Starship's Problem With Orbital-Refilling

[@FarokhBulsara4065]

i think there's a reason why Tom Mueller, the father of Falcon 9, quit SpaceX and founded Impulse Space to develops space tug, or kick stage for MEO, GTO, GEO, TLI even on their website, Helios kick stage is described to be compatible with Falcon 9, Falcon Heavy, Starship, even New Glenn it uses liquid methane btw

[@johgude5045]

​ @Piolet1549 it would be so nice to see a video on that. Especially on the reusable and refuelable space tug

[@mbmurphy777]

More launches is also more wear and tear on the equipment on the launchpad, the engines, stress on tanks and valves, etc. It’s not just the cost of the fuel

[@Piolet1549]

Good point

[@Blaze6108]

Yeah, something I think people discount when we talk reusability is that airliners already have a finite life due to pressure cycling and such, spacecraft would probably be even more short-lived - although still better than throwing them away, of course. That's why most airliners you'll ever fly are reasonably new, whereas in France you might instead take a train that is pushing 40 and still works perfectly.

[@ThePhantomRocket]

As a SpaceX employee: Great analysis! The armchair scientists in your comments are pissing me off though.

[@jaimeduncan6167]

You clearly correct. What you failed to mention (probably because you are trying to give the refuel crowd the best shoot) is that almost nobody needs to put 50Ton+ in GEO. People seldom need more than 10K kg. So yes Starship needs a GEO delivery stage as the Space Shuttle needed. IF it does not, it will make more sense to send the satellite in a Falcon Heavy, a Vulcan, or a Chinese or Indian rocket.

[@ohedd]

I suspect Tom Mueller did the math, and then he started Impulse Space to accommodate precisely this market demand. Helios would be the closest thing to whatever you outlined here as an option seeing that it's methalox.

[@Piolet1549]

Yeah, seems like some smart ppl have come to the same conclusion. Gives me confidence in my math lol

[@NovaCantera]

Thats also why SpaceX probably isn't too concerned about making their own at the moment as other companies seem perfectly happy filling that gap for them. Their apparent lack of kickstage development could also be due the missions they are focusing on atm requiring an entire starship to get to the destination, not just an internal payload.

[@ohedd]

@@NovaCantera strangely Tom Mueller left SpaceX specifically because he was done with Merlin and he wanted to do Impulse Space, after having mostly worked on Raptor and Mars ISRU stuff. So since he left SpaceX to pursue kick stages separately, he probably tried to get SpaceX to focus on it and they didn't want to. Maybe because it was too much on their plate? Who knows why exactly

[@mycalltoadventure9712]

@@NovaCanteraI would not be surprised if there is a team at SpaceX that is working on kick stages.

[@visyxl]

Why is piolet teaching me the exact centimeter to centimeter aerodynamics of the left foward starship fin 💀

[@Meaty_Michael_0]

Put the Methane in the tank lil bro 💀🙏

[@Meaty_Michael_0]

jk i love your content!

[@just_archan]

I think while you consider kick stage/orbital refueling, you forgot one more option: Dedicated spacetug. Vessel that will STAY in orbit. Powered by methalox, using ie single gimbaled rvac, and instead heavy stainless steel could be made out of lighter, while less robust materials, ie quite similar to falcon 9 material. It could utilise same refueling hardware as starship., with capacity ie of two tankers (never fully loaded tho, just will be refueled by one full tanker, even if is not empty. ). Proper insulation similar or better used in potential fuel depots or HLS would reduce boil off. Outside standard set necessary to function i. Orbit, could be equipped in something similar to canada arm on iss. On starship there should be something like detachable payload adapter with attachment for this canada arm, and hardware attachment for "docking" of this tug during swapping of payload from starship. Tug could have additional attachment point for empty payload adapter, that after retrieving payload from starship, it could mount old one back on starship so it would return to earth for reuse.

[@Ittiz]

I think SpaceX will never do a kick stage, too much extra complication. Which does have a cost. For a kick stage to be worth it over just refueling, only using more fuel, you'd need at least a thousand launches to GTO. Since pretty much all of Starship's launches past LEO are planned to leave Earth orbit entirely the math doesn't make sense at the end of the day.

[@WasatchWind]

That's why it's great that Helios is helping out 🙂

[@zachb1706]

I’m sure SpaceX will want to capture part of the GEO.

[@johgude5045]

@@WasatchWind exactly. not only for Mars but also for the moon. Why should a fully fueled starship in LEO carry only 130tons to the moon and be only fueled by 1/3? Oh because it can carry only 130 tons to LEO in the first place so a fully fueled one would need to get the extra payload loaded in during the LEO phase. Not so nice

[@NorrthStar]

What mods did you make for your super heavy in ksp at 0:51? If you tell me I will sub.

[@zam6877]

These are a great series People get a little manic SpaceX But the physics just needs to played out Solutions for these novel, more complex systems will eventually become clear

[@branch4747]

You know how hard it will be to send 2000 tons of fuel to orbit and the max we can sent was 140 which is the iss

[@zachb1706]

Just because we haven’t done it doesn’t mean it’s super hard. We haven’t really had a reason to use orbital refuelling

[@brunoscarlatto4679]

I think that space x should design a larger superheavy, which would allow the starship to be given more speed and save fuel. basically like what we used to see in traditional rockets regarding the proportions between the stages. It would also allow the launch of denser objects to low orbits and even achieve an unconventional and somewhat inefficient single stage to orbit.

[@cube2fox]

I think SpaceX should design a three stage Starship for improved efficiency. With the middle stage landing on a super large drone ship.

[@That_Awesome_Guy1]

I don't think starship was made with high earth orbits in mind. It's either leo or to the moon or mars. Space tugs or kick stages could be used for high earth orbits, but that's not a problem they're trying to solve right now.

[@samcg1492]

I'm loving all these videos

[@The1Jebrim]

In the age of LEO constellations, is there even much demand anymore for satellites to be launched into GTO? Could they not just use the extra launches to launch even larger amounts of LEO satellites instead?

[@NeilX2010]

If you propose a kick stage, u don't have to transport a kick stage on the starship every time, just build a reusable kick stage and rendervouzs with the payload the fuel it need, and let the kick stage do the job??

[@Piolet1549]

That's an interesting idea, idk why I hadn't thought of it. As you said it would need to be re-filled in orbit, guess one would have to run the numbers to see how it would all work out, but I think it could be a good idea

[@616CC]

Well sounds like I would use orbital refuelling with a kickstage problem solved

[@ValidatingUsername]

It’s certainly possible; but also necessary!

[@JonathanSchrock]

Why are we recovering the kick stage? That would require Starship staying in orbit for much longer to rendezvous with it, and more propellant for the stage for the same reason. Also, there would have to be hardware modifications in the payload bay and on the stage to allow for a recapture method that wouldn't let the stage bounce around on reentry. That adds a lot of mass. The economics of that make no sense.

[@Piolet1549]

Recovering the kick-stage from GTO only requires an additional ~8% of propellant, so from that perspective it would make sense. Doing a recovery would prolly require a ship to stay in orbit for an extra ~4 days. I personally don't think it would be a big deal, but I could understand if your concerned about re-use speed or something along those lines. In terms of hardware on the ship, I would actually expect that most cargo ships would include some type of re-capture mechanism to bring down old satellites for maintenance. Doesn't have to be something permanently attached, but could be swapped in when necessary. How much all of this weighs is obviously subjective but one thing I would consider is that it takes a while to build a rocket stage. If the launch cadence becomes what people think then having a new stage built in time may be difficult, might be simpler to just reuse. Those are my thoughts at least, is an interesting topic

[@josephmoore4764]

It seems odd to me to think in-orbit assembly would be so much more complex than a refueling operation. A special kick stage, or space-tug like you mentioned that could fit in the payload bay could be deposited in orbit, and meet with the payload to higher orbit, without the need to drag the heavy hull of starship along with it. Sure, it's not 100% reusable, but we also don't have any idea how easy it would be to reuse starship from high orbit re-entries either, if it can't that kind of defeats the purpose with starship having 2 contradictory capabilities

[@_mikolaj_]

I mean, look at it this way We have been doing in orbit assembly for past decades, and we are yet to achieve large scale propellant transfer in space

[@Asterra2]

Oh, so this is all about GTO? Fair enough. Orbital refueling isn't being pursued for that. It's being pursued because they want to send 200+ tons to Mars at a time. Conveniently, the same tech will let them put 200 tons on the moon in one go, when Artemis gets around to needing that.

[@Piolet1549]

Yeah I agree. My last vid was about GTO and that's where I got all the comments about re-filling, so that's why the focus is on GTO

[@johgude5045]

@@Piolet1549 A fully re-filled starship should be able to transfer much more than 130 tons to the moon as it has much more delta-v then needed for the 130 tons

[@ThePhantomRocket]

Hey, SpaceX employee here. That is the preferred goal but starship needs a near redesign for those numbers to work. Stop acting like starship is perfect in every way. It isn't.

[@Asterra2]

@@ThePhantomRocket I have it on good authority that redesigns are in the pipeline. And furthermore that Starship is still in prototyping. "Perfect" isn't a word being tossed around here, but I wouldn't hesitate to suggest that in the landscape of prospective rockets, it is super idealized for its particular goals.

[@MBMachine23]

@@johgude5045 That is true but the starship only has enough delta v to get 130 tons into orbit so that is the limiting factor here you have to be able to get it into a safe orbit for refueling in order to refuel it.

[@leoveenman3674]

If one can make fuel on the moon that is what one should do and bring this fuel to a refueling station at the optimal orbit.

[@bobo-cc1xw]

If i have a cargo plane I generally don't have a single use booster to help extend range. Probably business model has used to orbit mass to fill up depot

[@branch4747]

Starship was made to be reusable for dozens of missions and to be refueled fully in a day

[@ricardoabh3242]

Very informative

[@brandonfigueroa7399]

Can you calculate the effectiveness of using a starship/falcon variant of the Jupiter III. Would the ship get to orbit fully fueled?

[@hieunguyen-bj3fx]

I failed to see how 2 starship launch with kick stage would be cheaper than 5 launch, a falcon 9 stage 2 cost up to ~15M and is the majority of falcon 9 cost, a kick stage would likely be in a similar ballpark.

[@michalfaraday8135]

The kickstage is expected to be reusable :-)

[@demondoggy1825]

It's not really a kickstage then, it's an orbital tug, and that's a completely different argument

[@hieunguyen-bj3fx]

@@demondoggy1825 anything with an RL-10 engine would not be cheap

[@demondoggy1825]

The video is arguing for a tug to take the payload to GEO, then return to Starshjp and get recovered. While an RL-10 would be hilarious expensive, reusing it would likely make it cheap enough that such a setup makes sense. An actual expendable kickstage powered by one would be stupid though.

[@hieunguyen-bj3fx]

@@demondoggy1825 hmm I don't think that's what the video try to model in the graph but I guess you can do a whole lot of delta v with a 130t payload

[@znek4288]

I think destin from smarter everyday went with the same complaints to nasa engineers

[@demondoggy1825]

Hey OP, good video but you should probably call your hypothetical setup what it actually is, an orbital tug. A kickstage doesn't come back.

[@gregoryramoundos2034]

at the end of your video, you just basically answered your own question you’re talking about block two through most of the video but then you said that block three it probably would solve all the problems. That’s why he’s going to block three who knows they may be a block four.

[@MarkCupLee]

What cost more? An expendable kick stage, or couple of reusable starship launches?

[@JesbaamSanchez]

If that was the case, then why would Tom Mueller leave the company and develop another company that would develop kick stage that would be compatible with Falcon 9 and, maybe if they wanted to, develop a kickstage Starship

[@MarkCupLee]

@@JesbaamSanchez That was a genuine question of mine, and refueling is not an option for Falcon 9.

[@Super-Duper_Space_Goat]

Why would the kickstage be expended?

[@illustration7090]

@@Super-Duper_Space_GoatDefinitely. At an orbit that high they wouldn’t want to.

[@minerscale]

Five launches or throwing out one stage? Unless SpaceX is doing like a starship launch a week or even faster I imagine the expendable stage is cheaper.

[@RandomGoll]

banger video!

[@cjking7728]

Could we possibly maybe just just maybe and possibly and maybe possibly maybe get more possibly maybe more ksp vids 🙂‍↕️ also loving the new vids bro

[@pzkfw_warthunder]

There are KSP videos being made, I cannot say what's on but trust me there are some good ideas!

[@chalant-g2n]

wouldnt it be really hard to reuse a kickstage tho?

[@demondoggy1825]

Not really. Drop it, it burns to GTO releases the payload, then as it comes back to periapses it rendezvous with Starship and both return. The docking mechanism is going to be the most complicated part but there isn't any technical challenges to really prevent it.

[@Piolet1549]

Based on the numbers I used (which may or may not be accurate), reusing a kick stage required ~8% more propellant than if it were expended, simply because of how much more efficient it gets after payload deploy.

[@chalant-g2n]

@@demondoggy1825 exactly, docking back into a payload bay sounds like an insanely difficult maneuver, and one that would certainly require heavy rcs systems for proper precision the other option is bringing the stage back to land, which probably is far too infeasible

[@chalant-g2n]

@@Piolet1549 im more so talking about rendezvous in orbit with another starship or bringing it back being the difficult bit, in either case feels like itll have to take on quite a bit of extra mass to make the cut

[@Pamba07]

you really need keys for your graphs 🙏

[@Piolet1549]

I do try to add text on the graph when something not clear, but sounds like I need to improve. Will make changes for next vid

[@Pamba07]

@@Piolet1549 would also hugely appreciate X and Y axis title always present just so I don’t forget 🙏 ❤️

[@Piolet1549]

@@Pamba07 will do

[@snapshuttre]

at this point we need to understand which resourse will be more scarse in the future? the rocket fuel? or the materials that the kickstages are made out of? counting everything with today's market cost won't give us a proper look for the future.

[@saumyacow4435]

More expensive than the materials for the kick stage and the rocket fuel is all the overheads associated with the launch complex and the launch process. Peter Beck (the CEO of Rocket Lab) put it this way. He said that two thirds of the cost of launching stuff into orbit is the operations cost, not the vehicle.

[@hieunguyen-bj3fx]

@@saumyacow4435 Which meant that more launch would reduce the operations cost per launch.

[@saumyacow4435]

@@hieunguyen-bj3fx To some extent yes. The problem for Starship is the sheer complexity of the second stage and what that does for the cost/timing of reuse.

[@zachb1706]

Fuel is cheap.

[@liamoliverdarroch6482]

Cool vid

[@jackdbur]

Why in the #$@ would SpaceX fly Starship to GTO you toss out the payload in LEO with a kickstage 😊

[@WernherVonKerman.]

Stoke kickstage anybody?

[@ThePlecoPal]

Starship isn't a good platform outside LEO

[@theredstonehive]

8:08 Block 3's payload section in that render is the same as Block 2's, which is comically small (about 3 rings tall including the volume in the nosecone).

[@Asterra2]

The render is not transparent so I'd love to know your source. Officially, Starship V1's payload is 17 meters tall. I would be extremely surprised if the V2/V3 grew in size, doubled or quadrupled payload mass, but _shrunk the payload bay by over 60%._ But even if they did... that's the beauty of a vehicle that was designed from the ground up to be cheap to manufacture. If you actually need a fairing that's taller than 17 meters, you can kick out a custom Starship, like they'll be doing for HLS for example.

[@theredstonehive]

@@Asterra2 You can see where the starlink door is and that's always at the bottom of the payload bay.

[@philippeferreiradesousa4524]

Lol, I didn't watch the other video but the comments seem fair. You are missing the whole premise of Starship. It can deliver payload to GTO **fully-reuseable**, the return from GTO / TLI is delta-v free with aerobraking. You are saying that you believe that LEOGTO shuttles are cheaper per kg of payload as expendable. Maybe it is true, I want to know, but you are totally unaware of the argument you are making and do not even try to ballpark cost estimates of the 2 approach. You believe that you are looking at staging vs refueling while you are looking at expendable vs reuseable. 4t dry mass tug? Add a heat shield, and aerosurfaces. Remove them from the Starship that you are sending to GTO without mentioning you are getting it back. Heck yeah you may even keep it in orbit and do LEO GTO shuttles, but you'd want a Starship variant optimized for that, no fairing. An RL10 is $12M I am reading, that's likely more expensive than the whole Starship flight. Also what's with the attitude? This is an actually interesting topic. Maybe the 2 options are a wash, I want to run the numbers. I think that just using Starship is great for capital efficiency by of course in terms of marginal cost, an optimized fully reusable tug would be better. Actually mainly because Starship is optimal for 130t to any orbit. Good luck finding this customer. The reusable tug shuttle taxiing and refilling in orbit will put 30t to GTO per Starship flight and everybody will be happy.

[@philippeferreiradesousa4524]

The other thing to take into account is that Tanker Starships have more payload capacity for fuel than Cargo Starships. In particular for GTO / TLI where you refilling it half full, it would help to use smaller Cargo Starships. For example I believe that the HLS will stay Starship v1 size while the tanker will be bigger v3 Starships. That is lower dry mass, faster refilling, more optimal mass fraction.

[@demondoggy1825]

Rewatch this video. He's proposing a reusable tug, not an expendable kick stage. He's just bringing the tug down with Starship rather than leaving it up and rendezvousing with it

[@christiananderson9015]

Early is an understatement lmao

[@resvero8342]

Space tug

[@Qausar-q3s]

Hello👋

[@irhtirht]

Orbital refueling, not refilling, please. That is what it is normally called.

[@Jake-uc8mb]

I just refilled my water bottle from a larger water bottle. I believe that can be done with fuel also

[@boruta1034]

It's refilling, because you're transferring both fuel and liquid oxidizer.

[@carcinogen60yearsago]

Oxidizer isn't fuel so it's more accurate to call it refilling rather than to refuel because fuel isn't the only thing that's being put in the vehicle.

[@irhtirht]

Maybe it would be more accurate in some ways. It is still called orbital refuleing. If you google search "orbital refuleing" and "orbital refilling" you can clearly see that refuleing is the technical term used in english.

[@carcinogen60yearsago]

@@irhtirht And if he clearly look up in the dictionary gay means happy. But I doubt anyone using the word today uses it like that. Dictionaries are only so useful this is a descriptive language people just start using words and they apply meaning then they get added to the dictionary

[@Inbestigator]

0 views in 2 seconds, bro fell off

[@MergeManny]

😐

[@SleepyGamerPR]

Bro shut up, you probably couldn’t even get 1000 views in 10 days 🖕

[@illustration7090]

@@MergeMannyreal

[@Allthegoodhandlesaretakenlmao]

The commenter has 60 subscribers in 2 years. Bro fell off

[@man-from-2058]

How does it feel to be less original than Amy Schumer?

[@Papershields001]

130 tons of payload per flight for block 2 is exceedingly optimistic. The launches we’ve seen have been demoing around 25-30 tons for block 1. A much more likely figure for V2 is 60-80 tons with ship recovery if things are absolutely maximized.

[@sfslead]

what happened to your voice

[@Piolet1549]

idk what happened lol? I did record this video a little faster than usual so if there's issues thats prolly why

[@sfslead]

@@Piolet1549 your voice sounds deeper than 3 uears ago

[@sfslead]

3 years ago*

[@pzkfw_warthunder]

@@sfslead uhhhh.... do you know what puberty is

[@sfslead]

@@pzkfw_warthunder yes 💀 feels like puberty hit when he was 14-17 years old. i thought puberty starts at 11-13

[@ThePixelated_kris]

4:19 nice

[@SFSEngineer]

I can Make Thumbnail for you videos if you want.

[@pzkfw_warthunder]

He has people that do it for him

[@Piolet1549]

I have an A/B test running so the vid has two thumbnail right now. There's one with two sets of ships, one with an X and the other with a check. The other is one set of ships with a giant X in the middle. Which one did you get?

[@Blob_2_Ship]

According to me, starship is a bit too heavy.

[@ssvcraig]

You'll never land and re use those Falcon 9 rockets Elon...... you'll never use them more than a few times Elon...... you'll never......

[@kiverix]

starship is nice as hell

[@Jake-uc8mb]

Well as of now it's a temu version of space shuttle. But I'm sure they will improve eventually

[@MemeMan_MEMESQUAD]

@@Jake-uc8mb deranged take

[@carcinogen60yearsago]

​@@Jake-uc8mb 14 fatalities < 0

[@saumyacow4435]

"There isn't really any other option". Er, yes, there isn't really any other option for Starship. There are lots of options for getting to Mars that don't involve Starship, at all.

[@pzkfw_warthunder]

name three that do not include starship and can be developed in the next 10 years

[@saumyacow4435]

@@pzkfw_warthunder A tin can with rocket engines is not a fully developed Mars mission. Its not going to be ten years even if its a realistic exploratory mission. Thus I reject your premise.

[@pzkfw_warthunder]

@@saumyacow4435 reject? I doubt you have an answer. Starship is 7 years old, in 3 years it will defo be capable for mars. 10 years from startup to mars is the timeline I gave you, so, answer the question. Unless there is no answer

[@SpottedHares]

⁠@@pzkfw_warthunderdude their own milestone reports to their customer implies they won’t even be able to get the HLS to the by at least 2028.

[@ludwigvanzappa9548]

Starship is a white elephant...

[@Asterra2]

Wishful thinking or do you have some logic and facts to share?

[@ludwigvanzappa9548]

@@Asterra2 Wait and see...

[@Asterra2]

@@ludwigvanzappa9548 That's what I say. Wait a couple of years so SpaceX can release the sequel to their "how not to land a rocket" video, tongue-in-cheek showcasing all the RUDs on the path to a reasonably finalized vehicle. I do feel kind of bad for folks invested in the fantasy of Starship somehow failing. Imagine being on the constant prowl for ways to cope, even grasping at some nebulous perceived inadequacy that has nothing to do with the vehicle's intended purposes.

[@ludwigvanzappa9548]

​@@Asterra2It will get funny...

[@goldgamercommenting2990]

So starship just revealed its weakness Now it’s no better than the shuttle

[@ablert]

I'm pretty sure starship could lift more than 130 tons of propellant since it'd also have more propellant to burn while getting to orbit which translates into a higher payload capacity

[@zachb1706]

Depends what Super Heavy is capable of lifting off the ground.

[@ablert]

@@zachb1706 good point

[@SharkyKSP]

why is bro obsessed with starship 😭 💀

[@Ship_30w]

Shut up

[@penapvp2230]

Why aren’t you?

[@saumyacow4435]

@@penapvp2230 Because in terms of mounting realistic exploratory missions to Mars, there are better architectures than the one embodied by Starship.

[@hieunguyen-bj3fx]

@@saumyacow4435 Like?

[@saumyacow4435]

​@@hieunguyen-bj3fx Well, once upon a time we naively assumed that the way to get to the moon was to build a big rocket, point it at the moon, landing a smaller rocket on the moon and finally that one would take off and go back to Earth. Even Von Braun who championed this idea, eventually conceded that this was impractical. Instead we came up with the solution of reaching lunar orbit and then sending a lander to the surface. Years later we have Mr Zubrin committing the same mistakes - trying to send a rocket direct to Mars and thence directly back to Earth. Starship embodies that "Mars direct" architecture. It has a whole bunch of problems. Not the least of which is you have to establish an industrial scale, fully robotic mining infrastructure on Mars. Tens of thousands of tonnes of Martian soil have to be strip mined in order to fuel one Starship. So there's your first problem. The sheer scale of any vehicle capable of going directly back to Earth leads you into the mire. Where you need a multi megawatt class nuclear power sources and an entire ecosystem of robotics specialising in assembly, maintenance, repair and logistics. And none of this is strictly necessary for a realistic Mars exploration mission. Well, ok, ISRU oxygen is necessary, but that's a vastly simpler, less risk-laden and far less power hungry process. It doesn't require mining. A realistic Mars architecture sees us reach Mars via Mars orbit in both directions. And it uses specialised vehicles that are therefore fit for purpose, as robust as possible and not compromised by having multiple roles - which is the main problem with Starship. To launch you need a vehicle with powerful engines. To land you need the substantial mass of a thermal protection system, plus you need all the additional structural mass to cope with the stresses of re-entry. In Starship's case this means 5 or 6 gs. Whilst in transit, you need a vehicle where every kg of mass is dedicated to keeping the crew alive. It needs to be robust, redundant, have ample consumables and also have mass earmarked for radiation shielding. Can you see the irrevocable compromises going on? Starship is trying to be a jack of all trades and as such is compromised when it comes to the interplanetary long haul. It is saddled wit mass for 3 different purposes. On the other hand if you have an indirect architecture you can build a vehicle that does just one thing, and does it well. Transport humans safely between Earth orbit and Mars orbit and return. Whereas the vehicle specialised for Mars landings and ascent can be optimised to be far smaller and thus requires a fraction of the propellant. Speaking of which, Starship lands people on Mars using a "late lift" profile. Subjecting the crew to 5-6 gs. So by the time you reach the surface, you may have incapacitated crew. A dedicated lander can land on Mars with a profile of less than 2 gs. And then there is the crater that Starship digs into which it has to land. All that debris accelerated to supersonic speeds will, thanks to the thin air and low gravity, be lethal for many kilometers. Meaning you've got a hike between landing and your habitat. Which is even more fun if you've got crew that need to be stretchered out. A small lander can most avoid these issues. And that's the short answer.