Munar Cycler In Kerbal Space Program

[@unvergebeneid]

So what you're saying is that Buzz Aldrin on his trip to the moon was like "This is all nice and all, but... where is the bar?"

[@Garryck-1]

I wish I could thumbs up this more than once!

[@TheeGrumpy]

For the record, Aldrin had a sip of wine in his pocket, so he came prepared.

[@nicosmind3]

So what youre saying is were all lobsters?

[@unvergebeneid]

@ayy lmao I hope you are aware that my original comment was me dabbling in this "humor" thing you hoomons seem so fond about, right?

[@trisymphony]

Buzz needed to get his buzz on

[@rtrThanos]

So I was in the bathroom at work taking a leak and, before I could engage failsafes that filter what comes out of my brain and exits my mouth, I loudly blurted out “Hullo, it’s Scott Manly here.” I felt pretty stupid at that point because someone was in a stall taking a dump and heard it. So I zipped up, washed my hands, and was exiting the bathroom when I heard the person in the stall say “...fly safe!”

[@dw300]

I want to believe!

[@BrainforBrains]

amazing

[@anonymous_bacon2383]

True broskies

[@John-mf6ky]

Lol!

[@Fried_11901]

And then you all got ice cream

[@JPFanBoy2]

That sign off was so inspiring. "Things seem harder than they actually are," said by one already so accomplished. Keep pushing forward!

[@gallopinggoose6891]

Sprinkles Sundae Due to that. I think I'll go make my own liquid rocket😀

[@wilsonflores4558]

P

[@Denied1213]

Cyclers feel more feasible today since the ISS has driven modular tech a long way and the introduction of relatively efficient solar and ion engines, some of the neat new autopilots could even handle the course corrections in real time, minimizing the need for emergency burns.

[@carlsagan1377]

Hahahahahaha, this takes me back. So, two summers ago, I got to go to Kennedy Space Center while Buzz Aldrin was there to sign his autobiography. I had read his autobiography a few weeks prior, and I was very interested in the cycles concept. So I did some research, made some KSP models, etcetera. So by the time I got to meet Buzz, I was fairly familiar with the concept. I got to meet him for no more than ten seconds. I commented, “Dr. Aldrin, your work on the Mars Cycler is amazing,” to which he responded, “Yeah, I know.”

[@ryconroleplays]

I'd love to see a Duna cycler like the Mars cyclers in Semper Mars. Two running simultaneously

[@44kainne]

www.reddit.com/r/KerbalSpaceProgram/comments/610pts/duna_cycler_orbit/ We learned how to do this in my astronautics class at university.

[@Rickenbacker69]

Amazing how much easier it is to grasp the cycler concept when you see it demonstrated in KSP. So basically, you're trading slightly more DeltaV for a LOT more comfort :).

[@trainman222y78]

Love it! Using the USI LS mod and I thought it was unrealistic that you can gain a bunch of habitat time just by docking with a space station for a moment, but was preplexed thinking about how you could realistically take your habitat with you everywhere you go. This totally works for that mod and real-life issue!

[@Garryck-1]

Thanks.. I use USI LS too.. and this is a perfect solution, as you said.. I plan on sticking a few years of food on Kerbin-Mun and Kerbin-Minmus cyclers, so that I can send a bunch of missions with only emergency supplies on board.

[@themaster402]

Hey Scott. Longtime fan and current developer of Astronomer's Visual Pack here. As of version 3.63, there are no experience-ruining bugs I'm aware of in AVP; many call the lightning flashes on various atmospheric planets "bugs". It is quite discouraging when people label this product of more than a year of work "buggy" or "broken"... I hope you're enjoying it as much as I enjoyed developing it for 1.3! Thanks, and another great video :)

[@Archgeek0]

Indeed, those flashes are clearly just a glitch. An awesome glitch whose mechanism should be isolated and corralled into a proper feature. XD

[@aqib.a.a7513]

aahhh so you are the mastermind behind that mod i use... well done mate its amazing

[@workman88]

You do some great work with the mod my friend, keep up the good work.

[@ivy_47]

What the heck is wrong with Kerbin at 9:08 though? Way too blue.

[@cheddar2648]

busted! lol

[@eat_ze_bugs]

I swear I'm gonna start my own space agency soon, I can't handle KSP lag anymore.

[@jakubk.584]

This is the way.

[@Dead1Eagle6]

I'm probably not the only one that would like to see the Kerbin/Duna Cycler...

[@EbonRogue]

such an awesome concept. you can essentially gut out oxygen systems, food, toilets, crew quarters, and just about every crew accommodation besides a chair to sit in. this save TONS from a ground launch crewed rocket. IMO, this type of design will be near mandatory for future manned space missions.

[@johncochran8497]

Not quite. You always have to accelerate all of the required consumables in order to rendezvous with the cycler (remember, the point of the cycler is to NOT spend all that delta V accelerating and decelerating on infrastructure). But your shuttles can be stripped down of most creature comforts since the cycler can have nice large accommodations to make the trip in comfort. But as said, the actual consumables will have to be accelerated to match the cycler. So bulk oxygen, water, food, fuel, etc all have to be accelerated to match.

[@Quantiad]

The Uphoff/Crouch Lunar Cycler is referenced in Andy Weir's new book, Artemis.

[@maddridder8741]

check yo staging... never gets old

[@d00kiebird]

I like how his rocket did an atomic booty drop and wrecked the launchpad before zooming off.

[@dionemoolman]

I’ve just learned about cyclers and I now want to make stories about them. The idea of floating cities drifting between planets sounds so cool. It reminds me of Freedom Ship, a giant planned ship that would never stop and continuously go round the world, where people would arrive by plane or boat.

[@zact9941]

Awesome video. I read about the cycler concept in Dr. Aldrin's book: "Mission To Mars"

[@you_just]

_Permanence_ by Karl Schroeder is a great sci-fi book that includes cyclers as a major plot device.

[@alxo82]

I wasn't aware of this concept. It seems that it could make more sense than gateway if you want to explore lunar environment. Lots of time through the van allen belts though

[@edtun829]

"Artemis" by Endy Weir? There was a spacecraft like this there (but, of course, on the trajectory in 3 body's system)

[@sunov]

I was going to mention this too

[@wolfbyte3171]

Meatship. I forget how many there were, and what their names were.

[@Rickenbacker69]

"Encounter with Tiber" was the first time it was mentioned in fiction, I think. And since Buzz Aldrin was the co-author, that's probably not very surprising :).

[@notablegoat]

edtun They have Lunar cycler's in Ian McDonald's Luna series. Between McDonald's moon books and Weir's Artemis, I prefer the former

[@planefan082]

Yes! I love Artemis. If something like Artemis was built in real life that would be incredible...wait a minute, idea. MAKE ARTEMIS IN KSP

[@taiming71]

That spinning section would be a great place to go if you wanted to empty your stomach. That being said i think that a cycler would be a far better second major station than some thing like the Lunar gate way it could be used to return fuel to earth orbit and people and supplies to the moon.

[@Garryck-1]

Man.. I so wanna do this.. I Have a long series of Munar missions coming up, and for Minmus as well. This would work well as a solution for providing life-support. Instead of having to lug large quantities of supplies for each mission, I can just stick stick a few years worth of supplies on a cycler station, and mission vessels would only need a small emergency supply. Way to go, Buzz! A Moon-Earth cycler could include it's own greenhouses, which could then provide an ongoing supply of fresh food to crews on Lunar missions.

[@mattboyles6328]

Duna Cyclers! I think 42 should be enough, since it is the answer to everything you know...

[@foxfax2]

They've found out how many proteins there are in a cell, guess how many millions it is?

[@vpheonix]

If you had 2 ships plus the station, this might save cost. The launch vehicle would take off from Kerbin and rendezvous with the station. All the passengers would then transfer to the landing ship, which was already docked with the station, to land on the Mun. The lander would refuel on the Mun then take off and rendezvous back with the station, transfer the passengers back to the original ship which would then return to Kerbin. This would save having to launch all the equipment and fuel for landing from Kerbin and save cost. The landing ship could also be reused for multiple missions.

[@stephenselman9228]

First comment, long-time fan: Build the multiple Duna cyclers, and launch those things! THAT is a challenge worthy of you.

[@faulxeve6590]

From some of these early comments, it sounds like you need to emphasize the mass multiplying benefit of this type of space infrastructure. I.e. a cycler turns a cramped 3 person capsule to Mars into a luxury cruse line to Mars. Maybe when you do your Kerbin/Duna cycler, you should make it space-station sized to really emphasize the difference?

[@faulxeve6590]

You could also show the crew time spent in the various conditions, and compare the difference a cycler makes to driving cross country in a 4 door sedan on the highway vs riding on a train with sleeper cars and dining cars.

[@erikmnelson77]

Thanks for the video! I'd never heard of a cycler, but it makes perfect sense. A Kerbin/Duna cycler video would be AMAZING... just adding to the chorus :)

[@frankgulla2335]

Nice job explaining the situation. Thanks.

[@josepholiveira2873]

I'm but a humble humanities major, and I'm trying to wrap my mind around why the cycler system doesn't save on fuel. I think I more or less have it: because the 'taxi' spacecraft would have to accelerate to match the orbit of the cycler, yes? So it's basically exerting the same thrust as if it were getting into a regular Munar orbit, because it is--it just happens to be latching onto another spaceship as part of the process. This does, of course, raise the question of utility in a real-life scenario. It seems like there may not be much use for a lunar cycler, if all you get is a bit more free space (and, admittedly, radiation shielding) on the trip over, since the trip to the Moon is relatively short. It doesn't sound like the cyclers would necessarily be useful for hauling freight via robots, either. But the 'amenities' of the cycler (a larger craft for radiation shielding and the ability to have a rotating habitation module) may make a crewed trip to Mars survivable. Are there other major use-cases for a cycler in theoretical space exploration (crewed or otherwise)?

[@mrman5517]

i can see one problem with the Cycler straight away: what happens if you miss the rendezvous? for a standard LKO rendezvous you have plenty of opportunity for phasing orbits, lots of time for a gentle approach, and if everything goes south you have a relatively low-speed reentry. for a Cycler rendezvous you get one shot, and if you miss you are committed to a long elliptical orbit (hope you brought snacks!) and an eventual risky high speed-reentry

[@Garryck-1]

Good point.. something I'll have to think about.. Maybe pre-deploy one or two well-supplied emergency shelters (with ISRU) down on the surface, to allow a crew to winter over and refuel while they await the next window? Landers would need to be overbuilt enough that they were capable of a cycler rendezvous attempt *and* an emergency abort to the nearest shelter.

[@RealLuckless]

I've always liked the idea of the high-mass delta-v-sink cycler with solar/laser sails/ion drives, and launch/tether transfer systems. The idea being that you invest the energy into building up a high enough mass for your cycler-city that transfer crafts to and from become a minimal factor on momentum. Transfer craft make a low energy approach, where they tether and are dragged along to make up the change in delta-v to match the cycler orbit. Then while en route, the cycler will slowly make up the difference in energy change till it uses a long linear drive rail to transfer payload into its new orbit for reasonable areobraking.

[@jackvernian7779]

that is actually quite interesting but It would require some enormous ion drivers/laser sails, and that makes me wonder if it is a tackle-able engineering challenge at all.

[@RealLuckless]

Far from a trivial project, but the US interstate highway wasn't a trivial engineering problem either. For things like that to really be practical you're probably going to be doing orbital mining and fabrication for the bulk of such a thing, (And using likely relatively high thrust 'tugs' to bring small chunks of the project onto the cycle's orbit path over time) which renders much of your 'costs' for such things down to time rather than money.

[@SeaTacDelta]

Thanks for the video Scott. Always informative and entertaining. I'd don't comment often but you asked for clicks for the Duna cycler and I think that'd be great to see.

[@Variety_Pack]

Super cool!! Try Alt+F12'ing a Vacation Duna Cycler Hotel chain and fire off a series of Kerbals to go on the trip of a lifetime! Maybe I'll try it, too.

[@Chantillian]

Just one range violation to scrub a launch and now you gotta wait for the cycler to come around again.

[@hazezero689]

So its akin to driving your cheap non-luxury car to the harbor, jumping on a nice luxary cruise-liner for a 3 month long cruise out to Mars. Its pretty brilliant imo

[@ZerofeverOfficial]

"Check yo Staging" cracked me up, im still laughing.

[@TechyBen]

Wow. I mistakenly thought a cycler used a free return or Hoffman trajectory. Cool to see how it really works (pictures on Wiki' always fail to actual animations and voiceovers!).

[@dakel20]

Yep, I wanna see multiple Aldrin cyclers in KSP. Could you please do it?

[@stevebenz9741]

Great stuff! I wonder if one could, instead of cheating to get your craft in orbit, cheat to get a contract that asks you to put a satellite in the orbit... Hrm. Perhaps not, as the precision the contract will settle for probably isn't precise enough. Udunno. Maybe that's editable too? Certainly you could use inspection of the save file or maybe Kerbal Engineer would give you enough feedback to tweak the orbit perfectly...

[@captt2779]

Is anyone else's audio messed up? Mine was sped up for a while then sent me back to the start of the video and was completely normal.

[@therealjoshuacaleb4873]

HA! learned something new today! I didn't know about resonances in planetary bodies.

[@perrymitchell7118]

You're still the man Scott!

[@TarisRedwing]

That was cool. I'd like to see a Duna Cycler eventually.

[@donsample1002]

Have you read Artemis, by Andy Weir? He uses a cycler for people traveling to and from the moon, complete with a centrifuge that varies in speed to allow people to gradually adapt between lunar and earth gravity during the trip.

[@Antihistamin82]

Too hard? Too precise? That doesn't sound like the Scott Manley we have come to know and love! SSO version incoming? How about monopropellant only? No capsule challenge? We believe in you!

[@andrewhill5859]

Scott Love your Vids!

[@SciFiFactory]

Try using as litte time as possible to go around Kerbin! An active orbit, so to speak. ^^ Also thanks for the video. I didn't know about cyclers. Super interesting!

[@maxtdemsky4031]

Hey Scott if you could, I would love to see a Cycler station (probably more than 3) from Kerbin to Duna! Love ur explanations!!!!! Also if you could, I have been having trouble rendezvousing with my other space crafts and how to optimize deltaV, could you do a video explaining these in KSP thanks!

[@Forlorn79]

Rather than a cycler, SpaceX is making the Big Falcon Rocket!

[@hologrampizza5432]

Perhaps as a stepping stone you could create a cycler between the Joolian moons. Once you get it figured out, you could even move on to cyclers with life support mods or RO cyclers.

[@infectedbandaid3173]

Id love to see an updated tutorial guide on progression past minmus alot of guides stop there and alot of kerbals are missing out on everything beyond minmus.

[@Stoney3K]

One of the biggest advantage of using a cycler is that you can take advantage of ISRU and use the cycler as a fuel refinery. For example, in an Earth-Mars cycler, you could carry the raw materials up and use the solar arrays to refine the fuel. Craft that dock from Earth can then use the cycler as a refueling site. The best known example is the Hermes craft featured in The Martian, which was based on an actual concept using an Earth-Mars cycler. How did you build the circular section in the VAB? Because the VAB does not permit any nodes to be connected cyclically.

[@VelociraptorsOfSkyrim]

Stoney3K Lots of tweaking will the rotate tool in the VAB.

[@Stoney3K]

That will allow you to build a circle but you'd never be able to close the loop, and you're left with two nodes that overlap but never attach to each other.

[@Farisrulez]

Pretty sure the circular module is a mod. I've seen it inflate and rotate in other KSP video. Probably not Scott Manley's video, I forgot

[@VelociraptorsOfSkyrim]

Farisrulez There are rotating ring mods, but the one in this video appears to be made from Mrk 1 and Mrk 2 passenger parts.

[@VelociraptorsOfSkyrim]

Stoney3K That doesn't matter with the physics of the game, it would still rotate as if it was connected.

[@70lulatsch]

Please try the Kerbin - Duna cycler! It would be really interesting how that works in detail.

[@iainclark8695]

Loved this video.

[@EnderMalcolm]

So in the last bit when you started talking about stuff, my mind just went blank>.< Semi-major thingy and Aldrin Cycler with a 7 something integer or whatever lol^^ Now I remember why I'm not a rocket scientist

[@davidcampos1463]

Fascinating.

[@l00klikea]

could you make a Video exploring the Possibilities of a Earth - Mars Cycler, and resacrch that was done about it, seems extremly interesting-

[@LoneStarr1979]

Hello Scott, nicely explained (as always...) thing. To make this become somewhat more useful / meaningful in KSP, wouldn't it be a good Idea to attach a Lander to the station? So you end up flying to the station with just the transfer shuttle, land on the moon with the station lander and back vice versa. Thus, you would only need to bring the fuel for the landing Operation to the station, but not the whole lander. Also, the lander would not need re-entry abilitys... Maybe this would make sense even in this weird scenario known as "real life" ...

[@Garryck-1]

That's exactly the way I intend to use it for an upcoming series of Mun & Minmus missions. I use USI Life Support, so this will let me keep a couple of years of supplies on the station, while the shuttle carries no supplies, and the lander just emergency supplies.

[@calculon000]

Did you realize you put windows on the floor and ceiling of the ring section, instead of the walls?

[@starchives2365]

I know when I cross the void between worlds I want a glass floor

[@ErinyesOfficial]

Multiple Kerbin/Duna cyclers!

[@rtleitao78]

Here was i thinking i could easily pull a duna cycler off. And Scott Manley just comes and says that is too hard for him. I can barely put my head around the maths to do it. I'll still try it though.

[@pewpew1645]

Nothing is too difficult for Scott Manley when it comes to Kerbal Space Program! Meanwhile I struggle to land on Duna.

[@cokeforever]

Luke Gonzalez the easiest body to land on - use parachutes

[@FourKelvin]

In KSP this is unfortuntely useless, since you don't need supplies. And if you can dock with the cycler, you might aswell be able to return to kerbin

[@prdoyle]

The windows in the spinning section would be in the floor and ceiling. Shouldn't they be on the walls?

[@iamzid]

The only problem that I have with a rotating ring station is the sort of seal that would be used on the bearing to prevent air loss between the rotating and non rotating sections. Wouldn't it be much MUCH safer to simply rotate the entire station? This would also prevent any liquid fuel from floating about in the tanks.

[@johncochran8497]

There's no need to have an air tight bearing between the rotating and non-rotating portions of the station. Just have the non-rotating portion in vacuum and have the airlocks on the rotating portion of the station. And you want that non-rotating porting to make docking easier and safer.

[@enoughofyourkoicarp]

Now that sounds like a legal defense, "No, you honour, I did not run the cyclist off of the road, I performed an extremely aggressive rendezvous maneuver", I don't know that it would hold up in court but ok. O.o

[@vvoid8416]

Pretty sure the "spinny wheel thing" isn't there for fun but because the concept uses centrifugal force to simulate gravity.

[@QuasistellarNymphomaniac]

This is a brilliant idea. Sadly, nobody is willing to spend anything on space infrastructure today. Well, at least we have SpaceX.

[@colin8561]

well it doesnt take a lot of research to figure out that this is insanely wrong....

[@QuasistellarNymphomaniac]

Wikipedia: The Space Review estimated in 2010 the cost of Apollo from 1959 to 1973 as $20.4 billion, or $109 billion in 2010 dollars. ($120 billion in 2016 dollars[2])[133] Gravity budget, also from Wiki: $100 million I'm actually surprised how cheap those Saturn V's were, the ISS was also around $100 billion (mainly because SpaceShuttle launches were insanely expensive, including refurbishment but without payload around $ 1.5 billion per launch)

[@phantomflows0]

honestly, just watch there is a high chance Elon Musk will try to get this to work.

[@renealbrechtsen9743]

Elon Musk is trying to get this to work. His end goal is getting people to Mars.

[@nathanaelvetters2684]

I've never heard anything from SpaceX about these but it sounds neat. Maybe after they have a solid Mars colony established they'll use these to allow a greater range of people to go. I always thought the BFR might not be such a great place to be stuck in with 100 people in 0g for 6 months.

[@Digephil]

What about a cycler between two jovian moons? It'd be fun to see a constellation of cyclers going between Io, Europa and Ganymede, which are all in an orbital resonance with one another.

[@TheKiroshi]

Than you'd need people specifically on/around those moons.. But I love the idea of this, Sci-Fi stories could use this an an analog for a luxury yatche trip,

[@re11wind]

Here i was expecting a kerbal to cycle along the rotating habitat or something impressive along those lines, not the space equivalent of a ferry :( j/k :p Hopefully sometime in the future space ferries become just as safe and mundane as going to work in your car. Maybe in a thousand years.

[@jebediah246]

nice video. I saw your basketball video yesterday and I have a challenge. Kerbal darts. make a dart which hits a target. good luck

[@alanrobbie4851]

great idea!

[@millamulisha]

I've been waiting for someone to do this in KSP. Haha.

[@davidk1308]

Please do A Duna/Kerbin Cycler, that would be awesome. And could you talk about what you would put on one in real life?

[@kekrre]

I’m not certain that the cycler has any real utility. While it provides living space, it obviously requires quite a bit of heavy lifting to build. Since it doesn’t save any delta-V, why not just build a fleet of smaller non-atmospheric craft (like Hermes in The Martian) that decelerate and orbit at each planet? There are three cases I can see the cycler being used: bulk cargo, regular cargo, and passengers. In the bulk cargo case, why not just launch the stripped down cargo by itself? No need for a habitation ring. Worst case, it can have no engines and a craft at Mars has to intercept and capture the payload (kind of the opposite of how the cycler works). For regular cargo, again, simpler just to go direct, and you save on delta-v. You can just build the appropriately-sized ship rather than having your appropriately-sized ship dock to a white elephant cycler station. Plus only passengers realistically need to return from Mars, so most of the utility of the cycler is lost on the return journey. Cargo to Mars could just be carried on unmanned one-way ships. For passengers, *perhaps* the cycler makes sense *today*. However, as space construction techniques develop, I think smaller direct-to-Mars craft with smaller habitation sections (e.g. incomplete rings, tumbling pigeons, or rotating tether) make more sense. It’s a matter of how reliable our ships are (e.g. what is the failure rate of life support? meteoroid strike rate? do cyclers have better radiation sheltering?) and how cheap we can build in space. Economies of scale seem to always prefer smaller more nimble modes of transportation to larger “consolidated” forms. Look at the decline of the 747 and A380 as twin-engine jets have become more reliable. Besides, if Scott is correct and you need 15 cyclers to have regular yearly service, then only ~2/15 of your expensive heavy interplanetary fleet is doing anything at one time. And why? So passengers can have bigger cabins and a more comfortable flare shelter? I think the window for Aldrin cyclers versus SpaceX-style “on-float” ships and The Martian-style orbiters is very narrow. I think they’ll ultimately turn out to be completely infeasible when construction time and orbital insertion costs are considered. Besides, Mars isn’t *so* far that we need the cycler to provide 1-2 years of accommodations and space like a Jovian or Saturnian cycler might need to. OTOH, outer planet voyages are so far out there and traffic likely to be low for decades to centuries that a generic Mars passenger ship would probably make for a spacious Jovian exploration ship.

[@Garryck-1]

No real utility? What about the ability to grow food on-board? Fresh food and water on-tap for all your Lunar/Mun/Minmus mission crews? Without the constant overhead in boosting consumables to orbit for each individual mission, at thousands of dollars a kilo? Much cheaper to just send up some extra fertiliser with a mission every now and then.. To borrow from the Master Engineer himself; "So, is that worth somethin' to ye, laddie?"

[@kekrre]

1. I'm talking about the real world, not KSP. 2. I'm not sure you understand the mass balance of plants if you think you can just launch fertilizer up into space and have that magically turn into plants. That would only work if you were carrying around Martian carbon and nitrogen sources. 3. I think I made the economic argument for why the cycler is infeasible the first time around: in your case, we're talking about recycling. A ship that orbits Earth and Mars can recycle the same consumables at its destination that a fleet of 15 expensive cyclers could do whilst travelling through deep space. An Earth-Mars voyage is only a few months at the ideal launch point -- there's no need to send a greenhouse on orbit through deep space. Any consumables that *need* to be replenished *have* to be launched from the Earth anyway. All that the cycler is doing is putting a habitat space up in interplanetary space -- everything that you need for human survival has to be launched and sped up to rendezvous with the cycler, and it needs the same or more delta-V than a standard non-cycler mission. Because of this, for example, it makes no sense to send cargo payloads on the cycler -- just strip them down and send them direct. So again, my conclusion is we only need to evaluate the cycler for human travel (and recycling/growing consumables, as you point out). Instead of having 13 out of 15 ships flying around doing nothing but processing poo and growing salads, you can build one station over Earth, maybe one station over Mars (although the lower dV costs of a Mars launch mean you'd probably just do the processing on the ground), and do all of the resupplying and processing there. The ships don't have to carry their own landers/lifters (they can be based on Earth and Mars), just passengers. It's not like a ferry where each cycler is picking up and offloading passengers every time it crosses Earth or Mars orbit -- only one cycler is in position for the Earth-Mars trip and only one cycler is in position for the Mars-Earth trip at a time, and the others are out of position for 77% of their time -- Scott says 15 years in the video. Since an Earth-Mars trip doesn't take more than a year, that's where I'm getting 2/15 cyclers utilized at a time. That mass would be much better spent in end-destination recycling and a fleet of smaller ships that fly at 100% utilization whenever a launch window opens up. Not to mention, you can put up a much bigger recycling hub station (if that turns out to be necessary) in LEO than you could on a cycler orbit, since you don't have to heft it on an interplanetary trajectory with course correction fuel. Again, I expect the window in which a cycler would make economic sense to be fairly small. On one end, we have SpaceX's planned BFR fleet with null-gee ships. On the other end, we have advanced space manufacturing generating small, reliable, fast ships, perhaps with spin gravity. In the middle, we have a window where *maybe* sending building a fleet of partial-occupancy deep space habitats makes sense. But like draining the Mediterranean, I don't think it'll ever be economically feasible. And I don't think any orbital recycling would actually be necessary. I bet you could just draw a box around Earth and say everything that enters Earth orbit is part of the Mars consumables recycling plan, and just have everything recycled on the ground at Mars, in part to support the interplanetary fleet and in part to jumpstart the Martian fuel and food production industry. Besides, the only consumables that need to be launched up from Mars are those for the return voyage, and I bet fewer people will be returning than leaving by the time we have a functioning colony. In that case, I bet it's cheaper to launch supplies from Earth (and into the Martian economy) than sending supplies back to Earth and back to Mars again. I originally posted because I saw a lot of people suggesting that this would be something that SpaceX would be interested in -- nowhere in SpaceX's plan for a million person Mars colony has Elon Musk suggested that they'd like to build a cycler fleet, despite their desire to cart a million people to Mars. Instead, they've proposed building a fleet of small null-gee ships. I think the cycler is a nice thought experiment, but ultimately a red herring, and a pipe dream of yesteryear like the National Aerospace Plane, the Sea Dragon, and SSTO being the only way to launch cheap into space.

[@eternalmiasma5586]

Yo Scott I have an idea for you, you should make the x37B an experimental military space plane, the things kick ass

[@CausticLemons7]

More about cyclers please!

[@northerncold2081]

Scott. Sorry for the off-topic comment. But sometime in the future, could you show us some tricks on how to use gravity assist transfers in KSP?

[@micaiaskauss]

Yes to Kerbin-Duna cycler :)

[@josephgroves3176]

Kerbo-Duna cycled? DO IT!

[@jdmaine51084]

Anyone mention that all the kerbals would be walking on the windows in his artificial gravity ring?

[@ChAnimations]

Funny how the astronauts can't spend a few days in their ship during the transfer, but can live in it for a whole month on the munar surface - I guess in reality it would only make sense when their was already a station on the moon. It's kind of like a public transport in space.

[@scillyguy]

5:38 He does say presumably there would be a moon station if there was a cycler.

[@digitalnomad9985]

That is the eventual idea. Yes, spending a month in an Apollo/Orion can is inhumane and absurd.

[@asysi]

Have you attached the waffle sprocket to the flange modulator?

[@asvarien]

Did you remember to properly calibrate the samophlange and engage the self-sealing stem bolts?

[@cmdrterrorfirma4244]

since landing is so easy for you... we had to get you to do something outside your comfort zone.

[@Veptis]

I have never thought about this subject.... And I am not on my computer right now to read up on it. So a lunar cycler... Could be a transporter? Where you bring your payload to LEO and randevous with your cycler. Then payload and cycler aproach the moon and you detach and land on the moon... Next cycle you ascent again and randevous to detach close to earth aproach and reentry your mined moon rocks. The cycler wouldn't need any fuel other then orbital decay due to close earth aproach... But you put more mass to the cycler so the orbit changes again? Could you use a high mass body like an Astroid and but it into a cycler orbit and use it's mass and gravity as transport route? Has anyone tried it? Maybe a tech Demonstration? That just orbits the earth in a high eccentric orbit to go around the moon and comeback, in an endless cycle? Or opsite way around? Maybe we could do something like this to put cubesats into lunar orbit.

[@Garryck-1]

I suspect you'd need a shit-ton of dV to put a suitably large asteroid into such an orbit. And the kind of precision tuning that's required for such an orbit, with something that sluggish and unresponsive would be a barrel of laughs, I'm sure..

[@Smokeybear69420]

So if we got a SSTO to transfer from Earth's surface to the cycler, and a lander on the cycler, we could have a Fully Reusable Space Program.

[@MrMichalMalek]

That would be a shitload of DeltaV for the SSTO

[@Garryck-1]

But not as much as if your SSTO had to be capable of getting to the Moon and back. Put greenhouses on the cycler, and you'd have a constant supply of fresh food for your steady stream of mission crews, at a considerable saving on the dV costs of boosting every morsel of food and water into orbit.

[@5Andysalive]

Ever read seveneves? Some interesting orbital mechanics in the 3rd part.

[@franzfanz]

It felt like he got too caught up in explaining the technology in that final part and as a result the story kind of ended on a dud note for me.

[@5Andysalive]

I liked the technical part more then the actual story. I mean in the first part humanity acts unbelievably (literal) calm, serious and selfless. In the second part, with the same people involved, unbelievably stupid. That part felt very forced and constructed away from the technical section. Only that was interesting. So having a low story profile in the 3rd is ok. But l like that humans are still basically the same. That's more reasonable than esp the second part. Not a perfect book but a very interesting one.

[@makavelligaming7540]

watched your videos for hours finally got the game for pc ready to launch myself out of the solarsystem :P :P

[@dong9224]

Love to see this with rss and ro

[@atomicgeneral]

Scott, could you do a video showing why US would want (or not) to have a Mars cycler in real life?

[@liquividy]

duna-kerbin cycler!

[@incoggodneat-o9215]

Hey Scott, your game looks gorgeous! I'm just starting out with modding, is there a list of the mods you have available?

[@Etrehumain123]

I'm not sure to get it: to encounter the space station, you basically burn fuel to reach the same weird orbit. That's a lot of burning

[@Etrehumain123]

But I get the argument to live in spacestation if you're playing with food mods

[@stribika0]

Does this really work between Earth and Mars? If you fix one focus on the Sun, you have 3 parameters to play with, let's say sum of distances, distance to the other focus, direction of the other focus. You can pick other ones it doesn't matter. You want your eclipse to touch both Earth's and Mars' orbit, and for that you use the first two parameters. The third one just rotates the eclipse so it doesn't really matter. How do you make sure it's timed right? Get out of the plane of orbits maybe?

[@jackbrabham]

I'll just say one thing: Galileo Conquest.

[@SSanatobaJR]

People need room to live. Kerbal do not (unless you have a mod for that). Launching a small pod to Mars with humans on it is a bad idea. You would need a larger spacecraft for humans to survive in. But if you already have a cycler station in route, you can use a small pod to send people up to it and they will have space on the cycler. So in the long run you actually would save money and fuel.

[@TheBeardyPenguin]

Apologies if Scott has already answered this in another video, but what has happened to Galileo conquest?

[@Palpatine001]

1:52 least Rocket Lab didnt end up with that slight error

[@randomnessx3597]

kirbin duna would be cool

[@markus5888]

Nice VARM :)

[@andrelenz405]

Damn it looks good. Guys, which mod are not broken now in 2018? I'm having some problem to make KSP running..

[@Garryck-1]

Most of them are up to date and working.. the KSP forums are where you should be looking to know what's having problems.