Starship Orbital Refueling

[@PrawnDog420]

Babe wake up, Eager space just dropped a new videooo

[@w0ttheh3ll]

Why did SpaceX choose this architecture? Because Starship development is their priority and this way NASA pays for part of that.

[@EagerSpace]

Exactly, but that would be a very short video.

[@lagrangewei]

because SpaceX doesn't care if China get to the moon first when NASA is still struck refuelling xD

[@marcelmeinking1020]

​@@lagrangewei China is only 55 years to late for that

[@goontheracoon]

why is it needed? because we've already tried single launch rockets and all they where good for was increasing AD revenue during their off planet sighting trips.. none could carry enough equipment and load size for reaching sustainability.. if we make ALL genetic and disease based research illegal to do on earth then we'd have research lab on the moon within 10 years. the future is off planet mining and research away from moralistic laws and guidelines, yes- there will come some bad out of this, but humans are instinctually unable to work for the common good, we work for our own greed and curiosity. if humanity is to prosper then that prosperity must be an happy accident, not a forced goal. forcing that outcome is how we get utopian society's.

[@novachromatic]

I think what the US is really worried about is China colonizing the moon first with a moon base.

[@Ozie1981]

I think a lot of people are missing the part about using a rocket as a depot. The actual lunar lander isn’t going to fly up into orbit and then couple with 10-20 other starships flying around up there. It’s going to couple with a depot model starship which has already done that. This is an important distinction because it means the lander isn’t going through up to 20 opportunities for something to go wrong. The depot ship is the only vehicle to be doing that and that means it can be fitted with much more durable and robust coupling hardware, which will be much easier to do since that’s its sole purpose. So to recap: each fuel delivery rocket only has to couple once and the lunar lander only has to couple once. Also, this means that the depot rocket is the only rocket that needs to have a cryo plant on board.

[@angelainamarie9656]

All I know is, we got to the Moon before with ONE rocket launch, and now we need 20? From the 'Department of Government Efficiency" what this look like is a scam.

[@FredPauling]

I love how this channel cuts through all the FUD and does a reasonably balanced analysis of the basic issues

[@alexgustavsson5955]

He hasn't actually cut through much uncertainty, sure he's given options for propellant transfer and tank chilling, but those haven't flown on any of the starship flights so far. As for how many tanker flights are required per moon landing, he's not reduced uncertainty even the slightest amount. The program is supposed to have a moon landing by 2025(?), that seems impossible, so I remain doubtful. Can SpaceX keep effectively losing perhaps ~$500M or more per starship (assuming a reasonably high cost for the raptor engines) until they figure all of this out? Can they keep doing funding rounds to the tune of hundreds of millions or even billions into 2024-2025-2026 as they've done in 2021-2022?

[@SpaceAdvocate]

@@alexgustavsson5955 They will attempt to recover the Super Heavy on the next flight. Super Heavy is most of the cost of Starship. SpaceX is mostly self-funding, so they can likely keep the Starship program going indefinitely at the current burn rate, but it doesn't seem like they are going to need to.

[@alexgustavsson5955]

@@SpaceAdvocate They've gotten a whole lot of venture capital over the last few years for a self-funded company. Is that included in self-funding?

[@SpaceAdvocate]

@@alexgustavsson5955 It's a couple of years since the last time they raised money. The money they raised largely went into Starlink, which now has over 3 million customers. That's something like 300 million dollars in revenue every month. They also have revenue from commercial and government launches. So, at the moment, it doesn't seem like they will need to raise more money, unless they massively increase spending on Starship.

[@flaviosalatino8192]

​@@alexgustavsson5955 In what universe does a single starship cost 500 million per ship? The whole stack is 90 millions,NOW, not even considering the raptor 3. A starship V2 is probably in the 20 millions range.

[@Enregardant]

You are my favorite youtuber.

[@jacobjacob5735]

I really like your videos, I am always looking forward to them!

[@douginorlando6260]

Regarding fuel transfer in space, there is another good approach. Use a low rotation rate to create enough centrifugal force to pool the liquid at the “bottom” of the tanks. This allows pumping without the danger of fuel/(or oxidant) vapor mixed with the liquid being pumped. It also allows for capturing vapor vented through a relief valve at the “top” of the tank. I don’t know the minimum centrifugal force required to separate the fuel from the vapor inside the tanks but it must be on the order of 1% earth gravity acceleration. There are effective ways to allow docking at zero g and then induce rotation without expending fuel, then after fuel transfer to eliminate rotation and undock under zero G conditions without expending fuel and without the need for thrusters. Refueling in lunar orbit in order to return to earth sounds much riskier than refueling in earth orbit (there will be means to rescue in earth orbit but not in lunar orbit). The SpaceX lunar lander’s huge payload is vital for establishing a viable permanent lunar presence. A large Payload will be required for lunar infrastructure to extract lunar ice into water, oxygen, hydrogen, and probably frozen methane deposits. Once the moonbase can supply these necessities, support costs can drop by 99%. Payload is also required for adequate electric power for operating equipment including extracting oxygen from carbon dioxide, & temperature control. Also payload is required for a launch/landing pad.

[@EagerSpace]

Are you thinking "head over heels rotation" (x or y axis) rather than spinning around the z axis? If so, that seems difficult because the center of gravity is going to start in one place as the starship is just spinning around the propellant floating in the tanks and then migrate as (presumably) the inner baffles start pushing it in the right direction. And I'm not sure that puts it to the bottom of the tanks. And the center of gravity of the depot will change based on the amount of propellant in the tanks.

[@bbgun061]

Rotation seems like it could work. Ultimately, there are tradeoffs in every design, and I'm sure SpaceX will analyze all possible methods to determine what will work best.

[@kargaroc386]

So, using rotational artificial gravity for ullage management means that the fuel will be pushed outward, towards whatever the furthest end of the tank is. With the currently envisioned side-by-side docking method, that point where the fuel will pool is: the side of the tank directly opposite that of the QD mechanism / docking point. Your fuel pump would have inlets on that outer side of the tank, and the pipe would run along the side in a C shape to the docking point. This sounds reasonable.

[@RobinClaassen]

That's an interesting idea, which I've never heard of or considered before. It seems like an interesting trade-off: 1. You're pulling all the liquid propellant to one part of its respective tank where it can be pumped from. (Great!) 2. The part of its tank that you're pulling it to it the point furthest away from the spacecraft that you want to pump it to, meaning that you need to have a long pipe to pump it through. (More mass, and potentially wasted propellant left in the pipe) Is this an idea that you got from somewhere? Is there more information this technique that you can refer me to?

[@douginorlando6260]

@@EagerSpace I see them as manageable considerations. It’s easy to visualize rotating end over end with nose to nose or nose to tail or tail to tail. But side by side is possible especially if they aren’t exactly rotating on an axis parallel to the central axis of the two starships (otherwise the fuel will not pool in one place at the “bottom” but instead along the length of the tall tank). E.G. Link them in opposite directions so the center of mass of one starship is towards one end while the center of mass of the other starship is at the other end (that makes them rotate somewhere between head over heels and around an axis parallel to them, thus allowing a deep end pooling). Another manageable consideration is called the “Intermediate Axis Theorem” (odd tumbling to avoid).

[@Felix-no7nx]

Nice you reached 10.000 subscribers 🎉 Congratulations!!! you deserve that!

[@EagerSpace]

Thanks! 😃

[@Ionut-bg6vw]

More starship more happy

[@nv7213]

happ :)

[@Papershields001]

They chose that architecture because they are really building a LEO internet constellation launcher. They are partially paying for it with the lunar contract. What they’re doing isn’t all that dissimilar from the clunky idea of somehow getting shuttles out to the moon. The ship isn’t built for it but if you can launch frequently enough you can maybe change the paradigm. It’s a square peg in a round hole, but it’s Spacex, the bid was the cheapest and it’s a big rocket that we are all excited about it.

[@Not.a.bird.Person]

While it's true that starlink will eventually use Starship as its main delivery vehicle, the assumption that Starship is primarily designed to carry constellations is just baseless. Even in the first moments when SpaceX was developping Starship, they were always public about how they intended to use orbital refueling for long missions such as Mars missions. The fact that NASA is going to use this refueling for Moon missions was just an add on after the fact (that would help pay for the program) and doesn't explain why SpaceX planned for refueling Starships in the first place. This vehicle was always about Mars and Mars was always going to require refueling for large payloads.

[@Papershields001]

@@Not.a.bird.Person baseless? Payload bay door is literally a pez dispenser for Starlink satellites. They have facilities onsite that were made with the explicit intention of loading stacking and launching starlinks right now. There’s no white room or payload integration facility down there for anything else. Besides, say they’ve got ships fully fueled and ready to go by the next window: what are they going to put on that rocket? There’s nothing around that won’t take 10 years of development before it can serve a future manned mission.

[@Not.a.bird.Person]

@@Papershields001 The payload bay door came way after everything about the vehicle was known and it's not a massive leap. It's an add on just like the Artemis program. Gwyne Shotwell frequently talks about using residual capabilities to the max, this is no different. If you have a massive vehicle with the largest mass to LEO capabilities on Earth, what can you do with it? The answer is add a payload door to it to launch the largest amount of satellites ever seen. A rocket is a rocket, you can put whatever you want on it given that you provide the accomodations for it. SpaceX started with developping this as a vehicle for Mars, then came Artemis and then came Starlink profitability, now the 3 operate on parallel paths. The point is this myth that Starship was always designed to carry Starlink is just that, a myth propagated by people who don't know the context. It is completely anachronistic when taking into account the chronology of events surrounding the Starship and Starlink. For reference, when the Starship program was started, it wasn't even clear that Starlink could be profitable and SpaceX didn't even have a fraction of the satellites they operate now if any. It just appears obvious to put Starlink satellites on Starship now that both are where they are on their development and operational paths. People therefore just assume that it was always the plan but that's just an ad hoc rationalization.

[@That_Awesome_Guy1]

​@@Papershields001Starship is going to have many versions. The first versions will have a pez dispenser door, but that doesn't mean that's what it's going to be forever. The goal of starship was always to refuel in orbit to bring large payload masses to the moon and mars.

[@Papershields001]

@ I struggle to accept Elon Musk’s altruistic ideas about humanity’s future. He was feeding us those lines 10 years ago, back then he said a falcon 9 launch would cost 3 million. Spacex achieved their goals but what do they charge today? 60 million. It’s a business, capitalism, if you believe in it blindly you’ll get screwed. Has happened time and time again.

[@THX..1138]

The lower your orbit the more propellant you can get into orbit per launch. Given this fact a Fuel Depot launched to a low obit should not have an issue with using thrusters to transfer propellant as the transfer is also providing a much needed boost to the Depot's orbit.....In fact the Depot could be placed in a very low orbit where not only the propellant transfers are needed to provide periodic boost. The inevitable boil off gasses would also be needed to maintain the Depot's altitude. In such an orbit you could launch many tons more propellant into orbit per launch and still rely totally on boiloff gasses for propellant transfer and Depot station keeping.

[@bbgun061]

I like the idea of doing something useful with the boiloff gases. However I think the difference in payload to high vs low LEO is negligible.

[@THX..1138]

@@bbgun061 Actually you need about 1.6% more propellant to achieve a 300 mile orbit vs a 100 mile orbit. For a fully loaded Starship tanker that's somewhere in the neighborhood of 73 tons more propellant for the higher orbit. So yeah, you definitely wanna aim for the lowest altitude you can get away with for your Depot.

[@bbgun061]

@@THX..1138 I agree they will want to aim for a lower orbit, but how much does that increase the payload? Will that actually reduce the number of tankers required?

[@THX..1138]

@@bbgun061 I'd guess it would increase payload anywhere from maybe 10 to 25 tons. Probably enough to shave off at least 1 tanker launch.... Which is likely why SpaceX doesn't yet know how many launches they'll need as things like how low you can put the Depot are still unknowable at this point.

[@christianhenderson5471]

Eager Space and CSI starbase are my two favourite technical space channels now

[@Jason-gq8fo]

SLS makes me sad. Obviously happy we’re going back to the moon, but it is very short term because of sls. I hope in the future nasa can abandon it and focus on science and planning of a base on the moon and future Mars missions

[@ludwigvanzappa9548]

Thank you my friend, that was fast ! Very interesting!

[@PetesGuide]

Future video idea: How much does having to truck in methane to the launch site instead of building a pipeline for it impact the cost of each launch, and of one complete HLS mission? The why if the question is when do you think SpaceX will want to build that methane/natural gas/pipeline, or are they better off figuring out how close they can get an LNG tanker to Starbase?

[@EagerSpace]

I do expect them to build a LOX plant at some point. Methane is harder because natural gas varies in methane content and you need to separate the methane that you want and do something useful with the other components. So far they're content letting somebody else deal with that.

[@johnjackson917]

@@EagerSpace if they had a lox plant they'd use it for ln2 as well i bet you're right about the methane. they won't do a pipe from the port for that reason

[@solarissv777]

I wonder if it would make sense for them to build a railroad from the port of Brownsville to Starbase plant and the launch complex. I recon, they could even use double track platforms to transport the parts of the starships. Advantages: ability to quickly transport large payloads and amounts of fuel as well as starships, without any road closures.

[@PetesGuide]

@@EagerSpace They used to have a small scale air separation plant at the build site, but tore it down. A new LOX/N2 plant is shown in the site map drawings for the proposed expansion of the launch site, but it doesn’t show anything for Methane pipelines, which is why I’m asking. I’m am exquisitely curious about the economics involved in deciding if and when they switch from driving it in on trucks to something more efficient.

[@thermusaquaticusPCR]

​@@EagerSpaceif they're already building a cryogenic distillation plant for LOX production why not build one for cryogenic distillation of methane out of natural gas?

[@rigomrtz]

1st of your updates I've watched, instantly subscribed excellent work, thanks

[@EagerSpace]

Awesome, thank you!

[@Telencephelon]

This is such a great video

[@lowstrife]

So this brings up an interesting topic I don't see talked about too often - Starship, the platform. We've got what, a starlink version, a tanker, a depot, a lunar lander, and presumably a human rated crew version. Each of these is a unique development fork on a base shared core architecture. But what else is possible? A version designed to be retrofitted in orbit, into a station or a larger ship? Strapping multiple stages in orbit together to make a larger space-only ship? Thinking of them as a modular architecture opens up all kinds of interesting possibilities.

[@CJisDJ]

9m space telescope like hubble but bigger

[@frankmcgowan9457]

​@@CJisDJ Or several such fixed into an "L" or "X" shaped array to provide the detail of a single telescope the size of the array...

[@stanleydodds9]

It's like when you're playing KSP. You take a bunch of contracts to send random parts to pointless trajectories. You don't build a custom spacecraft for each part - you try to stick them to your existing spacecraft that are actually doing something else (the main obejectives that you want to do - the milestone contracts in the case of KSP). In the real world, of course, the R&D is a much longer process that requires a lot more real world experience, and that especially lends itself to this "taking random contracts" approach. Now, instead of trying to adjust your important missions to include these contracts, you can just do your more flexible R&D missions to fulfill the contracts.

[@mossyslopes]

I like your style of presentation. Subbed👍

[@EagerSpace]

Thanks and welcome

[@cabanford]

Great clip! Many thanks ❤❤❤ (More such please)

[@Tanstaaflitis]

Somehow, i doubt the initial lunar missions will make use of Starship's full cargo potential. That means it should take fewer refuelling trips. I'm also curious if there's a source of carbon on the moon. We know ice can be found and potentially electrolized in situ. If there's a source of carbon, perhaps methane and oxygen can be produced on the moon. That would be an interesting experiment ahead of a Mars flight and the need to synthesize fuel there.

[@coreygraybz]

I think cargo missions to support Artemis will involve sacrificing the Ship's to the surface in order to maximize payload, with the ships themselves being able to be tipped over and converted into habitats buried with regolith. The logistics of tipping a ship over would not likely be available for several years though until enough infrastructure was available plus the demand for such a large habitat.

[@Tanstaaflitis]

@@coreygraybz I'm interested in what it takes to convert the empty fuel tanks to something habitable. It may just be simpler to send up inflatable habitats that can be buried than worry about on-site ship breaking. But the future is a foreign land.

[@Tanstaaflitis]

@@coreygraybz The more and more I think about it. Tipping over Starships to create habitats is kind of silly. It may be more mass efficient to offload the entire upper portion as a well outfitted habitat. Then potentially the remaining portion--having deposited dozens of tons of cargo--has enough delta V to return to Earth, becoming a lunar tug of sorts. As I see it, outfitting any potential habitat is going to require substantial tonnage. Enough that I doubt you can ship enough to make it worthwhile to crack open the fuel tanks to make space. Better to ship something already setup like the Bigelow inflatable habitats and bury them.

[@bhartley1024]

Why would they have to tip them over? Skyscraper living on the moon! Think of the views!

[@RinPi15]

That was the shortest sponsorship I’ve ever seen, nice😂

[@nithishwarai5998]

don't let the sponsors read this!

[@MaroKrile-s3d]

excelent, how could private spacex moon mision work with crew rated starship, with hsl and moon base

[@EagerSpace]

See my video "commercial space" which I should have talked about...

[@saliman4874]

Amazing channel, up there with Scott Manley. Hope you have 100k subscriber soon

[@EagerSpace]

I'm hoping.

[@dionysus2006]

Well done. So basically this all depends on rapid reuse of Starship to keep the orbital propellent depot full. So even when there isn't a launch coming up you keep flying propellent to the depot or have multiple depots with cryo-chillers. Now you don't have to depend on a bunch of flights all happening within a short time period because you have more than you need already in LEO. They could even set up a pipeline that puts a propellent depot in Lunar orbit for the reusable HLS. The point is that keeping the depots full is a separate project from the Lunar mission. This all depends on being able to fly Starship a few times a week at low cost. The more they fly the better they get.

[@TheEvilmooseofdoom]

Why do they need to keep is full if there are no missions going?

[@dionysus2006]

@@TheEvilmooseofdoom For the next mission plus it reduces logistics problems if the propellant is there well ahead of time for the current mission. Plans are to use cryo-chillers to prevent boil off. They could put multiple depots in LEO and then whenever someone needs propellant they just tank up at a reasonable price. This lets you launch into LEO but then go to the Moon or Mars with a smaller rocket. If you have to bring your own propellant you have to have a much bigger rocket (due to the rocket equation)

[@Benloehr]

Dr. K^^ definitely works. I used it on my nuclear ssto. I was able to get double the performance out of those ntps^^.

[@GawainNYC]

I tried it in my suped up Toyota, and it blew the doors off! Literally! Frount doors went flying left and right, and the back doors up and down! Made like a cross!

[@rigomrtz]

I rubbed some on my knee & the joint pain left like a stumbled across snake 😂

[@2150dalek]

That explained why refueling is needed. I didn't know the weight difference between Apollo missions & Orion spacecraft. I hope SpaceX is able to pull it off.

[@hkmp5kpdw]

That looks complex and risky…

[@EveryoneWhoUsesThisTV]

Would the ullage thrusters need to run for the entire duration of the propellant transfer to keep the propellants settled?

[@EagerSpace]

Yes, but it's not a ton of thrust.

[@EveryoneWhoUsesThisTV]

@@EagerSpace I'm wondering if they have plans to minimize the propellant use yet... :) By pulsing the ullage thrusters, just enough to maintain acceleration, or increasing the pump size/speed to reduce the transfer duration. Less hours spent refueling will be propellant saved...

[@mrrolandlawrence]

awesome. this is one of the best space channels out there. I love this channel because there is no "hype" just statistical analysis and predictable scenarios. i would also wager that space-x has done some calculations on a 3 stage rocket in disposable mode. the moon mission is politically sensitive. showing your full hand to the world might not be in national interests.

[@rikkafe6050]

Although your explanations are concise they are still very informative. A difficult balance to find. Thanks for the video.

[@EagerSpace]

Thanks. I try to simplify things enough but not too much.

[@chrissouthgate4554]

This may be too weight-restricted, but an inner flexible tank skin that can be pressurised on the other side from the fuel would force the propellent to the exit for the tank. I believe a similar system was either used or proposed for early re-ignitable rockets.

[@kargaroc386]

Using an inner bladder to store fuel is sometimes used on satellites. But not rocket stages, as the dry mass is high. There's another variant that uses a contracting piston instead of a bladder, that sounds even heavier.

[@SpaceAdvocate]

Bladders don't really work for cryogenic propellant.

[@EagerSpace]

This. Flexible at room temperature is very much not flexible at cryo temperatures.

[@casualbird7671]

The odd repeat at 8:50 made me feel like I was going crazy for a moment

[@michaelswisher9574]

Is it feasible to create a collapsing fuel tank that would force the fuel into the other tank?

[@EagerSpace]

Probably feasible, but it sounds very heavy and therefore it's probably not practical.

[@AmericanCrusader222]

BABE WAKE UP. NEW EAGER SPACE STARSHIP VIDEO DROPPED.

[@JoshKaufmanstuff]

Yes exactly my thoughts as well, All of this hubbub about how many flights it's going to take when the falcon 9 puts over a hundred launches into orbit/ year. I could see the concern if they were talking about ULA or Blue origin but a complete non-issue for a company that leads the world in launch frequency by a huge margin

[@coreygraybz]

It's going to be a few years before we get the Starship cadence necessary plus if something goes wrong it will create a cascade effect on missions down the line, creating schedule slips and logistics issues. A starship RUD is going to cause a much large delay that the quick 2 week delay recently suffered by F9.

[@SpaceAdvocate]

@@coreygraybz It depends on the RUD. As long as the RUD didn't cause a safety hazard, they can get FAA approval to launch in a similar timeframe as the Falcon 9. That of course assumes SpaceX is comfortable risking hardware on another launch. It means they need to rapidly figure out what happened, like with Falcon 9.

[@JoshKaufmanstuff]

@@coreygraybz I partially agree. What we are looking for has never been done so there can be no dogmatic assumptions as to what the timeline is . . . Having said that, once the SuperHeavy booster design is complete you will have a reusable vehicle that does not suffer from the coking of RP-1 fuel, there are no heat tiles to replace/ repair. Post landing inspections will be thorough at first but as long as the physics is sound the heavens will be opened to a fully functional fuel depot in LEO that will facilitate max payload to anywhere. That first bit is certainly no chip shot, but assuming SpaceX solves booster landing then it's Game Over for legacy expendable rockets because the capability and expense will obsolete all of the slow/ expensive alternatives.

[@gasdive]

​@@JoshKaufmanstuffthe game is already over for the legacy rockets. Starship and booster are designed to be fast and cheap to build. They're a tenth the time to build and can be produced at a tenth of the cost. Even without reusability, the game is over for everyone else. SX already demonstrated successfully reaching orbit, which is all the expendable rockets ever do. Reusable ships are just the icing on the cake.

[@mattkingston6157]

@@gasdive never been to orbit and they are many many tons away from their payload target. last estimate was 30-40 tons to orbit. which is actually 0 proven tons to orbit. there is no payload deployment mechanism and no plans for starship to launch a payload in the foreseeable future. meanwhile ariane 6 launched with payload and made orbit on the first launch, BO is launching a rocket to mars before end of year and ULA has already launched a lander to the moon all of these are on first flights of their respective rockets indicating a good level of confidence. maybe Spacex can actually get to orbit on their 5th try, albeit still with 0 payload. hey maybe they can figure out how to relight their engines in space too. something we've been able to do since the 60s

[@willyouwright]

You have to consider just hooking 3 starships up and sending all 3.. 1 for cargo, 1 for habitation, 1 for fuel... that way also a built in emergency and spare parts ship..

[@kevinmccarthy8746]

I do love your show.

[@w3xyz]

10k subscribers!

[@arubaga]

There would be many Starlink launches that generate cost amortized booster stages, using them in expendable mode would not be that bad. Maybe separate a kick stage and the lander to launch them separately. Then you can do direct lunar orbit as in Apollo.

[@cabanford]

You should do an episode together with JMG - two epic voices!

[@bobbarclay316]

The SLS 2 will require boeing to completely rebuild the launch tower. You may recall what a disaster that was.

[@jblob5764]

With Boeing's current woes chances are theyll never even make a block 1b

[@gravityawsome]

I imagine they'll keep improving the raptor engine until they can get an ISP that's high enough to the point where they won't require as many tankers. Since i don't know if theres much else they can really do.

[@cube2fox]

All Raptor versions so far had the same I_sp.

[@m_disulphide]

Yeah the ISP is bound to prop choice

[@stevep8485]

You could have a piston to push all the propellant out of the depot. Or inflate a balloon inside it.

[@EagerSpace]

A piston would involve a large and heavy mechanism. And pretty much any flexible material is not flexible at cryogenic temperatures (you can break balloons in liquid nitrogen, and it's a lot warmer than these propellants.

[@tomg6284]

What about soild fuel boosters that bolt on in orbit. No transfer pumps. Bolt on 6 and use 3 going and 3 coming back. Total amount is variable. Just thinking outloud.

[@EagerSpace]

You need to somehow get them into orbit and get them back and solids are much less fuel efficient than liquid fuels.

[@jimkennedy2339]

Could 3 falcon heavy launches lift a modular equivalent of a fueled sivb /lm and cm to LEO?

[@mathiaslist6705]

In a previous video you quoted that a starship build from carbon fiber composit will be at least 49 tons lighter. So if the heast shield and braking fuel is not included it might be at least 60 tons lighter. The HLS starship needs just vacuum engines and that further reduces mass however the legs might add up. The question is how many times they plan to refill. Probably refilling in GSO and lunar orbit makes sense too.

[@EagerSpace]

Vacuum engines alone aren't enough to get into orbit unless you have six of them - possible - and they don't gimble so you can't steer. It is true you could build HLS out of carbon fiber. If you are willing to build a billion dollar factory to do it and wait a few more years.

[@Shrouded_reaper]

Option you didn't mention is rotating lengthwise down it's axis and having fluid pickups on the edge of the cylinder, I have a feeling this is how they will do it. Im not sure if those kind of pipes on the edge of the tank would be a great idea for starship but on a depot that just floats in orbit? Why not?

[@EagerSpace]

Could be possible, seems less likely to me. Starship already has to have piping to flow propellants in normal gravity orientation, and they will *probably* try to reuse that. But they will do their own trades.

[@rasimbot]

What about squeezing propellant out with a piston?

[@EagerSpace]

Maybe sortof possible. The problem is where you would put the rod that pushes the piston and all the mechanicals that drive it. You would also need to figure out how to seal the edges, and there aren't many materials that are flexible at the very low cryogenic temperatures.

[@rasimbot]

@@EagerSpace | A central guide rod along the tank can be used in theory if the piston with a central hole is pushed by the pressure on the other side. The pressure can be created by gasifying propellant leaking through the seals. I thought also about another alternative. It can be a loop between the depo and the tanker. A pump sucks from the tanker and blows into the depo, but the return path of the loop allows only gaseous phase to pass from the depo to tanker, preventing liquid back transfer

[@Steve-Richter]

Is there any concern of a RUD while in orbit? Could there be an explosion while transferring fuel?

[@EagerSpace]

The worrisome parts of flight are generally the high-energy ones - ascent and reentry. Apollo 13 is an exception, but that was a problem with hardware. ISS transferred the far more dangerous hypergolic propellants early on with no issues. Always a chance, however, especially if something weird happens.

[@dipakahir4688]

Space x can reduce the size of hls or use the f9 upper stage maybe? Tell me if I'm missing something

[@breezyx976]

@EagerSpace What are your thoughts on Propulsive Fluid Accumulators? They using air-breathing ion (or magnetohydrodynamic) thruster satellites in LEO to harvest oxygen from the upper atmosphere as LOX which can be used for orbital refueling, removing the need to carry LOX from the earth's surface. It's a reusable method of generating a theoretically unlimited quantity of LOX at LEO. This significantly reduces the total mass needed to reach orbit to refuel a spacecraft, since we would only need to bring LH and cargo. Boeing's PROFAC proposed a nuclear reactor to power it, but modern designs propose solar panels instead. Maybe a cool idea for a video?

[@EagerSpace]

I have "air breathing satellites" on my list.

[@andrewparker318]

Couldn't you just use a giant pusher plate like what you might find inside a syringe to transfer propellant from one vehicle to another?

[@EagerSpace]

Yes. How much will the giant pusher plate and the machinery to operate it weigh?

[@SpaceAdvocate]

If you have a pusher plate you can't have slosh baffles, and the seals around the edge of the plate can be a bit problematic.

[@andrewparker318]

@@EagerSpace I guess it depends on how long you're willing for the transfer to take. If you're ok with waiting several hours, then a single high torque motor might be all that it takes to push the propellant out of the tanker. At the very least, you could just have a plunger that pushes all the fuel to the correct side of the tank, and then let a regular pump do the job. But then again I have no experience in this kind of engineering, so there could be several flaws that make this idea unfeasible compared to the other options.

[@andrewparker318]

@@SpaceAdvocate Good point

[@EagerSpace]

Because of orbital dynamics you can't bring starship back to the launch site for about 12 or 24 hours (depending on what the FAA allows you to do).

[@resvero8342]

What if they but a pad inside the fuel tank which pushes out the fuel

[@slimeking101]

How do you not get more views!!!

[@Lemurion287]

I think the only problem with SpaceX's architecture is getting the FAA to sign off on that many launches in quick succession.

[@EagerSpace]

It may not be the only problem but it certainly may be a significant one.

[@plainText384]

The more interesting question is why NASA didn't plan from the start to fly 2 SLS rockets per Artemis mission, one with the Orion Stack (and possibly a co-manifested payload like a gateway segment) and one with a relatively large lunar lander (38t). It's what the chinese are planing to do with Long March 10 and it would have allowed NASA to only develop a single method of getting large payloads to the moon, rather than what they are currently doing, which is developing two additional orbital-refueling-based methods of getting a large and heavy object (like a lunar lander) into NRHO. The answer is of course that SLS is very expensive and struggling to be produced at mediocre rate, but still.

[@EagerSpace]

That's pretty close to what constellation would have done with its architecture, but SLS was just designed to be a big rocket and not actually part of a real architecture.

[@ivonakis]

Every milestone will accelerate starship development immensely - booster catch/ reuse - starship land / reuse and raptor 3.

[@v44n7]

13:30 I think spacex still needs to prove rapid reusability of starship. Lets not forget Falcon 9 booster comes back to earth with much less energy than Starship from orbit. Starship is way more complex too and has tiles, etc. But I still think they will do it. About using gravity here on earth to transfer fuel. What if we can rotate the main tank inside the depot to make the fuel reach the wall of the tank by centrifugal forces?

[@paulroberts7429]

What your really saying is we need a joint program, space is expensive for any nation, NASA, Space x, China, Russia, EU, Russia and China who are leaders in space stations, we need, why? all ISS life-support is Russian and is human certified, 55yrs of supporting human's , US life-support (experimental) is 400litres a year behind EU, EU is 800litres a year behind Russia, Great Channel, thank you.

[@EagerSpace]

Any new US + Russian program is politically impossible at this point, and it's not very interesting because Russia has gutted their space program. US + China would be interesting but Congress has decided not to do anything in space with China.

[@paulroberts7429]

@@EagerSpace no they haven't they have developed some new rockets, a methane engine, a new rd-171 worlds most powerful rocket will eat starship for breakfast, new rd-180/91, US government/NASA use rd-180 on Atlas 5 till 2030, that is not the same as Russia's Rd-181m, at the moment Russia uses greatest rocket of all Soyuz with 1700 launches crew/cargo to ISS, it won't be beat and Russia as finished its Orbital Service Station frame work its core module NEM-1 is built, its being tested.

[@SpaceAdvocate]

@@paulroberts7429 The RD-170/-171/-180 are excellent kerolox engines, but they've mostly been rendered obsolete by the move to reusable engines. It's also doubtful Russia could produce modern engines with the same level of skill. The Soviet Union was able to do it, but Russia completely underfunded Roscosmos for decades, and on top of that is corruption and incompetence. Soyuz was a great rocket, for the 60s, but today it's mediocre at best.

[@paulroberts7429]

@@SpaceAdvocate They are reusable, Russia built fully reusable, they just stopped product becaue no reason to use, its a moon rocket, US purchased RD-180 because of desperation they had nothing after shuttle retired, Soyuz for 11yrs was NASA's only ferry to ISS, Russian engine's only have a 3 flight lifespan are cheap and super efficient, space x are not fully honest on how reusable there engines are, Nasa is charged a set fee per flight plus NASA gave space x a $2 billion deal, who is benefiting from reusable, space x by law as a private company does not have to release a audit.

[@SpaceAdvocate]

@@paulroberts7429 Kerolox has issues with coking, meaning the engines need to be cleaned between flights. Engines intended for rapid reuse use low carbon fuels like hydrogen or methane. And the Soviet engines have never been recovered and flown again, so it's exceedingly likely that if this was attempted, it would require redesigns. After the Shuttle retired, the US didn't need to buy RD-180. They also had the RS-68 that was used successfully on the Delta IV, and they also had other options that could have been chosen. If you look at the present, the US now has a plethora of different engines - RS-25, Merlin, Raptor, BE-4, Rutherford, Reaver, E2 and that's just the ones that are currently flying. And while it is true that US crewed spaceflight had a bit of a lull after the Shuttle stopped flying, that is the past. Crew Dragon is flying regularly, and is significantly more capable than the Soyuz, while also having a perfect record, unlike Soyuz. Soyuz has killed 4 cosmonauts.

[@retromute5387]

I’m no rocket scientist, so this might be a dumb idea, but could SpaceX add two side boosters to the main one like they do with Falcon Heavy? Wouldn't that cut down on refueling time? Heck, why not go all out and slap 4-6 boosters around it like Boeing’s LMLV?

[@alvianchoiriapriliansyah9882]

Slapping few boosters are not easier than developing a new rocket

[@retromute5387]

Yeah, it’s definitely not easy, but neither is doing 8-16 separate launches with multiple towers and refueling in orbit. It’s probably the best way right now to get some solid experience in docking a Starship though

[@Wisald]

I wonder if spinning the tanker and docked ship could be used to settle the propellant on walls and transfer it out. Fluids would simply stick to tank walls making draining it out relatively easy (I assume) but the connection would need to hold and mass transfer while spinning would definitely introduce a lot of forces where we don't want them however it could save a lot of fuel because it only needs to spin up and spin down, in between they can take as long as they want to transfer propellant unlike ullage that needs constant acceleration to keep propellant from moving.

[@phdnk]

I was entertaining an alternative idea: of a lung-like fuel bag inside of the rigid fuel tank that allows variable gas pressure in between the rigid and the soft tank envelopes.

[@SpaceAdvocate]

@@phdnk You're describing a bladder tank, which is the traditional way of doing this, like on the ISS. But it doesn't work with cryogenic propellant. Material that is flexible and gas tight at cryogenic temperatures doesn't exist.

[@phdnk]

@@SpaceAdvocate thanks for telling me the standard name. In comments below Mr. Eager Space already told someone about rigidity and brittleness of bladders. They also discussed pistons there. Yet I doubt that gas tightness is a requirement. Leaky pistons are ok to me, more so than leaky bladders.

[@phdnk]

I think your spin idea can work without spinning the entire tank. It suffices to spin the fluids inside by some mechanical stirring propeller, gas viscosity will impart the motion to the entire fluid supply.

[@Wisald]

@@phdnk Interesting idea but spinning fluids inside tanks mechanically would cause the whole ship to spin in the opposite direction, just like in a helicopter, angular momentum has to be conserved so you would need to despin using thrusters anyways and you would also have the weight penalty of this spinning device.

[@thehiddunicorn8917]

I'm probably missing something, but I think the Starship is a brilliant interplanetary ship. However, I don't think it would make any sense to land it on the moon's surface. Creating a new version of the lander, which, when combined with the starship, could create a very safe and flexible mission. With the amount of space and fuel the starship can carry, it would make a trip to the moon downright convenient. In my opinion, the Starship (despite how reliable it will be) lacks the redundancy that the Apollo 13 landers represented.

[@TheEvilmooseofdoom]

Takes a lot more money to make specialty craft. How can you say starship lacks anything? It's not nearly done it's development.

[@donjones4719]

The Apollo landers had no redundancy. If the ascent engine failed to light the astronauts were doomed. Do you mean a Starship should carry the crew in a cabin and also a lander in the cargo bay? The current BO lander proposal is too large to make that work and anything smaller won't meet NASA's objectives. There are a number of other problems. Starship is meant to be able to land, designed to be so even before it bid for the HLS program.. For a number of reasons it's more stable than it looks. It'll also be safer to land than Apollo or similar landers. If the terrain it sets down on is too uneven it can sense it and just lift off immediately and fly to another spot. Its large propellant supply will make this possible. Also, the landing legs will be self-leveling. Finally, the landing spot can be carefully chosen, we have much higher resolution pics than Apollo did.

[@thehiddunicorn8917]

@@donjones4719 Thank you for your response. This has been on my mind for a long time, especially after watching one of the episodes of Smarter Every Day. I went through the Apollo mission lander's manual myself and was surprised by the emergency options they had (including exiting the module and manually cutting off the lander's legs with scissors). (Im referring to "I Was SCARED To Say This To NASA... (But I said it anyway) - Smarter Every Day 293" and "Apollo Operations Handbook Lunar Module (LM 11 and Subsequent) Vol. 2 Operational Procedures"). As for the lander, I imagined it more like an extended version of the Apollo 13 mission's spacecraft, where the lander was attached to the front of the ship. Transporting the lander in the Starship wouldn’t make sense.

[@donjones4719]

@@thehiddunicorn8917 Yes, I saw the Smarter Ever Day episode. IMO it was definitely not Destin's best. He didn't comprehend the paradigm shift of Starship and was judging its feasibility from his background of working on government defense projects. Starship HLS is far from the usual government project. It was also clear he didn't do a deep enough dive before recording. Many in the space community were critical of it (and not just SpaceX fanboys). Too bad, because he does do some nice work. You'll be interested in the Eager Space video "Will Starship Fall Over?". Spoiler alert: Eric says no, it'll be quite stable. Yes, transporting the lander on the front of a Starship would make more sense. There is the problem of mass, though. The BO lander, for example, is pretty sizable for a space vehicle. When fully fueled that's a lot of mass to accelerate to TLI and decelerate to NRHO. Would there be enough propellant left for TEI of the Starship? Refilling in NRHO might be required - logistically difficult and a nightmare for NASA to contemplate. Even if there was enough propellant the ship would have to use atmospheric reentry to decelerate to land. NASA won't be a fan of that for a long time. Another Eager Space video, "Commercial Moon", provides a lot of insight about the masses to be moved around when going to the Moon and landing. See Options 3 thru 5. This doesn't directly address your lander proposal but it'll give you an idea of the problem. There is good news in there.

[@thehiddunicorn8917]

@@donjones4719 Thanks a lot, that clarified a lot for me, I'll watch these videos and read a bit more. I'm definitely interested in the further development of the return to the Moon.

[@SRQRay]

Question: If its so expensive to get mass to space, why are we so focused on returning the same mass back to earth?

[@Shrouded_reaper]

Because the mass of the launch vehicles is a very expensive piece of high technology that you can't afford to throw away every time if you want to get serious about spaceflight.

[@andrzejdudzinski57]

Why transfer fuel in space from one tank to another instead of transferring the whole tank from one starship to another?

[@EagerSpace]

There is not internal tank for starship. The walls of the tank are the walls of starship. If you went with internal tanks, you would add a lot of mass and you would need to figure out how to reload them.

[@xyzero1682]

09:00 you double-spoke on the gravity pump bit.

[@nommy8599]

Actually I bet he pasted the recording twice but only spoke that sentence once in the video. 😉

[@admarsandbeyond]

Spacex already had a successful refilling test between tanks inside a Starship.

[@jblob5764]

Why does the Advanced Exploration Lander look like a beginner's KSP moon lander?

[@EagerSpace]

Maybe KSP based their design on the NASA design...

[@mbmurphy777]

It sounds to me like the solution is to get a better transfer vehicle. Orion needs more Delta V. Not a simple fix, but I really need to take workload off of the lander and give a better safety margin on the transfer vehicle. Starship should be able to put Orion with a big transfer stage into orbit

[@mudkatt2003]

great stuff

[@bbgun061]

Can methane be stored as a supercritical fluid like LO2? I think that would simplify the ullage problem.

[@EagerSpace]

LOX requires 50 bar (ish) pressure to be supercritical, which I would expect means thicker tanks plus you have to be warmer, which means you can't get the density bump subchilling gives you. I think liquid methane behaves the same but was too lazy to find the temperature and pressures.

[@Tanstaaflitis]

I imagine the thrust to settle the fuel is provided by the Starship mating to the depot. I wonder if the lowest throttle setting of one Raptor is within a sufficient range?

[@SpaceAdvocate]

That's way, way too much thrust. Two Starships and 200 tons of propellant with a raptor at 50% throttle would still be around 0.3G. You want more like 0.01G.

[@Tanstaaflitis]

@@SpaceAdvocate Can Raptor throttle down to 10%? If not, maybe the cold gas thrusters are sufficient. Their reservoirs can be increased for the mission. Or do a cryo bleed on Raptors, which could provide thrust as well as chilling the engines for relight.

[@SpaceAdvocate]

@@Tanstaaflitis No, they can't. And even at 10% it would still be far too much. I believe they'll use the methalox hot gas thrusters they've been talking about.

[@Tanstaaflitis]

@@SpaceAdvocate I haven't heard about those. I know there's many potential solutions.

[@EagerSpace]

My guess - and I didn't talk about this - is that you get part of it just by gas venting from the target tanks. If you need more you can add a little heat.

[@wakamoli8248]

It seems to me SpaceX should test their Mars spacecraft and use the moon to run feasibility test such as adding a moonbase with back and forth transportation before being setting for Mars.

[@mick_hyde]

I wonder what will be needed for mars?

[@TerezaTaylor-l8f]

Great video, however you deal with possibilities like possible to launch starship rapidly, despite this not being done. Payload to orbit via starship is another hypothetical scenario, so far 0 payload was delivered, so any numbers you use are arbitrary and being changed by space x on regular basis. I prefer to reserve judgement until some tangible achievement is actually reached.

[@EagerSpace]

Orbital refueling works fine if you launch once every few days, and it likely works if you launch once every week. I did a video on propellant depots where I did some calculations. Do you not consider catching super heavy and getting Starship back to a controlled landing in water twice tangible achievements?

[@TerezaTaylor-l8f]

Anything is hypothetically possible, however catching the booster although an achievement, has no bearing on rapid reusability due to the heat damage to the engines, damage to the launch pad. Theoretically you can turn around and go again but engines will need changing, launch pad needs fixing and so far only payload is a banana to low earth orbit. In a greater scheme of things not much of achievement when NASA has been to the moon several times, sent rovers to Mars, probes to the far reaches of Solar system, when you compare it to that, space x is not making a dent. I would like to make clear that I really enjoyed your video, just don’t share the optimism.

[@EagerSpace]

I'm generally on the skeptical side of the house. In this case I think SpaceX has a really good track record of working through hard problems with Falcon 9 and I expect that they will be able to deal with similar problems with Starship and super heavy. Or they will have to modify their approach to something that will work.

[@alicelund147]

What if the Starship was split in two parts to make a 3-stage rocket? The present lander is unnecessary large mostly being empty fuel-tanks.

[@nikolatasev4948]

This would involve throwing away some of the stages, and needing to build more. Full reuse makes the launch far cheaper.

[@EagerSpace]

How do you land and reuse the second stage?

[@alicelund147]

@@EagerSpace If it separates in high earth orbit with just a bit fuel left to make it reentry. The third stage/spacecraft has then much less mass to propel to the moon, when the empty tanks for getting in to orbit is separated.

[@EagerSpace]

Ah. So you are talking about a two-stage rocket and then using some sort of kick stage to get to the moon. That's pretty much the constellation architecture. It's workable but you would need to build something different from starship/

[@UmmerFarooq-wx4yo]

Why not stitch 16 spacex launchers together?

[@mrbruce307]

how big will rocket be carrying the fuel to gas station? I don't see any larger rockets being made to carry extra fuel. When we see rocket being fuel up, it is full. There is no extra space for anything, so where will this extra fuel go?

[@SpaceAdvocate]

The tanker variant will likely extend the tanks into the payload section of the Starship. This adds up to around 1000 cubic meters extra propellant. But even if they don't make this specialized variant immediately, you can use a standard Starship with no payload. Without payload, Starship burns less propellant getting into orbit. It will arrive in orbit with up to around 100 tons of of propellant left over in the tanks, which can then be transferred into the propellant depot.

[@ch4.hayabusa]

Make a video about the feasibility of sneaking into a cargo mission to mars. Assume life support will be tested and you can steal a space suit from Axiom.

[@EagerSpace]

Cargo missions to Mars are likely to be at least 6 months long. Maybe there's food, water, and air, but maybe no space toilet. And what will you do with your time?

[@imaginary_friend7300]

Why would cargo need life support?

[@ch4.hayabusa]

@@imaginary_friend7300 for testing purposes... You can never test life support equipment enough.

[@saltmine59]

Is it realistic to expect Starship to be refurbished in such a short time (6 and even 12 days)? Super heavy is much bigger and complex than the first stage of falcon 9 and yet his refurbishment could be done faster (for 6 days) or only take 3 more days (for 12 days) than the best falcon 9 refurbishment (9 days)? Starship has to go through reentry, but they are going to check everything in 6 to 12 days?

[@EagerSpace]

Super heavy is bigger but less complex in terms of refurbishment. The big difference is that the raptors don't need to be cleaned the way the Merlins do because methane doesn't produce soot the way RP-1 does. Starship is a different question. The goal for the system is "airplane-like operation". That implies very quick turnaround.

[@saltmine59]

Sure raptor don't need to be cleaned the way the Merlins do, but there is 33 raptors on super heavy and only 9 engines falcon 9. That is still a lot of cleaning to do. As for the airplane-like operation for Starship, SpaceX kinda had a similar goal for falcon 9 (24h for the first stage) and they did not reach it (yet). So to me, it seem less likely that they are going to archived something like that with a vehicle that undergoes temperatures of 2000 C. Certainly they are going to check in some way most of the tiles and that would not be a quick process.

[@SpaceAdvocate]

@@saltmine59 They don't plan on cleaning them at all. Just fill the rocket with propellant and go again. Obviously, getting to that point will take a bit of time. I'm sure that for the life leader, they'll be doing static fire testing between each flight. And there may be engines that need replacement/refurbishment between flights. But once they have boosters that have flown a bunch of times, they won't be doing static fire tests between flights. They'll just load up propellant and go again. Some engines may fail, but that is fine, because they have engine out capability. Over time, the number of failed engines will drop and it will become a very rare occurrence. When it comes to the heat shield, they seem to be going for a redundant solution, where they have an ablative heat shield below the ceramic heat shield. They are likely to do some checks between flights, but if they lose a tile because of insufficient checks, that's fine. They'll just replace the ablative material and the tile. Taking a day to potentially replace a missing tile is better than spending days and weeks going over the heat shield between flights.

[@saltmine59]

@@SpaceAdvocate Ok, and when is SpaceX going to be able to do that? They are already late for Artemis, certainly they do not want to delay Artemis missions more. As for the heat shield, we have seen, with ITF4, that a missing heat tile can have a cascading effect, which is not desirable. As for the ablative material, it was my understanding that it is a last resort solution in case a new (unuse/first flight) tile fell off during reentry. Is the ablative material alone capable of protecting starship for the duration of the reentry? If not, Starship must not lose a tile during take off. To archived that (with the current technology), i do not see any realistic procedure other than checking most if not all the tiles. To archived that cadence of launch, I think that (with the current technology) SpaceX is going to need more than 1 or 2 starships to make the refueling. Maybe 4 or more in rotation.

[@SpaceAdvocate]

@@saltmine59 "Ok, and when is SpaceX going to be able to do that?" We're probably a few years away for turnaround time in under a week. But reducing the turnaround time will be a gradual process, and SpaceX doesn't need a turnaround time in under a week to do Artemis. SpaceX currently has 3 Super Heavy boosters near ready for flight, and 3 Super Heavy boosters in construction, as well as two Starships near ready for flight and another being constructed. Only having two full stacks isn't a very relevant scenario. SpaceX is gearing up to have a lot of vehicles. They are planning on having four operational pads towrds the end of next year. And I would expect SpaceX to have several vehicles per pad. For the heat shield on IFT4, we saw that the design wasn't ideal around the hinges on the front flaps. The burn through probably wasn't a result of losing a tile. The design just had a weak spot. The flight was performed with missing tiles on the aft skirt, and it's quite likely that other tiles fell off. Yet the vehicle was able to complete the full mission and make a soft splashdown. So already, we know that missing tiles can be surviveable. Though likely with substantial damage. I believe the ablative material is primarily to avoid needing to scrap the vehicle, if you lose a tile.

[@mustang607]

Another KZbinr who does "rocket science" did a number of calculations using the new SpaceX Raptor 3 engines. After prototyping is finished, it seems it will take some 4 to 5 refilling Starships depending on the required tonnage to get to and land on the moon.

[@SpaceAdvocate]

I agree with Eager Space here, it's not about doing math. There are just too many unknowns. If HLS Starship ends up with a propellant load of 2300 tons and Starship isn't able to get past 100 tons to LEO with full and rapid reuse, that's a minimum of 23 launches. If HLS Starship has a propellant load of 1200 tons and Starship gets to 200 tons to LEO, that's a minimum of 6 launches. We just don't know. Once Starship is operational, and capable of full and rapid reuse, then it will be possible to do the math with much more accuracy.

[@regolith1350]

What are your thoughts on the Starship HLS landing engines? When SpaceX revealed their first HLS render with that ring of small thruster engines halfway up the nosecone, I thought it was genius and obvious in hindsight. It completely erases the engine plume problem that every lander has to deal with (which many thought would be a dealbreaker on a ship as massive as Starship) for both landing and takeoff. The best landing engine is no landing engine. But it does add a lot of complexity and Musk has hinted in the past that he'd prefer not to have to use them, and use the raptors on the bottom of the ship if he can (yikes), but he hasn't discussed that in a while.

[@EagerSpace]

No idea. I'd love to have an update on their thinking, but other than a new render there hasn't been much on the lander.

[@QuiLe-qw5jb]

Do we walk before run???!!! 😅

[@amirsa7140]

Spacex has the option of extended starship with 400 ton payload to orbit, sometimes i wonder if reusability of second stage is needed for starship or not, elon says all the time that they are going to lower the cost of raptors to 200k, and stainless steel body woth out heat shilds and flaps is really easy and cheap to build, why using it twice

[@mattfgln]

Make the lander a 2 x 17 tonnes modules and assemble it in orbit

[@FishyAltFishy]

this is a very beneficial way to do it as spacex, they get to launch way more starships and get data, but poor Artemis, this might actually make Artemis one of the many failed "lets go back to the moon" programs.

[@สวนพวงพกา]

1. SpaceX launch several of Starship tanker to space station for propellant storage 2. Send the starship to LEO and fill up the propellant for moon. 3. Transfer astronaut to stay at Space station by crew dragon 4. Dedicated Astronaut transfer to Starship and travel to moon nas Mars and return to space station 5. back to earth with Crew Dragon

[@fmilan1]

Dr. K maximizes my delta V?... What kind of delta V we are talking about? Horizontal delta V or vertical delta V?

[@EagerSpace]

Depends on which was your rocket is pointing...

[@fmilan1]

@@EagerSpace True.

[@davidrpayton]

They need to build a transporter system...

[@beefstew6512]

8:50 editing error

[@diamondzoyd]

An Artemis moon landing is not happening, Starship will take the next humans to the moon.

[@imaginary_friend7300]

If not for Artemis why would starship go to the moon at all?

[@espeterson522]

Why did SpaceX choose this architecture? Because physics. It's ALWAYS because of physics.

[@PeteSty]

52 years Apollo did it in one shot. No refueling.

[@admarsandbeyond]

Apples to oranges. Starship has massive capability that will allow a sustainable presence and large scale exploration and settlement, it won't just plant some flags and leave.

[@fauzin3338]

Different mission scope. Artemis' scope is certainly larger than Apollo's. NASA could easily replicate Apollo's mission architecture if they really wanted it, but they didn't.

[@miguellopez3392]

They landed a 15 ton vehicle on the surface while starship will be 100 tons.

[@michaeljorgensen790]

Seems complicated? When we first went to the moon NASA very quickly gave up on the idea that everything landed on the moon had to come back off of it. That simplified everything.

[@donjones4719]

That also limited everything. NASA is looking for maximum reusability of lunar components in the Artemis program.

[@mountainshark2388]

They just don't understand what a fully reusable starship means.

[@brianbynum4487]

Yes, you started off good , but 2 starships and 2 boosters.but let's continue

[@1fastal1]

Buy ULA and make 1 way tankers with aluminum. ULA has all the tech for that

[@SpaceAdvocate]

So does SpaceX. Falcon 9 is aluminium.

[@GordonWrigley]

Simplicity... occams razor is not less refuelling events, it's less types of refuelling events.

[@АртёмМоисеенко-л2з]

The problem with statship is that it is only 2 staged and fully reusable wich makes it less efficient but on the other hand makes each launch cheaper and SpaceX trying to balance on top of that

[@nommy8599]

You think 3 stage fully reusable would be better? Why?

[@АртёмМоисеенко-л2з]

Did you play KSP?

[@logicalfundy]

SpaceX does not like needless complexity, and they are banking on the idea that fuel is cheap.

[@АртёмМоисеенко-л2з]

@@nommy8599 yes, because you will not have to have a heavy but empty tank all the time which is useless, but it is not great for reusability.

[@nommy8599]

@@АртёмМоисеенко-л2з It can't be empty, it needs fuel to land. That's kinda my point, perhaps multiple stages lose their benefit somewhat when they're required to be fully reusable. You know?