Manned Mars mission poll

[DAL59]

7 hours ago, tater said:

The chance that SpaceX sends people to Mars first is frankly absurd. Should they gain the capability to do so, they would far more likely sell that capability to their major customer, NASA.

Spacex has been valuated at 21 billion dollars- more than NASA's annual budget.  Although NASA is pretty much guaranteed to get at least 15 billion every year, Spacex launches are much cheaper per payload to orbit.     

[tater]

27 minutes ago, DAL59 said:

Spacex has been valuated at 21 billion dollars- more than NASA's annual budget.  Although NASA is pretty much guaranteed to get at least 15 billion every year, Spacex launches are much cheaper per payload to orbit.     

One, the NASA budget is more like 19 B$/year.

Two, no NASA, no SpaceX.

Three, What the notional value of SpaceX happened to be is entirely disconnected from reality. 19B+ each year, every year to NASA. If SpaceX wants to test ITSy to Mars someday (a clear prerequisite for ever sending people), then they would leverage that cost by getting NASA to pay for elements of it, because it is technology and information that NASA wants---in the same way NASA was interested in Red Dragon when that was a thing. A full ITSy test with ISRU and return would generate huge interest from NASA, and any NASA sample return would involve a flagship mission, and billions of dollars. SpaceX offering such an opportunity would be something they could not ignore, which would get elements of it paid for (along with DSN support, use of extant Mars comm equipment for relay, etc).

Four, payload to orbit cost doesn't mean anything without someone wanting to buy it. If you want to go to Mars, you have to sell it to someone, or have Bezos levels of @#$! you money. SpaceX needs to sell it to someone, and their primary customer is the US government.

[DAL59]

18 minutes ago, tater said:

NASA budget is more like 19 B$/year.

I know.  I'm just saying it is unlikely it will dip below 15 billion in the next several years.  

[Bill Phil]

1 hour ago, DAL59 said:

Spacex has been valuated at 21 billion dollars- more than NASA's annual budget.  Although NASA is pretty much guaranteed to get at least 15 billion every year, Spacex launches are much cheaper per payload to orbit.     

Source? I can't seem to find that.

And what about NASA's value? Or should we say assets? 

[DAL59]

http://money.cnn.com/2017/07/27/technology/business/spacex-valuation-21-billion/index.html

https://arstechnica.com/science/2017/07/as-dominance-of-launch-market-looms-spacex-now-valued-at-21-billion/

[DDE]

15 hours ago, Bill Phil said:

And what about NASA's value? Or should we say assets? 

Yes, because NASA literally discards every bit of equipment after one year and totally doesn't have absurd fixed, non-material or mothballed assets, right?

[wumpus]

16 hours ago, Bill Phil said:

Source? I can't seem to find that.

And what about NASA's value? Or should we say assets? 

What boggles my mind is that Spacex still seems to be in "startup mode" and investing more money in itself than it makes in revenue.  You would think they would give that up and stop being the cheapest way to orbit, but no.  Presumably the "build it and they will come" model is critical to Spacex's long term model.  Remember that Spacex is private (and Elon Musk insists it will remain that way until it starts bringing colonists to Mars), so doesn't have to file most of the SEC records a public corporation would.

NASA certainly has some critical assets.  Huge campuses (campi?) in [now] expensive cities full of [fairly old] buildings.  A deep space network that would be extremely expensive to rebuild, even with Spacex launch prices.  All those ground RADAR and launch pads (and unique buildings such as the VAB).

But don't forget how many of those assets tend to depreciate rapidly.  Lots of computers.  Tape silos.  Even land [and air] vehicles (they had to retire the original vomit comet a decade or so ago).  And certainly some parts of NASA may consider some of its "assets" to have a negative cost, with Congress requiring upkeep of obsolete parts and pushing things like SLS.

What makes the Spacex NASA comparisons so compelling is the absolute absurdity of it.  But don't underestimate the absurdity of estimating value, NASA has a ton of assets left over from the Apollo budgets that simply are irreplaceable with modern budgets.

[DAL59]

Actually, Spacex has downsized its ITS, so it doesn't need to build a new VAB.  

[ModZero]

1. Other. US is becoming increasingly unstable, and SpaceX is practically limited by it. I also think that upstart countries like China and India have more motivation to do silly, prestige things like Mars missions. PR requirements of US can be satisfactorily met by launching empty cans on high suborbital trajectories once every five years.
2. 2030 or later. Mostly when it becomes easy enough that sending a basic, return mission becomes more of a question of "why not" ("because it's expensive", but maybe you want show off how much you can afford) than "why."
3. Hopefully neither. Or, "domes", because that's least permanent. Frankly, if we survive the next few decades in a shape allowing for flying something heavier than a kite, we'll probably grow up to the point where "terraforming" is considered an atrocity. Because it is one, it's a planetary equivalent of turning everything into a McDonalds and a parking lot. And "bioforming"? Hah, lol, nope, that's fantasy land.

EDIT: also, use the term "crewed," "manned" is anachronistic.

Edited September 21, 2017 by ModZero

[Helmetman]

I selected after 2045 and SpaceX will do it because Nasa never will.

Tell me I'm sour and that I got bad dreams and stuff, idc. I'm just being realistic. 

I also believe in having a settlement there first. Meaning one would launch a carefully devised base with necessary modules, carefully tested before any humans are send there. You should also not forget that if something goes wrong during the mission, you can kiss your ass another 2 years before another launch is commited. Even if everything, I say again, everything went A-OK one way I would still be pessimistic it would get done before 2030.

Elon's expectations on his projects are also salesman talks. It's very likely that if the guy says 10 years, that "20" is being screamed through his head.
And getting to 20 year project probably involves setting small time frames to get people to go overboard.

[Northstar1989]

On 9/16/2017 at 1:59 AM, Nibb31 said:

So basically, we should divert billions of money into a Mars landing project for your generation's entertainment ? Are you aware that you were preceded by thousands of generations that didn't see humans walking on Mars ? Are you aware that there will be more generations after you ? So what exactly makes you so special that you should get that gratification during your lifetime while others didn't ?

You confirm that there is no rush, that is just a generation's selfish desire for instant gratification.

Nibb, there is a massive opportunity cost to NOT going to Mars.

If we start a colonization effort just 2 years earlier, then at every point of that colony's development it will be 2 years further along.  You lose a MASSIVE amount of economic development over time just by a tiny delay.  We should be thinking of the future generations here, not our own, which is PRECISELY why we should get ceacking on colonizing Mars today- because that goal might take 100 years to accomplish from the time we initiate it, and every second counts for the future of the human species...

Just imagine the economic value of a fully-developed Mars with a population on the hundreds of millions in a *single second*.  THAT is why we must start trying to colonize Mars immediately- so we can get to that point as soon as possible...

 

Regards,

Northstar

Edited September 22, 2017 by Northstar1989

[Northstar1989]

On 9/19/2017 at 7:06 PM, DAL59 said:

Actually, Spacex has downsized its ITS, so it doesn't need to build a new VAB.  

Now if only Musk would implement some other cost-saving measures, like relying on Solar Electric propulsion to get to Mars... (if they're really planning on sending as many people as Elon claims, designing a state-of-the-art electric propulsion system and adding enormous solar panels to the ITS craft will pay for itself MANY times over...)

Of course if we assume that he's really going to send enough people to fill a few hundred ITS flights or more to Mars, developing Cycler Ships to carry people from Earth to Mars and sending the surface habitats ahead of the crew on a much slower trajectory a full transfer-window ahead also becomes a no-brainer...

Why accelerate your orbital and surface habitation modules to Mars on fast trajectories over and over when you can just accelerate your orbital habitats ONCE (and over the course of many months, with low g-forces on the Cycler Ship, at no risk of crew-loss, and a full transfer-window ahead of the crew with electric propulsion at that) and then re-use them over and over, and your surface habitats on super-slow (18 months with multiple gravity-assists) trajectories, unmanned and ahead of the crew?

Edited September 22, 2017 by Northstar1989

[KSK]

1 hour ago, Northstar1989 said:

Now if only Musk would implement some other cost-saving measures, like relying on Solar Electric propulsion to get to Mars... (if they're really planning on sending as many people as Elon claims, designing a state-of-the-art electric propulsion system and adding enormous solar panels to the ITS craft will pay for itself MANY times over...)

Of course if we assume that he's really going to send enough people to fill a few hundred ITS flights or more to Mars, developing Cycler Ships to carry people from Earth to Mars and sending the surface habitats ahead of the crew on a much slower trajectory a full transfer-window ahead also becomes a no-brainer...

Why accelerate your orbital and surface habitation modules to Mars on fast trajectories over and over when you can just accelerate your orbital habitats ONCE (and over the course of many months, with low g-forces on the Cycler Ship, at no risk of crew-loss, and a full transfer-window ahead of the crew with electric propulsion at that) and then re-use them over and over, and your surface habitats on super-slow (18 months with multiple gravity-assists) trajectories, unmanned and ahead of the crew?

Citation needed on your first point I would say. How do the costs of developing a state of the art electric propulsion system stack up against developing an ISRU refuelling system and getting it to Mars? The basic science behind either option is understood, the engineering details and costs, I have no idea about but if anyone cares to provide a link to any studies we could debate them.

As for the rest - you may be right. Cycler ships, slowboating infrastructure, solar electric propulsion and all the rest, may be the best way to get a lot of people to Mars. I just don't think it's the no-brainer option that you're advocating.

 

If I'm understanding the links on your other thread correctly, the Cycler ship mission profile would use a large, relatively heavy ship with adequate radiation shielding, possibly spin-based artificial gravity to support the colonists on the relatively long journey to Mars. Transport to and from the Cycler at either end of the journey is handled by lighter ships that don't need all the heavy life support gear that the Cycler does. Those lighter ships still have to match velocity with the Cycler at one end and lose that velocity at the other, so they're not exactly trivial to design, build and operate. Then you get into the whole debate of how best to get your crew off the Cycler and down to Mars. Reusable shuttle? Possibly but the logistics of operating and maintaining one out at Mars aren't simple. Limited use shuttle? Possibly but then you need to send a steady supply of them to Mars which to some extent offsets the advantages of your reusable Cycler. Disposable shuttle(s) (aka the MDV and MAV arrangement from The Martian)? Even more ships required, further offsetting the advantage of your reusable Cycler.

Also, looking at the Wikipedia link you sent, there are non-trivial tradeoffs in picking a good Cycler. You need to juggle crew journey time, vs frequency of journey, vs non-useful journey time (as in the original Aldrin cycler) where your ship is travelling way out beyond Mars orbit and back.

Compare all this to the ITS concept which takes a single ship to Mars surface and back relying on orbital refuelling in LEO and refueling at Mars. Not a remotely trivial thing to design build and operate either but it's a potential workhorse ship for getting everything to Mars on a more flexible timescale than the Cycler ship and/or slowboating colony infrastructure. Sure its maybe a bit over the top for getting infrastructure there but again - you're only using a single ship, rather than a flotilla of different vessels. 

OK, possibly two vessels - ITS does need tanker support to LEO. But at a pinch that can be achieved using existing SpaceX technology and infrastructure. They already have the infrastructure to get propellant to orbit (on-orbit refuelling yet to be proven) reasonably efficiently with Falcon 9 and (hopefully) in more useful quantities at a time with Falcon Heavy. 

It's all trade-offs and - until somebody starts trying to fly serious hardware to Mars - mostly speculative trade-offs at this point. All we can say is that either option is going to be expensive.

 

 

[ModZero]

8 hours ago, Northstar1989 said:

Nibb, there is a massive opportunity cost to NOT going to Mars.

Sorry, but what? There's little proven benefit to going to Mars, outside of prestige stuff. Meanwhile there a ton of opportunity lost by not spending the resources  - materials, people's time, money - on pretty much anything else. Opportunity cost is what Mars mission advocates routinely miss. Going to Mars misses other opportunities, like hiring your presumably highly qualified colonists in some actually productive jobs, like, say, teaching. Or manufacturing faucets. Still more productive.

8 hours ago, Northstar1989 said:

You lose a MASSIVE amount of economic development over time just by a tiny delay.

Huh? That doesn't matter. There's little benefit of this for us here, there's no global crisis this is going to prevent, if anything you're missing out on 2 years of sending rescue missions. From the colony perspective, it doesn't matter at all, because its development *starts* when the thing happens. It's an isolated economy anyway.

8 hours ago, Northstar1989 said:

Just imagine the economic value of a fully-developed Mars with a population on the hundreds of millions in a *single second*.

We can have great famines here on Earth, we don't need to go to Mars for that.

[tater]

There is no opportunity cost associated with not going to Mars with people that I can even imagine, since there is no plausible economic benefit of doing so, ever, as far as I can tell.

If there is any economic benefit in people living and working in space, I would expect that benefit to be realized in Earth orbit first. All human activity in space requires living within an entirely constructed environment, and it might as well be spun to 1g, and in orbit. How many people need to be there ever is pretty debatable, honestly, unless you start talking about adding more humans in space than fit on Earth, which is pretty far in the future, and not relevant to discussions that involve anyone now alive, or even their future grandchildren.

 

[p1t1o]

Sorry to gang up on you NorthStar, but im in a rather cynical space right now...

 

10 hours ago, Northstar1989 said:

If we start a colonization effort just 2 years earlier, then at every point of that colony's development it will be 2 years further along.

 

10 hours ago, Northstar1989 said:

You lose a MASSIVE amount of economic development over time just by a tiny delay.

You contradict yourself. You lose two years for a two year delay., there is no magnification of time.

10 hours ago, Northstar1989 said:

We should be thinking of the future generations here, not our own

Exactly why spending billions on another planet is a poor idea....at this point in time, with our current tech level and cash-based society....and myriad significant problems here at home begging for financial impetus, which would not be affected at all by advances in space exploration/colonisation. There are no cures or fast-growing cheap food sources waiting on Mars. No raw materials of any use to anyone except Martians. No society-changing technologies just waiting for a close look at Martian soil.

10 hours ago, Northstar1989 said:

because that goal might take 100 years to accomplish

Exactly. Delaying a 100year project for 100years will have little impact on its long-term benefit.

10 hours ago, Northstar1989 said:

Just imagine the economic value of a fully-developed Mars with a population on the hundreds of millions in a *single second*.  THAT is why we must start trying to colonize Mars immediately- so we can get to that point as soon as possible...

WAT

 

You do know that the entire population of a fully colonised Mars wont just be shipping crates of cash back to Earth to improve our lives right? Exactly what "economic value" are you referring to?

 

Space exploration is not a romantic adventure. It is only made possible by people being harshly, honestly realistic - diverging only to inject a healthy dose of pessimism - in terms of capabilities and difficulties. There is no room for sentiment, only cold, hard calculations.

And all calculations say we can create vastly more benefit here on Earth more with 10¹¹ dollars/pounds than we can on Mars. And that situation will remain until something Big changes. And I dont mean "someone invents a new high efficiency nuclear space drive." or "Rich entrepeneur draws up pictures of a new rocket."

 

As an illustration, when was America first discovered by Europeans? It was sometime around 1000AD by Vikings, at the latest. It took another 500 years before a meaningful expedition could be sent, and centuries after that before it was a self-sufficient country.

 

Do you think there would be ANY difference to history if the Vikings had set foot in America in 1050 or 1100AD instead?

 

This is where we are at, we are vikings setting sail in tiny wooden longboats and you are pushing for haste because you cant wait for ocean liners, you want to accelerate a millenia-long process so that it can be done a few decades earlier.

 

 

Edited September 22, 2017 by p1t1o
changed a 6 to a 5

[tater]

Any economic benefit of space (ignoring satellites to help us out here on Earth) would be predicated on resource extraction at some level. The need for infrastructure to achieve this would drive any need for humans to actually live in space (which with robotics improvements and teleoperation is less and less needed, anyway).

The obvious candidate for such extraction would in fact be asteroids and other near Earth objects that could be moved to the Earth-Moon region for extraction. Mars has no possible economic benefit, it's too far from what is now 100% of human economies to be useful, both in actual distance, and time. There is no intellectual work that can be done on Mars that could not be done on Earth, or near Earth, that's a non-starter. Honestly, the cost of developing Mars (all sunk with no chance of RoI on any timescale even measured in many generations) could be spent on developing a safe AGI system (artificial general intelligence) that would likely move the ball of technology development forward at a far brisker pace than will ever be possible with people. 

Mars it pitched by Musk as a solution to the existential threat of extinction events (natural or artificial) on Earth, not because it's economically viable in a historical, colonial sense. Developing the constellation of technologies required to colonize space (planets or orbital habitats) themselves actually largely mitigates the existential risk question without actually doing it, as then you can divert most threats, greatly decreasing the risk to humanity.

[DDE]

6 hours ago, tater said:

Any economic benefit of space (ignoring satellites to help us out here on Earth) would be predicated on resource extraction at some level.

With the likely caveat that the consumers have to be spaceborne.

Thus, there's only one way to jumpstart space settlement:

Spoiler

 

[G'th]

10 hours ago, p1t1o said:

And all calculations say we can create vastly more benefit here on Earth more with 10¹¹ dollars/pounds than we can on Mars.

You're right. We could use that money to blow up people in deserts or under oppressive dictatorships. 

I'll say it again. You can't use cost as an argument when so much of the world and the United States in particular wastes vastly more resources than the cost of an entire Mars program on designing new ways to kill people.

If we're going to waste hundreds of billions of dollars, we may as well waste it on Mars. Because its been proven time and time again we aren't going to see these billions spent where it really needs to be spent. 

 

[tater]

Government space budgets will cruise along where they are, so you do it within the existing framework, or you do it outside of that framework.

[PakledHostage]

I am wondering how long it will be before more posts get deleted from this thread... because apparently it is verboten to discuss whether manned spaceflight makes sense in a thread about manned missions to Mars.

[Northstar1989]

22 hours ago, KSK said:

Citation needed on your first point I would say. How do the costs of developing a state of the art electric propulsion system stack up against developing an ISRU refuelling system and getting it to Mars? The basic science behind either option is understood, the engineering details and costs, I have no idea about but if anyone cares to provide a link to any studies we could debate them.

Developing better electric propulsion is a one-time cost.  Being able to launch fewer refueling missions for each ITSy, and thus able to launch more crew/cargo with the same number of launch stages in rotation (thus requiring fewer total launch stages be built, or allowing for a more rapid timetable on getting crew/cargo to Mars- allowing SpaceX to rake in revenues from sale of tickets to Mars faster, and pay off their loans for developing the ITS sooner) is a permanent economic benefit.  As is the value of the intellectual property- which can be licensed out to NASA (for their interplanetary probes) and perhaps eventually other space sector startups, such as those looking to pursue asteroid-mining...

If SpaceX Doesn't pursue better electric propulsion technology, eventually some other company will (because NASA has proven they're never going to be cost-effective or at all rapid in their electric propulsion research), and chances are good SpaceX will end up paying whoever develops it to use it on their ITS, missing out on the opportunity to own the relevant patents forever... (because if it's cheaper to pay licensing fees for cutting-edge electric propulsion developed by somebody else than to use chemical rockets, why WOULDN'T they do it?)

ISRU infrastructure is the same thing- a one time cost for a permanent cost benefit.  You must remember, SpaceX doesn't plan to just send one flag-and-footprints mission to Mars and be done with it- they plan to send rockets there for DECADES or even generations of time, and slowly build a permanent colony there...

Over so many launches (over 1000 launches over 60+ years), the costs of electric propulsion or ISRU amortize to a negligible cost pre-mission.  If they can raise the money to research them, they should.  It doesn't take a published study to prove this to you, and indeed it's highly likely nobody has ever published on the topic in the specific context of SpaceX's mission-plan (there ARE studies that look at whether the costs make sense when you amortized them over a single one-off NASA flag-and-footprints mission, but that's nit what we're talking here...)  So.e simple napkin-math should be more than enough to prove this to you...

 

Alright, so let's say, first of all that it would cost $10 Billion in R&D money for SpaceX to develop an ITSy with chemical propulsion...

And let's say that a cutting-edge electric propulsion system capable of handling large power-inputs (such as from a massive solar array 10x the size of what they already have planned) and operating at high efficiency under those conditions (this would probably mean a plasma thruster- plasma thrusters tend to scale well to high power-levels) enabling a 1-month burn time to reach a Mars transfer-orbit would cost an additional $2 billion to develop.

Now, let's say the cost of BUILDING each ITSy were, say $70 million (not accounting for any associated R&D costs) with chemical propulsion, capacity for 40 passengers (for the downsized, 9-meter ITSy), a 5-month Mars journey, and the ability to re-use the launch stage 40 times and the upper stage 10 times... (once every 2 years)

Adding electric propulsion to that upper stage for its Mars-transfer could easily allow for an increase of the payload to 50 people for each launch (because you can upside the payload, add an electric thruster and solar panel system, and *STILL* reduce the mass of everything above the Launch Stage with all the propellant you save for the transfer-trajectory as electric thrusters have 10-1000x the ISP of chemical rockets...), and the ability to re-use the upper stage two additional times due to not needing to fire the chemical rockets as many times each mission (for the Mars-transfer or the Earth-return, reducing the number of major chemical maneuvers each mission from a minimum of 7, to a minimum of 5).

Now let's say adding electric thrusters and propellants (likely Argon or Nitrogen, for their lower ISP and higher Thrust than Xenon), extra solar panels, extra crew-space and radiation-shielding (both for the larger crew, and the additional month spent in orbit to initiate the Mars transfer: you don't want crew getting over-stressed or over-irradiated) and extra crew provisions added up to an additional $20 million per mission, for a total cost now of $90 million to build and equip each new ITSy (this is NOT including any R&D costs...)

Now, if SpaceX were going to build 120 ITSy craft and send just 40,000 people to Mars over the first 45 years (with the first 15 years being for R&D, the next 5 years for building the first ITSy craft, and 20% of possible launches with these 120 craft either not occurring during this timeframe or being cargo-only launches to get their Mars base started) in their original plan, then with a 25% increase in cargo capacity and the ability to re-use craft 2 additional times (all due to electric propulsion) they might be able to send 50,400 to Mars with 120 craft in 45 years with the same assumptions about mission-cadence (except now, 30% of possible launches either don't occur or carry cargo during this timeframe, due mostly to the longer lifespan of each ITSy).

So, when you amortize the R&D costs over the number of passengers sent, they decrease from $250,000 per passenger to $238,095 per passenger.  Additionally, amortized construction-costs for each ITSy increase from $210,000 per passenger, to $214,286 per passenger- but this is due to the higher percentage of launches that do not occur during this timeframe: the amortized construction costs per-passenger for an ITSy able to perform ALL its 10-12 lifetime launches, with 85% of them being for passengers become $205,882 per-passenger for an all-chemical ITSy, vs. $176,471 per passenger with an ITSy with electric thrusters for its Mars-transfer.

With these assumptions, the TOTAL COST PER PASSENGER when accounting for construction and R&D costs (Note: fixed costs associated with the # of launches, such as ground crew cost, also DECREASE by 4% relative to the number of passengers for the lifetime costs of an electric-assisted ITSy, as it launches 20% more, but carries 25% more passenger per launch...) DECREASE from $460,000 per passenger with an all-chemical ITSy to $452,381 per passenger with an electric-assisted ITSy over this timeframe- with more aggregate lifetime-launches remaining for the ITSy's that have not yet been retired at the end of this timeframe, and a lower marginal cost of $176,471 rather than $205,882 per passenger for additional ITSy's constructed after this timeframe (assuming, once again, 15% of passenger-capacity is instead used for cargo in future missions)

And before you suggest that it's not fair to compare the two approaches with different #'s of passengers, and the chemical ITSy should also be used to transport 50,400 passengers in this timeframe- it would cost $2.17 Billion to build the 31 additional all-chemical ITSy's necessary to do that- more than the additional R&D just to develop electric propulsion (sticking with the same ratio of 15% of all launches being used for cargo that has been adhered to all along in this analysis to determine the # of additional chemical ITSy's required)- meaning that is that case, the electric propulsion would have paid for itself as soon as the fleet of ITSy's was completed, rather than needing to rely on transporting more passengers with the same-sized fleet over time to pay for itself...

 

SUMMARY:

So, given some conservative assumptions about costs that are likely less favorable to incorporating electric propulsion than reality, in a period of 45 years (with no ITSy launches during the first 20 years), with 120 ITSy's built and flown during that period and 40k-50.4k passengers, utilizing electric propulsion on ITSy's manages to not only pay for its research-costs, but increase the profit-margins for each launch by $7,619 per passenger, with even larger cost-savings of more than $29,000 per passenger further in the future once all R&D costs have been paid for...

Edited September 23, 2017 by Northstar1989

[Northstar1989]

On 9/22/2017 at 2:35 AM, KSK said:

As for the rest - you may be right. Cycler ships, slowboating infrastructure, solar electric propulsion and all the rest, may be the best way to get a lot of people to Mars. I just don't think it's the no-brainer option that you're advocating.

Slowboating infrastructure is ABSOLUTELY a no-brainer.  It's so obvious that even NASA adopted it for their Constellation mission plan (and later for the Design Reference Missions), despite their relative conservatism in adopting new ideas about how to travel space (it took them until the 90's to fully embrace the usefulness of the Interplanetary Transport Network in the Earth-Moon-Sun system and use it to collect solar wind samples at low cost, for crying out loud...)  With a slower transfer-trajectory, you can drastically decrease your Delta-V requirements and send the same exact infrastructure in fewer or smaller launches- with no real associated costs to doing so.  Infrastructure doesn't care if it takes 12-18 months to reach Mars, only humans do...

The rest will take some time to explain/prove as to why it's so clearly superior, though.  The reasons are a little complicated...

Edited September 23, 2017 by Northstar1989

[Northstar1989]

23 hours ago, KSK said:

If I'm understanding the links on your other thread correctly, the Cycler ship mission profile would use a large, relatively heavy ship with adequate radiation shielding, possibly spin-based artificial gravity to support the colonists on the relatively long journey to Mars. Transport to and from the Cycler at either end of the journey is handled by lighter ships that don't need all the heavy life support gear that the Cycler does. Those lighter ships still have to match velocity with the Cycler at one end and lose that velocity at the other, so they're not exactly trivial to design, build and operate. Then you get into the whole debate of how best to get your crew off the Cycler and down to Mars. Reusable shuttle? Possibly but the logistics of operating and maintaining one out at Mars aren't simple. Limited use shuttle? Possibly but then you need to send a steady supply of them to Mars which to some extent offsets the advantages of your reusable Cycler. Disposable shuttle(s) (aka the MDV and MAV arrangement from The Martian)? Even more ships required, further offsetting the advantage of your reusable Cycler.

Unfortunately you don't understand the entire idea correctly- your difficulties in understanding evident in this paragraph mainly center around the "shuttles" as you call them (by which I assume you mean dedicated landers).

Separate landing-craft simply aren't required in an Aldrin Cycler arrangement. They can prove beneficial, if you can amortize their R&D costs over enough flights, but they are not at all required to complete the mission successfully.

Assuming, like Elon Musk did, that there is no reason a craft capable of bridging the Delta-V gap between Earth and Mars can't also re-enter and descend to the surface, there is also no reason your Interceptor Ships- the craft that ferry the crew from Low Earth Orbit to the outbound Mars Cycler, and then from the outbound Mars Cycler to Low Mars Orbit- can't make the descent and land/takeoff from Mars as well.

The Delta-V needed to rendezvous with an Aldrin Cycler, and then to capture into Mars Orbit and land on the red planet is in fact nearly identical (differing only in the small amounts of Delta-V needed by the RCS system for docking and undocking with the Aldrin Cycler) to the Delta-V needed to make a 5-month journey to Mars and then land on it.

In fact, an Aldrin Cycler Orbit is really just a 5-month transfer journey where the orbital habitat doesn't enter Mars' atmosphere, and instead just keeps on going in its orbital trajectory around the Sun, with a slight gravity-assist from Mars.  Think of it as what would happen if the Mars transfer-burn were the correct length but a little off in starting-time, or the mission were just to make a flyby of Mars rather than land...

Don't get me wrong- a fleet of dedicated landers CAN be used to ferry the crew from Low Mars Orbit to the Martian surface, and in fact would be preferable for economic and safety reasons (if the Interceptor Ship doesn't have to also land on Mars and take off from it again, it can have smaller fuel tanks, no landing legs, lighter heat-shielding, and be designed in shapes that wouldn't make for good landing-craft, but are fine for aerobraking and docking; and if you have a dedicated lander it can be much smaller, only ferrying 2-3 people to the surface of Mars at a time, so that it has a lower Ballistic Coefficient, and doesn't risk the entire crew of the Interceptor Ship dying if a single thermal tile, or a single critical engine part, fails during re-entry or landing...), but landers are not NECESSARY any more than they are for Musk's base-plan with an ITSy that, like the Interceptor Ship, makes the whole Mars journey and then lands on the Martian surface, before returning to Earth.

The Interceptor Ship is basically just an ITSy without the capability for sustaining humans for a 5-month journey.  Other than that it's basically the same craft, with the sane capabilities.

The MAIN ADVANTAGE of a Cycler Ship mission architecture is that you only need to accelerate your orbital Habitat on the Delta-V equivalent of a 5-month Mars journey (establishing a Cycler Orbit or making a transfer-burn for a 5-month journey to Mars require *exactly* the same amount of Delta-V: and indeed the "short" leg of an Aldrin Cycler's Earth-Mars cycle takes 5 months to complete.  It is essentially the same orbit with a slightly more distant Mars-approach...) and you can do so ahead of time, a full transfer-window or more before the crew ever leaves Mars, using electric thrusters and however long you like (limited only by the shifting phase between Earth and Mars that give the transfer-window a limited duration).

Not only do you only have to accelerate your orbital habitat ONCE, you can in fact take 27 months to do it if you want (assuming by the end of this you can end up in the correct orbit), and use nothing but electric thrusters to make the change from Low Earth Orbit to an Aldrin Cycler Orbit...  The crew can board the Mars Cycler 27 months after launch, when it swings by Earth during the next transfer-window.

The Interceptor Ship, to re-iterate, can double as your Mars lander.

Edited September 23, 2017 by Northstar1989

[Northstar1989]

23 hours ago, KSK said:

Also, looking at the Wikipedia link you sent, there are non-trivial tradeoffs in picking a good Cycler. You need to juggle crew journey time, vs frequency of journey, vs non-useful journey time (as in the original Aldrin cycler) where your ship is travelling way out beyond Mars orbit and back.

The Wikipedia link lists a number of ALTERNATIVE Cycler designs to the Aldrin Cycler.  Just because there are msny alternatives doesn't mean one option isn't the stand-out best option among them all.

When you have trade-offs, that doesn't mean both options are equally good- often when you make a tradeoff you are trading one thing that is not very valuable (in this case frequency of use, non-useful journey time, *AND* the fuel costs to establish the Cycler Orbit in the first place) for something that is MASSIVELY more valuable (the ability to re-use the Cycler ever Earth-Mars transfer window, and intercept the Cycler with an Interceptor Ship for a fraction the Delta-V cost of any of the other Cycler orbits).

I'm pretty sure the only reason Wikipedia even lists the other orbits at all despite how obviously inferior they are for reaching Mars is to preserve the knowledge, give credit to the people who discovered the other Cycler orbits, and because many of the other Cycler orbits were discovered BEFORE the Aldrin Cycler Orbit... (so Buzz Alsrin did not truly discover the concept of a Mars Cycler- only the first, and perhaps only, truly useful Earth-Mars Cycler Orbit...)

Also, some of the other orbits could one day be more useful than the Aldrin Cycler for mining the Mars-Jupiter asteroid belt...(but are CLEARLY inferior for reaching Mars from Earth...)

Edited September 23, 2017 by Northstar1989