Starship flight N5 in 57minutes and they try to Catch the Booster - Page 1
Forum section: electronics / general

author: Gyro
author_rank: Super Contributor
timestamp: October 13, 2024, 12:50:45 pm
content: That was surreal!

author: tom66
author_rank: Super Contributor
timestamp: October 13, 2024, 01:41:17 pm
content: Holy crap, they actually bloody did it. They caught a booster. First time attempt! Incredible engineering. Small fire but that can be resolved right?

author: DH7DN
author_rank: Regular Contributor
timestamp: October 13, 2024, 01:58:30 pm
content: Amazing engineering feat! This was surreal, history has been made today!Congrats SpaceX & Elon Musk

author: Psi
author_rank: Super Contributor
timestamp: October 13, 2024, 02:02:19 pm
content: It was awesomeNow observe all the news organizations. They will totally ignore the successful and awesome booster catch and instead focus on the negative. "SpaceX rocket explodes on landing", when it actually landed, and then exploded.I'm not too sure if they terminated the ship on purpose after landing was over to sink it, or if the ship falling over ruptured a tank. Probably the former.

author: iMo
author_rank: Super Contributor
timestamp: October 13, 2024, 02:39:03 pm
content: The Starship landed nicely perhaps 50m off the target buoy with camera, and the "explosions" were just the gases pushed upwards from the tanks when it failed over (and perhaps it raptured so the water pushed the propellants off)..

author: coppice
author_rank: Super Contributor
timestamp: October 13, 2024, 02:57:05 pm
content: Lots of great stuff in this trip. All of it progress. However, they are really struggling with the Starship heat shield. NASA did. Everyone has. If they had recovered that Starship it would clearly have required a massive refurbishment of the heat shield, just like the Space Shuttle required after every flight. That isn't going to bring Space X to the kind of cheap, fast turnaround reuse they are aiming for. Could this be an insurmountable problem that will wreck the Starship program? I hope not.

author: coppercone2
author_rank: Super Contributor
timestamp: October 13, 2024, 03:00:58 pm
content: given what i see about ceramics and particularly hot ceramics just working with them a little bit and imagining the incremental improvements that you can get in materials (comparing it to metal science) I think that is a distinct possibility.A space elevator is insane unless your opinion of ceramic materials is as low as mineTurn my kiln inside out and try to drop it 400 miles, thats just going to be problematiccrumbly bullshit materials that break for no reasonthis is the technology I would eventually put my money on, active shield. I bet that will be developed before trustworthy ceramics.https://www.universetoday.com/46474/the-next-generation-of-heat-shield-magnetic/

author: Per Hansson
author_rank: Unknown
timestamp: October 13, 2024, 06:09:06 pm
content: Quote from: iMo on October 13, 2024, 02:39:03 pmThe first explosion is pretty big, my guess would be that was the flight termination system: better to use it than to have unexploded ordnance on the seabed or possibly floating around...Was truly amazing to watch the live feed by Tim Dodd (Everyday Astronaut).

author: coppice
author_rank: Super Contributor
timestamp: October 13, 2024, 07:15:31 pm
content: Quote from: coppercone2 on October 13, 2024, 03:00:58 pmElectromagnetic fields act upon plasmas, so field based solutions for heat shields have been looked at since the earliest days of space flight. It never seems to get very far. The link is to something 15 years old. No signs of progress since then.

author: coppercone2
author_rank: Super Contributor
timestamp: October 13, 2024, 07:39:51 pm
content: It's that or magic ceramic.I think they should bring a stock of tiles on board a space station so they can put new tiles on things that need to go back to earth with robots instead of trying to reuse them.Have you seen much progress in ceramics in the last 15 years? I think they have some wonder materials that are just way too hard to make at scale right now.at least, a space based tile inspector drone to do a check before going back to earth

author: Gyro
author_rank: Super Contributor
timestamp: October 13, 2024, 07:47:49 pm
content: In other news, Boeing spits feathers (and plans to shed 17k jobs, but that's another story).

author: coppercone2
author_rank: Super Contributor
timestamp: October 13, 2024, 08:00:44 pm
content: And I really think it might be possible to make magnetic shields, at least we have maglev trains that are highly successful. now they need to flyI think magnetic technologies have the most realistic chances of coming to life. It might be a realistic but very complicated design that does not have wishful thinking like 'robust insulators'. a FTL drive might be more realistic then expecting a tile not to crack lolI am imagining what a ceramic computer motherboard might be like. Expecting 20k of them to stay intact on a plane is amusing

author: coppice
author_rank: Super Contributor
timestamp: October 13, 2024, 08:48:51 pm
content: Quote from: coppercone2 on October 13, 2024, 08:00:44 pmMost magnetic solutions are very heavy. Not a big issue for a maglev train, but a very big issue for anything flying a little higher. Some of these high temperature ceramic tape superconductors don't seem very heavy in themselves, but involve some substantial cooling equipment. If someone could get past that.....

author: BrianHG
author_rank: Super Contributor
timestamp: October 14, 2024, 12:57:31 am
content: As insanely impressive that catch was, somehow I feel a rocket landing on the ground balanced like a pencil dropped on it's eraser staying standing vertical is just more difficult and impressive.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 14, 2024, 01:23:10 am
content: Quote from: coppercone2 on October 13, 2024, 08:00:44 pmFor heat shields, I don't think magnetic will ever be practical. The power-to-weight requirements just don't compete with ablative ceramics for re-entry.However, magnetic shields are the only practical method of radiation protection for manned Mars missions, so the technology is definitely being worked upon, just not for heat shielding.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 14, 2024, 01:28:15 am
content: Quote from: Psi on October 13, 2024, 02:02:19 pmSurprisingly, not yet.So far all the mainstream media seems to be focused on the "chopstick" catch, and have completely ignored the exploding Starship.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 14, 2024, 03:40:02 am
content: Hard to say based on the video to date how far the heat shield was from working.My takeaways from a quick watch. There was much less burning/debris than on the last re-entry. The camera views remained unobscured much longer. Damage to the flaps is hard to evaluate. The cameras turned down gain until I was only seeing the bright glowing spots. Which may have been burn through or merely very hot stainless. After things cooled down I didn't see any holes. There were clearly some losses and failures based on the occasional showers of sparks. When the camera gain went back up all I could see was intact.Hopefully a full Starship landing is coming soon and a postflight will truly answer how much needs to be fixed and how hard it will be to repair and possibly prevent future damage.All in all an incredible accomplishment. When the chopstick system was first announced I thought it was batshit crazy. It appears they were closer to right than I was.

author: iMo
author_rank: Super Contributor
timestamp: October 14, 2024, 06:11:06 am
content: Quote from: CatalinaWOW on October 14, 2024, 03:40:02 amA couple minutes longer flight of the Starship and it would land in Australia. The continent is large enough and almost empty so they may try next time with the landing there.. And Dave may report directly from the landing site..

author: Psi
author_rank: Super Contributor
timestamp: October 14, 2024, 08:37:33 am
content: Quote from: Andy Chee on October 14, 2024, 01:28:15 amYou are right, i'm happy to be wrong.

author: wraper
author_rank: Unknown
timestamp: October 14, 2024, 11:23:02 am
content: ^Surprisingly even CNN reported this fairly. Unfortunately it was mostly positioned as some socondary news, which is undeserved as this is a major advancement of rocket technology and IMHO order of magnitude more important than some mundane news on top of the front page.

author: Ice-Tea
author_rank: Super Contributor
timestamp: October 14, 2024, 11:35:54 am
content: Quote from: Per Hansson on October 13, 2024, 06:09:06 pmTheir shot of the redhot engine bay was just insane.

author: coppice
author_rank: Super Contributor
timestamp: October 14, 2024, 11:41:31 am
content: Finally they have some raptor engines back, which have not been salt damaged, to be able to do a real assessment of how well they hold up to use. I find it one of the most satisfying moments, as an engineer, to be able to sift through the aftermath of using things I designed, looking at how well my decisions worked out.

author: paulca
author_rank: Super Contributor
timestamp: October 14, 2024, 12:21:17 pm
content: Quote from: tom66 on October 13, 2024, 01:41:17 pmMe and my brother were discussing this. In order to run a rocket motor you need a turbo pump. Turbo pumps burn either fuel rich or oxydizer rich. Looking at the footage I believe the raptors in use during 'landing' share a turbo pump or a turbo pump exhaust. You can see when the engines back off the turbo pump is spewing unburnt fuel everywhere in a big plume of yellow flame (O2 starved gas burn).In order to light, extinguish, relight, throttle etc those engines the turbo pump must be kept running, no? You won't see it on the way up as (apparently) they are normally "closed cycle" and the turbo pump exhaust is reinjected and not vented.I may have to go and rewatch all the techie detail videos on the raptors again.

author: paulca
author_rank: Super Contributor
timestamp: October 14, 2024, 12:22:47 pm
content: Somewhere in SpaceX there are a room full of engineers all picking from a cup of straws.He who draws the shortest is the one who walks up to it first.Note. The condensation rings top and bottom suggest it's still got fuel and oxydizer onboard. It could very well still go boomksi.

author: paulca
author_rank: Super Contributor
timestamp: October 14, 2024, 12:28:06 pm
content: Quote from: Psi on October 13, 2024, 02:02:19 pmSpeculation, but it looked like some of the rocketry stuff was still running when it landed.I think we got to find out what happens if you run a raptor engine under water.

author: tom66
author_rank: Super Contributor
timestamp: October 14, 2024, 12:53:57 pm
content: Quote from: paulca on October 14, 2024, 12:21:17 pmI don't think that's strictly required.The fuel pumps are probably electrically started and then run on combustion energy. These run on partially burned fuel - oxygen-rich methane or methane-rich oxygen gas output. This partially combusted fuel is then sent to the main combustion chamber where it is fully combusted to provide thrust.The ignition is via spark ignition so does not require any pump to operate.So turn electric fuel/LOX pump on, engage igniters, igniters cause fuel combustion which causes turbos to spool. All it would need is the minimum amount of fuel/LOX to get the reaction going. Some very rapid control electronics and software will be monitoring the fuel/LOX rates to ensure that the engine starts up quickly as I am sure it is possible to put it into very dangerous and failure-prone operating modes.Shutdown would be by isolating fuel/LOX which will result in engine running fuel rich as methane is denser than oxygen. This results in the visible dark orange flames of poor combustion before shutdown. They might keep methane going for a tad longer to avoid overheating the nozzle, as that is fuel cooled, but just a guess on my part.As can be seen here, the startup and shutdown are pretty rapid.SpaceX relies on this since the three Raptors aren't enough to slow down until the terminal phase of the flight so they have to alternate between 13 and 3 raptors on at various stages. On Falcon 9 a single Merlin engine is actually sufficient to allow the empty Falcon 9 to lift off again so the descent profile is based on very careful timing of the single engine relight. Merlin uses a consumable liquid ignition fuel and takes longer to ignite than Raptor, but not exactly sure on why.

author: Psi
author_rank: Super Contributor
timestamp: October 15, 2024, 07:08:16 am
content: Quote from: paulca on October 14, 2024, 12:28:06 pmPossible. Something definitely detonated violently though, you can see the exploded shock and many parts flew up in the air and rained back down. It's possible it was something other than a tank explosion. Like an engine, or a COPV or something.But the flight termination system does make a lot of sense based on what we saw.Also you wouldn't want to leave the explosives in the flight termination system intact. Otherwise they might wash up on some beach somewhere. So setting them off after landing is complete would make a lot of sense if you don't plan to recover it intact.

author: Psi
author_rank: Super Contributor
timestamp: October 15, 2024, 07:18:20 am
content: Quote from: paulca on October 14, 2024, 12:21:17 pmI'm 99% sure each raptor engine has its own dedicated turbo pumps, and that they only have to spin them up a few seconds before they want to start the engine. So the pumps are fully off if the engine is off.The outer ring of raptors doesn't have the plumbing needed to spin up the turbo pumps with pressured gas from the tanks. So those ones require the pressure feeds from the launch pad to start them. They can never be relit in flight.All the center engines, including the 3 they use for landing, can relight by spinning the pumps up with gas a few sec before starting the engine

author: paulca
author_rank: Super Contributor
timestamp: October 15, 2024, 08:25:33 am
content: So the plume of yellow "rich" flame up the side?Maybe it's not the turbo pumps "running", but just spinning down? Maybe there is venting required and it just happens to get lit due to the rage under it?

author: paulca
author_rank: Super Contributor
timestamp: October 15, 2024, 08:27:55 am
content: The best bit, was when the footage from the tower itself appears, you can see the booster does not get "caught" at all.The booster "lands" exactly 1 foot over the rails, lowers itself onto them and then lifts its own weight back off again and settles finally.It's not like it threw itself into the arms, it deliberately settled itself and made sure. Amazing.

author: tom66
author_rank: Super Contributor
timestamp: October 15, 2024, 09:10:25 am
content: Quote from: paulca on October 15, 2024, 08:27:55 amIt's very similar to Falcon 9, but obviously on a much larger scale. F9 intercepts the landing pad at, hopefully 0m/s. Though realistically it is going some small velocity into the ground surface when it impacts and the sea undulating below means that the springs inside the landing legs (which are also designed to break safely if the load is too much) have to absorb some energy. Since Starship Heavy can hover (for a short period of time) they can keep the time spent close to 0m/s longer to allow for a more precise docking. F9 will just go up in a parabola on one engine until it crashes so timing with the engine there is critical. In some senses you could argue the F9 landing is more impressive because of this interception speed at zero... though obviously landing a ~twenty-storey building-sized rocket is something else altogether.

author: paulca
author_rank: Super Contributor
timestamp: October 15, 2024, 09:13:58 am
content: .... and they absolutely have to have the gantry make a loud"KaKlunk! PSSSSSSSsssss." Noises just like sci-fi would.

author: Psi
author_rank: Super Contributor
timestamp: October 15, 2024, 10:57:54 am
content: Quote from: paulca on October 15, 2024, 08:25:33 amPretty sure the fire from the side was an unintended leak or vent of some sort.One of the raceway panels (that cover up the plumbing that runs up the side of the booster) exploded off for some reason when the engines were lit, which is probably related.There was also some fire coming out of the 'quick disconnect' used to load fuel into the rocket. Perhaps what was sitting in the fueling pipes.As far as i'm aware, anything coming from the turbo pumps can only vent out the nozzle.There are a few vents for various other things on the rocket, like bleed off vents to keep the tanks at the right pressure, and vents used to quickly detank all fuel from the rocket in an emergency. It's possible one of those got damaged by atmospheric heating and started leaking.Just rewatched the video, you can see gas leaking out the side, and then flames from the engine reach that and ignites it. After that there's a fire on the side of the rocket.

author: coppice
author_rank: Super Contributor
timestamp: October 15, 2024, 11:47:02 am
content: Quote from: paulca on October 15, 2024, 08:27:55 amOf course. If you are going to hold a massive heavy and rather fragile structure by 2 small lugs you've got to settle gently onto the supports. The real operation is a combination of catching and fine control by the thrusters. The arms move in AND the thrusters settle the ship into place. What I found interesting is the way the booster descended over the water, and only at the last moment nudged itself over to the land and the tower. Some people seem to think that path showed a lack of control, but it was clearly an intentional path to avoid risk to the tower and other facilities until the last moment.

author: paulca
author_rank: Super Contributor
timestamp: October 15, 2024, 12:05:50 pm
content: Yep and you can guarantee that the ABORT button would cause it to point out to sea, fire fully away and then blow up.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 15, 2024, 12:32:20 pm
content: Quote from: paulca on October 15, 2024, 12:05:50 pmThat plan requires a functioning attitude control system.I always envisaged an ABORT system being activated in the event attitude control was completely lost.

author: tom66
author_rank: Super Contributor
timestamp: October 15, 2024, 01:29:03 pm
content: I imagine ABORT for this case was the landing pad area was completely evacuated and they accepted that in the event of close FTS activation they'd have to rebuild the pad. They would be carefully monitoring its descent the whole way and if it went outside of nominal trajectory then 'boom'.How that works when SpaceX imagines these craft being used as Earth point to Earth point passenger transport is unknown to me. That itself presents some very interesting challenges and I think those will ultimately prevent it from being a commercially feasible operation. At least if an aircraft crashes, it usually leaves the airport intact, damaging at most the runway and hardware nearby. (There are of course exceptions but they are rare.)

author: coppice
author_rank: Super Contributor
timestamp: October 15, 2024, 01:35:34 pm
content: Quote from: tom66 on October 15, 2024, 01:29:03 pmObviously everyone has to be cleared from a big enough area that a disastrous failed catch won't kill people. That's a bit beyond abort. I assume the last abort point was just before they steered the descending craft from over water to over land. After that any failure is going to be pretty costly, and will cause a long outage. I'm surprised how close the 2 towers are. I assume that spacing is considered adequate for a failed landing taking out one tower to not affect the other. I find it hard to imagine that a major failure on the way up is not going to take out both towers.

author: paulca
author_rank: Super Contributor
timestamp: October 16, 2024, 01:17:33 pm
content: The rising issue they are increasingly having to consider is simply put as:The global public are now starting to state they would like "that which rains down from space" to be regulated.Not all of it breaks up.Texas, the FAA etc had a spat with them recently about the ablative tiles (silicon dioxide?) cause particulates which can be termed "toxic".They have had many a spat with the FAA because the flight rules for these "exceptional flights" as they are filed, do NOT permit deliberate failures. Sending up a rocket (or anything) with the complete expectation it will fail is illegal. The FAA can not permit you otherwise. The military might help though.China unfortunately has been giving the hand-wringers the ammunition by dropping half fuelled, orange smoke spewing hypergolic(sp?) rockets on villages with no more than an "Oops".

author: iMo
author_rank: Super Contributor
timestamp: October 19, 2024, 04:59:22 pm
content: Some new video footage from the splashdown..

author: Brumby
author_rank: Unknown
timestamp: October 19, 2024, 10:57:19 pm
content: Quote from: coppice on October 13, 2024, 02:57:05 pmI wouldn't be too concerned at this point. Yes, there are some stiff challenges, but then SpaceX has addressed quite a few already ... and they're still not done. Remember, this is still a DEVELOPMENT program!

author: Brumby
author_rank: Unknown
timestamp: October 19, 2024, 11:07:03 pm
content: Quote from: BrianHG on October 14, 2024, 12:57:31 amI think landing a rocket on the crane that's going to put it back on the launch pad is impressive enough for me.Yes, yes, I know there is the concept of landing directly back onto the launch pad, but I think that is impractical for several reasons. Besides, the chopstick "catch" manoeuvre makes for excellent theatre.

author: RJSV
author_rank: Super Contributor
timestamp: October 19, 2024, 11:52:33 pm
content: I've only been paying casual attention, but can somebody answer: Isn't that about the same as the previous Booster landing in almost backwards running video ?Booster would come down, powered, and land.How, is this new, then ?...(just curious, thanks).

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 20, 2024, 03:58:56 am
content: Quote from: RJSV on October 19, 2024, 11:52:33 pmIn the same sense that a small business jet and an Airbus 380 are the same. Both put wheels and flaps down, slow down and land.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: October 20, 2024, 04:03:21 am
content: Quote from: coppice on October 13, 2024, 02:57:05 pmAnother thought on this subject. While refurbishment after each flight won't lead to the incredible price reduction they want, there are things about the Starship design that will still dramatically reduce costs. On of the cost drivers on the shuttle was that most, perhaps all of the tiles were a custom design, specifically shaped for their location. On Starship the vast majority of the tiles are one of two different varieties. The savings from just having to stock a handful of replacement part numbers is enormous.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 20, 2024, 05:06:42 am
content: Quote from: RJSV on October 19, 2024, 11:52:33 pmThe "new" thing is that; instead of the booster landing on land, the booster is now landing on the tower structure.Landing on a tower structure requires greater precision in both attitude control, and thrust control.Returning to the launch structure could potentially see a massive time saving between successive launches, assuming that the rocket can be refueled and payload assembled at the tower. OTOH, if transport to the vehicale assembly buiilding is still required, then the "chopsticks" landing doesn't gain much advantage.Successive launches is an important requirement for launching Starlink and other low earth orbit cube sats. Cube sats by their nature, will deorbit rapidly compared to geosynchronous satellites, hence the cube sats need to be constantly replaced.

author: Psi
author_rank: Super Contributor
timestamp: October 20, 2024, 10:54:18 am
content: Some people for scale, since its easy to miss just how huge starship and the booster actually are.

author: iMo
author_rank: Super Contributor
timestamp: October 20, 2024, 11:08:40 am
content: By 2m larger diameter than the Airbus 380 has got..

author: wraper
author_rank: Unknown
timestamp: October 20, 2024, 01:42:30 pm
content: Quote from: Andy Chee on October 20, 2024, 05:06:42 amWhile its true that LEO sattelite orbit decays without propulsion, and Starlink sattelites need to be replaced in about 5 years, sounds like you either misundesrstand what are Starlink sattelites or misunderstand what is called a cubesat, or both.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 20, 2024, 02:14:49 pm
content: Quote from: wraper on October 20, 2024, 01:42:30 pmNot at all. I'm merely classifying satellites into two simple categories; long lived satellites and short lived satellites.Short lived satellites are the ones that greatly benefit from economical rocket launch facilities.

author: wraper
author_rank: Unknown
timestamp: October 20, 2024, 04:44:41 pm
content: Cubesat is a very specific form factor of a very tiny sattelite used for rideshare launches (generally with no propulsion due to size and cost so live for months). This form factor has nothing to do with LEO by its nature. However due to short life, lack of propulsion, cost, nobody launches them above LEO since they will become forever space junk with no reasonable justification. Calling all LEO sattelites as cubesats is nonsense, not all of them are small, nor Starlink are that small either, they're like 50-300+ times larger than cubesats (depending on cubesat type and starlink sattelite generation).

author: Andy Chee
author_rank: Super Contributor
timestamp: October 20, 2024, 10:58:27 pm
content: Quote from: wraper on October 20, 2024, 04:44:41 pmI never intended to say that, any such interpretation misses the point I'm actually trying to convey.My only claim was that some satellites are intentionally designed with short functional lifetimes, thus necessitating more frequent replacement relative to the average geosync satellites.

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2024, 11:07:43 pm
content: Quote from: Andy Chee on October 20, 2024, 10:58:27 pmThey do generally have fairly short lives, but that is a choice. They have mechanisms for oribital correction. They could have more capacity in those, but the additional weight would increase the launch cost, or decrease the satellite's capabilities. This is much the same for geosync satellites. Although they see less orbital decay, they still need to regularly correct for errors in their position, and the eventually run out of propellant. They could carry more, but that would cost.

author: wraper
author_rank: Unknown
timestamp: October 21, 2024, 04:46:03 am
content: Quote from: Andy Chee on October 20, 2024, 10:58:27 pmWell, you compared GEO sattelites with cubesats and impllied that Starlink are cubesats. It might not have been your intention but it was written as such.Quote

author: wraper
author_rank: Unknown
timestamp: November 07, 2024, 10:06:04 pm
content: 6th flight might be as soon as November 18https://www.spacex.com/launches/mission/?missionId=starship-flight-6

author: Psi
author_rank: Super Contributor
timestamp: November 08, 2024, 04:31:43 am
content: If they manage to land it perfectly a 2nd time it really will prove they know what they are doingOnce could be first time luck, but twice in a row is significantly more impressive.Not that I wasn't crazy impressed by the first catch, i was.I think once they catch a ship, and perhaps reuse one, they will have got all/most the really hard design tasks behind them.In-orbit refueling shouldn't be that hard. So getting a starship fully refueled in space should come after that without too much trouble.Then it's off to mars to deploy some starlinks or attempt a landing.30 successful mars landings later the risks should be low enough that people will accept the risk of being onboardI do wonder if they will get some kickback when they start landing/crashing 30,40,50 starships on mars. People will say they are littering/contaminating mars. Which is stupid, having piles of pure metal/materials on mars is like piles of gold. So useful to build habitats out of. But people will still complain about it.

author: paulca
author_rank: Super Contributor
timestamp: November 08, 2024, 01:15:58 pm
content: Quote from: Psi on November 08, 2024, 04:31:43 amThey are still actually debating just how many launches it will take to fully fill one starship in orbit.The last time I seen figures they were suggesting between 8 and 12 depending on if they reuse things or dump them.Elaborating. It's simple maths. The current payload to fuel ratios for starship are between 1:10 and 1:20.Even taking the highly optimistic value of 1:10 and assuming a starship can retain 20% of it's fuel once reaching orbit.... that ratio means, you need 10 times the fuel burnt to lift. If the total fuel onboard was 100 tons (it's a lot more) then to lift 80 tons to orbit you will need to burn 800 tons and thus 8 launches. Make the total fuel 1 millions tons and the ratio still holds.Having each of these starships lift fuel up and then return to land will place starship at it's weakest payload to orbit ratio, as a lot of fuel is required to recover the booster and starship. Leaving less mass for payload and more than likely ending up at the higher end 1:20.There is a great video by "Smarter Everday" let me find it. He basically reads teh Apollo rule book to the modern day space planners at a conference in Europe. He presents the current Nasa moon project as the comedy... it is and basically asks them, "What are you doing?"

author: paulca
author_rank: Super Contributor
timestamp: November 08, 2024, 01:17:52 pm
content: Quote from: Psi on November 08, 2024, 04:31:43 amMia and the mars first team in Kim Stanley Robinson's 'Red/green/blue Mars' trilogy.

author: Psi
author_rank: Super Contributor
timestamp: November 10, 2024, 06:28:58 am
content: Quote from: paulca on November 08, 2024, 01:15:58 pmYep, rapid reusability is very important.Keep in mind that SpaceX are not building rockets. They are building a production line to mass produce rockets like cans of soft drink.