After that, the exciting work will be in Starship making LEO and testing propellant transfer (a humanity first) [1] and Blue Origin testing its rocket and lunar lander [2], both scheduled for 2026, to enable Artemis II (EDIT: III), currently scheduled—optimistically, in my opinion—for next year.
Starship "making LEO" is not a significant challenge--the existing flights have explicitly targeted a (very slightly) suborbital trajectory. They could have done otherwise at any point, but for now it's more important to guarantee that the stage comes down immediately. None of their current objectives require more than ~1/2 of an orbit.
Starship v3 flying will be a significant leap, though. It's the first with the Raptor v3 engines and has many other improvements as well, such as updated grid fins and hot staging ring. It will be the first that achieves close to the intended capacity of ~100 tons.
Propellant transfer is indeed a significant challenge. They have already demonstrated internal transfers between tanks, but not between spacecraft.
Starship "making LEO" is not a significant challenge
Of course it is. I say this as someone who sturdied astronautics.
You’re broadly correct, though. My point is the action shifts to Hawthorne and West Texas for the next year or so. Then pivots back to NASA for Artemis IV.
It’s not a significant challenge compared to what they’ve already done.
Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer.
OPs point is that they intentionally didn’t.
achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls
It’s not a significant challenge compared to what they’ve already done
I don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics.
> Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer
Which risks recovery. Given they were replacing their Raptors in the next refresh, pushing an already-obsolete engine for shits and giggles doesn't make sense when you can get good data on e.g. skin performance.
> achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those control
There is zero indication diplomatic pressure has been a constraint on the U.S. space programmes in the last couple years.
They didn't have to increase speeds, they already achieved orbital velocity. To circularize all they need to do is relight. Relighting an engine is very difficult for an engine like Raptor, but they've already demonstrated relight.
They didn't have to increase speeds, they already achieved orbital velocity
My undertstanding is Starship didn't hit 17,000 mph [1]. LEO orbits tend to be 17,500 mph and up.
Like, I'm not arguing that SpaceX couldn't have circularised on previous tests. But it would have added material risk without any reward. And taking a ship, particularly a re-usable one, particularly a novel one, into its first orbital flight is always exhausting and novel.
It is like a runway taxi test on a plane that is fully capable of flight. Sometimes the plane takes off unexpectedly but the plan is not to do it. Starship can do orbital insertion now despite no plan to do it yet.
Odd. As a side note, your comment was posted [dead]. I vouched it to restore it back to life.
This is the second time I’ve seen such insta-dead comments. (One was my own, and I thought I did something wrong. Now it looks like there’s some kind of bug in HN that’s killing on-topic comments when they’re posted.)
Your comment wasn’t deep or insightful, but not every comment should be. A simple rejection of a premise is certainly on-topic. So it’s hard to argue that your comment was “bad”. That narrows the possibilities down to a bug in the algorithm. Maybe the mods are experimenting with ML auto classifying whether new comments should be killed or not.
Nothing. Now that I’ve seen it once for me and once for you, both on comments that seemed lightweight-but-harmless, I’m convinced there’s some sort of bug. So don’t take it personally.
Also HN != YC. They’re separate organizations, iirc. When Sam Altman was running YC one of the first things he did was “refactor” HN so that it has editorial independence.
Either way, it would be hard to imagine someone from YC telling Dan “you should boost so-and-so” and him going along with it unless it directly benefitted the HN community.
I guess I was a little distracted by the tangent to starship over the orion/Artemis
I was disappointed to see that after all these years NASA trying the old trick again and hoping people get excited.
As for spaceX and starship, I haven't kept up with it but I trust it's still putting NASA to shame wrt setting the state of the art.
Their objectives keep shifting and starship is far behind schedule. Sure, it's a success if you keep objectives small. They could have tried for LEO ages ago but didn't. Each launch should maximize learning and having small objectives is anathema to that. And very wasteful.
If you think Starship is behind, look at the 'competition'.
Learnings per flight may not be maximal, but they are measured with enough risk so that bureaucrats will approve it (not restrict future launches) and other countries won't be impacted by a failure.
What would going into LEO have taught them? They have been there hundreds of times.
They don’t have small connectives, or was catching the Super Heavy booster and then reusing it too small for you? Not everything they are doing is public.
How do they hope to make prop transfer work without a working heat shield to enable reuse of the tankers? Unless SpaceX pulls a hat trick, Starship is borderline useless.
They have a working heat shield (see last flight). It may not be quickly reusable, but that doesn’t matter at this stage.
For the transfer test, just left over fuel in two Starships is enough. They aren’t full blown finished tankers yet.
For HLS, if they are unable to get Starship reuse working in time, they can use expendable tankers.
>> Starship making LEO and testing propellant transfer (a humanity first)
No. We have to stop listing to AI and twitter idiots trying to upsell stories into "firsts". The first propellant transfer, the first refueling of a spacecraft on orbit, was by the soviets nearly 50 years ago.
"Progress 1 was the first of twelve Progress spacecraft used to supply the Salyut 6 space station between 1978 and 1981.[6] Its payload of 2,300 kilograms (5,100 lb) consisted of 1,000 kilograms (2,200 lb) of propellant and oxygen, as well as 1,300 kilograms (2,900 lb) of food, replacement parts, scientific instruments, and other supplies. Whilst Progress 1 was docked, the EO-1 crew, consisting of cosmonauts Yuri Romanenko and Georgi Grechko, was aboard the station. Progress 1 demonstrated the capability to refuel a spacecraft on orbit, critical for long-term station operations.[11] Once the cosmonauts had unloaded the cargo delivered by Progress 1, they loaded refuse onto the freighter for disposal."
If SpaceX wants a first, then it would be the first transfer of cryogenic fuel. But even that could be debated as arguably Shuttle "transferred" cryogenic fuel between the tank and the orbiter during the launch process. So SpaceX might get the first of (cryogenic + on-orbit). Any simplification is a denial of what has already been done.
Which is weird, because "X", "10", "XI", "XII", "12", "XIII", "13" are all unambiguous, while "11" could be read as "II" = 2 depending on the font. In other words, they switched exactly as to maximise ambiguity.
Judging by the fact it's 2026 you must be writing this from the Mars base
SpaceX was started in 2001. It announced Falcon 9 and messaged its reusability ambitions in 2005.
Falcon 1 wasn’t going anywhere because making rockets is too hard. Falcons 5 and 9 weren’t going anywhere because medium lift is a different ball game. Falcon Heavy wasn’t going anywhere because timing that many engines impossible. Reuse is impossible. (The kerosene will clog everything.) Then, after refly: the total launch market will never be more than $5bn, so reuse is useless.
More recently stainless steel can’t work. Now it’s shifted to reuse and refurbishment being too difficult, or refueling being impossible because of boil-off. Because keeping shit from boiling, apparently, is just unsolved engineering. ಠ_ಠ
Not everything SpaceX does is genius the first time. But they’re ridiculously good at not persisting with stupid. The idea that a dozen rapid depot launches is somehow a gating concern, again, as a tech demo, we’re building the depot eventually, is just such a weirdly small and big concern.
I dunno, the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12? And that the lunar orbit chosen due to available energy makes rapid extraction impossible?
If they get less performance or more mission payload, they can add tanker launches. If they get more performance or less mission payload, they can remove tanker launches.
People ran into "the design is 10% heavier than planned for unexpected engineering reasons and now we have to make hard choices" on space missions far less complex than a literal Moon landing. SpaceX has externalized the "hard choices" into the tanker count, pre-emptively.
The lunar orbit of Artemis is defined mainly by SLS/Orion's performance, or lack of thereof. The specific NRHO was a Gateway choice, and might now be dead alongside it, but by itself, Orion can't get to low Lunar orbit. Which drives some peculiar design choices.
So many (perceived) problems with spaceflight and building moon bases and the like are solved by simply making the process and cost of launching faster, easier and cheaper; the problem that NASA has always had is that each launch, even with the reusable space shuttles, cost billions and took years of engineering, planning, etc. To the point where yesterday's launch was done with (what I perceive to be) salvaged parts where the engineering was done decades ago, because engineering something new would be too expensive and take too long.
Sure, don't fix what isn't broken and all - *nix tools are decades old too after all - but still.
the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12?
Nobody has ever done in-orbit propellant transfer or storage. We’re building it to see what those numbers shake out to, and how the propellant gets lost. (Boil off? Leaks? Incomplete transfer? Weird, unexpected degradation because space? ¯\_(ツ)_/¯.)
If it works, it dramatically reduces the cost of lunar and deep-space access. You’re saying that isn’t worth it because it isn’t certain? This is spaceflight. Nothing is certain. We have to weigh risks and payoffs. And then mitigate them. The time for mitigating this risk is this (and probably next) year. If the refuelling is dumb, the plan changes—Blue Origin is testing its own approach on the same timeline.
Like, in Apollo 11 we fucked up the lander’s fuel budget. The astronauts were literally running out of fuel because a foreseeable problem, the surface being bumpier than expected, wasn’t contingency planned for over ten preceding missions. And we’re trying to do better than just retreading Apollo, because Apollo—strategically—failed as a platform for further manned spaceflight.
> the lunar orbit chosen due to available energy makes rapid extraction impossible
Isn’t NRHO an Orion limitation? Can Orion circularise on its own?
Also, rapid extraction hasn’t been a requirement for the Moon since ever? If you want rapid extraction, plant a ship that can motor off the Moon home in one shot as an emergency-egress option down the road. In the meantime, you’re days away from help under ideal circumstances; realistically, we don’t have rescue options.
Starship might be crap. But the bets look good, and the project is on the whole no more ambitious than the original Apollo missions. The criticisms you’re raising are either fundamental to the mission architecture because it’s developing a new spacefaring capability (refueling and rapid relaunch) or cost-cutting choices irrelevant to HLS (Orion’s second stages being efficient but underpowered).
Ughhh, Elon Moosk amirite? Such a fraud, because [???]
I don't really understand why these kinds of comments persist except as some pathological cope when confronted with a world that doesn't work the way you want it to.
It's not convincing, it immediately outs you as a zealot, it's counterproductive in every single way. Why keep doing it?
don't really understand why these kinds of comments persist
One, you can make money criticizing Elon on the internet.
Two, controversy is catnip to the man. DOGE was a disaster. X and xAI look like aborted disasters. And he’s clearly gotten bored with Tesla. It isn’t hard to project that on SpaceX if you don’t know the heritage.
My guess is Tesla's pivoting to batteries and storage. Huge demand, great margins, competitive advantage.
I'm very disappointed Tesla has (seemingly) abandoned its goal of producing 20m Model 2 per year. Forfeiting the mass market is a bummer. More so every passing day.
(I'm bearish on Robotaxi and (Tesla's) self-driving.)
Lots of powerful people are unpleasant, but Musk additionally got involved in politics in a very visible way at a very partisan, polarising time in American history. He didn't attract as much hate before 2024.
Maybe more people should listen to Musk's political message. The Biden Administration was playing nasty games, blocking progress on both SpaceX and AI generally.
just saying: he is good at vaporware on a large scale and kind of a fucked up person. It's not weird people are skeptical. But he also has basically an endless money supply so he can throw money at problems and make them go away eventually. But his timelines are basically all lies used to get venture and retail money into the game.
confronted with a world that doesn't work the way you want it to
Sure.
Some of us are just trying to figure out the new rules. What is all this hypercapitalism stuff (aka Muskism) and who are the people (lunatics) pushing us there?
So it's natural to kibitz about one of the most powerful people on the planet. Especially when he's also a world-striding shit poster, antagonizing everyone, demanding a response.
FWIW: the writings of Jill Lepore, Quinn Slobobian, and Ben Tarnoff have been most illuminating. Ditto their misc guest appearances on various podcasts.
Musk has saved the tax payer (through the government) billions of dollars on every project SpaceX has been involved with. They have earned money by providing vital Internet services to the disconnected and left behind in rural areas all over the world.
Starship is just obscene. The thing is never going to work for its designed purpose once you understand what the mission looks like (basically insane amount of refuel dockings while the thing is in orbit)
insane amount of refuel dockings while the thing is in orbit
What's wrong with this? Lots of launches is fine until we build the scale required to make a proper depot worthwhile. (Which, by the way, is part of Artemis's plans. Though currently it looks like a bunch of glued-together Starship tankers.)
People act like with Falcon, they basically just get it off the drone ship, fill er up, and she is good to go again. There is a shitload of repairs/maintenance that has to be done to Falcon vehicles after every launch.
In space, you can't do that kind of repair/maintenance, you have to make sure the refueling is PERFECT. And this is with deep cryogenic propellants that very much like to boil off and cause pressure increases in the tanks they are contained.
That problem hasn't even been touched yet. In order to make Spaceship X happen, they need to figure one refueling out, which is difficult given the fact that Raptors run on cryogenic propellant that likes to boil off, then they need to figure out how to do 10 in a row without any issues, which is exponentially difficult.
And then there is the whole thing about everything working well for trip to Mars, and back.
And if there is a configuration that exists that can do all of that, its very unlikely that a company under the leadership of someone as Musk can ever figure this out.
For interplanetary travel, things need to start from either orbit or the moon. This has been known for quite some time.
Also all those missions can be unmanned. If you want to get good at something then you do it a lot.
The only question is whether the cost of flying all those missions would be prohibitive: by the stated goals, starship should be able to do the refueling missions cheaper then an SLS launch.
Obviously if it can't then it's failed, but the point of it is cheap heavy lift to LEO which is very obviously quite valuable.
Building a big specialty rocket to get to the moon is waste.
If you're thinking of passenger service, perhaps it is a bit unattractive in the short term. No good launching and landing spots.
But for military use - think logistics. Rapid delivery of equipment to unusual places. This applies to civilian purposes as well. All kinds of use-cases for speeding up cargo.
The entire economics of Starship and rapid reusability was presented at the beginning of the Starbase work, way back when Hoppy was a thing. He's been sticking to the plan since then. You might want it to be fiction, but he's been very good at figuring out business plans to leverage his ultimate goals.
> But for military use - think logistics. Rapid delivery of equipment to unusual places.
Surely it's too fragile/explodey for military use - the whole thing's a very volatile fuel tank - could it survive being shot at, even a single high-powered rifle bullet (during landing, or even post-landing) without going boom?
It doesn’t have to be able to deliver in a combat zone to be able to deliver halfway around the world close to a combat zone. Or do you think the Hercules is worthless because it isn’t armored and doesn’t have weapons?
Many promises that never materialized or resulted in mediocre or bad products, from the Mars mission to the Hyperloop, and from Teslas dismal software and often promised, never materializing fully autonomous drive to the Cybertruck. Let's not go into the robot vapourware either...
Hyperloop is the only thing you listed that is accurate, although it was only a whitepaper + competition. It was open for others to pursue.
Tesla easily has the best vehicle software + OTA and has since the S in 2012. It still feels better than most new vehicles.
You can buy a Tesla (including Cybertruck) today that will do 95+% of drives with 0 intervention. It may not be 100% autonomous yet, but there isn't anything obvious limiting the last step.
The robots exist but are still being developed. Within 5 years, it is hard to imagine them not becoming super valuable within factory settings.
And yet SpaceX flies the most reliable rocket in history more frequently than anyone in the world has ever flown, takes astronauts to the ISS regularly, and does so for far less then any competition. Tesla changed the automobile from ICE to BEV in a way people wanted to buy and was practical as a replacement for any use, and created a charging standard so successful every US car company is switching to.
And yet SpaceX flies the most reliable rocket in history more frequently than anyone in the world has ever flown, takes astronauts to the ISS regularly, and does so for far less then any competition
Yeah, after almost half a century, they passed 70s-era Soyuz numbers.
>Tesla changed the automobile from ICE to BEV in a way people wanted to buy and was practical as a replacement for any use
The magic of EV subsidies (for both Tesla and buyers).
>And the Mars missions so far are just delayed.
The magic of that statement is that it can be true at any point in the future!
The American people didn’t pay for the R&D if SpaceX, Musk did and then customers did. Customers (including the federal government) that saved millions on every purchase.
NASA gave SpaceX 400 Million just for the development of Falcon 9 and there is a video were Musk said SpaceX was bancrupt if NASA wouldnt have stepd in.
NASA also another 6 Billion upfront to SpaceX for Dragon and HLS.
So yes the american paid for the R&D of SpaceX.
SpaceX took the 'risk' but either succeeding or not in your main business is hardly a risk if you need to succeed anyway to have that business.
Yes, but recall that those contracts were made in a competitive marketplace where SpaceX was the lower bidder.
If not for SpaceX, the American People would have paid more to the ULA group for what has clearly turned out to be inferior results, since ULA has received far more money for far fewer services.
I will be watching the launch from Europe, so it will be not earlier than half past midnight for us. My kids (9 and 10) are sleeping on the couch in front of the projection screen, so that they do not even have to get up when I wake them up at midnight, which I promised.
Just wanted to add my grain of positivity here. Godspeed Artemis 2!
Do you prefer that we not even try to spread beyond our one planet, when an entire galaxy, or maybe even the neighboring ones, might be in reach if we try? What if someday at the very end of the lifetime of our sun and similar stars, we look back, and regret not trying?
> Do you prefer that we not even try to spread beyond our one planet, when an entire galaxy, or maybe even the neighboring ones, might be in reach if we try? What if someday at the very end of the lifetime of our sun and similar stars, we look back, and regret not trying?
The timeline you are speaking of is in billions of year. Yes, in that timescale, it definitely makes sense to try.
This very century, there are very serious scientific concerns about the continued comfortable habitability of Earth and the ensuing geopolitical instability caused by the accumulation of greenhouse gases in the atmosphere, the sixth mass extinction event, etc. We have solutions to mitigate those to some degree, but this requires very significant resource allocation to that goal, and so far it seems possible that we would fall short.
I don't think there should be zero resources allocated to space exploration, but it's at least reasonable to question whether we have our priorities set right.
Exactly what I mean. People who obsess over space are so egotistical they can’t imagine someone not thinking it’s “the best”. It’s interesting, but no more important than any other science or field of study.
And no, I’d prefer we take care of our home planet and make it a sustainable place to live first. It’s ludicrous to think we have any chance of surviving elsewhere if we can’t stop ourselves from making our natural habitat unlivable.
Yes we can do both. I still think it’s stupid to place human spaceflight on a pedestal. It’s putting the cart before the horse.
I don't agree with you. An endeavour like this is bringing humanity closer together. After the moon landing people all over the world said "we landed on the moon", not "the US landed on the moon". After they released the photograph of earth as seen from the moon people started to see earth differently, and a flurry of environment protection laws followed.
I too wish we would all hold hands and sing kumbaya and collectively decide to simply make things better here on Earth but sadly it seems far off.
The best alternative demonstrated so far seems to be for some of us to push the limits of what is possible and watch all boats rise with the tide. Better this than slinging Tomahawks at school children.
People who obsess over space are so egotistical they can’t imagine someone not thinking it’s “the best”
What? No I don't. Some people want to spend money on sports or making our planet sustainable before doing anything else. I think that's fine. It doesn't interest me, however, so I'm looking at this other thing. We can coexist without having to insult each other.
> It’s putting the cart before the horse
How many times in history did necessity create efficiencies versus ambition?
Fair, my first point was poorly worded. People who think space is the best and can’t imagine anyone else thinking it’s not the best are still self centered and lacking in empathy imo.
> How many times in history did necessity create efficiencies versus ambition?
Literally all the time? There’s another saying, “necessity is the mother of invention”.
There have always been lame people like this and for all of human history we have continued to explore and expand. I think at this point those people can safely be ignored.
Even though you could question the whole Artemis concept, it's still extremely exciting watching the countdown with my son. I just missed the original Apollo flights and had assumed I would never see a moon landing in my lifetime. We may well not have a landing for quite some time yet, but it's still cool to see a Moon bound rocket standing on the launchpad...
I don't know if it's feasible for you, but if you can, try to take your kid to see a live rocket launch. The TV is grossly unable to display how awesome these things are in person.
Concur. My kids and watched a “small” Falcon 9 launch from the mainland park nearest the pad at Cape Canaveral. The noise alone was astonishing; bring binoculars to see detail.
It is one of the things I regret not ever getting to see a shuttle launch. The closest I ever got was when I flew over Florida while a shuttle was on the pad.
I was wondering how the zoom was so clear. However, I'm familiar with the struggle of shooting that way. I don't have a phone mount for my telescope, but with enough struggle, I can get a decent pic from the viewfinder on my phone. So don't play it off as cheating. It was a bit of skill to get both the binocs and the phone steady and aligned enough to get it.
Either way, it's a shot not everyone is going to have posted to their socials.
That's what I thought standing at the rim of the Grand Canyon. Pictures just do not do it justice. Same thing with Starship. My brain knows it's massive, yet feels underwhelmed looking at it on video. Musk should let his ego build replica Saturn V and a Shuttle next the Starship launch pad so there will be proper perspective available
Have you been to the rocket garden at KSC? The Saturn V isn't vertical, but they've got almost everything from the Redstone and later vertical. I was in Florida in 2018 and I think they were getting ready to display a pair of SRBs. They did have Atlantis inside, too. And of course a horizontal Saturn V.
I saw that Saturn V as a child once, too. I think that the Saturn V really made me the person that I am today. Seeing something so huge, that is literally engineered down to every last tenth of a millimeter - that was profound for a young child. I could not believe how detailed that rocket was, yet so huge. There should be an engineering term for the size of a machine divided by the smallest critical engineered component of the machine. I don't think any machine would have beat that in the Saturn V's day - maybe some ocean liners?
I've never been to KSC. I've been to Houston a few times. I couldn't imagine trying to have a Saturn V permanently standing would be an easy feat with both locations susceptible to hurricanes and tornadoes. Walking the length of it is still pretty impressive.
I come from a construction family, so I'd put some of the famous sky scrapers in that category too. Especially thinking about the crazy beam walkers like that famous photo of the guys riding the I-beam up eating their lunch on the way up.
A few years ago Spacex did a homage to that photo, with the crew working on the Starship. One of those amazing Human For Scale photos that emphasize just how huge that rocket is.
I saw the one in Houston for the first time last week. It was so cool. My favorite spacecraft as a kid, but in real life it was about 4x as big as I expected.
That's a great point. And it raises the question if we consider the nanometer scale features of the processor against the size of the rocket as a whole.
I lived in Port Orange FL until i was 12, during night launches my dad would take the family to New Smyrna Beach or some where a short drive South where we watched the shuttles come up over the water somehow. I can't remember the details it was a lonnnng time ago haha. I do remember the launches sounding like popcorn popping.
I live in Dallas now and will be turning 50 soon, i want to catch the next Starship launch live but would have to time it perfectly to get time off of work ahead of time.
You probably watched from the Florida side of the intercoastal waterway between the main part of Florida and Cape Canaveral. Because of the 3-mile minimum and Patrick AFB it is pretty hard to find a good watching place that is actually on the cape.
80 miles for me! I was a Space Shuttle era kid though. Saw the Challenger disaster during my lunchtime. And then on perpetual replay for the rest of the week on WESH/WCPX/WFTV most likely. Even still, just knowing we were launching all those people into space was awe-inspiring.
It's even more exciting when you realize that the last crewed mission beyond Low Earth Orbit was 1972 and each person on that spacecraft today are younger than that.
Minutes after launch they reached "ten thousand miles per hour". That's 2.78 miles per second. Nuts. No doubt the speeds go even higher later too.
I'm sure people here are already familiar with the speeds these things go, but that's the first time I've confronted a fact like that and it blew me away.
Escape velocity is 25,020 mph (6.95 mps), so not completely surprising.
Note that escape velocity applies to a situation without continued propulsion and also without air resistance, but still you can imagine that the order of magnitude is similar.
Maybe you’ll like this too: The Earth’s speed around the sun is around 67,000 mph. So it moves significantly faster than the rocket, though not orders of magnitude. The solar system itself moves at 43,000 mph relative to its local neighborhood.
But speed is always just relative to some frame of reference. Acceleration, on the other hand, is absolute, and so might be the more interesting thing to look at here.
Acceleration is change in speed, so it is, by its very nature, relative just like speed is.
If I fall, I might accelerate at G meters per second, relative to the earth, but I don't absolutely accelerate. If the earth decelerates at the same time, I'm now both accelerating an decelerating. It's relative.
It’s absolute in the sense that you can determine your acceleration without any external reference. You feel a certain force (like what you feel in an elevator). That’s your acceleration. You don’t accelerate relative to Earth, or relative to anything else. You accelerate relative to when you wouldn’t be accelerating (your inertial rest frame, a state of free fall).
If you are in space accelerating and the Earth would decelerate (which is just an acceleration in the other direction), you would still feel exactly the same force (minus Earth’s gravity, to the small extent you’d still feel it), and people on the Earth would feel the Earth’s acceleration. (For them it would feel like “down” isn’t perpendicular to the Earth’s surface anymore, or as if the Earth’s surface was tilted.)
When you sit on a chair on Earth, the pressure you feel on your butt is your acceleration upwards. If there was no chair and no ground (and no air), so that you’d be in free fall, that’s when you’d have zero acceleration. Your inertial rest frame is the trajectory you’d take in free fall. When you’re sitting on a chair, or lying in bed, or standing on the ground, you’re accelerating upwards relative to that rest frame, and that’s the pressure you feel on your butt, or on your body, or under your feet.
I am in a gravitational field. I have no idea what my acceleration is, I just know that I feel 1G (I could be falling in a stronger gravity and only feel 1G, or I could be climbing in a weaker gravity and feel 1G). The only way of determining it is to see if I'm moving relative to the stuff around me. Even then, that's not definite - I could be in an elevator and everything around me is also accelerating.
I'm not disagreeing with you, I'm just pointing out that there are circumstances where "you can determine your acceleration without any external reference" isn't true. You might even say that this is relative to your circumstances ;)
According to general relativity, you (and the ground) are accelerating at 1g, and feel weight because your inertia resists that acceleration. If you jump off a cliff, you'll stop accelerating for a bit, until the ground hits you.
Edit to reply:
> I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?
You are accelerating at 1g through curved spacetime. Newtonian "speed" behaves strangely in curved spacetime.
According to general relativity, you (and the ground) are accelerating at 1g
I don't believe this is correct. If I lock two rockets in opposition to each other, they aren't accelerating. They're pushing at each other. And their propellant is accelarating away. But their displacement and orientation are unchanging, which means their velocity is zero which means acceleration isn't happening.
Similarly, the normal force resists your gravitational force to produce zero net acceleration. (An object at rest in a gravity well is its own local frame.)
> If you jump off a cliff, you'll stop accelerating for a bit, until the ground hits you
I don't believe this is correct. In GR, free fall is still inertial motion. You're just free of fictitious forces and thus following the curvature of spacetime.
As I understand it, in GR acceleration is indistinguishable* from gravity, so while you're on the ground feeling 1 gee, you're being accelerated up at 1 gee, and so is the ground.
When you're in free-fall, that's when you're in a non-accelerating frame, even though a non-relativistic description** would say that you are, in fact, accelerating.
Caveat: I only do physics as a hobby, neither academically nor professionally, so take with appropriate degree of doubt.
It is correct, and you're also right that two rockets tethered to each other would not feel acceleration. The acceleration we feel in Earth's gravitational field is affecting our speed, though - it's slowing down the speed at which we move towards the future.
Declaring some forces as "fictitious" is just a convention and in my opinion it is a useless convention that brings more complexities than simplifications.
In my opinion, a much healthier way of thinking is to not apply any such conventional labels to some forces and to just treat all forces equally, which is simpler, and it also matches the real world, where there is no practical difference between "fictitious" and "non-fictitious" forces.
If you treat all forces equally, then the rule (a.k.a. Newton's 2nd law) is that the resultant of all forces that act in a point is always null. From this, the conservation of energy is an obvious consequence, because whenever that point moves the total mechanical work is null.
The mechanical work of the "fictitious" forces is the variation of the kinetic energy, in the same way as the mechanical work of other forces is equal to the variation of some corresponding kinds of energy. For instance, the mechanical work of an elastic force is the variation of a potential elastic energy.
A "fictitious" force can squish you like a bug exactly like a "non-fictitious" force, and when that happens you would not be saved by the thought that the force is "fictitious".
There is a baseless claim that "fictitious" forces can be distinguished from "non-fictitious" forces because they depend on the system of reference. However the same is true for some of the so-called "non-fictitious" forces, which are functions of velocities and accelerations of bodies, in the same way as the inertial forces. Moreover, what actually varies between systems of reference is how forces are distributed into various kinds of components, not the resultant forces.
If you are pressed on a wall by a so-called "fictitious" inertial force, no change in the system of reference will change the compression force that you feel, but it may change the interpretation of the kind of forces that result in the compression that you feel.
In general relativity the "fictitious" forces do not disappear, but like in classic mechanics where you can define the "fictitious" forces using the variation of the kinetic energy, in relativistic mechanics there is an analogous definition based on the variation of the momentum-energy quadri-vector. In the gravitation theory of Einstein you can compute this inertial 4-force using the gravity force that is derived from the "curvature" of the space (which is in turn determined by the spatial distribution of the momentum-energy 4-vector of matter). The rule of a null resultant 4-force remains true in general relativity, so for a body that moves freely, like a satellite or a body in free fall, the inertial 4-force is equal in magnitude and opposite in sign with the gravitational 4-force.
In some problems of general relativity, you do not need to compute the inertial forces, because e.g. the trajectory of some body might be along a geodesic and that is all that is of interest for you. This is the same like when you use kinematics to determine the possible movement of a mechanism, where you want to know the path on which something moves, but you do not care which forces are exerted on the parts of the mechanism. However, in other problems of general relativity, you may want to know the forces that act upon a body, for instance for computing the required strength of materials, and then you may need to compute inertial forces, exactly like in classic mechanics.
The physics as taught in schools is full of such useless conventions caused by historical accidents. Moreover, besides conventions that just make things more complex than they should be, the standard textbooks contain definite mistakes that have been perpetuated for generations, like wrong definitions for all physical quantities related to rotation motions. In conclusion, trusting the "authority" of the school textbooks is a mistake and people must attempt to verify with their minds all that they are taught, instead of trusting. As a schoolboy I was more skeptical than most, so some of the less competent teachers feared my questions, but I still believed much of what I was being taught and only years later I realized that I was duped.
The fact that the AI models are trained on scientific literature that contains widespread inefficient methods or even mistakes, guarantees that they will provide wrong answers in comparison with really competent humans.
You say later that you think gravity and acceleration look the same but cannot be the same , which is funny since that’s exactly what relativity says: if two things are indistinguishable from each other even in principle, then they must be the same. Which is what led Einstein to realize that gravity really is just a curvature in space time. Hard to wrap your head around that! But if you study relativity, you eventually understand what being relative actually means.
Your speed relative to what? There is no absolute speed. Relative to an inertial rest frame, you're accelerating upwards at 1G, which is what you are feeling and what an accelerometer is measuring. Of course, relative to the non-inertial reference frame of the ground, your speed doesn't change.
You need to take into account your entire 4-vector for speed. You don't just have a speed in the 3 spatial coordinates, you're also moving thorough the "time" coordinate, and that is happening at a slower pace near a large mass like the Earth than it would of you were far away from here.
If you measure acceleration in a single point, without other information you cannot know whether it is caused by gravitational attraction or by movement that is not rectilinear and uniform.
However, if you measure acceleration in many points, you typically can discriminate the 2 cases, because the spatial variation of the 2 kinds of acceleration fields is normally very different.
If you also move relatively to the local system of reference while measuring acceleration, you have additional distinguishing information from Coriolis forces.
So with enough measurements, gravitational forces and inertial forces can always be separated.
You can always hold an accelerometer in your hand. If you did so now, assuming you're on Earth's surface, it'd register approximately 9.8m/s/s pointing in the upward direction.
You could also perform one of many historical experiments, such as dropping an object from an elevated height with careful timing, or rolling a round ball down a gently sloped track, and so on.
I don't think I understand the difference. I have always been told that acceleration is change in velocity over time. Is that wrong? Are there other types of acceleration?
"Similarly, standing on a non-rotating planet (and on earth for practical purposes) observers experience an upward proper-acceleration due to the normal force exerted by the earth on the bottom of their shoes."
Thank you for that precision "without continued propulsion", because when talking about rockets, physics teachers always talk about escape velocity, as if it was an absolutely necessary condition to escape earth's gravity.
But can't you escape gravity slower, just by going higher and higher at lower speed? Like a plane? (ie not vertically, but at an angle)
If you don't accelerate, my understanding is that you will slow down. In other words, it takes more and more energy to escape orbit. Eventually, if you don't accelerate, your speed drops to zero and you "fall back down". Escape velocity is about how much energy you put into your motion, not the velocity as such.
That seems wrong. If you have a way to maintain enough propulsion for long enough you can escape the gravity well at any arbitrarily low speed. You "just" need to maintain that speed long enough for the escape velocity from the gravity well to go below it as it diminishes with distance from the mass.
Exactly. Your rocket can escape the earth at the speed of a slow elevator if you burn the engines continuously and you can carry an infinite amount of fuel and your fuel weighs nothing.
Since those constraints are impossible to meet in the real world, we have to get going fast enough to coast most of the trip on inertia after the fuel runs out.
Artemis II won't fly by the moon until Day 6, but it only took Apollo 8 to Day 4 to get to the moon. Looking at the wiki for Apollo 8, it shows the moon was 218k miles at launch while they said the moon is currently 240k, so it still looks like Apollo was moving faster than Artemis.
Apollo put a lot more burden on the Service Module than Artemis plans to put on the Orion. Apollo put the CSM/LM into a low lunar orbit while Artemis plans to put Orion into a high lunar orbit and make the Starship carry a lot more delta-V to land from a much higher velocity (and then accelerate back up to that velocity when coming back).
On top of that there weren’t really solar panels in the 1960s so the Service Module had to carry tons of chemicals to produce electricity, as well as extra fuel for all of that weight. As a result it was massively overbuilt compared to anything we’d try today and even so had to take an expedited flight path to the moon of 3 days in order to conserve operational lifetime. Artemis does not have nearly as severe constraints on either the Orion or the future Starship and so can afford to take a more fuel efficient 5 day coast up to the Moon and make the design tradeoffs on Orion that that entails.
My understanding is Artemis II orbits earth for 23.5 hours before heading to the moon while Apollo 8 did so for under 3 hours, so that accounts for some of the difference.
That would account for some of it. I was surprised the TLI burn wasn't until tomorrow, but I guess we didn't get the Apollo 2-7 tests of the system either, so maybe those are getting compressed into the additional time in earth orbit before TLI???
It's kind of said that we are having to do all of this repeated work just to get to where we've already been even if we are doing it on a much more accelerated schedule.
Yup, that's how long it takes. There are a bunch of competing requirements and 9 minutes to orbit is the sweet spot, you can't change it much in either direction. If you go slower you waste all of your fuel just holding yourself up against gravity ("gravity drag" which is a bit of a tongue in cheek engineering term) If you go much faster you're accelerating too hard for your passengers or your structure.
To understand gravity drag think about the rocket firing just hard enough to hover 1 meter above the pad, you burn out all your fuel in 10 or 15 minutes and go nowhere...
In the other direction if you want to accelerate harder you need to make your structure stronger so you need to burn more fuel per second and have to displace some fuel in exchange for more structure and you keep doing that until you're so heavy you can't produce any more acceleration and you're all engine and structure and no fuel.
I get the physics and engineering intellectually, but it’s very different to be standing there, still watching the smoke clear, and hear the announcement.
The acceleration of a rocket is slower than a normal car at lift off. It's pulling about 1.2G, but 1G of that is fighting gravity, so effective acceleration is only 0.2G. Almost any car can do that at low speeds.
But a car's acceleration slows almost instantly. The rocket just keeps accelerating faster as the tank empties and it gets lighter. By main engine cut off it might be pulling 5G.
One fact that I found unintuitive (while we're at cars doing things they can't):
If you could drive your car straight up vertically, you'd have to cruise just for an hour or so at 100 km/h (<65 mph) until you reached space. It's not that far.
Your comment inspired me to vibe code https://calcubest.com/other/shuttle to see how fast the space shuttle travels between world cities. Pretty darn fast.
(also my first time trying to vibe code with Gemini as opposed to Claude and I don't know if I noticed a big difference, which probably makes sense for such a simple project).
It is a bit chilling to watch these astronaut profiles having just read yesterday about the heat shield issues observed on the prior mission, and that this will be the first time we can test the heat shield in the actual pressures and temperatures that it will have to endure.
After spending years as a kid seeing footage of these things on TV outside living outside of America, I finally got to see it live!
Brought my camera and got a few good pics too! Very invested in this entire mission!
Someone behind me kept whisper crying "That's it! Go baby, go baby go" like it was his child and was encouraging them on. Very emotional, loved it.
Also when that engine sparked it really hit me just how many hours of deep thought and technical innovation goes not only into getting us as humanity to that point, but also the crews at NASA planning, building and executing these missions
The politicization of everything and constant doomerish on here sure has echoes of early 2000s Slashdot. That's not a compliment. Reading the comments here is actually depressing. Human progress is never all at once, we can't even celebrate this triumph? Life is almost never "one or the other," the program could be scrapped to a junk yard and that wouldn't solve global hunger or global conflicts. Setting human eyes forward is good.
Found a stream on YouTube earlier (which presumably wasn't an official one because it disappeared 15 minutes later after a claim by "FUBO TV") and it had a poll attached: "Will the Artemis astronauts land on the moon?"
40% of people had voted yes. Which is somewhat worrying given the mission plan and hardware.
Regardless of whether this particular mission is perfectly planned, this is precisely the kind of thing that will help humanity outgrow the dark age of war, inequality and climate mismanagement.
It is a noble endeavor - science, engineering and peaceful exploration hold the keys to our survival and prosperity.
It is also important psychologically to our survival - a reminder there is a bigger pie, that we can solve hard problems, that progress can be made, that competence and education counts, as does courage, and that we can work together for a common cause.
This is the best of America, and for a while we can be proud of the human race.
The SpaceX cameras of live launches are way better. This NASA stream is mostly all computer generated art after the initial pad launch. Hardly any live space feeds from the ship.
Does anyone know of a good status tracker for the mission? I'm watching the official feed on Youtube and it's great for commentary but I'd love a live Kerbal-style UI I could poke around.
As someone who watched the Apollo 11 launch live on TV, this is no less awe-inspiring. This transcends nations, languages, and politics. This is of and by all humanity.
(If anyone managed to get the perfect shot of the spark-filled separation feed, please share. That was... incredible.)
I do hope the doomers who think that the entire US government has been completely gutted will take note of this. The government workforce is in a bad spot for sure, SLS is far from a perfect program, but this still demonstrates that we are doing some real work still.
The camera work was just terrible. They really need to learn from SpaceX how to do this right. Minus the obnoxious cheering.
SpaceX does these beautiful drone shots and live telemetry so well. Considering that each SLS launch costs in the billions it would be nice to do a little better on production
I felt the commentary during the launch also wasn't good. And I am not too interested in hearing from some Hollywood people before the launch
I'm having trouble finding a simple tracker of whereabouts the craft is at in terms of the path to the moon? Might just be me but the fancy 3-d rendering thing on the NASA page just shows me a close-up of the craft and not much else?
Wish them all the best and safe travels. I’ll be tuning in as you never know when the next crewed mission will be, probably not another 50 years if advancements in space travel happen.
> “the expert evidence we have heard strongly suggests that the use of autonomous robots alone will very significantly limit what can be learned about our nearest potentially habitable planet” (Close et al. (2005; paragraph 70).
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> Putting it more bluntly, Steve Squyres, the Principal Investigator for the Mars Exploration Rovers Spirit and Opportunity, has written:
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> “[t]he unfortunate truth is that most things our rovers can do in a perfect sol [i.e. a martian day] a human explorer could do in less than a minute” (Squyres, 2005, pp. 234-5).
Yes, a robot car that drives on its own will be a better driver than most humans who text and drive, or have 400ms reaction times.
But making a machine that can beat a 110ms reaction time human with 2SD+ IQ – and the ability to override the ground controllers with human curiosity – for exploration is much harder. Healthy, smart humans have high dexterity, are extremely capable of switching roles fast, are surprisingly efficient, and force us to return back home.
So in terms of total science return, one Apollo mission did more for lunar science and discovery than 53 years of robots on the surface and in orbit.
Is there any website that gives me updates mirroring the livestream but in plain text? I won't be able to tune in for the launch but this is exciting and I'd like to follow the developments! I'm sure the answer is "Twitter" but I don't understand how that platform works.
It's good to see NASA finally do something beyond navel gazing. Nonetheless, calling this flight historic is a stretch. Other than flying a few miles further than Apollo 13, it will actually accomplish less than Apollo 8 did 57 years ago.
Just listened on the radio driving the kids to swim class! I'm curious, does anyone think the show For All Mankind provided any peer pressure or influence to help propel NASA to this moment?
Is anybody aware of audio-only coverage of this mission? I'd have loved to just tuned into most of the launch like radio, rather than having my unwatched youtube running.
This is the first live launch I've seen on TV (well, YouTube in this case) since the Challenger disaster. Was a nice relief to see this one go so smoothly.
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April 10: splashdown
After that, the exciting work will be in Starship making LEO and testing propellant transfer (a humanity first) [1] and Blue Origin testing its rocket and lunar lander [2], both scheduled for 2026, to enable Artemis II (EDIT: III), currently scheduled—optimistically, in my opinion—for next year.
[1] https://en.wikipedia.org/wiki/List_of_Starship_launches#Futu...
[2] https://en.wikipedia.org/wiki/Blue_Moon_Pathfinder_Mission_1
Starship v3 flying will be a significant leap, though. It's the first with the Raptor v3 engines and has many other improvements as well, such as updated grid fins and hot staging ring. It will be the first that achieves close to the intended capacity of ~100 tons.
Propellant transfer is indeed a significant challenge. They have already demonstrated internal transfers between tanks, but not between spacecraft.
Very exciting times ahead!
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Starship "making LEO" is not a significant challengeOf course it is. I say this as someone who sturdied astronautics.
You’re broadly correct, though. My point is the action shifts to Hawthorne and West Texas for the next year or so. Then pivots back to NASA for Artemis IV.
Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer.
OPs point is that they intentionally didn’t.
achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls
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It’s not a significant challenge compared to what they’ve already doneI don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics.
> Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer
Which risks recovery. Given they were replacing their Raptors in the next refresh, pushing an already-obsolete engine for shits and giggles doesn't make sense when you can get good data on e.g. skin performance.
> achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those control
There is zero indication diplomatic pressure has been a constraint on the U.S. space programmes in the last couple years.
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They didn't have to increase speeds, they already achieved orbital velocityMy undertstanding is Starship didn't hit 17,000 mph [1]. LEO orbits tend to be 17,500 mph and up.
Like, I'm not arguing that SpaceX couldn't have circularised on previous tests. But it would have added material risk without any reward. And taking a ship, particularly a re-usable one, particularly a novel one, into its first orbital flight is always exhausting and novel.
[1] https://www.thespacereview.com/article/4761/1#:~:text=As%20S...
You’re also incorrect that a separate burn is required for orbit. You only need to do that if you want a circular orbit.
This is the second time I’ve seen such insta-dead comments. (One was my own, and I thought I did something wrong. Now it looks like there’s some kind of bug in HN that’s killing on-topic comments when they’re posted.)
Your comment wasn’t deep or insightful, but not every comment should be. A simple rejection of a premise is certainly on-topic. So it’s hard to argue that your comment was “bad”. That narrows the possibilities down to a bug in the algorithm. Maybe the mods are experimenting with ML auto classifying whether new comments should be killed or not.
Also HN != YC. They’re separate organizations, iirc. When Sam Altman was running YC one of the first things he did was “refactor” HN so that it has editorial independence.
Either way, it would be hard to imagine someone from YC telling Dan “you should boost so-and-so” and him going along with it unless it directly benefitted the HN community.
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Did I do that right?Unless you’re trying to make a reference to the Gemini programme. No.
As for spaceX and starship, I haven't kept up with it but I trust it's still putting NASA to shame wrt setting the state of the art.
Learnings per flight may not be maximal, but they are measured with enough risk so that bureaucrats will approve it (not restrict future launches) and other countries won't be impacted by a failure.
They don’t have small connectives, or was catching the Super Heavy booster and then reusing it too small for you? Not everything they are doing is public.
>> Starship making LEO and testing propellant transfer (a humanity first)
No. We have to stop listing to AI and twitter idiots trying to upsell stories into "firsts". The first propellant transfer, the first refueling of a spacecraft on orbit, was by the soviets nearly 50 years ago.
"Progress 1 was the first of twelve Progress spacecraft used to supply the Salyut 6 space station between 1978 and 1981.[6] Its payload of 2,300 kilograms (5,100 lb) consisted of 1,000 kilograms (2,200 lb) of propellant and oxygen, as well as 1,300 kilograms (2,900 lb) of food, replacement parts, scientific instruments, and other supplies. Whilst Progress 1 was docked, the EO-1 crew, consisting of cosmonauts Yuri Romanenko and Georgi Grechko, was aboard the station. Progress 1 demonstrated the capability to refuel a spacecraft on orbit, critical for long-term station operations.[11] Once the cosmonauts had unloaded the cargo delivered by Progress 1, they loaded refuse onto the freighter for disposal."
https://en.wikipedia.org/wiki/Progress_1
If SpaceX wants a first, then it would be the first transfer of cryogenic fuel. But even that could be debated as arguably Shuttle "transferred" cryogenic fuel between the tank and the orbiter during the launch process. So SpaceX might get the first of (cryogenic + on-orbit). Any simplification is a denial of what has already been done.
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Is Artemis III the one with a lander?Not anymore. Artemis III is now a LEO systems check [1]. Comparable to Apollo 9.
(Side note: when did we switch from Arabic to Roman numerals?)
[1] https://en.wikipedia.org/wiki/Artemis_III
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HLS isn't going anywhereI've been hearing this about every SpaceX project for the last twenty years.
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Judging by the fact it's 2026 you must be writing this from the Mars baseSpaceX was started in 2001. It announced Falcon 9 and messaged its reusability ambitions in 2005.
Falcon 1 wasn’t going anywhere because making rockets is too hard. Falcons 5 and 9 weren’t going anywhere because medium lift is a different ball game. Falcon Heavy wasn’t going anywhere because timing that many engines impossible. Reuse is impossible. (The kerosene will clog everything.) Then, after refly: the total launch market will never be more than $5bn, so reuse is useless.
More recently stainless steel can’t work. Now it’s shifted to reuse and refurbishment being too difficult, or refueling being impossible because of boil-off. Because keeping shit from boiling, apparently, is just unsolved engineering. ಠ_ಠ
Not everything SpaceX does is genius the first time. But they’re ridiculously good at not persisting with stupid. The idea that a dozen rapid depot launches is somehow a gating concern, again, as a tech demo, we’re building the depot eventually, is just such a weirdly small and big concern.
> But they’re ridiculously good at not persisting with stupid.
They are persisting with HLS though.
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They are persisting with HLS thoughThrough what? What experimental data do you think renders this path foolish?
Because I’m seeing a rapid-reuse heavy lift system with a fuel depot being built.
If they get less performance or more mission payload, they can add tanker launches. If they get more performance or less mission payload, they can remove tanker launches.
People ran into "the design is 10% heavier than planned for unexpected engineering reasons and now we have to make hard choices" on space missions far less complex than a literal Moon landing. SpaceX has externalized the "hard choices" into the tanker count, pre-emptively.
The lunar orbit of Artemis is defined mainly by SLS/Orion's performance, or lack of thereof. The specific NRHO was a Gateway choice, and might now be dead alongside it, but by itself, Orion can't get to low Lunar orbit. Which drives some peculiar design choices.
Sure, don't fix what isn't broken and all - *nix tools are decades old too after all - but still.
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the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12?Nobody has ever done in-orbit propellant transfer or storage. We’re building it to see what those numbers shake out to, and how the propellant gets lost. (Boil off? Leaks? Incomplete transfer? Weird, unexpected degradation because space? ¯\_(ツ)_/¯.)
If it works, it dramatically reduces the cost of lunar and deep-space access. You’re saying that isn’t worth it because it isn’t certain? This is spaceflight. Nothing is certain. We have to weigh risks and payoffs. And then mitigate them. The time for mitigating this risk is this (and probably next) year. If the refuelling is dumb, the plan changes—Blue Origin is testing its own approach on the same timeline.
Like, in Apollo 11 we fucked up the lander’s fuel budget. The astronauts were literally running out of fuel because a foreseeable problem, the surface being bumpier than expected, wasn’t contingency planned for over ten preceding missions. And we’re trying to do better than just retreading Apollo, because Apollo—strategically—failed as a platform for further manned spaceflight.
> the lunar orbit chosen due to available energy makes rapid extraction impossible
Isn’t NRHO an Orion limitation? Can Orion circularise on its own?
Also, rapid extraction hasn’t been a requirement for the Moon since ever? If you want rapid extraction, plant a ship that can motor off the Moon home in one shot as an emergency-egress option down the road. In the meantime, you’re days away from help under ideal circumstances; realistically, we don’t have rescue options.
Starship might be crap. But the bets look good, and the project is on the whole no more ambitious than the original Apollo missions. The criticisms you’re raising are either fundamental to the mission architecture because it’s developing a new spacefaring capability (refueling and rapid relaunch) or cost-cutting choices irrelevant to HLS (Orion’s second stages being efficient but underpowered).
I don't really understand why these kinds of comments persist except as some pathological cope when confronted with a world that doesn't work the way you want it to.
It's not convincing, it immediately outs you as a zealot, it's counterproductive in every single way. Why keep doing it?
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don't really understand why these kinds of comments persistOne, you can make money criticizing Elon on the internet.
Two, controversy is catnip to the man. DOGE was a disaster. X and xAI look like aborted disasters. And he’s clearly gotten bored with Tesla. It isn’t hard to project that on SpaceX if you don’t know the heritage.
I'm very disappointed Tesla has (seemingly) abandoned its goal of producing 20m Model 2 per year. Forfeiting the mass market is a bummer. More so every passing day.
(I'm bearish on Robotaxi and (Tesla's) self-driving.)
Also SpaceX, Tesla, PayPal, OpenAI, Grok and Neuralink aren't vaporware...
The claim fundamentally doesn't make any sense.
Making promises and "it's essentially ready, it's just about regulators" are quite different, if not for Trump he'd be done for securities fraud.
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confronted with a world that doesn't work the way you want it toSure.
Some of us are just trying to figure out the new rules. What is all this hypercapitalism stuff (aka Muskism) and who are the people (lunatics) pushing us there?
So it's natural to kibitz about one of the most powerful people on the planet. Especially when he's also a world-striding shit poster, antagonizing everyone, demanding a response.
FWIW: the writings of Jill Lepore, Quinn Slobobian, and Ben Tarnoff have been most illuminating. Ditto their misc guest appearances on various podcasts.
X Man: The Elon Musk Origin Story
https://www.pushkin.fm/podcasts/elon-musk-the-evening-rocket
Elon Musk Is Building a Sci-Fi World, and the Rest of Us Are Trapped in It Nov. 4, 2021
https://www.nytimes.com/2021/11/04/opinion/elon-musk-capital...
Muskism: Guide for the Perplexed
https://www.amazon.com/Muskism-Guide-Perplexed-Quinn-Slobodi...
https://bookshop.org/p/books/muskism-a-guide-for-the-perplex...
https://www.theguardian.com/books/2026/mar/26/muskism-by-qui...
https://www.standard.co.uk/culture/books/muskism-review-elon...
My (noob) understanding is the challenge is achieving reuse (safety, reliability) while keeping the (economically necessary) 100 ton payload capacity.
If this doesn't play out to be reducing costs for the avg american, Musk was able to get funded by the american tax payer nicely.
Thats not a lot of people.
And with the satelites risk and disruption to astronomy and the co2 usage, it might have affected more people negativly than positivly.
Time will show, plenty of ignorant decisions from Musk inbetween so yeah...
Whats your source?
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insane amount of refuel dockings while the thing is in orbitWhat's wrong with this? Lots of launches is fine until we build the scale required to make a proper depot worthwhile. (Which, by the way, is part of Artemis's plans. Though currently it looks like a bunch of glued-together Starship tankers.)
In space, you can't do that kind of repair/maintenance, you have to make sure the refueling is PERFECT. And this is with deep cryogenic propellants that very much like to boil off and cause pressure increases in the tanks they are contained.
That problem hasn't even been touched yet. In order to make Spaceship X happen, they need to figure one refueling out, which is difficult given the fact that Raptors run on cryogenic propellant that likes to boil off, then they need to figure out how to do 10 in a row without any issues, which is exponentially difficult.
And then there is the whole thing about everything working well for trip to Mars, and back.
And if there is a configuration that exists that can do all of that, its very unlikely that a company under the leadership of someone as Musk can ever figure this out.
For interplanetary travel, things need to start from either orbit or the moon. This has been known for quite some time.
The only question is whether the cost of flying all those missions would be prohibitive: by the stated goals, starship should be able to do the refueling missions cheaper then an SLS launch.
Obviously if it can't then it's failed, but the point of it is cheap heavy lift to LEO which is very obviously quite valuable.
Building a big specialty rocket to get to the moon is waste.
Starship's true purpose is to compete with airlines in trans oceanic flights.
Musk has said so many times but then he intentionally obfuscates it with all the Mars and Moon talk.
But remember that you heard this before it was widely realized to be true; Starship isn't about going to Mars. Starship is about going to China.
And too fragile/explodey for niche military uses (long range troop drops?)
But for military use - think logistics. Rapid delivery of equipment to unusual places. This applies to civilian purposes as well. All kinds of use-cases for speeding up cargo.
The entire economics of Starship and rapid reusability was presented at the beginning of the Starbase work, way back when Hoppy was a thing. He's been sticking to the plan since then. You might want it to be fiction, but he's been very good at figuring out business plans to leverage his ultimate goals.
> But for military use - think logistics. Rapid delivery of equipment to unusual places.
Surely it's too fragile/explodey for military use - the whole thing's a very volatile fuel tank - could it survive being shot at, even a single high-powered rifle bullet (during landing, or even post-landing) without going boom?
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You might want it to be fiction, but he's been very good at figuring out business plans to leverage his ultimate goals.Not very good on delivering tech though, which is what makes it more fiction than not.
Tesla easily has the best vehicle software + OTA and has since the S in 2012. It still feels better than most new vehicles.
You can buy a Tesla (including Cybertruck) today that will do 95+% of drives with 0 intervention. It may not be 100% autonomous yet, but there isn't anything obvious limiting the last step.
The robots exist but are still being developed. Within 5 years, it is hard to imagine them not becoming super valuable within factory settings.
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Tesla easily has the best vehicle software + OTA and has since the S in 2012Sure: https://www.theguardian.com/technology/2025/jul/05/the-vehic...
https://www.wired.com/story/tesla-drivers-are-paying-big-buc...
https://www.thestreet.com/automotive/tesla-employees-shared-...
https://doctorow.medium.com/https-pluralistic-net-2025-04-15...
https://www.torquenews.com/17998/after-software-update-left-...
https://www.motherjones.com/environment/2022/10/tesla-autopi...
the cases are endless...
>The robots exist but are still being developed. Within 5 years, it is hard to imagine them not becoming super valuable within factory settings.
Yeah, let's check back in 5 years.
https://www.reddit.com/r/TeslaSupport/comments/1poig9a/night...
https://teslamotorsclub.com/tmc/threads/when-a-software-upda...
And the Mars missions so far are just delayed.
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And yet SpaceX flies the most reliable rocket in history more frequently than anyone in the world has ever flown, takes astronauts to the ISS regularly, and does so for far less then any competitionYeah, after almost half a century, they passed 70s-era Soyuz numbers.
>Tesla changed the automobile from ICE to BEV in a way people wanted to buy and was practical as a replacement for any use
The magic of EV subsidies (for both Tesla and buyers).
>And the Mars missions so far are just delayed.
The magic of that statement is that it can be true at any point in the future!
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Far too dangerousFalcon 9 is clearly proving that doesn’t have to be the case.
Transportships even reduce speed to reduce costs.
If the payload doesn't pay for all of this, it was a huge R&D investmen from the american people to Musks scifi ideas
NASA also another 6 Billion upfront to SpaceX for Dragon and HLS.
So yes the american paid for the R&D of SpaceX.
SpaceX took the 'risk' but either succeeding or not in your main business is hardly a risk if you need to succeed anyway to have that business.
If not for SpaceX, the American People would have paid more to the ULA group for what has clearly turned out to be inferior results, since ULA has received far more money for far fewer services.
SpaceX was the underdog.
Just wanted to add my grain of positivity here. Godspeed Artemis 2!
> add my grain of positivity
The best of science, reason, research, engineering, training, expertise, co-operation...
The best of humanity. Le meilleur de l'humanité.
> Do you prefer that we not even try to spread beyond our one planet, when an entire galaxy, or maybe even the neighboring ones, might be in reach if we try? What if someday at the very end of the lifetime of our sun and similar stars, we look back, and regret not trying?
The timeline you are speaking of is in billions of year. Yes, in that timescale, it definitely makes sense to try.
This very century, there are very serious scientific concerns about the continued comfortable habitability of Earth and the ensuing geopolitical instability caused by the accumulation of greenhouse gases in the atmosphere, the sixth mass extinction event, etc. We have solutions to mitigate those to some degree, but this requires very significant resource allocation to that goal, and so far it seems possible that we would fall short.
I don't think there should be zero resources allocated to space exploration, but it's at least reasonable to question whether we have our priorities set right.
And no, I’d prefer we take care of our home planet and make it a sustainable place to live first. It’s ludicrous to think we have any chance of surviving elsewhere if we can’t stop ourselves from making our natural habitat unlivable.
Yes we can do both. I still think it’s stupid to place human spaceflight on a pedestal. It’s putting the cart before the horse.
The best alternative demonstrated so far seems to be for some of us to push the limits of what is possible and watch all boats rise with the tide. Better this than slinging Tomahawks at school children.
> Better this than slinging Tomahawks at school children.
I’d rather the one be slinging tomahawks, than the one receiving tomahawks because my country decided to reduce military spending.
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People who obsess over space are so egotistical they can’t imagine someone not thinking it’s “the best”What? No I don't. Some people want to spend money on sports or making our planet sustainable before doing anything else. I think that's fine. It doesn't interest me, however, so I'm looking at this other thing. We can coexist without having to insult each other.
> It’s putting the cart before the horse
How many times in history did necessity create efficiencies versus ambition?
> How many times in history did necessity create efficiencies versus ambition?
Literally all the time? There’s another saying, “necessity is the mother of invention”.
For the more adventurous and/or bilingual the beaches on the Mexican side seem to have awesome views too.
https://imgur.com/a/Mlyxk9u
(and I checked, it was iPhone 4 not 5)
Either way, it's a shot not everyone is going to have posted to their socials.
I saw that Saturn V as a child once, too. I think that the Saturn V really made me the person that I am today. Seeing something so huge, that is literally engineered down to every last tenth of a millimeter - that was profound for a young child. I could not believe how detailed that rocket was, yet so huge. There should be an engineering term for the size of a machine divided by the smallest critical engineered component of the machine. I don't think any machine would have beat that in the Saturn V's day - maybe some ocean liners?
I come from a construction family, so I'd put some of the famous sky scrapers in that category too. Especially thinking about the crazy beam walkers like that famous photo of the guys riding the I-beam up eating their lunch on the way up.
Computer processors probably take that cake.
I live in Dallas now and will be turning 50 soon, i want to catch the next Starship launch live but would have to time it perfectly to get time off of work ahead of time.
> I just missed the original Apollo flights and had assumed I would never see a moon landing in my lifetime.
The PR Chinese might want to go for a significant landing, too, just for the prestige?
I'm sure people here are already familiar with the speeds these things go, but that's the first time I've confronted a fact like that and it blew me away.
Note that escape velocity applies to a situation without continued propulsion and also without air resistance, but still you can imagine that the order of magnitude is similar.
But speed is always just relative to some frame of reference. Acceleration, on the other hand, is absolute, and so might be the more interesting thing to look at here.
If I fall, I might accelerate at G meters per second, relative to the earth, but I don't absolutely accelerate. If the earth decelerates at the same time, I'm now both accelerating an decelerating. It's relative.
If you are in space accelerating and the Earth would decelerate (which is just an acceleration in the other direction), you would still feel exactly the same force (minus Earth’s gravity, to the small extent you’d still feel it), and people on the Earth would feel the Earth’s acceleration. (For them it would feel like “down” isn’t perpendicular to the Earth’s surface anymore, or as if the Earth’s surface was tilted.)
When you sit on a chair on Earth, the pressure you feel on your butt is your acceleration upwards. If there was no chair and no ground (and no air), so that you’d be in free fall, that’s when you’d have zero acceleration. Your inertial rest frame is the trajectory you’d take in free fall. When you’re sitting on a chair, or lying in bed, or standing on the ground, you’re accelerating upwards relative to that rest frame, and that’s the pressure you feel on your butt, or on your body, or under your feet.
I'm not disagreeing with you, I'm just pointing out that there are circumstances where "you can determine your acceleration without any external reference" isn't true. You might even say that this is relative to your circumstances ;)
Edit to reply:
> I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?
You are accelerating at 1g through curved spacetime. Newtonian "speed" behaves strangely in curved spacetime.
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According to general relativity, you (and the ground) are accelerating at 1gI don't believe this is correct. If I lock two rockets in opposition to each other, they aren't accelerating. They're pushing at each other. And their propellant is accelarating away. But their displacement and orientation are unchanging, which means their velocity is zero which means acceleration isn't happening.
Similarly, the normal force resists your gravitational force to produce zero net acceleration. (An object at rest in a gravity well is its own local frame.)
> If you jump off a cliff, you'll stop accelerating for a bit, until the ground hits you
I don't believe this is correct. In GR, free fall is still inertial motion. You're just free of fictitious forces and thus following the curvature of spacetime.
When you're in free-fall, that's when you're in a non-accelerating frame, even though a non-relativistic description** would say that you are, in fact, accelerating.
Caveat: I only do physics as a hobby, neither academically nor professionally, so take with appropriate degree of doubt.
* for point-like observers at least
** ignoring rotation and curved orbits
In my opinion, a much healthier way of thinking is to not apply any such conventional labels to some forces and to just treat all forces equally, which is simpler, and it also matches the real world, where there is no practical difference between "fictitious" and "non-fictitious" forces.
If you treat all forces equally, then the rule (a.k.a. Newton's 2nd law) is that the resultant of all forces that act in a point is always null. From this, the conservation of energy is an obvious consequence, because whenever that point moves the total mechanical work is null.
The mechanical work of the "fictitious" forces is the variation of the kinetic energy, in the same way as the mechanical work of other forces is equal to the variation of some corresponding kinds of energy. For instance, the mechanical work of an elastic force is the variation of a potential elastic energy.
A "fictitious" force can squish you like a bug exactly like a "non-fictitious" force, and when that happens you would not be saved by the thought that the force is "fictitious".
There is a baseless claim that "fictitious" forces can be distinguished from "non-fictitious" forces because they depend on the system of reference. However the same is true for some of the so-called "non-fictitious" forces, which are functions of velocities and accelerations of bodies, in the same way as the inertial forces. Moreover, what actually varies between systems of reference is how forces are distributed into various kinds of components, not the resultant forces.
If you are pressed on a wall by a so-called "fictitious" inertial force, no change in the system of reference will change the compression force that you feel, but it may change the interpretation of the kind of forces that result in the compression that you feel.
In general relativity the "fictitious" forces do not disappear, but like in classic mechanics where you can define the "fictitious" forces using the variation of the kinetic energy, in relativistic mechanics there is an analogous definition based on the variation of the momentum-energy quadri-vector. In the gravitation theory of Einstein you can compute this inertial 4-force using the gravity force that is derived from the "curvature" of the space (which is in turn determined by the spatial distribution of the momentum-energy 4-vector of matter). The rule of a null resultant 4-force remains true in general relativity, so for a body that moves freely, like a satellite or a body in free fall, the inertial 4-force is equal in magnitude and opposite in sign with the gravitational 4-force.
In some problems of general relativity, you do not need to compute the inertial forces, because e.g. the trajectory of some body might be along a geodesic and that is all that is of interest for you. This is the same like when you use kinematics to determine the possible movement of a mechanism, where you want to know the path on which something moves, but you do not care which forces are exerted on the parts of the mechanism. However, in other problems of general relativity, you may want to know the forces that act upon a body, for instance for computing the required strength of materials, and then you may need to compute inertial forces, exactly like in classic mechanics.
The physics as taught in schools is full of such useless conventions caused by historical accidents. Moreover, besides conventions that just make things more complex than they should be, the standard textbooks contain definite mistakes that have been perpetuated for generations, like wrong definitions for all physical quantities related to rotation motions. In conclusion, trusting the "authority" of the school textbooks is a mistake and people must attempt to verify with their minds all that they are taught, instead of trusting. As a schoolboy I was more skeptical than most, so some of the less competent teachers feared my questions, but I still believed much of what I was being taught and only years later I realized that I was duped.
The fact that the AI models are trained on scientific literature that contains widespread inefficient methods or even mistakes, guarantees that they will provide wrong answers in comparison with really competent humans.
However, if you measure acceleration in many points, you typically can discriminate the 2 cases, because the spatial variation of the 2 kinds of acceleration fields is normally very different.
If you also move relatively to the local system of reference while measuring acceleration, you have additional distinguishing information from Coriolis forces.
So with enough measurements, gravitational forces and inertial forces can always be separated.
You could also perform one of many historical experiments, such as dropping an object from an elevated height with careful timing, or rolling a round ball down a gently sloped track, and so on.
> I have always been told that acceleration is change in velocity over time. Is that wrong?
Not per se, but it's more complicated when relativity gets involved.
Wikipedia has some decent starting points:
https://en.wikipedia.org/wiki/Proper_velocity
https://en.wikipedia.org/wiki/Proper_acceleration
https://en.wikipedia.org/wiki/Four-acceleration
"Similarly, standing on a non-rotating planet (and on earth for practical purposes) observers experience an upward proper-acceleration due to the normal force exerted by the earth on the bottom of their shoes."
But can't you escape gravity slower, just by going higher and higher at lower speed? Like a plane? (ie not vertically, but at an angle)
Since those constraints are impossible to meet in the real world, we have to get going fast enough to coast most of the trip on inertia after the fuel runs out.
On top of that there weren’t really solar panels in the 1960s so the Service Module had to carry tons of chemicals to produce electricity, as well as extra fuel for all of that weight. As a result it was massively overbuilt compared to anything we’d try today and even so had to take an expedited flight path to the moon of 3 days in order to conserve operational lifetime. Artemis does not have nearly as severe constraints on either the Orion or the future Starship and so can afford to take a more fuel efficient 5 day coast up to the Moon and make the design tradeoffs on Orion that that entails.
It's kind of said that we are having to do all of this repeated work just to get to where we've already been even if we are doing it on a much more accelerated schedule.
Nine minutes after launch, it was in orbit.
Nine minutes.
To understand gravity drag think about the rocket firing just hard enough to hover 1 meter above the pad, you burn out all your fuel in 10 or 15 minutes and go nowhere...
In the other direction if you want to accelerate harder you need to make your structure stronger so you need to burn more fuel per second and have to displace some fuel in exchange for more structure and you keep doing that until you're so heavy you can't produce any more acceleration and you're all engine and structure and no fuel.
So yes, you can buy a car today that'll let you feel the G's like you're a space pilot.
But a car's acceleration slows almost instantly. The rocket just keeps accelerating faster as the tank empties and it gets lighter. By main engine cut off it might be pulling 5G.
If you could drive your car straight up vertically, you'd have to cruise just for an hour or so at 100 km/h (<65 mph) until you reached space. It's not that far.
(also my first time trying to vibe code with Gemini as opposed to Claude and I don't know if I noticed a big difference, which probably makes sense for such a simple project).
Godspeed crew of Artemis II.
Brought my camera and got a few good pics too! Very invested in this entire mission!
Someone behind me kept whisper crying "That's it! Go baby, go baby go" like it was his child and was encouraging them on. Very emotional, loved it.
Also when that engine sparked it really hit me just how many hours of deep thought and technical innovation goes not only into getting us as humanity to that point, but also the crews at NASA planning, building and executing these missions
https://science.nasa.gov/missions/what-are-jpls-lucky-peanut...
40% of people had voted yes. Which is somewhat worrying given the mission plan and hardware.
It is a noble endeavor - science, engineering and peaceful exploration hold the keys to our survival and prosperity.
It is also important psychologically to our survival - a reminder there is a bigger pie, that we can solve hard problems, that progress can be made, that competence and education counts, as does courage, and that we can work together for a common cause.
This is the best of America, and for a while we can be proud of the human race.
(If anyone managed to get the perfect shot of the spark-filled separation feed, please share. That was... incredible.)
it's better to invest in human progress than in war
SpaceX does these beautiful drone shots and live telemetry so well. Considering that each SLS launch costs in the billions it would be nice to do a little better on production
I felt the commentary during the launch also wasn't good. And I am not too interested in hearing from some Hollywood people before the launch
54 years.
I hope we as humanity never stop again.
Good luck!
The best of humanity is remarkably capable as compared to the best physical machines / robots. There's a great paper called the "dispelling the myth of robotic efficiency." https://academic.oup.com/astrogeo/article-abstract/53/2/2.22... // https://lasp.colorado.edu/mop/files/2019/08/RobotMyth.pdf
Yes, a robot car that drives on its own will be a better driver than most humans who text and drive, or have 400ms reaction times.But making a machine that can beat a 110ms reaction time human with 2SD+ IQ – and the ability to override the ground controllers with human curiosity – for exploration is much harder. Healthy, smart humans have high dexterity, are extremely capable of switching roles fast, are surprisingly efficient, and force us to return back home.
So in terms of total science return, one Apollo mission did more for lunar science and discovery than 53 years of robots on the surface and in orbit.
https://www.nasa.gov/missions/artemis-ii/arow/
Moderate geomagnetic storm watch until April 2.