380s for ISP for the Raptor vacuum engine seems durn good, considering the tradeoffs between hydrogen and methane.
The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid hydrogen is twofold: it is not very dense, and to keep it from boiling away in liquid form, it needs to be really cold. So you need huge, insulated tanks to store it. Hydrogen is everywhere, but it's kind of a pain to use as rocket fuel.
Merlin Vacuum [2], which is currently used on the Falcon vehicles gets 311s. The RD-0110 [3], used on the Soyuz gets 326s. These use RP-1, which is highly refined kerosene. It's super easy to work with. On earth. Where we have 200 years of infrastructure in place to support using hydrocarbons. It takes that infrastructure to refine it into a form that rocket engines can use without gunking up the works with unburnt carbon and other particulate crap.
Raptor uses methane, which is kind of like a jack of all trades between density, efficiency, ease of processing, storage, and ease of use in engines. This is basically how SpaceX seems to operate: rather than optimizing a single part of the system (like trying to get the most efficient engine), they try to optimize from a systems level. I don't really know much more than that, because there hasn't really been a lot of stuff for civilians to read on methane engines. This is kind of the cutting edge of the second golden age of space exploration. This freaking rules, what a time to be alive.
I am so amazed by the genius of making it out of steel. It's just so completely counter intuitive but has accelerated their progress so much.
If they told you the stats of the material, better strength at cryo tempertures meaning mass reduction, higher melting point meaning minimal heat shielding and great thermal conductivity it would be easy to imagine it was some new super composite. Then your head explodes when they tell you it's 2% the cost of what they were using before and it's so easy to work with they don't even need a factory they can just weld it in a field.
Imo Elon is starting to get into contention for greatest engineer of all time.
Didn't the Russians use a lot of steel in their Space Age era rockets? It always seemed to me like we went too high tech too quickly and the Soviets were practical to a fault, and the truth should be something in between.
I know there are 1000 of them 100x smarter than me at all of this, but I have my doubts that the specs for "cold rolled" stainless will hold up after tens of re-entries, as it is effectively being tempered over and over.
I totally understand why they've gone for that design but the welded together steel plates really make me think of the sort of thing Wallace and Gromit would build.
I am totally with you on this - I just can't get over how utterly rudimentary and basic this thing looks! I can't wait to see it fly!
I am so used to seeing space stuff done in clean rooms, and things taking years and years to come to fruition (e.g. hearing about and seeing NASA or ESA probes etc getting made) that to see what is essentially a bunch of guys in a field just welding something together blows my mind.
I mean, is it just the outside that looks like that and inside it is ultra-exotic materials and tanks? Of course the engines are sophisticated machinery, but what about the insides? Are we just seeing the outer shell and it's all unobtanium nano-tube composite on the inside?
We work with multiple tens of ton of SS steel per month, and I would have never thought this heavy thing could fly with all the stress of the sky. I hope it fly good.
he addressed in presentation, from what i remember it had a lot to do with cost. Like $130k/ton with carbon vs $3k/ton with steel. He mentioned a few other factors. Also it allowed them to build outside, not sure if t that is true in production.
What I loved the most was the optimistic outlook, the forward looking focus and the implicit belief that any problem will be solved and we'll advance.
This is exceedingly rare in a pessimistic world drowning in the voice of Luddites and backwards-looking preservationists.
Like always, technology solving real world problems versus politicians (professional or amateurs) creating (and never really solving) self-serving perpetual issues.
NASA is still waiting for SpaceX to complete the Crew Dragon spacecraft that will fly astronauts to and from the International Space Station. The space agency has picked SpaceX (and another company, Boeing) to provide commercial crew flights to the station.
While SpaceX did launch an unpiloted Crew Dragon test flight to the space station this year, a subsequent abort system test failed, leading to the destruction of the vehicle. SpaceX aims to resume abort system tests later this year ahead of the first crewed test flight.
NASA Administrator Jim Bridenstine, it seems, is not happy with the years-long delays of Crew Dragon, as well as Boeing's Starliner spacecraft, especially after seeing SpaceX build Starship Mk1 this year ahead of its own test flight.
"I am looking forward to the SpaceX announcement tomorrow," Bridenstine wrote on Twitter Friday. "In the meantime, Commercial Crew is years behind schedule. NASA expects to see the same level of enthusiasm focused on the investments of the taxpayer. It's time to deliver."
I would love to know what the "Day-in-the-life" of a welder working on those ships would be. Did they train specifically for aerospace welding? How did they land that specific gig. Must be so inspiring to wake up and work on that.
I'd love to know the hiring process. There must be many people applying for these positions and I doubt that whiteboard welding is a thing. Or is it? :)
I imagine for the Mk1/2 they are using in house teams but for the hopper they contracted out the construction to a company that builds water towers (Caldwell Tanks). I mean - it makes sense, it's really just a water tank with an extra bulkhead that SpaceX just so happens to want to attach a rocket engine to...
For me the biggest "wow" (and there were a lot of those) was the capacity comparison:
Currently the entire world has a launch capacity of 200-300 tons into LEO per year.
With just ten starship/booster combos, that will change to a max capacity of over a million tons into LEO per year.
A factor of over a thousand. The entire current capacity (including the Falcons) at less than 0.1% of the new capacity, a mere footnote. Not even a footnote, really. And apparently they're cheap(er) to build as well. Complete game changer. And game over for everybody else in the launch business.
I'm surprised to hear Musk tone. He's not that friendly usually. Maybe it's because Tesla is a different business and its struggle got to him. Maybe it's because his inner child dreamt of this ship for decades..
That was a very dense an informative presentation last night, but I think the main take away is that rapid reusability is a game changer. In fact, game-changer is probably an understatement, basically every intuition and rule-of-thumb we have about space launches and travel will have to be rethought. And this will be true even of SpaceX falls well short of meeting their stated targets (2020 orbit, 150t capability, multiple refights per day, etc.
Musk stated (I think he just did some mental napkin math at one point) that if they meet their goals, the world's launch capacity will be expanded by two orders of magnitude. How often does any new development in any field bring about two orders of extra capacity? How does this incredible capacity change how you use this thing?
First consider prices. A launch would cost fuel + support operations + amortized cost of rocket. The last two will tend towards zero as they can be increasingly automated and will be a small fixed cost. IIRC, fuel costs roughly $60-100 per kilo to LEO, a 100kg person with 100kg of supplies and life-support equipment can reasonably expect to get to LEO for $20000 in fuel costs. Ok, so you need to "rent" the rocket (you want to stay there at least a few days), pay operations, SpaceX margin, R&D etc. Even then, imagine weekend LEO launches for $50,000 in the late 2020s. That's astounding. Given millenials' propensity for "experiences", they're going to have hoards of people buying this.
But what about risk? They've been trying to launch Crew Dragon for many years and still haven't. Well, with expandable rockets, you have to establish a safety record, it takes multiple flights, it's extremely expensive, you need a new rocket for each one. With fully reusable rockets, you can literally establish a safety record for an individual rocket within a matter of weeks, not years. Even launching once every three days (ie, far from their daily targets), it would take only a year to do more launches than Falcon or Arienne 5 have made in decades. Also, people are far more willing to take risks than organizations like NASA. Consider a thought experiment: SpaceX does 100 launches of Starship and establishes a safety record of 99% (1 blew up). They then start selling tickets, will people still buy, fully signing away any liability? Yes, you'll still have hoards of people lining up for a chance.
Finally, this is going to change science as well. Today, sending a 1 ton rover to the surface of Mars is a Really Big Deal. Hence, probes are made very carefully, very expensively and very very slowly. Not just design and build (it takes a decade), but operations as well (Curiosity traveled only 20km in the last 8 years). Everything is essentially super-low bandwidth. But once you know you can get a cheap ride to Mars (of anywhere else) any time, you don't have to go to such extremes. You can easily send more rovers, more radio relays, they can travel further, experiment more, take more risks and if you lose one, it's just not a big deal anymore!
In an interview Musk said there is this strange rule that no matter what you make the schedule, it takes twice as long, so what makes the most sense is to just set it unreasonably short, and then it will take longer, but be as fast as possible.
Some statements are so absolute that they cannot possibly be correct.
> "The best part is no part."
Simple design is better because less moving parts means less complexity.
> "The best process is no process."
No single process is a panacea for all situations, so strictly adhering to a process will eventually cripple you. The best process is the ability to quickly change your process when it is necessary.
I’d be interested to learn if advances in digital computing/controlling potentially solve most of the problems that were seemingly unsolvable in the Soviet era N1 rocket failures.
I’m assuming the inability to control and harmonise 30 rocket engines on the N1 first stage for pitch/yaw contributed significantly to the N1 failures and cancellation.
Will digital computing/control advances control for that and the 42 rocket engines on the SpaceX starships 1st stage?
Or are there other major engineering problems(such as aeronautical/mechanical) to solve as well?
Falcon Heavy managed 27 rocket engines just fine, so the N1 problems has been solved. In fact I don’t think multiple rocket engines ever was a problem with the N1. Its problems were quite different.
SpaceX is able to shut down failing engines quickly, as has been demonstrated so multiple engines don’t present added risk.
Vibrations from multiple engines is something they are able to model much easier with computer simulations today.
I'm slightly reminded of Sea Dragon[1]. That is, using fairly standard steal construction has the possibility to decrease costs even if it increases the net weight of the vehicle simply because it's so much easier to work with and cheaper than minimum weight high tech alloys. Also, because both are quite big though Elon's ship isn't as huge as Sea Dragon was proposed as being.
I just want to point out that SpaceX has not yet successfully put a human in LEO. The moon seems well beyond their technical capabilites at the moment and Mars seems like a fools dream at this point in time.
It is going to be interesting to see what happens to SLS once SS/SH starts flying. I am guessing there is going to be big public campaign for NASA to cancel SLS and go with the SpaceX craft.
Cranes are far and away the lightest way to move something up and down. Wires are incredibly strong for their weight; five times stronger than normal mild steel. Thats due to the stress exerted when they are made affecting the crystal structure.
Not only that, but tensile stress is the strongest mode in general. Structures holding up mass have to resist buckling from all directions. Tensile structures can use every bit of mass budget to hold force going precisely down.
Not only that, but you dont need all of rhe structure to hold a crane up, since its just sticking out the side of the rocket.
Not only that, but you dont even need a motor since you just need to slow things down a bit as they descend.
Cranes aren't especially heavy. You would need a boom to extend 2x the maximum dimension of the cargo hatch, so probably 8 feet, out past the exterior skin, plus some dyneema or steel cable, plus a winch motor of some sort. Not 100 lbs but probably less than 1000.
[+] [-] hoorayimhelping|6 years ago|reply
The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid hydrogen is twofold: it is not very dense, and to keep it from boiling away in liquid form, it needs to be really cold. So you need huge, insulated tanks to store it. Hydrogen is everywhere, but it's kind of a pain to use as rocket fuel.
Merlin Vacuum [2], which is currently used on the Falcon vehicles gets 311s. The RD-0110 [3], used on the Soyuz gets 326s. These use RP-1, which is highly refined kerosene. It's super easy to work with. On earth. Where we have 200 years of infrastructure in place to support using hydrocarbons. It takes that infrastructure to refine it into a form that rocket engines can use without gunking up the works with unburnt carbon and other particulate crap.
Raptor uses methane, which is kind of like a jack of all trades between density, efficiency, ease of processing, storage, and ease of use in engines. This is basically how SpaceX seems to operate: rather than optimizing a single part of the system (like trying to get the most efficient engine), they try to optimize from a systems level. I don't really know much more than that, because there hasn't really been a lot of stuff for civilians to read on methane engines. This is kind of the cutting edge of the second golden age of space exploration. This freaking rules, what a time to be alive.
[0] https://en.wikipedia.org/wiki/RL10
[1] https://en.wikipedia.org/wiki/RS-25
[2] https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)
[3] https://en.wikipedia.org/wiki/RD-0110
[+] [-] drchewbacca|6 years ago|reply
If they told you the stats of the material, better strength at cryo tempertures meaning mass reduction, higher melting point meaning minimal heat shielding and great thermal conductivity it would be easy to imagine it was some new super composite. Then your head explodes when they tell you it's 2% the cost of what they were using before and it's so easy to work with they don't even need a factory they can just weld it in a field.
Imo Elon is starting to get into contention for greatest engineer of all time.
[+] [-] hinkley|6 years ago|reply
[+] [-] afterburner|6 years ago|reply
I don't know man, did he design it himself?
[+] [-] elif|6 years ago|reply
[+] [-] chasd00|6 years ago|reply
[+] [-] davidivadavid|6 years ago|reply
[+] [-] SomeOldThrow|6 years ago|reply
[+] [-] codeulike|6 years ago|reply
[+] [-] mattlondon|6 years ago|reply
I am so used to seeing space stuff done in clean rooms, and things taking years and years to come to fruition (e.g. hearing about and seeing NASA or ESA probes etc getting made) that to see what is essentially a bunch of guys in a field just welding something together blows my mind.
I mean, is it just the outside that looks like that and inside it is ultra-exotic materials and tanks? Of course the engines are sophisticated machinery, but what about the insides? Are we just seeing the outer shell and it's all unobtanium nano-tube composite on the inside?
[+] [-] HenryKissinger|6 years ago|reply
Or the F-86 Sabre: https://upload.wikimedia.org/wikipedia/commons/3/39/F86F_Sab...
[+] [-] iamgopal|6 years ago|reply
[+] [-] Florin_Andrei|6 years ago|reply
The most beautiful thing in the world is success.
[+] [-] de_watcher|6 years ago|reply
[+] [-] faead_|6 years ago|reply
[+] [-] unknown|6 years ago|reply
[deleted]
[+] [-] unknown|6 years ago|reply
[deleted]
[+] [-] nickpp|6 years ago|reply
This is exceedingly rare in a pessimistic world drowning in the voice of Luddites and backwards-looking preservationists.
Like always, technology solving real world problems versus politicians (professional or amateurs) creating (and never really solving) self-serving perpetual issues.
[+] [-] philwelch|6 years ago|reply
[+] [-] nerdponx|6 years ago|reply
While SpaceX did launch an unpiloted Crew Dragon test flight to the space station this year, a subsequent abort system test failed, leading to the destruction of the vehicle. SpaceX aims to resume abort system tests later this year ahead of the first crewed test flight.
NASA Administrator Jim Bridenstine, it seems, is not happy with the years-long delays of Crew Dragon, as well as Boeing's Starliner spacecraft, especially after seeing SpaceX build Starship Mk1 this year ahead of its own test flight.
"I am looking forward to the SpaceX announcement tomorrow," Bridenstine wrote on Twitter Friday. "In the meantime, Commercial Crew is years behind schedule. NASA expects to see the same level of enthusiasm focused on the investments of the taxpayer. It's time to deliver."
Interesting.
[+] [-] abledon|6 years ago|reply
[+] [-] thinkingkong|6 years ago|reply
[+] [-] discordianfish|6 years ago|reply
[+] [-] varjag|6 years ago|reply
[+] [-] mbell|6 years ago|reply
[+] [-] mncharity|6 years ago|reply
The https://www.spacex.com/careers/list ? There are currently several entries for Welder (Starship) and Tank Fabricator/Welder.
[+] [-] infectoid|6 years ago|reply
[+] [-] JulianMorrison|6 years ago|reply
[+] [-] schizoidboy|6 years ago|reply
[+] [-] mpweiher|6 years ago|reply
Currently the entire world has a launch capacity of 200-300 tons into LEO per year.
With just ten starship/booster combos, that will change to a max capacity of over a million tons into LEO per year.
A factor of over a thousand. The entire current capacity (including the Falcons) at less than 0.1% of the new capacity, a mere footnote. Not even a footnote, really. And apparently they're cheap(er) to build as well. Complete game changer. And game over for everybody else in the launch business.
Wow
[+] [-] agumonkey|6 years ago|reply
[+] [-] RivieraKid|6 years ago|reply
[+] [-] jniedrauer|6 years ago|reply
[+] [-] martythemaniak|6 years ago|reply
Musk stated (I think he just did some mental napkin math at one point) that if they meet their goals, the world's launch capacity will be expanded by two orders of magnitude. How often does any new development in any field bring about two orders of extra capacity? How does this incredible capacity change how you use this thing?
First consider prices. A launch would cost fuel + support operations + amortized cost of rocket. The last two will tend towards zero as they can be increasingly automated and will be a small fixed cost. IIRC, fuel costs roughly $60-100 per kilo to LEO, a 100kg person with 100kg of supplies and life-support equipment can reasonably expect to get to LEO for $20000 in fuel costs. Ok, so you need to "rent" the rocket (you want to stay there at least a few days), pay operations, SpaceX margin, R&D etc. Even then, imagine weekend LEO launches for $50,000 in the late 2020s. That's astounding. Given millenials' propensity for "experiences", they're going to have hoards of people buying this.
But what about risk? They've been trying to launch Crew Dragon for many years and still haven't. Well, with expandable rockets, you have to establish a safety record, it takes multiple flights, it's extremely expensive, you need a new rocket for each one. With fully reusable rockets, you can literally establish a safety record for an individual rocket within a matter of weeks, not years. Even launching once every three days (ie, far from their daily targets), it would take only a year to do more launches than Falcon or Arienne 5 have made in decades. Also, people are far more willing to take risks than organizations like NASA. Consider a thought experiment: SpaceX does 100 launches of Starship and establishes a safety record of 99% (1 blew up). They then start selling tickets, will people still buy, fully signing away any liability? Yes, you'll still have hoards of people lining up for a chance.
Finally, this is going to change science as well. Today, sending a 1 ton rover to the surface of Mars is a Really Big Deal. Hence, probes are made very carefully, very expensively and very very slowly. Not just design and build (it takes a decade), but operations as well (Curiosity traveled only 20km in the last 8 years). Everything is essentially super-low bandwidth. But once you know you can get a cheap ride to Mars (of anywhere else) any time, you don't have to go to such extremes. You can easily send more rovers, more radio relays, they can travel further, experiment more, take more risks and if you lose one, it's just not a big deal anymore!
[+] [-] mlindner|6 years ago|reply
"If the schedule is long it's wrong, if it's tight its right."
"The best part is no part."
"The best process is no process."
This really is different compared to how the space industry has done things in the past.
[+] [-] woodandsteel|6 years ago|reply
[+] [-] anonytrary|6 years ago|reply
> "The best part is no part."
Simple design is better because less moving parts means less complexity.
> "The best process is no process."
No single process is a panacea for all situations, so strictly adhering to a process will eventually cripple you. The best process is the ability to quickly change your process when it is necessary.
[+] [-] chriselles|6 years ago|reply
I’m assuming the inability to control and harmonise 30 rocket engines on the N1 first stage for pitch/yaw contributed significantly to the N1 failures and cancellation.
Will digital computing/control advances control for that and the 42 rocket engines on the SpaceX starships 1st stage?
Or are there other major engineering problems(such as aeronautical/mechanical) to solve as well?
[+] [-] socialdemocrat|6 years ago|reply
SpaceX is able to shut down failing engines quickly, as has been demonstrated so multiple engines don’t present added risk.
Vibrations from multiple engines is something they are able to model much easier with computer simulations today.
[+] [-] Symmetry|6 years ago|reply
[1]https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)
[+] [-] computerex|6 years ago|reply
[+] [-] woodandsteel|6 years ago|reply
[+] [-] sbr464|6 years ago|reply
[+] [-] ninjamayo|6 years ago|reply
[+] [-] ryanmarsh|6 years ago|reply
[+] [-] hwillis|6 years ago|reply
Cranes are far and away the lightest way to move something up and down. Wires are incredibly strong for their weight; five times stronger than normal mild steel. Thats due to the stress exerted when they are made affecting the crystal structure.
Not only that, but tensile stress is the strongest mode in general. Structures holding up mass have to resist buckling from all directions. Tensile structures can use every bit of mass budget to hold force going precisely down.
Not only that, but you dont need all of rhe structure to hold a crane up, since its just sticking out the side of the rocket.
Not only that, but you dont even need a motor since you just need to slow things down a bit as they descend.
Yes, they'll use a crane.
[+] [-] Tepix|6 years ago|reply
The weight of the crane isn't a big factor, you open a hatch and lower stuff to the ground.
[+] [-] hadlock|6 years ago|reply
[+] [-] twic|6 years ago|reply
http://www.projectrho.com/public_html/rocket/embarking.php
[+] [-] anonytrary|6 years ago|reply