I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc.
The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are:
- the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it is the most advanced rocket engine ever made and I'm not aware of any upcoming engine that can compete with it.
- Stainless steel construction. What we're seeing with SN5 is the basic tank structure of the second stage. The hopper that flew last year was a neat demo, but SN5 was pressurized and the design is way closer to what the actual starship will end up having. The first stage tanks will also be a stretched version of these tanks, so that's why you see them focus on this so much right now.
- belly-flop landing. To land, starship will be coming downhorizontal until a few hundred meters above ground when it'll make itself vertical to land. SN5 won't have the fins and cone to perform this, but SN6 will. It might be possible to see this before the end of the year - SN6 (with 3 engines) goes up 20km, goes horizontal to burn off speed, then lands vertically.
- belly-first re-entry. Instead of a heatshielf that withstands a high temperature, Starship will burn off speed with its belly, but do it over a longer time period of time so that while the total heat is the same, the max temperature doesn't rise too much. The stainless steel can't take the temperatures ablative heatshields on capsules can. Don't know if Starhip will be able to perform this meaningfully without a booster.
- in-orbit refueling. Starship is big and heavy and basically can't get anywhere unless it's re-fueled in orbit. I don't think this has been done before, definitely gonna need 2+ starhips and boosters to show this.
- superheavy booster. This might be the simplest part of the whole system - a first stage with 31 raptor engines.
There's the criminally underfunded SABRE engine, an a air-hydrogen mix breathing-rocket hybrid design from Reaction Engines that rated to reach speeds of Mach 25 (roughly 35,000 miles per hour).
As modelled, it's more efficient than any other current or proposed chemical propulsion technology, and the proposed single-stage runway launchable system would be capable of delivering around 11 tons of cargo to the ISS. The costs to go to orbit and beyond using this engine could be less than half that of current best in class technology; even less after development cost amortization. Not sure why SpaceX haven't invested in it yet. Perhaps it doesn't fit in with their current vertical integration philosophy, but it seems like a game changing technology.
SABRE engine is not really upcoming. It never even got close to production or prototype.
And the estimate cost of that vehicle were very optimistic with lots and lots of problems to overcome. A proposal like that from people who have never really done all that much is highly speculative.
The projected cost they could reach with that vehicle, is already beat by Falcon 9.
Elon Musk has even told the Royal Aeronautical Society that he thinks air-breathing engines are a bad idea. Massive complexity for not so much gain. Invest that money into better first stage engine, push threw the atmo quickly get out of it, and make optimal use of your second stage engine.
Its pretty save to say SpaceX will not invest in what is mostly a paper rocket with an engine that has only ever tested the cooling system.
SpaceX needs $kg to orbit to be much lower for their Mars plans to be possible. It is planning on their starship and superheavy rocket combo to bring down current launch costs by a factor of around 100 in the long term. A factor of two improvement in costs is not interesting to them.
Apart from the other reasons pointed out by others:
Single stage to orbit is sexy, but multiple stage to orbit is inherently more efficient and I see no reason why it Would be more expensive if you reuse all stages.
SABRE might be an option for a first stage on vertically launched vehicle, to be used in that part of the atmosphere where the engine can get most - or even all - of its oxygen from the air.
Then again, if that stage were to be limited to a maximum height of ~20km it might as well be equipped with a stack of upgraded J58 engines (as uses in the SR-71), saving the weight of the cryogenic coolers used to produce LOX for those rocket engines. I guess SABRE makes more sense for a space plane than it does for a vertically launched rocket.
> - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it is the most advanced rocket engine ever made and I'm not aware of any upcoming engine that can compete with it.
I believe the Raptor is the first actually working full flow staged combustion engine. It is sort of a holy-grail of engine for liquid rockets. Tim Dodd has a lot more info on it here:
However please call it what it really is. It isn't a belly flop so much as it is a skydiver maneuver. Just like how a skydiver splays out their arms and legs to maintain stability and slow down a bit, starship will do the same. Also like a skydiver, it will upright itself before landing as a belly flop would almost guarantee a RUD.
>> - in-orbit refueling. Starship is big and heavy and basically can't get anywhere unless it's re-fueled in orbit.
This is one of those "let's see" things that SpaceX has talked about but never actually explained. Their current rocket tech offers no hint as to how this is might happen. They aren't running internal bladders in their tanks. So the physical act of moving fuel from one tank to another is an open question.
The options are really limited. Either you use an internal bladder, something never done with cryogenic fuels, or some sort of maneuver to shift all the fuel over towards the pump. Maybe they plan on docking the two ships and then spinning the entire rig to create sufficient G to stabilize the fuel on one side of the tank? The entire operation seems more kerbal than reality atm.
It's not particularly hard. Just like with regular rocket upper stages that require multiple burns to complete the mission, you can use small ullage thrusters to settle the propellant and make sure liquid (instead of pressurant gas) is transferred from one tank to another. The physics is exactly the same as making sure the engine receives fuel. Just need the thrusters to be fired longer.
SpaceX has done experiments with how much thrust is necessary for ensuring propellant settling. That's one reason you often see a video feed of inside the upper stage liquid oxygen tank during a Falcon 9 mission. It doesn't take much thrust to ensure propellant settling. Not at all an open question.
This always struck me as one of the least questionable new things in SpaceX's architecture. Much less Kerbal than most Mars architectures which require assembling a massive craft in LEO or whatever.
(One would be remiss to not mention the history of refueling... SpaceX's competitor ULA had been pushing refueling and orbital depots, which it called "distributed launch", since its formation, but has only been able to do small experiments since one of its parent companies, Boeing, sees orbital refueling as a threat to NASA's SLS rocket, which Boeing is the main contractor for. That's a huge reason for a lot of the "skepticism" about orbital refueling you sometimes see in aerospace circles, besides the usual pathologically conservative mindset of many grey beards...)
At the last presentation on Starship, Elon said they planned to do the refueling by applying a small amount of thrust during the procedure, giving a small g-force that's enough to drive the fuel from one ship to the other.
Some rockets have already used small acceleration prior to engine ignition to settle the propellant in zero gravity situations: https://en.wikipedia.org/wiki/Ullage_motor
I am not a rocket scientist, but one of the main reasons it is so unique is that it will be the first full-flow staged combustion rocket engines to successfully be used on rockets.
Rocket engines have powerful turbo pumps to move large amounts of fuel quickly to the combustion chamber to create thrust. Usually these pumps are powered by burning some of the propellant in a turbine and exhausting the resulting gas on the side of the engine. A full-flow engine mixes this turbo pump exhaust gas back into the main combustion chamber. This makes the engine more fuel efficient but it is a difficult engineering problem. All previous types of these engines blew up too often to be used on spacecraft. Check out the Wikipedia page for more info [1].
It's basically a sweet-spot between being very powerful, very efficient, cheap and easy to operate and highly reusable. To get all these, they implemented a design that never got past the basic demo stage before, which included independently working out the secret sauce of the best Russian-made engine.
There are two main metrics of rockets and rocket engines. Specific Impulse (ISP), and the Thrust to Weight Ratio (TWR).
ISP is essentially a measure of the fuel efficiency. And since there are no gas stations in space, the further you can go per kg of fuel, the further you can go, period.[1]
TWR is the measure of useful power.
TWR is the key measure for the first stage because a ton of power is required to escape Earth's gravity and atmosphere. For subsequent stages ISP is the main metric.
The Space Shuttle Main engines have an excellent ISP but because hydrogen needs massive tanks, it has a crappy TWR. Which is why the shuttle had a couple of strap on solids with a high TWR.
But instead of specialized engines, SpaceX designs engines that are good at everything. The ISP isn't as high as an advanced hydrogen engine and the TWR isn't as good as a solid, but both numbers are quite respectable and they bring other advantages such as the ability to relight and to be reused without refurbishment, they don't need use ablative cooling.
1: Although SpaceX is relying on in flight refueling for it's Moon and Mars plans. Nobody's done it before, but that doesn't stop SpaceX.
In addition to being full-flow, Raptor runs on methane (CH4, the simplest hydrocarbon), which already exists many places in the solar system (including Mars), and is easier to manufacture than kerosene or liquid hydrogen.
The raptor uses a full flow staged combustion cycle. This makes a very efficient engine but increase the complexity. Everyday astronaut and Scott Manly on youtube do an excellent job explaining this in more detail
I mean we know for a fact that there is already (in small amounts) methane and plenty of CO2 on Mars. Obviously if we find lots of H2O this all becomes even easier as we can just combine the abundant CO2 with the H2O to get loads of CH4 and O2.
No one has seemed to have mentioned it yet, but the game changer of Starship will be full reusability of both the first and second stage of the rocket. Falcon 9's reusability of the first stage was a huge step towards making access to space a lot cheaper. If SpaceX can realize full reusability with Starship it will enable things like large scale moon bases, space hotels and mars colonization. They still have a lot of challenges ahead of them, but today's hop takes us that much closer to the future of space as presented in films like 2001 A Space Odyssey.
Absolutely, and the quantitative analysis is just stunning.
In 2018 all of humanity launched a total of 111 payloads into space (out of 114 attempts). At around 5t per launch, that would be 555 tons.
Starship is supposed to have a payload to LEO of > 100 tons. So 5-6 launches would handle all of that, by weight.
But SpaceX says their goal is to fly these up to 3 times a day. So let's assume they can do this 300 days a year, that would be 900 launches per year. If they have a half dozen in operation, that would be 5400 launches per year. Of 100 tons each, or 540 kilotons. That's 1000x what the whole planet launched in 2018!
In other words, the entire current launch capacity of the whole planet is 0.1% of the capacity of a fleet of 6 active Starships.
And they're building an assembly line for them.
"Game changer" is absolutely right, but doesn't really convey the magnitude of the change. It's truly astounding.
Indeed these numbers are impressive, but can it even be done?
Is it even possible both in terms of climate change/overall environmental impact, and in terms of how much methane (fuel) we actually have.
Elon Musk's vision is getting 1 million people to Mars (if I remember correctly) within this century. 100 per starship will require 10000 launches. Distributed over 70 years, that's about 1300 Martian voyages per year.
So approximately 3 per day. Each of those launches, however will require launches of refuelling tanks (is it 6 each?)... So we are talking 19 launches per day just _people_ going to Mars!!!
Sorry, but isn't that completely impossible!??
Not just for the required fuel and environmental impact, but also given how often they just postpone basic launches due to weather.
Another significant thing is that Starship is designed to be mass manufactured at a relatively low cost. SpaceX can crank out thousands of Starships, fly them to Mars and build a million people colony. Starship is truly a game changer!
Yep, and in addition to both of these, Starship is also designed:
* to be fueled / ignited such that it can be refueled in-situ on Mars & then launched back to Earth, without advanced rocket fuels or the TEA-TEB chemical igniter.
* to be able to refuel from another Starship in-orbit
The combination of all of this, if they pull it off, will be the ability to send truly massive payloads to Mars, faster and cheaper than anyone could have imagined just a few years ago.
To me it does really show the benefit of taking a systematic approach, working backwards from the goal "get to Mars and stay" in a resource-constrained environment. They've very strategically targeted the technology/engineering required to bring the costs down to something reasonable, while NASA's approach for 50 years has basically been versions of "can you give us one trillion dollars?" (or "we can put a couple humans on Mars for 3 days for $100 billion")
Today's Starship hop is getting very near the nail in the coffin for SLS. I still have some concerns about their crazy re-entry flip, but the speed SpaceX is moving is leaving everyone else in the dust.
The Falcon 9 isn’t cheap because of reuse (yet). It’s cheap because of mass manufacturing. The Rs-25 engine costs over $100m each, Ariansoace Vulcains around $20M, typical large rocket engines over $10M.
SoaceX Merlin costs about $200,000 each to make. The Raptor will be close to that. Thats why SpaceX can pursue the large number of redundant smaller engines design strategy so successfully.
Reuse has lowered Falcon 9 costs internally, and increased its private discounts, but not it’s public pricing. When the cost benefits of reuse finally cascade through public pricing and through the entire stack with Starship, you have a SuperHeavy launch system putting 150 tons in orbit even cheaper than a single Falcon 9 launch.
For comparison, the Shuttle was over $40,000 per pound to Orbit. The SLS will be around $10,000/lb to orbit if you don’t count developmental costs at least 3x that.
The Falcon 9 is $1,500/lb to orbit, and Falcon Heavy $1,100/lb to orbit. Starship will lift more payload to orbit than the SLS, and 4x as much as the Shuttle, for between $100 and $300 per pound.
You write that as if it is a done deal. Mars' atmosphere is roughly .5% of that of Earth and almost exclusively CO2. Temperature ranges are well out of what they are on Earth. It is hard for technology to survive there, it is impossible for people to survive there until there has been an unbelievable investment in infrastructure.
If you think there will be a million people colony on Mars in your lifetime than you are not in touch with the physics of this kind of endeavor. All of our GDP for the next 50 years pooled together would likely not be enough to pull off a feat like that. The scale we're talking about here is too large to even contemplate.
10 people in a shitty little dome, maybe. Right up to the moment they die because of some small mishap.
... which also explains Tesla, mass production of Earth-faring machines is one way to prepare for mass production of space-faring machines (and battery tech is going to be important for living in space). When you look at Musk's ventures, they really all end at Mars.
Future of space as presented in shows like the Expanse. controlled by trillionaires and their companies and powerful people in governments all killing each other over space rocks. We're a long way from Star Trek, that's going to take a more fundamental advance not at all related to technology.
Many of the colonies that make up the US and Canada were at one time controlled by the rich elite of the time. A few hundred years and they rebel to the point nobody even remembers them.
An interesting thing mentioned in the script, but not shown in the film, is that all of the images of beautiful space ships in the early sequence of the film are in fact space-based nuclear missile launchers, and that there are 27 nuclear nations with space weapons.
I sometimes imagine what an alien visitor would think about us if they came to our planet and saw that we had such destructive technology, pointed at _ourselves_.
Oh my goodness. I had heard of Starship from the initial PR, and from those photos I had somehow assumed it was about the same size as a train carriage (~60ft.)
I did some great work today. I coded something pretty cool and useful. I built a little deck to explain it. My coworkers loved it. My job security went up. I enjoyed it. The journey is the reward.
But these guys are making rockets in tents.
Should I be rethinking life? Because that's how it feels. I love it. I admire them. But it feels unobtainable. I want to make that kind of a dent in the universe. And yes I know it's thousands of people working there.
It sounds like you're passionate about your work and that's an important quality. As gorgoiler points out, "Making a difference in the world is what counts."
Out of curiosity and without any condescention implied, are you saying this because the business you're currently working on seems less important / relevant / urgent, to you, than space exploration ?
Because, "these guys are making rockets in tents", sure ; but, meanwhile, someone is "fixing up human beeings in an hospital", "teaching kids how to read in a school", "writing poetry in a basement", etc...
There probably isn't any objective way to rank pursuits (or at least, no "objective" way that does not end up in a dystopian society and / or Golgafrincham [1].)
And it's not like anyone is actually counting score (unless you're Chinese. Someone is counting score on you at the moment. Deities have mercy on you.)
Those precautions aside, if such an event is triggering you to pause and reconsider you life choices, than go for it ! Maybe you actually need to branch and try and get to work in space exploration after all.
And if you're not clever enough, educated enough, US Citizen-enough, etc... there are opportunities to inspire others, educate others, help others...
And in the end, just plain looking at the sky. This thing is darn cute.
It sounds like you are not working in a field that is intrinsically motivating to you. Perhaps you should find an employer with a product whose end value you can appreciate?
For example I work in CAD. I'm just a software engineer. But the products we make help engineering companies design huge beautiful monsters of steel an concrete.
Sure, they are not rockets, but they are things that impact peoples lives.
Working on a product, that have users who you appreciate is intrinsically satisfying. At least to me.
I feel the code I write is kind of meaningless, but the work my users do is not. Hence I find meaning in their constributions.
> Perhaps you should find an employer with a product whose end value you can appreciate?
If only it were that simple. Sometimes the stars align and that happens yes, but for many people - especially those of us with families that can't just up and move somewhere else - it's not reality.
Let's say you reside in an area with such a job to begin with. First your resume has to be looked at, so let's assume it makes it through the various automated filters. Then it gets picked up by an actual person who glances at it for maybe 1-2 minutes tops and throws you into the "to be considered" pile. Next your resume is competing against a relatively large pool of other resumes. If it makes it through that, you then have to captivate the recruiting/hiring manager enough to move to the next step. Now you're at the dreaded technical interview where all sorts of shit can go wrong (especially since this is a highly sought position); maybe you're a little too slow at figuring something out, maybe you're not a good "cultural fit", maybe they don't like the way you look or dress, maybe you're a genius but your communication skills are abysmal etc. If you somehow make it through that garbage disposal unit then you have to talk to some manager who gauges your personality and how you handle stress; room for more screwing up. You make it through all that, but wait! You're still competing with 10 other folks that are just as good if not better than you. You get lucky and make it and get an offer letter - but the pay is dreadful and doesn't match the cost of living. Now what?
Not at all, rather I see every step on their journey as making easier for people who like space and rockets to get involved in the future, without having to win the "astronaut lottery".
Well, won't your pretty cool and useful code make the lives easier for some people, including yourself? The idea is to leave the World a little better place than it was when we got here, and it sounds like you just did something that will help you achieve just that.
Personally, things like this motivate me. If those guys can send a giant steel tube into space then goddammit I will be able to finish project XYZ on time, and provide a useful service to a customer, thereby contributing to the greater whole.
There's a lot of speculation on that, it's probably either wiring/tubing insulation or paint that got ignited, or a small leak. It seems to put itself out at 0:51.
As a child I read all the Tintin books. My favourite ones were Destination Moon, and Explorers on the Moon. The rocket used in those stories is iconic. For me, Starship taps directly into those memories. I know it's infeasible, but if they ever painted the production Starships white and red, it would make me SO happy.
I'm too old now (approaching a de-orbit burn for 50) to be able to go to space, but I'm still loving the thought that my future grand-kids should be able to.
One thing I remember from those books is how they lay on their stomach during acceleration, whereas I believe all real life astronauts have been sitting, or on their backs:
Which is also interesting given the recent (well... not even so recent now) discovery of the benefits of placing COVID patients in a prone position to ease breathing.
What a week for SpaceX! Two days ago they landed Bob and Doug, and now they succeeded to hop a water tower (as a side project nonetheless, AFAIK only a small part of SpaceX is on this team)! Can't wait to see future iterations and improvements of this beast, especially to see more Raptors strapped on!
Thank God for that guy in the corner helping me to know how to feel.
Seriously though, this has been an incredibly annoying trend for a few years, everything has to be tagged with some pre-packaged emotional reaction. Such a dumbing down of public discourse.
I mean, feel free to be annoyed with the commentary, but there was no official live stream of the event.
There were 3-4 non-official live streams, I think all of them provided by people who have streamed every single one of these tests live.
Asking those people to not have a reaction when the thing actually flies is a little far-fetched, unreasonable, and contrary to what their audience wants and expects.
This isn't a reaction video with "some pre-packaged emotional reaction", it's sitting down to watch an historical event with friends - hardly a dumbing down of anything.
Even in the official streams of other events the hosts become emotional, and are often drowned out by the cheers of those around them. I really have no idea what it is you want or expect from these live streams.
Readit News
- the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it is the most advanced rocket engine ever made and I'm not aware of any upcoming engine that can compete with it.
- Stainless steel construction. What we're seeing with SN5 is the basic tank structure of the second stage. The hopper that flew last year was a neat demo, but SN5 was pressurized and the design is way closer to what the actual starship will end up having. The first stage tanks will also be a stretched version of these tanks, so that's why you see them focus on this so much right now.
- belly-flop landing. To land, starship will be coming downhorizontal until a few hundred meters above ground when it'll make itself vertical to land. SN5 won't have the fins and cone to perform this, but SN6 will. It might be possible to see this before the end of the year - SN6 (with 3 engines) goes up 20km, goes horizontal to burn off speed, then lands vertically.
- belly-first re-entry. Instead of a heatshielf that withstands a high temperature, Starship will burn off speed with its belly, but do it over a longer time period of time so that while the total heat is the same, the max temperature doesn't rise too much. The stainless steel can't take the temperatures ablative heatshields on capsules can. Don't know if Starhip will be able to perform this meaningfully without a booster.
- in-orbit refueling. Starship is big and heavy and basically can't get anywhere unless it's re-fueled in orbit. I don't think this has been done before, definitely gonna need 2+ starhips and boosters to show this.
- superheavy booster. This might be the simplest part of the whole system - a first stage with 31 raptor engines.
Lots of stuff coming in the next few years.
There's the criminally underfunded SABRE engine, an a air-hydrogen mix breathing-rocket hybrid design from Reaction Engines that rated to reach speeds of Mach 25 (roughly 35,000 miles per hour).
As modelled, it's more efficient than any other current or proposed chemical propulsion technology, and the proposed single-stage runway launchable system would be capable of delivering around 11 tons of cargo to the ISS. The costs to go to orbit and beyond using this engine could be less than half that of current best in class technology; even less after development cost amortization. Not sure why SpaceX haven't invested in it yet. Perhaps it doesn't fit in with their current vertical integration philosophy, but it seems like a game changing technology.
> an a air-hydrogen mix breathing-rocket hybrid design
Tough to use a breathing rocket anywhere but Earth. And SpaceX's goal is to use this to land on the Moon, Mars, everywhere.
And the estimate cost of that vehicle were very optimistic with lots and lots of problems to overcome. A proposal like that from people who have never really done all that much is highly speculative.
The projected cost they could reach with that vehicle, is already beat by Falcon 9.
Elon Musk has even told the Royal Aeronautical Society that he thinks air-breathing engines are a bad idea. Massive complexity for not so much gain. Invest that money into better first stage engine, push threw the atmo quickly get out of it, and make optimal use of your second stage engine.
Its pretty save to say SpaceX will not invest in what is mostly a paper rocket with an engine that has only ever tested the cooling system.
That much cryogenic hydrogen and massive temperature differences is as the limit of engineering possibilities.
Single stage to orbit is sexy, but multiple stage to orbit is inherently more efficient and I see no reason why it Would be more expensive if you reuse all stages.
Then again, if that stage were to be limited to a maximum height of ~20km it might as well be equipped with a stack of upgraded J58 engines (as uses in the SR-71), saving the weight of the cryogenic coolers used to produce LOX for those rocket engines. I guess SABRE makes more sense for a space plane than it does for a vertically launched rocket.
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I believe the Raptor is the first actually working full flow staged combustion engine. It is sort of a holy-grail of engine for liquid rockets. Tim Dodd has a lot more info on it here:
https://everydayastronaut.com/raptor-engine/
However please call it what it really is. It isn't a belly flop so much as it is a skydiver maneuver. Just like how a skydiver splays out their arms and legs to maintain stability and slow down a bit, starship will do the same. Also like a skydiver, it will upright itself before landing as a belly flop would almost guarantee a RUD.
This is one of those "let's see" things that SpaceX has talked about but never actually explained. Their current rocket tech offers no hint as to how this is might happen. They aren't running internal bladders in their tanks. So the physical act of moving fuel from one tank to another is an open question.
The options are really limited. Either you use an internal bladder, something never done with cryogenic fuels, or some sort of maneuver to shift all the fuel over towards the pump. Maybe they plan on docking the two ships and then spinning the entire rig to create sufficient G to stabilize the fuel on one side of the tank? The entire operation seems more kerbal than reality atm.
SpaceX has done experiments with how much thrust is necessary for ensuring propellant settling. That's one reason you often see a video feed of inside the upper stage liquid oxygen tank during a Falcon 9 mission. It doesn't take much thrust to ensure propellant settling. Not at all an open question.
This always struck me as one of the least questionable new things in SpaceX's architecture. Much less Kerbal than most Mars architectures which require assembling a massive craft in LEO or whatever.
(One would be remiss to not mention the history of refueling... SpaceX's competitor ULA had been pushing refueling and orbital depots, which it called "distributed launch", since its formation, but has only been able to do small experiments since one of its parent companies, Boeing, sees orbital refueling as a threat to NASA's SLS rocket, which Boeing is the main contractor for. That's a huge reason for a lot of the "skepticism" about orbital refueling you sometimes see in aerospace circles, besides the usual pathologically conservative mindset of many grey beards...)
[slide] https://spaceflight101.com/spx/wp-content/uploads/sites/113/... [video] https://youtu.be/tdUX3ypDVwI?t=1411
Would love to learn more about this, can you expand? What makes Raptor so unique?
Rocket engines have powerful turbo pumps to move large amounts of fuel quickly to the combustion chamber to create thrust. Usually these pumps are powered by burning some of the propellant in a turbine and exhausting the resulting gas on the side of the engine. A full-flow engine mixes this turbo pump exhaust gas back into the main combustion chamber. This makes the engine more fuel efficient but it is a difficult engineering problem. All previous types of these engines blew up too often to be used on spacecraft. Check out the Wikipedia page for more info [1].
[1]https://en.wikipedia.org/wiki/SpaceX_Raptor
It's basically a sweet-spot between being very powerful, very efficient, cheap and easy to operate and highly reusable. To get all these, they implemented a design that never got past the basic demo stage before, which included independently working out the secret sauce of the best Russian-made engine.
ISP is essentially a measure of the fuel efficiency. And since there are no gas stations in space, the further you can go per kg of fuel, the further you can go, period.[1]
TWR is the measure of useful power.
TWR is the key measure for the first stage because a ton of power is required to escape Earth's gravity and atmosphere. For subsequent stages ISP is the main metric.
The Space Shuttle Main engines have an excellent ISP but because hydrogen needs massive tanks, it has a crappy TWR. Which is why the shuttle had a couple of strap on solids with a high TWR.
But instead of specialized engines, SpaceX designs engines that are good at everything. The ISP isn't as high as an advanced hydrogen engine and the TWR isn't as good as a solid, but both numbers are quite respectable and they bring other advantages such as the ability to relight and to be reused without refurbishment, they don't need use ablative cooling.
1: Although SpaceX is relying on in flight refueling for it's Moon and Mars plans. Nobody's done it before, but that doesn't stop SpaceX.
https://everydayastronaut.com/raptor-engine/
* The Russians built one in the 60s but it never got past static fire tests
SpaceX developed an incredibly advanced simulator to make it happen: https://www.youtube.com/watch?v=vYA0f6R5KAI
AFAIK it's the only flying, non-research example of such an engine.
That'll be something to see haha N1
[1]: https://en.wikipedia.org/wiki/N1_(rocket)#Block_A_first_stag...
It will probably circle the Moon before NASA SLS.
The future is exciting!
Absolutely, and the quantitative analysis is just stunning.
In 2018 all of humanity launched a total of 111 payloads into space (out of 114 attempts). At around 5t per launch, that would be 555 tons.
Starship is supposed to have a payload to LEO of > 100 tons. So 5-6 launches would handle all of that, by weight.
But SpaceX says their goal is to fly these up to 3 times a day. So let's assume they can do this 300 days a year, that would be 900 launches per year. If they have a half dozen in operation, that would be 5400 launches per year. Of 100 tons each, or 540 kilotons. That's 1000x what the whole planet launched in 2018!
In other words, the entire current launch capacity of the whole planet is 0.1% of the capacity of a fleet of 6 active Starships.
And they're building an assembly line for them.
"Game changer" is absolutely right, but doesn't really convey the magnitude of the change. It's truly astounding.
Obviously most of that mass would have to leave orbit in order for it not to end up looking like an LA freeway in rush hour.
edit: i guess propellant/fuel would be one of the heaviest and important payloads we would need to get up there.
Is it even possible both in terms of climate change/overall environmental impact, and in terms of how much methane (fuel) we actually have.
Elon Musk's vision is getting 1 million people to Mars (if I remember correctly) within this century. 100 per starship will require 10000 launches. Distributed over 70 years, that's about 1300 Martian voyages per year.
So approximately 3 per day. Each of those launches, however will require launches of refuelling tanks (is it 6 each?)... So we are talking 19 launches per day just _people_ going to Mars!!!
Sorry, but isn't that completely impossible!??
Not just for the required fuel and environmental impact, but also given how often they just postpone basic launches due to weather.
* to be fueled / ignited such that it can be refueled in-situ on Mars & then launched back to Earth, without advanced rocket fuels or the TEA-TEB chemical igniter.
* to be able to refuel from another Starship in-orbit
The combination of all of this, if they pull it off, will be the ability to send truly massive payloads to Mars, faster and cheaper than anyone could have imagined just a few years ago.
To me it does really show the benefit of taking a systematic approach, working backwards from the goal "get to Mars and stay" in a resource-constrained environment. They've very strategically targeted the technology/engineering required to bring the costs down to something reasonable, while NASA's approach for 50 years has basically been versions of "can you give us one trillion dollars?" (or "we can put a couple humans on Mars for 3 days for $100 billion")
Today's Starship hop is getting very near the nail in the coffin for SLS. I still have some concerns about their crazy re-entry flip, but the speed SpaceX is moving is leaving everyone else in the dust.
The Falcon 9 isn’t cheap because of reuse (yet). It’s cheap because of mass manufacturing. The Rs-25 engine costs over $100m each, Ariansoace Vulcains around $20M, typical large rocket engines over $10M.
SoaceX Merlin costs about $200,000 each to make. The Raptor will be close to that. Thats why SpaceX can pursue the large number of redundant smaller engines design strategy so successfully.
Reuse has lowered Falcon 9 costs internally, and increased its private discounts, but not it’s public pricing. When the cost benefits of reuse finally cascade through public pricing and through the entire stack with Starship, you have a SuperHeavy launch system putting 150 tons in orbit even cheaper than a single Falcon 9 launch.
For comparison, the Shuttle was over $40,000 per pound to Orbit. The SLS will be around $10,000/lb to orbit if you don’t count developmental costs at least 3x that.
The Falcon 9 is $1,500/lb to orbit, and Falcon Heavy $1,100/lb to orbit. Starship will lift more payload to orbit than the SLS, and 4x as much as the Shuttle, for between $100 and $300 per pound.
If you think there will be a million people colony on Mars in your lifetime than you are not in touch with the physics of this kind of endeavor. All of our GDP for the next 50 years pooled together would likely not be enough to pull off a feat like that. The scale we're talking about here is too large to even contemplate.
10 people in a shitty little dome, maybe. Right up to the moment they die because of some small mishap.
... which also explains Tesla, mass production of Earth-faring machines is one way to prepare for mass production of space-faring machines (and battery tech is going to be important for living in space). When you look at Musk's ventures, they really all end at Mars.
An interesting thing mentioned in the script, but not shown in the film, is that all of the images of beautiful space ships in the early sequence of the film are in fact space-based nuclear missile launchers, and that there are 27 nuclear nations with space weapons.
I sometimes imagine what an alien visitor would think about us if they came to our planet and saw that we had such destructive technology, pointed at _ourselves_.
It seems likely that all species that make it to space might have similar pressures because they have a similar environment.
See convergent evolution. https://en.m.wikipedia.org/wiki/Convergent_evolution
That is, if they exist at all. Maybe we all converge to the great filter.
9m (30 ft) in diameter 50m (160 ft) in height (or would be with the nose-cone)
That's the height of a 12-story building. And this is the upper stage of the full rocket.
Update: I think the hopper in the video is a prototype of the lower stage, which is planned to have 31 engines. The upper stage is planned to have 6.
https://s.yimg.com/ny/api/res/1.2/mz7KZlvgwTBa5cs4xfM_aA--~A...
I did some great work today. I coded something pretty cool and useful. I built a little deck to explain it. My coworkers loved it. My job security went up. I enjoyed it. The journey is the reward.
But these guys are making rockets in tents.
Should I be rethinking life? Because that's how it feels. I love it. I admire them. But it feels unobtainable. I want to make that kind of a dent in the universe. And yes I know it's thousands of people working there.
But still.
It sounds like you're passionate about your work and that's an important quality. As gorgoiler points out, "Making a difference in the world is what counts."
If you'd like to help, consider applying! :)
As a very experienced engineer, I can’t accept being judged on (historical) trivia.
I don't work overtime and I'm not a fan of Thai food
Because, "these guys are making rockets in tents", sure ; but, meanwhile, someone is "fixing up human beeings in an hospital", "teaching kids how to read in a school", "writing poetry in a basement", etc...
There probably isn't any objective way to rank pursuits (or at least, no "objective" way that does not end up in a dystopian society and / or Golgafrincham [1].)
And it's not like anyone is actually counting score (unless you're Chinese. Someone is counting score on you at the moment. Deities have mercy on you.)
Those precautions aside, if such an event is triggering you to pause and reconsider you life choices, than go for it ! Maybe you actually need to branch and try and get to work in space exploration after all.
And if you're not clever enough, educated enough, US Citizen-enough, etc... there are opportunities to inspire others, educate others, help others...
And in the end, just plain looking at the sky. This thing is darn cute.
Enjoy the journey.
[1] https://hitchhikers.fandom.com/wiki/Golgafrinchans
Measure what you do by the change in yourself and others, and how it makes society better.
For example I work in CAD. I'm just a software engineer. But the products we make help engineering companies design huge beautiful monsters of steel an concrete.
Sure, they are not rockets, but they are things that impact peoples lives.
Working on a product, that have users who you appreciate is intrinsically satisfying. At least to me.
I feel the code I write is kind of meaningless, but the work my users do is not. Hence I find meaning in their constributions.
If only it were that simple. Sometimes the stars align and that happens yes, but for many people - especially those of us with families that can't just up and move somewhere else - it's not reality.
Let's say you reside in an area with such a job to begin with. First your resume has to be looked at, so let's assume it makes it through the various automated filters. Then it gets picked up by an actual person who glances at it for maybe 1-2 minutes tops and throws you into the "to be considered" pile. Next your resume is competing against a relatively large pool of other resumes. If it makes it through that, you then have to captivate the recruiting/hiring manager enough to move to the next step. Now you're at the dreaded technical interview where all sorts of shit can go wrong (especially since this is a highly sought position); maybe you're a little too slow at figuring something out, maybe you're not a good "cultural fit", maybe they don't like the way you look or dress, maybe you're a genius but your communication skills are abysmal etc. If you somehow make it through that garbage disposal unit then you have to talk to some manager who gauges your personality and how you handle stress; room for more screwing up. You make it through all that, but wait! You're still competing with 10 other folks that are just as good if not better than you. You get lucky and make it and get an offer letter - but the pay is dreadful and doesn't match the cost of living. Now what?
Personally, things like this motivate me. If those guys can send a giant steel tube into space then goddammit I will be able to finish project XYZ on time, and provide a useful service to a customer, thereby contributing to the greater whole.
Were they incredibly lucky
I'm too old now (approaching a de-orbit burn for 50) to be able to go to space, but I'm still loving the thought that my future grand-kids should be able to.
http://www.projectrho.com/public_html/rocket/images/deckplan...
Which is also interesting given the recent (well... not even so recent now) discovery of the benefits of placing COVID patients in a prone position to ease breathing.
EDIT: More grain silo than water tower. ;)
Seriously though, this has been an incredibly annoying trend for a few years, everything has to be tagged with some pre-packaged emotional reaction. Such a dumbing down of public discourse.
Someone linked the official video and it's amazing: https://youtu.be/s1HA9LlFNM0
If you don't want that, there's other streams without presenters, or with less obnoxious presenters.
There were 3-4 non-official live streams, I think all of them provided by people who have streamed every single one of these tests live.
Asking those people to not have a reaction when the thing actually flies is a little far-fetched, unreasonable, and contrary to what their audience wants and expects.
This isn't a reaction video with "some pre-packaged emotional reaction", it's sitting down to watch an historical event with friends - hardly a dumbing down of anything.
Even in the official streams of other events the hosts become emotional, and are often drowned out by the cheers of those around them. I really have no idea what it is you want or expect from these live streams.