TLI, and that the vehicle will cost more than $250mln each, therefore it’s little better than SLS 2.0. But when you look at the arithmetic, it turns out they assert Raptor engines will cost $2mln each (as opposed to the target cost of $250K) and the Starship structure will be 95 tons (which is the structural weight of fully reusable Starship). This all asserts that reusability and refueling will fail, and that SpaceX will be too dumb to notice. That’s another example of what I’m talking about.

          1. –Regarding misinformation, I’ll just cite the requirement for eccentric high earth orbit refueling as an example.–

            Well only thing I said Musk “should do” is make cheap artificial gravity station.
            NASA should do it, or NASA should have done it decades ago, but Musk could do it, and though it might cost him somewhere around 50 million dollars- it should be worth it. Or, it should be worth it to Bezos, to pay Musk to do it. and worth it for NASA to pay Musk to do it.
            And that cheap artificial gravity station probably would at least start in a LEO, say 300 by 300 km {or higher orbit}. Or it cost a lot more and not needed now, to be in some high earth orbit.
            Or sending crew to it, is the higher cost of running the artificial gravity station, and could have quite number crew missions to it, and each of the crew trip mission costs around $100 million each trip.
            [Or station about $50 plus sending crew is 100 million plus another 100 million each for crew trip, and end of life of station, one would need to put somewhere other than LEO- one could de-orbit it, but I think one should refuel the falcon 9 second stage which attached to station- and sent somewhere else in space. Or lifetime total cost associated it’s operations is not 50 million. Or when say ISS costs more 150 billion you are including all costs over the decades of ISS use]
            And it much more costly per mission trip if not in LEO.
            And would be done using falcon 9.
            But perhaps Musk would want to do it with the Starship
            But right now, it costs Musk less than sending greenhouse to Mars, and seems it as important in terms of goal of making Mars settlements as sending a greenhouse to Mars.
            “I admit I sometimes have trouble disentangling your long posts, each with many subtopics. I’m sure my many confusing typos don’t help anything in return.”

            Yes many people complain about that. But if any comfort about 1/2 posts that I badly type- never actually get posted- for various reasons. One of the reason is it just gets too long and rambling.
            [And like posting where I can edit, and I post, and then end up editing it- a lot, such as, at:
            But I think even worse there, because can edit it.

  7. I don’t have any problem with artificial gravity stations, and I think one day they will be needed and important. My problem is with the idea they will be cheap.

    You suggested sending two Starships to Venus and twirling them around one another for artificial gravity. My question is, What good is that, other than as a wasteful experiment. At Venus, they could be way stations for a handful of astronauts waiting for Hohmann-orbit launch windows. Why not just load a hundred colonists in each one and send them on their fast transits to Mars? The ships can come home with cargo and returnees, if any, and be ready to head out again at the next synod.

    The fact is, for inner system voyages (to the Moon, Mars, NEOs, maybe Venus), the problem is radiation, not zero gee. Hanging around in Venus orbit doesn’t solve that. And big or small, you still have the problem of supplying a Venus orbital station. Especially a large one.

    One day, people will be traveling around the solar system in large, nuclear electric interplanetary liners built on a NautilusX planform, carrying latter-day Starships as landers. And workers in the outer solar system (Main Belt, Jovian Trojans, Saturn system, etc.) will be living in large rotating habitats. I do believe we should build the first experimental ones soonish. Not in LEO, though, as that’s too risky. I’d build one at SEL1 and see how it worked out.

    1. “You suggested sending two Starships to Venus and twirling them around one another for artificial gravity. My question is, What good is that, other than as a wasteful experiment.”
      I would less of wasteful experiment if did the wasteful experiment first in LEO.
      By adding 20 meters to the top of falcon 9 stage, one could experiment to determine 1/3 earth gravity can prevent the harmful effects of microgravity.
      If spend say 6 months in microgravity, then spend 3 month in 1/3 gee, will it reduce the effects of the 6 month in microgravity {in some fashion similar to 3 month after returning to Earth surface}.
      Or what are effect of 6 month of 1/3 gravity as compared to 6 months in microgravity.
      The cheap artificial gravity station is not designed for one gee or more, but do need a more expensive artificial gravity station which provide 1 gee [or even higher than 1 gee].
      If send people to Mars in 3 months, when they land on Mars, they have some effects from the 3 months of microgravity, will these effects lessen over time on Mars surface , or will they continue to worsen, and only recover when one returns to Earth.
      It seems exercise does not significantly reduce the effects of microgravity. What about exercise while within 1/3 gravity?
      What kinds of exercise on Mars surface, will most quickly return to some kind of normal after one lands on the surface of Mars?

      1. One could do something less than adding 20 meter to second stage
        You just send dragon crew and not separate from the second stage rocket, and spin it.
        But seems adding 20 meter to stage, would be better plan.

        1. None of those things (which are stunts) will accomplish any goal. My only reason for not wanting a large rotating station built in LEO is it’s dangerous beyond what it accomplishes. 1) what it reenters and dumps its mass on a population center? 2) What if LEO winds up hosting 94,000 comsats?

          The reason I say this, and oppose “cheap” is because builting an AG “station” for six mouse experimenters won’t accomplish anything. What’s needed is something in the several thousand tons range, with hundreds or thousands of crew aboard.

          And, of course, a LEO station teaches us nothing about radiation mitigation. *Is* there a way to shield from solar and cosmic radiation that doesn’t involve fantasies about meters of regolith? Will polyethylene clothing and sleeping bags do the trick? On a spaceship, maybe you could hide inside the cargo of food and water for a few months. But not on a 10,000 ton rotating space station for decades.

          SEL1 is a handy spot to build a big, rotating space station, and then use it as a base to build a solar power transmitter annex. Projects on that scale are a ways off. They won’t happen unless Mars is colonized first. Without the Mars colony, solar system industrialization is unlikely to happen. Cheap little space station stunts is a quick route to flags, footprints, and failure.

          1. A rotating station in equatorial LEO would be useful as the lowest-cost space hotel (and waypoint to other destinations, as in 2001). It would be unlikely to enter and dump its mass on a population center, and the likelihood would vastly decrease if its ground track was over the equator. There is no reason that we can’t have them in multiple locations, but equatorial LEO is the place to start. It would simply have to be below the altitude of the lowest communications constellations.

          2. ” It would simply have to be below the altitude of the lowest communications constellations.”

            Why not higher than most communications constellations in LEO- and get bigger view of Earth. The higher orbit would have less radiation to inclined orbits like ISS or maybe less radiation than 28 inclination. And hotel has less drag and less threat from space debris, one has further line sight for direct communication, One could want more solar panels [and less drag from them] and a slightly longer daytime for solar energy. Or per person one might want as much power electrical as per person on ISS.

          3. I don’t think there’s enough room below the constellation for something that size to remain in orbit for long. What are we talking about here? I was thinking something around a thousand times the size of ISS (450 tons), so around 50,000 tons. ISS is a low density tinkertoy; a rotating cylinder will have much more structural mass to support the rotational stresss that goes with a 1G rim. I’ve note the same issue with LEO fuel depots. These things will be visible in the daytime sky! And building little, cheap ones probably won’t be worth anything, other than as yet another small research project.

            As far as an AG LEO hotel in equatorial orbit, what is the point of that? What’s a space hotel for, other than zero-gee sex and looking out the window? So, no zero gee and the view out the window is ocean and clouds rotating around.

            And why do we think we need a LEO waystation? Because people thinking about this stuff in the 30s – 50s were looking at a technology that required it. It’s almost a century later. The problem isn’t AG. The problem is radiation.

          4. –I was thinking something around a thousand times the size of ISS (450 tons), so around 50,000 tons. —

            One start smaller and make bigger.
            To get bigger, start with a lot electrical power. If have available the most electrical power in LEO, you get people/projects who are wanting/needing a lot electrical power.
            And might want electrical storage capacity in which one deliver a lot electrical power for a minute or two. Ie for testing things which need a lot power.
            So lots of power to manufacture something, and peak power ability to test things and/or to make things.

  8. Btw, on the refueling of Falcon 9 upper stage, or any other contemporary rocket, such as Centaur: I think it’s too little, too late, and it’s the very essense of OldSpace thinking. What your going to have is a refuelable space tug based on Starkicker. 1200 tons of fuel, in a vehicle already designed as refuelable with engines already designed to be reusable. The only competitor to that will be Blue Origin’s supposed Jarvis upper stage. Stainless steel, 7 meters in diameter, one BE-4U engine.

    1. It depends. Are launch companies able to create such a stage that they can sell and make a profit? There is probably enough room in the market for a variety of space tugs.

      NG uses Cygnus as a product right up until it burns up in the atmosphere. Looking for ways to utilize products prior to their destruction is a good idea, especially if the numbers on the back end support it.

      1. That would be true if they’d done it ten years ago, and had it now. The market will be very different in just a few years, if current projections hold (and if the don’t, the future is over). A refuelable Starkicker and a refuelable Jarvis will capture the entire market from converted expendable upper stages. The very small tugs and converted satellite buses (e.g., Cygnus) succeeding now are doing so because they can be designed and put into service quickly. Think about the service life and activity structure of these things.

        1. I don’t know what the market will look like but I was speaking more to a mindset of finding ways to market your product through its lifespan. I could be wrong here but it seems like the industry didn’t utilize their products this way and it wasn’t until we had a reusable rocket that companies took serious efforts to use every part of the buffalo.

          Whether or not any specific product would pan out depends on idiosyncrasies of that product. It is all very speculative until we look at things that exist and the actual development and operational costs.

  9. “A new space race has begun. But the rivals in this case are not superpowers but competing entrepreneurs.”

    What we will likely see is the rise of new powers that punch above their weight as small countries leapfrog the launch bottleneck to take advantage of other people solving that expensive problem so that they can focus on doing things in space for a fraction of the cost of doing everything inhouse.

    Consider that even if a country is motivated by the desire to have a weapon, it is probably still cheaper to buy a ride to space and then do some weapons work on the sly.

  10. Re, the Bob Zubrin
    He didn’t mention Venus.
    And failed to mention water in space.
    I like the history, and let’s say, the moral requirement
    to opposed to the “evil” idea of shortage, rather the endless
    abundance that we have.
    I was bit surprised he thinks global warming is some kind
    of “concern”.
    I don’t think Mars is good location to get resources from space rocks. Though it’s better than Earth. Or seems to NEOs are limited
    and hard to get to, whereas space rocks near Mars {or “NEOs of Mars” would be easy to get to] But space rocks of Main belt and Jupiter’s rocks are not obviously better to get to from Mars. Though Mars has the rocks of it’s moons which would be starting point of mining space rocks, and if one mining Mars moon, adding more space rocks to Mars orbits, would endless new source of stuff mine in Mars orbit. And if have that infrastructure in Mars orbit- the amount delta-v one needs to add more space rocks, could not as important issue as the existing infrastructure in Mars orbit.
    But as general matter, it seems Venus is the better place to bring water from Space. And said, I think Venus orbit will become the high population in space. Or I think Earth orbit will higher population and eventually, Venus orbit will have highest population, in space.
    But triangle of Mars providing food for all places other than Earth surface seem to begin and will continue to be Mars.
    But Mars when we will get fusion energy, is interesting.
    I guess it depends on how economical the fusion energy is, or it might similar the current economic of fission nuclear energy as currently have on Earth.
    And it seems to me, fission nuclear energy in space will become far more economical then fission nuclear energy that have on Earth surface.
    But if fusion energy is cheaper than fusion energy from our star, at Venus or an closer distance to our star- that would be radical change of everything.

    1. “I don’t think Mars is good location to get resources from space rocks. ”
      Oh, I guess to get from Mars, one can go to Venus then to a space rock, then from rock, go to Venus and end up at Mars.
      Or use Mercury, and/or Venus, and/or Earth. And end up at Mars.

      So, my bad, it seems Mars is good location to mine main belt and beyond space rocks.
      But it still seems would tend to mine the nearer space rocks to Mars, because some of them should/could be easier.

    2. I think Zubrin is mired in his own past. Mars Direct with SDV. Oh, wait! Mars Direct with Falcon Heavy! Oh, wait. Mars Direct with Starship!

      I think the big problem with solar is the size of the collection apparatus. And fusion is always a day away. What we have right now is nuclear fission, so we should go with that. My vision of the future is large interplanetary liners with nuclear electric propulsion, AG passenger accommodations (say for 500 passengers), using something like Starships as landing craft (where necessary).

      In that future, it may be that Earth primary export will wind up being thorium, uranium, and plutonium. And that might be where the surface of Venus comes into play, if it turns out there are rich radionuclide ore deposits on those uplands, which are most likely granitic “continents.”

      We’ll see. Hope I live long enough!

      1. In that future, it may be that Earth primary export will wind up being thorium, uranium, and plutonium. ”

        It seems in that future, one will have large scale mining of the Moon. And mining hydrogen {and helium] from the Moon’s surface, and that can make huge amount of Iron- and will have lots of thorium and uranium mined also.
        Though there could better places to mine iron, but the Moon would be far better place to mine iron than Earth, because Moon has a lot of dust- though Mars is also rusty and has a lot dust, also.

      2. “I think Zubrin is mired in his own past. Mars Direct with SDV. Oh, wait! Mars Direct with Falcon Heavy! Oh, wait. Mars Direct with Starship!”

        Zubrin is a great cheerleader and he is creative. He always needs some new angle or scheme to create content that furthers his advocacy. It is a lot of fun to answer what if questions.

  11. I seems at current rate of filling the tank farm, it take couple weeks before Starship prototype can launch and land near Hawaii.
    Of course the other factor is FAA approval which some imagine could take 1 to 3 months. It seems SpaceX has some reasons to be more optimistic due to rate they filling tank farms {or maybe filling the tank farms is a part of FAA approval, fill it early and hold for months, is another thing to check off- and sooner the better.

    “Musk’s space flight operation has not identified all potential options for future landing sites and “may plan to land the Starship on islands in the Pacific Ocean, ” which would be analyzed in future reports if plans develop, according to the environmental assessment.
    Ted Ralston, a retired aerospace engineer, said Hawaii would likely be ruled out for a land-based return. Rather, SpaceX may have in mind sparsely populated or uninhabited islands in the Western Pacific with little commercial air traffic, he said.
    “Getting the permits to do the landings in Texas of the type that they are thinking of doing, which is a ballistic reentry, might be more complicated than getting that kind of permission in a more inviting atmosphere in the Western Pacific, ” Ralston said. “And then you get the thing developed under say, three or four flights—now you’ve proven it. Now you can move it back to Texas. So you kind of look for the path of least resistance and develop and establish capability and credibility, and with that you can back your claim that you are OK to go back to the FAA.”

    1. It’s amazing how many people have missed the technology SpaceX is developing. They are refitting to ocean going platforms that can both launch and land the components of SuperHeavy/Starship. The platforms can be situated anywhere, and two (currently named Phobos and Deimos) is not the limit. Islands are not necessary.

        1. If you use pipelaunchers and stuff like pipelaunchers, you don’t need breakwater, but breakwater can be “things” like small pipelaunchers.
          But better to just make a floating breakwater and have a ocean port and floating electrical powerplants- if smallish it’s cost about 50 million, city size, hundreds of millions dollars.

          And big cities are worth, trillions of dollars.

      1. Islands wont be necessary but initially, the oil platforms wont be used. In the Everyday Astronaut tour, Elon said the platforms aren’t a focus right now. SpaceX can change their focus quickly but it sounds like platforms wont be a thing until further along until after they are doing landings.

        Unless SpaceX has secured the use of an island and built up the infrastructure, which could have happened without people knowing, it looks like the current launch site is where landings will take place, maybe after dumping a few in the ocean.

        1. It seems an island with docks is not enough, one needs an island with ocean port. Guam has one ocean port- and probably countless various docks.
          Also one would want an island with airport one can land business jets on.
          Other than perhaps food and entertainment, what else would you want island for?

          A large enclosed lagoon has perhaps some uses.
          And a cluster of islands might reduce the large ocean swells.

          Anyhow, if island is built up, and therefore has considerable population- say more 10,000 pop, and could have political problem if you want to make airport or ocean port- as that going to change the lives of people living on the island. One think it would only could be good news, but they living on the island for various reasons.
          Any kind of change, might be annoying. If was one tribe and they mostly wanted a better life- could less of issue.

          But the expression cargo cult could be relevant, wiki:
          “A cargo cult is an indigenist millenarian belief system in which adherents perform rituals which they believe will cause a more technologically advanced society to deliver goods. These cults were first described in Melanesia in the wake of contact with allied military forces during the Second World War.”
          Could be clear sailing with something like that.

        2. Not initially, but as soon as Musk deems them necessary. He wouldn’t have bought them yet, otherwise. I think SuperHeavy will land at Starbase because it’s low and slow. But those sea landings will prove whether or not the overpressure predicted by some for Starship is true or false. If true, then I think Musk will prioritize Phobos and Deimos.

          My personal hope is, the US will approve inland launch sites for proven fully reusable launch vehicles. Edwards, White Sands, Jackass Flats, etc. These things are either going to work or not over the next few years. It won’t take long for Starship to fly a hundred times.

    1. I don’t see how the thing keeps from dying under a constant 450C environment. It must be expending coolant at an exorbitant rate to keep its electronics from melting. What kind of coolant can be compressed and “cooled” to 450C for a closed loop system that upon expansion gets down to 20C or even 50C? Also the ATM pressure at Venusian surface is what exactly? I forget and don’t have the time to look up right now. And isn’t that atmosphere highly corrosive at the surface?

      1. Venus Leviathan is powered by a Kilopower reactor, and the only cooled part is the sphere. The rest of it is at ambient, since it’s mainly just a big metal balloon. The author made some mistakes with the reactor, despite being a Naval officer and nuclear engineer, so is now thinking it needs two Kilopower reactors to run the Stirling engines that run the heat pumps and charge the batteries. The atmposhperic pressure at the flat plain surface is 93bar, but falls below 50bar in the highlands I predict will be of industrial interest. The corrosive atmosphere is concentrated at the tropopause, not at the surface, but Starship is made from Stainless 304L, which is corrosion resistant enough for the task. This concept clearly needs a lot of work, which the author acknowledges, but it’s not unworkable.

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