It is approximately a 30 storey building. The majority of it is filled with extremely dense liquid fuel.

The ability to lift that into orbit (minus most fuel and booster) with both halves still able to land is an insane feat.

You mean, extremely cold. Not particularly dense, methane is about half of water density, oxygen is about 10% more.

Given most buildings are upwards of 90% air by volume, that's still quite dense.

Wanted to argue with you but apparently concrete is only 2.5g/cm3 so not that much different from water.

There have been ships made of concrete which I always found interesting. Ferrocement (I believe) is a form of boatcraft that can be done in your backyard without any special tools.

When supercooled they’re a bit more dense than that. But as the sibling comment said, most 30 story buildings aren’t filled with water.

the supercooling system and its nitrate gasses will freeze the core of the space ship

Presumably they mean compared to hydrolox like Delta IV or the Space Shuttle.

I've walked along the length of the rocket at NASA in Houston. It's massive and to think it took all that power to get that tiny capsule to the moon with a few men. Pretty amazing...

The Starship is designed to carry 100 people. SpaceX will be able to send more people to the moon in one mission than all the moon landings ever sent. Wow...

There's another Saturn V you can walk the length of in Huntsville, AL. It made quite an impression on me -- on first sight from below it's like that opening scene in Star Wars IV when the Star Destroyer hoves into view.

Also one in Florida at the Cape. Amazing perspective to see it in person. I've never seen a picture that came close to the impression from seeing it in person.

I believe it requires a refuel in orbit to get to the moon. So, two missions, but still super impressive.

More than that actually, it takes I think 3 tankers to fully top up a Starship in orbit, and the Lunar model needs to go into an elliptical orbit towards the moon and have at least one more top up again before having enough fuel for the rest of the mission.

I thought the full refuel was only necessary for a Mars mission?

It’s interesting. Going to the moon, propulsive my landing, and propulsively taking off and returning to Earth takes more dV than just a boost to Mars. If you think about it boosting to Luna and Mars aren’t much different in dV, but then you have lunar landing and takeoff again to do. Even with a very thin atmosphere, you can still shed the vast majority of your interplanetary velocity with aero braking at Mars.

As a result the Lunar variant actually needs a lot more fuel delivered to it than the Mars version. Even one full refuel in LEO isn’t enough, and it needs to boost part way to an intermediate elliptical orbit and get another top up.

Genuine question, how will tankers get into space? If most of the ship's size is already dedicated to fuel that's burnt, that seems to leave little left for fuel payload. I also assume fuel payload would be much heavier than other types of payload, requiring more ship fuel to launch it, further taking up space.

It seems like for every full refill you could provide in space it'd take an additional 3-4 ships just to get it up there?

The tyranny of the rocket equation, combined with Earth's deep gravity well, and the higher efficiency of rocket engines in vacuum makes it seem much worse than it is.

E.g. for a lunar mission: it takes 9.4 km/s Δv to get to low Earth orbit (LEO), but only 5.5 km/s Δv to get from there to the Moon [1]. Raptor (the engine used on Starship) has an exhaust velocity of 3.2 km/s on Earth, and 3.7 km/s in vacuum [2]. Plugging those numbers in the rocket equation, to get to LEO you need about 19x your payload mass in fuel. However, to get from LEO to the moon surface, you only need 4x your payload mass in fuel. So while a tanker can indeed only bring a small fraction of its launch mass as fuel to orbit, once you're in orbit you don't need that much fuel to get to the moon.

In reality the numbers to get to LEO are lower because of staging and the vacuum engines on Starship which can be used in the upper atmosphere, and you also need fuel to get back from the moon, but it probably won't add up to a full Starship.

[1] https://www.reddit.com/r/space/comments/29cxi6/i_made_a_delt... [2] https://en.wikipedia.org/wiki/SpaceX_Raptor [3] https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

The plan, at least as originally described is to have (at least) three variants of Starship: One for passengers, one for bulk cargo, and a tanker.

Each would be launched atop the common Super Heavy booster.

Depending on the trip, a passenger Starship would do an on-orbit refuelling from the tanker variant.

About that yes, but remember that a fully loaded starship in orbit can land on any solid surface in the solar system and return to earth (except for Venus)

Starship’s usable volume is over 100 times that of an Apollo lunar lander.

You could also add 3-4 extra stages and put an even bigger tanker into space. But I guess there will be diminishing returns due to the crushing weight. It would probably be cheaper to make many smaller unmanned vessels and boost them via an electromagnetic rail, then assemble it in orbit.

Why not launch a bunch of larger payload tanker bays, empty, then link them together in orbit and then send Many smaller multiple regular trips to fill it up such that you have an orbital fueling station?

I don't get it, how does that answer the question about the economics of lifting fuel into orbit? Could you elaborate your point?

I think they are trying to imply that refueling a starship in orbit is worth it, whatever the cost - it gives a capability we didn't have before.

To land the volume of one starship on the moon takes 3 or 4 launches of a fully reusable craft - so just the fuel.

To land that with Apollo would take 100 launches of a single use craft.

My layman’s understanding is that doubling the payload quadruples the fuel requirement. So it is much more efficient to launch multiple rockets with a small amount of fuel than one big one with all the fuel you need. It’s the difference between O(n) and O(n^2).

400 feet = 121.9 meters, 30 feet = 9.1 meters

Feet, not feets.

"Feets" evokes a vision of Gollum, looking at gleaming Starship and hissing "What a sssstrange fisssssh!"

A nice combination of SF and fantasy in one picture :-)

Thanks!

Not foot?

I never noticed this, but after thinking about it for a few minutes it seems that in standard usage there is a difference between attributive adjectives and predicative adjectives.

As an attributive adjective, "foot" is indeed correct, e.g. "a 130 foot yacht."

As a predicative adjective, "feet" is correct, e.g. "the yacht was 130 feet long."

Occasionally, in certain regional variations, you may hear "foot" used in the second case: "the yacht was 130 foot long."

I'm really interested in seeing how it will perform its "belly flop" landing. Seems like a high risk maneuver https://www.youtube.com/watch?v=DdTYMry7fq0#t=1m17s

They've already done it[0], and it was a complete success until a propellant pressure issue resulted in lower than needed thrust, and a hard impact on the pad.

[0]: https://www.youtube.com/watch?v=_qwLHlVjRyw

It oriented almost perfectly. I'm truly amazed at what SpaceX has accomplished so far. Just need to stick that landing a few dozen more times. It's quite a reorientation.

Curious why does it need to wait so long to reorient? I thought it was going to crash and in last few hundred feet, it flipped! Can it orient straight - way up in the air like Falcon boosters?

Reorienting requires the use of main engines. You want to relight them only once, to ensure that the header tanks and the "downcomer" remain full. Additionally you want to burn off as much speed as possible with the bellyflop, so flipping vertical as late as possible. All combined this means combining the landing burn with the flip is best, as close to landing as possible.

It has a cute nickname, “Suicide Burn”.

Why is it efficient? [https://www.reddit.com/r/KerbalSpaceProgram/comments/2z534g/...]

Guessing we won't be using constant altitude landings in real life?

It actuallyoriented perfectly, but due to the flip, fuel pressure was lost leading an oxygen rich exhaust eating away the engine (becoming what's known as engine rich exhaust) before it was able to complete the landing burn. They should just have to fix the fuel pressure problem to have a complete success.

I'm very dumb so I'm asking: is "engine rich exhaust" a real term?

What do you mean by "real term"?

Real rocket science teams really use phrases like this, including this one. Is it a joke? Yeah, kind of. Is it what they would say if they had no sense of humour? No, probably not. Is it still a thing the experts actually say to actually talk about what's going on? Yeah, it is.

a few more examples:

"Rapid Unscheduled Disassembly" : explosive destruction of the rocket

"Lithobraking" : it's like aerobraking, but with less aero and more litho

Wow, that's surely one of the most amazing feats of human achievement I've ever witnessed - incredible!

On landing video, I see only 2 engines turn on instead of 3 - why is that? Was one engine malfunctioning, or was it the result of low pressure?

The rocket weighs quite a bit less at the end, having used most of its fuel, so only two engines are needed to land. The engines cannot be throttled down more than ~50% (as all rocket engines), so a third one would add too much thrust.

Falcon 9 does the same, relighting 3 engines (out of 9 total) for the boostback burn, 3 for the entry burn and then just 1 for landing.

For that flight the engines are even too powerful for the ascent (it wasn't fully fueled, I think) and as soon as they couldn't throttle any lower, an engine was turned off instead.

Thanks for the explanation! it this also the reason why Raptor is (relatively compared to like F-1) small and BFR uses so many of them?

That, and for redundancy. I've heard it's designed so that even if a significant number of engines malfunction, others can be used to compensate.

A complete resounding success until it burst into flames!

> “a hard impact on the pad.”

It’s called a RUD: Rapid Unscheduled Disassembly

I guess the counterargument is that as long as you bring it down in a "safe" area, you don't really need a 100% success rate.

If you can reuse it, great, if not, well, it's a rocket.

The belly flop is also how passenger variants will be landing so you do actually need a reliable program....

...eventually.

They didn’t launch humans on the Falcon 9 for the first 10 years either. Lots of time to iron out the kinks (though it will likely be much less than 10 years this time)

Humans aren’t landing propulsively on f9 either - if the landing fails it just costs money. The capsule lands with parachutes.

The Mars mission has a somewhat tighter timeline.

Aspirationally, yes, but it's not like they run out of money if they don't get to Mars that fast.

How many G’s will passenger experience when the ship transitions from the belly flop to the suicide burn?

That looks like an awful lot of G’s that this maneuver is pulling there.

I think it would depend on how close they can line up the centre of rotation and the passenger seating.

The capsule containing passengers will separate during re-entry and land with parachutes.

This suicide burn is just to try to recover the rocket to save money.

This is the first I’ve heard of this description of a separate crew module.

This sounds even crazier than the bellyflop-swivel-to-suicide-burn (BSTSB).

So the Starship system is some type of 3 piece mechanism? Where the 3rd piece is the human module?

And they’re going to land this with parachutes? Where? In the ocean?

Won’t this kill the reusability of the plan, for quick turn around time?

Granted, if the BSTSB is to only be used for transporting inorganic materials, like fuel, then G-forces does not matter for human usage.

Edit: Disregard this, it's wrong entirely.

The fuel used to attempt the landing the instead be used to launch.

That's true, but a suicide burn uses a _lot_ less propellant than you'd think. The atmosphere does most of the work.

My guess would be it will still have a launch escape system for the passenger variant. So if the belly flop doesn't look right or if it doesn't stick the landing it just ejects the crew.

Well Everyday Astronaut did a long article and YouTube video about why starship won’t have a launch abort system. [1] I don’t believe I’ve watched the video but I remembered it exists so I thought I’d share.

https://everydayastronaut.com/starship-abort/

Where would you put a 100 person LES? I don’t think a solid rocket escape system would work in the belly flop position anyways since you wouldn’t gain any altitude, you’d actually be making it more dangerous since you’d be increasing horizontal velocity. Airliners don’t have ejection seats or parachutes.

A launch escape system is not necessarily safer than without one.

In theory you’re right, in reality Space Shuttle.

IIRC never fired in actual missions; did not help avoid any of the two fatal accidents.

All of standalone LES activation ever in the history of human spaceflight had been successful in saving all occupants' lives.

Space Shuttle failed twice on the other hand, each time killing all aboard, and in neither cases of it its integral abort systems/abort modes did help at all.

So in theory the lack of capsule-only LES do not necessarily mean safer rocket, in the history and in the statistics it does.

Statistics say you shouldn’t call your reusable ship a word beginning with ‘C’

In 1963 a LES killed someone, in 1983 it saved lives.

> In 1963 a LES killed someone

Which manned abort in 1963 is that specifically? Why are you trying to skew discussion into some direction?

Note: LES stands for Launch Escape System, usually a small solid rocket that activates in case of a failure during ascent to take the manned capsule away from exploding rocket under it, perhaps equivalent to airbags in a car.

IIRC this is the case when Soyuz LES activated on the pad before an unmanned test flight, killing some of the ground crew.

So not in flight. Not relevant.

People gets hurt by airbags all the time trying to service them. That doesn’t tell if it’s worth having them in actual situations they’re designed for, nor whether the situations are worth preparing for.

It is relevant. If (giving an extreme example to make the point), statistically two humans were killed servicing airbags for every life saved by airbags, cars wouldn’t have airbags (with possible exceptions for cars of the super rich and super important such as the POTUS)

Also, an escape system adds weight to a rocket. That weight could be used for other stuff that makes the rest of the system more reliable (slightly stronger fuel tanks, redundant pumps, whatever). Designing the escape system also takes resources away that could be used to improve the safety of the primary system.

For rockets, it’s not easy to decide what’s the best choice; we launch too few of them, and the ones we launch change too often to gather reliable statistics. Getting real-world data on the reliability of escape systems definitely is hard, as it requires numerous rocket failures or elaborate test setups (a full test must include high speed and an explosion that may throw material through the engine of the escape capsule)

> All of standalone LES activation ever in the history of human spaceflight had been successful in saving all occupants' lives.

> Space Shuttle failed twice on the other hand, each time killing all aboard, and in neither cases of it its integral abort systems/abort modes did help at all.

> So in theory the lack of capsule-only LES do not necessarily mean safer rocket, in the history and in the statistics it does.

Is this supposed to be a recursion joke? Sorry if I'm not getting it.

This factoid [1] may soon need an update.

[1]: https://www.guinnessworldrecords.com/world-records/largest-r... "Largest rocket"

Nice use of "factoid". Most people use this world incorrectly.

Probably because most of the world has a different definition.

1 : an invented fact believed to be true because it appears in print 2 : a briefly stated and usually trivial fact

https://www.merriam-webster.com/dictionary/factoid

Note that these are OPPOSITES.

Ah, what would be the most common incorrect way to use it? Being a non-native English speaker I'm always fascinated to learn new things like this one.

It's often used for a "trivial or minor fact" but by comparison with planetoid (something like a planet but not a planet) or cuboid (like a cube but not an actual cube) or asteroid (looks like a star but is not a star) or humanoid / android (having the form of a human or man while not actually being one), you can see what the 'correct' usage should be.

Trivial fact would perhaps be better as 'factette' or 'microfact'.

I have also heard people use it to describe a "bite sized fact". The "oid" part of the word, for some people, seems to mean "small" or "compartmentalized".

In this incorrect usage of the word, take the following sentence: "Nice little factoid!", could also be written as "Nice little nugget of info!"

If most people are using a word to mean something different, doesn't that mean the meaning of the word has changed?

If I choose to label them "incorrect" for their usage of "factoid", by your own argument I'm absolutely right.

Descriptivists may say yes, but that doesn’t mean people won’t try to stop the meaning drifting to prevent the past becoming inaccessible.

Seems to have happened with "momentarily". Used to mean "for a moment" but now most people use it to mean "in a moment".

I remember being amused the first time a flight attendant said "we'll be taking off momentarily".

It depends which people you are talking to.

Reminds me of Norm's use of the word when reciting a joke about Danny Devito (and Norm's a stickler for proper usage of words)

I live on a partly forested hill that towers about 250 ft over the river valley where the railway is. When I go to the railway station and wait for a train, the hill is really dominant on the near horizon.

And whenever I realize that the full Starship + SuperHeavy stack is going to be much taller than that hill, I am just speechless. That is one big freaking rocket, one big trampoline for mankind, so to say.

Yes it is. Starship, the part that will end up in orbit is longer than the truss section, which is the longest section of the ISS and has the solar panels on it. At the crash sight of SN8 watching the people walk around the wreckage, it gave a good indication of scale.

Starship alone (the orbiter) is 50m. The truss of the ISS is 109m[1] long. While massive, Starship will still be dwarfed by the station (other than planned habitable volume or individual modules/elements).

[1] https://www.nasa.gov/feature/facts-and-figures

considering this is over 50 years after Saturn V, I don't feel this is such a huge feat.

2001 predicted we'd be permanently living in the moon with orbital space hotels two decades ago, and no one ever thought they were being unreasonable if we kept the same momentum as the 60s, so yes it's sad. But we have to take things for what they are and what spacex is doing is definitely progress.

I grew up in the 1980s. Back then, the year 2000 was a magical year where we'd have flying cars and live on the moon.

I've adjusted my expectations quite a bit due to the lack of mobility progress since then.

With the amount of money NASA was spending at the time, doing those things was not feasible.

A MASSIVE 30 story building that can land vertically isn't a huge feat?

vertical landing isn't new, either.

Yeah in some ways the Saturn program is the more amazing. Technology finally caught up to the amazing accomplishment of the Saturn rocket program, if that makes sense.

The Apollo program was indeed amazing. Government bureaucracy and mediocrity is responsible for 50 years of regression. What SpaceX is doing with Starship is also amazing on so many levels (Raptor engine, reusable, goal of Mars, etc).

Government bureaucracy also made the Apollo program.

What got in the way was politics.

What revived space tech was competition.

Politics and bureaucracy can plague private enterprise and competition can be had between or at the behest of government institutions.

It's not as simple as government bad, private good. In fact that simplification can be quite dangerous if it leads to the erosion of government as policy.

Isn't the current government bureaucracy paying for starship development?

Almost not at all... something like 50 million so far for a program whose costs are probably in the low billions. Mostly spacex is paying for it with its capital raises

Yeah, all I've heard is $53M for testing in-orbit refueling and $135M for developing the lunar lander version of Starship for the Artemis program.

SpaceX has received contracts worth over $10 billion from the DoD and NASA. Its estimated that they have over 60% of Government launch contracts.

That of course is biased towards the contracted projects, but still provides cashflow and leverage for capital.

No, government funding to hit work milestones is totally different than government bureaucracy attempting to actually do the work.

It can actually land. The Saturn V cost absurd amounts of money and used gigantic amounts of army of people.The Starship program also wants to solve many problem that the Saturn V or even Apollo didn't.

This is not true technic wise but true politics wise, or politically incorrect, you should not be downvoted.

Considering this can carry 100 people instead of 3, I'd say it's a pretty big deal.

The Saturn V can carry those 3 people way further, though.

Nope, cause it didn’t have a second stage they could refuel in orbit, a reusable second stage they could use as a tanker, or a reusable first stage that provides the cadence to do in orbit refueling.

Because of in-orbit refueling each Starship will land over ten times the payload on Mars as each Apollo mission landed on the moon.

Still, that is multiple Starships.

Also, the Saturn V came back. That requires quite a bit more delta v. Actually, going to the moon and back is not that far off a one way trip to Mars.

> Still, that is multiple Starships. [...] Also, the Saturn V came back.

Since we're nitpicking: The Saturn V didn't come back – the tiny command module came back, and it wasn't reusable. In fact, the only reusable part of the Saturn V were the astronauts.

> Actually, going to the moon and back is not that far off a one way trip to Mars.

You're moving the goalpost. This is getting ridiculous. What are you even arguing about? Starship + Super Heavy will be a much more capable rocket, superior to the Saturn V in almost every way. That doesn't detract from the incredible engineering of the Saturn V, which was developed 55 years earlier, in record time, with slide rules (!), and which first launched 10 years after the first artificial satellite (!!) That is impossible to beat, and there's no need for a pissing contest.

They are two completely different vehicles. One is made for a return mission, the other made is made for a one way mission, while the other is reusable.

That being said, that rocket alone isn't going to be more capable than the Saturn V in moving a payload around. It will be less capable. If you have many rockets then you'll have the capacity to move that payload around as a far as a Saturn V.

A single SuperHeavy can put a loaded Starship weighing roughly 360,000 total pounds into low earth orbit, SaturnV could only put 310,000 lbs total payload into low earth orbit.

There, is that the comparison you wanted?

> The Saturn V can carry those 3 people way further, though.

Saturn V: 3 people to the Moon; Starship: 100 people to Mars (unproven, of course). Mars is a little further than the Moon. Granted, that's with in-orbit refueling.

The Saturn V would be three people to the moon and back. Starship is 100 people more or less around GTO. Multiple starships are needed to go to Mars. It's a pretty ridiculous comparison.

Isn’t excluding comparisons that include refuelling, when contrasting a refuel-able and a non refuel-able vehicle, somewhat ridiculous? Starship is refuel-able , that’s one of its capabilities. Nobody on these vehicles going to Mars will care about you sitting there complaining that is doesn’t count.

Kinda reminds me of the argument that the Wright Bros didn't invent the airplane because a catapult was used to launch later models.

(Apparently the aircraft launched from an aircraft carrier aren't really airplanes, either!)

If you only care about one way travel then any refuealable vehicle technically has infinite delta v.

People on these vehicles going to Mars are mostly going to complain about not being able to go back, as any kind of return mission will be Non-reusable.

> People on these vehicles going to Mars are mostly going to complain about not being able to go back, as any kind of return mission will be Non-reusable.

What are you talking about? Starships will be refueled on Mars and will return back to Earth. Why shouldn't they be reusable after their return?

>If you only care about one way...

I care about actual practical capabilities and achievable mission profiles. What do you are about?

Getting to LEO is already halfway to anywhere in the Solar System, though. And then Starship can go back and land.

The Saturn V didn't come back with people did it? Just a small capsule splashing in the ocean

It shouldn't be (given the 50 years) but NO ONE else has done anything close to it.

Ask the engineers who built the N1 how hard it is.