Starship Prototype Unveiled
space.com
space.com
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)
https://www.wired.co.uk/article/spacex-raptor-engine-starshi...
"Raptor is designed to power the new reusable vehicles SpaceX’s is building, the Starship spacecraft and the Super Heavy rocket."
Also they call Tim Dodd an "industry expert"...
[1] https://www.youtube.com/channel/UC6uKrU_WqJ1R2HMTY3LIx5Q/vid...
I would not be at all surprised if there's a List Of Things Apple PR Hereby Politely Requests That Scott Doesn't Mention.
When I was at AWS I was similarly forbidden from mentioning anything to do with video games to just about anybody, despite not having anything to do with video games myself, and many other topics besides the obvious (e.g. "don't disclose EC2/S3 capacity numbers"[1], "don't reveal how Glacier works"[2]), and in fact there was a whole programme of PR training and tiered permission to speak at conferences or to the press/analysts that boiled down, mostly, to knowing what you could and couldn't say, and how diplomatically you parried questions on the latter.
Either that or Terry Pratchett's law of rewritten rules applies.
[1] no-one would believe me anyway
[2] it's a massively redundant array of vinyl records
It’s also a bitch to work with. When it’s not trying to immolate or suffocate you it’s busy turning every metal part it touches to garbage [1].
They're optimizing for "real" reusability, as in eventually aiming for airline-like turnarounds. None of the earlier engines you noted were reusable except the RS-25, and given how long it took to turn the Shuttle around one could argue it doesn't really count as "reusable" in sense SpaceX is aiming for.
Aiming for reusability and ease of maintenance leads to different optimization paths, in particular we should expect that any one component is going to be less powerful, it'll need to account for wear & tear, not use once and crash it into the ocean.
But raw performance on a single trip doesn't matter much if you can just deliver the same payload in two trips to orbit instead.
Not just the time but the cost, if you take the figure of how much the space shuttle program cost, and divide it by total number of flights (including the two lethal ones), it cost somewhere between $900 million to $1.1bn every time the thing launched. It was very far from the early 1970s dream of an economically reusable spacecraft.
Except that you're doubling the cost if you have to do two trips.
If the rocket is reusable, then the vehicle cost gets amortized over the total number of trips, and the per-trip cost gets closer to just the cost of fuel (hopefully at least an order of magnitude less than a new vehicle+fuel on each flight).
Methane, which is cryogenic and less dense, ought to deliver more? Otherwise bigger tanks and operational issues will eat out the benefits.
For example, Merlin vacuum has a 1:165 expansion ratio. The RD-58MF has a 1:500 ratio. The Wikipedia article for the RD-58 family shows the increase in Isp from various expansion ratios.
Interesting that using http://rocketworkbench.sourceforge.net/equil.phtml I couldn't get declared Isp (380) for methane-LOX for reasonable nozzle expansion ratios. Maybe the model is too approximate...
But the raptors on the second stage have to operate efficiently in a vacuuum, but also work well and sea level for the landing. So even taking Mars out of the equation (which we really shouldn't, but just for sake of argument), it's requirements are quite different to anything we've built before.
The falcon doors also provide a surprising benefit: cover in the rain. And they are very practical with small children.
Musk is very much responsible for why the team works the way it does. He specifically focused on hiring people who experiment and try out things a lot. He did not want just pure theoretical guys.
https://zlsadesign.com/post/tom-mueller-interview-2017-05-02...
So, he knew about a problem, he heard someone mention a possible solution, and he insisted they use that solution.
That is not what designing is.
https://www.youtube.com/watch?v=sOpMrVnjYeY&feature=youtu.be...
A system of local optimums is an inefficient system. Sort of the self-identified takeaway of the book _The Goal_, and I haven't stopped thinking about this statement since I read it.
[0] https://www.youtube.com/watch?v=LQTnWEHl5qU
[1] https://www.youtube.com/watch?v=6YyV-otP3pI
[2] https://www.youtube.com/watch?&v=TOieURpnbm0
This appears to me to make each flight much more complicated to pull off, introducing more points for it to fail without contingencies, and it makes me nervous. But, again, I am an just an unenlightened observer from an unrelated field. I don't even play Kerbal Space Program! I'm sure they've weighed a million different options and their risks, and have arrived at this one after a lot of thinking, but it has been bugging me. The stainless steel construction certainly looks beautiful out there in Texas.
This approach is more or less the same as what the starship is doing here, except instead of using a glider trajectory for the controlled landing they instead use retropropulsive landing. This is needed because what SpaceX is landing here is a second stage, not a first stage. Way more heat, way more power.
So they need propulsive landing.
The big difference you're seeing compensated for is that Mars atmosphere is less than 1% dense as Earth. So to slow yourself down you need a much larger exposed surface area. Do that exact maneuver on Earth and you'd get an 'unplanned rapid disassembly' during reentry thanks to the thicker atmosphere. That danger and complexity is also something that's hidden.
I cannot recommend Kerbal enough for anybody even vaguely interested in space. Just absurdly fun and does really help you get a feel for all of these issues.
That is the planned Earth re-entry maneuver. Belly first almost all the way down, using the heat shield on one side, then flipping and completely re-orienting near the ground so that the vehicle is pointed upwards, and then the final burn to land upright.
But it does make sense that this path has arisen from a secondary capability: to land on planets or moons with less atmosphere. It still doesn't make me less nervous about their ability to pulli it off reliably. Here's hoping.
Hydrogen + CO2 => Methane + Water
This is an extremely important reaction. Mars, for instance, has effectively unlimited Hydrogen and CO2 which also means effectively unlimited Methane and Water. How just absurdly convenient is that?
But it also plays a major role in things like life support. We breathe out CO2. On Earth where we have an enormous atmosphere this doesn't matter. But in closed systems, such as the ISS or what will be the habitation regions on Mars, this is a major issue that needs to be dealt with or we'd kill ourselves with our own exhaust.
NASA, on the ISS, used to deal with life support by producing oxygen from imported water, and discarding the produced hydrogen. They'd then collect exhaled CO2 from the air using CO2 scrubbers and also discard that. That was a pretty inefficient system that required large amounts of imported water to sustain. Now they use the Sabatier Reaction to convert the exhaled CO2 into water and methane. Only the methane is discarded. And as a result of this, instead of needing to import large amounts of water, now all they need to import is a small amount of hydrogen to keep the reaction running.
On Mars this will result in a really cool system. What will be an increasingly large scale life support system will be literally creating rocket fuel as a byproduct. Of course methane is also a controlled and efficient gas, so it can also be safely used for things like cooking dinner.
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.
Steel becomes harder and more brittle if quenched (hardening), and softer and less brittle if cooled slowly (tempering).
Cold Rolling steel is done to avoid the heat cycle which would otherwise result in tempering, which is why its specific stats don't strike me as particularly relevant past the first launch.
Heat cycles also have the effect of warping steel.
Smaller grain size leading to stronger material -- this is a result of more grain boundaries as the scale of the grain goes down. Hall-Petch strengthening.[0] A secondary effect is that with smaller grains oriented in random directions the metal is more resistant in general from stresses in all directions; whereas with larger grains you tend to get weakness in a particular direction (along the slip planes.)
This is common knowledge, at least it's basic material physics that I learned in college.
[0] https://en.wikipedia.org/wiki/Grain_boundary_strengthening
It is more practical to discuss the hardness and ductility at specific temperatures, as well as its ability to keep its carbon content under those temperature conditions.
But I think the word GP was looking for was annealing. Annealed metal bends quite easily (that's the analogy in 'simulated annealing' in optimization theory). For instance the wire bonsai practitioners use is traditionally made of annealed copper. Copper is already pretty ductile but once annealed it's positively floppy. Bending it work-hardens it, causing it to stiffen back up. Eventually one learns that if you bend it just so, it will stay where you wanted it to stay.
You do not want your space craft reconfiguring itself.
from Wikipedia:
"Tempering [...] is done by heating the metal to some temperature below the critical point for a certain period of time, then allowing it to cool in still air."
Here's a good description https://www.metalsupermarkets.com/difference-annealing-tempe...
Although its a curious topic, I would have no doubt that whatever temperature cycling they design parts of the structure to go through in their "rapidly reusable" regime, the effects of "heat fatigue" or whatever to call it will have been rigorously assessed .
Is this why jet fuel can't mel..... ah never mind.
Steel won't melt at 300-400 Celsius but "handling" those temperatures for 10 minutes will change the properties of the material, possibly by a lot, so you don't need "melting" for structural collapse (Twin Towers style).
As the GP says, if you put cold rolled steel, which has an elastic yield strength of >1500 MPa, at 300-400 Celsius, then it is only a matter of time (30-120 min) till the elastic yield strength sinks to 500 MPa or less.
So either this is a single use device, or the steel isn't reaching temperatures over 250 Celsius, or the steel isn't cold rolled but is a low strength steel instead (although that would have other problems).
> or the steel isn't reaching temperatures over 250 Celsius
That might be the case. The space shuttle had an aluminum structure that would fail at 175C, and now we have 40 years of technology advancements for the heat shield.
[1] https://www.engineeringtoolbox.com/young-modulus-d_773.html
Soyouz is simple.
Soyouz is reliable.
Soyouz is cheap.
Soyouz is in use for 50+
Soyouz is still there while NASA has no launcher available nowadays, despite decades of « on the edge innovation ».
Soyouz is great. Its an engineering marvel.
And Starship is likely to become even greater.
Only in relation to other single-use rockets.
SpaceX has been eating russian's (and other countries') space business for years now, simply because they are cheaper.
His nuclear cruise missile program is so lame by comparison.
Building a dynamic, innovative organisation capable of developing a re-usable architecture would be very expensive, and unless they can not just equal but handily beat SpaceX, there's just no money in it. Their current launch systems already meet their military needs, so there's no political support from that quarter either.
Their war chest is not looking too healthy though, the hit to oil prices in the last 5 years depleted a lot of their reserves. Thanks for the correction.
I don't know man, did he design it himself?
I wasn't like them, but that ability to understand on a fundamental level, not forget, and then very quickly tackle more and more complex problems so fast was like a superpower. It took me much much longer, without the detailed understanding.
Many jurisdictions would still have an issue with him using the title engineer. (edit: it's recently been determined to infringe on first amendment rights [3]. Still applies in Canada)
[1] https://www.reddit.com/r/spacex/comments/davt2l/cnn_intervie... timestamp around 2:30
[2] https://twitter.com/lrocket/status/1099411086711746560
[3] https://www.vice.com/en_us/article/yw798m/oregon-unconstitut...
[1] https://www.youtube.com/watch?v=P06X2TZUKZU&list=PLpEqMkxe7X... (From the "Dan Rasky: SpaceX's Collaborative Design Approach" video of the "COTS: Dan Rasky" playlist of "Knowledge @ NASA".)
I was as entranced with the possibility of a permanent extraterrestrial base while watching the presentation last night as I was when I saw the boosters land tandem style in 2018.
What an amazing thing to see happen, the people Elon has brought together have done amazing things on the shoulders of already incredible work.
Here, specifically, with regard to steel rockets? SpaceX stopped optimizing for weight and used thick steel. SpaceX optimized for cost and practicality. Brute force rocket engineering, rather than "the best performance numbers on paper" which is where a lot of rocket designs seemed to get lost in the weeds of some component that ends up being a massive maintenance mess but gives you "the best performance".
The steel tanks that collapsed in the sixtys? They were so thin they needed pressurization at all times or they would collapse. SpaceX realized that was a design and maintenance risk, and just built thick tanks.
Also, it's a lot easier to foresee the weight of a design than its cost so most space programs use it as a proxy for cost. So generally the space industry would optimize for minimizing weight and not even try to think about how the materials used would affect cost.
The number of rings is roughly 35 for Starship, with about ten vertical seams each.
For easier thinking, line the vertical seams up and you see that this gives 50m length per vertical seam from bottom to top of Starship. So there are a total of 500m for that.
35 rings with ~28m circumference add up to about 1km of seams between them.
Now if they can use rolls twice as wide and only a single vertical weld each, then that's 500m between the rings and 50m for a single vertical seam. 550m of welds there instead of 1.5m before. This should speed things up quite a lot and reduce the cost of labour.
Raptor production is the real bottleneck, though.
They are shooting for one per day, no? Based on the differences identified in the three hanging under the Boca Chica vehicle now, it’s still in development.
No, they'll do a helical weld, exactly like large pipes (like this: http://www.xysteelpipe.com/upload/201512118145340710.jpg)
You basically need to do that as the steel rolls off the press, though, which is why they didn't do that for Mk I. They'll need to cold roll the steel onsite.
Composite tanks on few rockets being flown with them are made in one of a kind, purpose built autoclaves
Both characteristics combine to give a lighter rocket than one built out of Al / carbon fiber.
The price is just the cherry on top.
Or the F-86 Sabre: https://upload.wikimedia.org/wikipedia/commons/3/39/F86F_Sab...
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?
Once the temperatures get reasonable, it might be aluminum or or carbon fiber. The passenger/cargo/avionics section are probably the only areas where this would be true, so a bulk of the rocket will be steel.
When Canondale hit the big time, they had one model year where they made the dropouts out of solid aluminum and in the next model year the derailleur hanger was bolted on. It's the easiest part to bend and there's no repairing it. Bad enough for road bikes, spectacularly dumb for mountain bikes.
Nope, it's just steel. Outside shell is the tank.
I think the military was looking at a similar material to replace depleted uranium with something non-radioactive (depleted uranium still experiences alpha particle decay, which is fine if you don't aspirate or ingest it, but a shell can pulverize on impact with a target. Also it's still a heavy metal even if you don't take rads from it).
I thought the point of depleted uranium projectiles was simply the density of uranium, giving them large impact energy for a given volume. If that's the case, titanium (4.5 g/cm^3) will not even be as good as steel (8 g/cm^3), let alone uranium (19 g/cm^3).
The most beautiful thing in the world is success.
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.
I'm certain it will be a long time until it can get to Mars, but LEO within the next 2-3 years is probably realistic.
No way, that's where most of the differences are. The Falcon 9 second stage is a classic expendable stage but Starship is a brand new design which aims to be fully reusable.
Starship is designed to land from interplanetary speeds (not just LEO orbital speeds), can re-fuel in orbit, and has the world'd most advanced rocket engines. The jump from F9 -> Starship is substantially larger than the jump from F9 -> FH.
edit: spelling
What similarities are you referring to? They're designed to be launched atop another, bigger rocket. Other than that...?
I know I'm piling on here with this quote but I just don't understand why you'd say this if you'd done the least amount of research. They are about as different as two rockets can be—do you think Starship is "just a bigger version" because it's an upper stage? Because it's built by the same company? Its design and (theoretical, until it flies) capabilities are radically different and expanded relative to F9 stage 2.
In 2011, FH was supposed to have "arrival at launch site" by 2H 2012. It first launched in 2018 (after arriving at launch site in 2018 not 2012). The same level of delay would mean the first Starship does not reach orbit until ~2025. That seems crazy pessimistic and would be a dramatic departure from the otherwise normal delays faced by SpaceX.
I think it's extremely unlikely that Starship would face FH-level delays. That would cancel the Starlink constellation, cede the space-internet game to others, hand the torch to BO or others working on large projects, and absolutely destroy morale at SpaceX.
I just don't see it happening.
Keeping that in mind, having 5 year delay on brand new design, using totally different materials, new engine, etc isn't far fetched.
Starship has none of those potential delays and has already solved most of the hard problems (as evidenced by the Hopper hopping already). Starship has all of the learnings and experience that FH and F9 didn't have.
There will be delays, sure. But we won't be waiting 5+ years again for a single launch. Those days are over, and SpaceX is proving it.
Some context, I haven't read this yet: https://www.quora.com/What-makes-SpaceXs-Falcon-Heavy-more-t...
Edit:
> Keeping that in mind, having 5 year delay on brand new design, using totally different materials, new engine, etc isn't far fetched.
The first full size Starship prototype is already built though (within ~2 years of initial announcement? Not behind schedule basically at all, so far?). IIRC for FH it was a ~5 year delay before SpaceX even starting construction on the first parts. The difference with Starship is staggering. The pace is dramatically faster, the risks are reduced up-front, and the tests are planned on a much shorter timeframe.
We would frequently go 6 months to a year and hear no news at all about FH. There is news, updates and progress available to the public on an hourly or daily basis about the Starship progress. Night and day.
Experience from FH and F9 is useful, but it's a totally different type of spacecraft, with different use-cases, different materials, engines, cooling, etc. There's TONS of new stuff that they have to research, experiment, fail, try again, etc, until it's doing even 50% of what Elon promised.
StarHopper seems like it can use those learnings, and that was tested recently. The engine was already functioning on a test stand and mated to Hopper for static fires; the Hopper hop itself is testing the engine, sure, but also the complex math of doing a vertical landing with a gimballing engine, etc.
The general space industry considered reusabable spacecraft that land vertically to be pretty much impossible until F9 and FH did it. But Hopper just does that casually, you don't bat an eye, you don't even comment that Hopper was testing a new rocket dynamics/physics for the math that (almost) only SpaceX has figured out.
I just don't see the pessimism here. I've been watching SpaceX for 12+ years and I don't see any of the same issues plaguing them today as did in the past.
New issues, but not the same ones. The new issues have dramatically smaller turnaround time to resolve.
The days of 5-year SpaceX delays are over.
They are building 4 partially functional prototypes to mess up and learn stuff fast.
VTVL isn't new. To do it you need ability to throttle engine and do trust vectoring - once you have that, it's "fairly" simple math and physics.
SpaceX is first company that commercialized it, and huge props for that. No one cracked economy of it before (and it's not 100% sure that spacex did - no one saw their financials).
> New issues, but not the same ones. The new issues have dramatically smaller turnaround time to resolve.
We'll see, but I'm extremely sceptic about it. With F9/FH SpaceX did amazing but incremental improvements to current rocket technology. Starship has tons of uncharted territories.
The payload of the 2011 version was almost reached by the Falcon 9 itself. That was one of the major reasons for the delay, not design and production issues. The Falcon Heavy profited from all the advancments on Falcon 9 and it made no sense to actually build a Falcon Heavy before Block 4.
In fact the first costumers for Falcon Heavy flew on Falcon 9 instead.
Starship wasn’t built by the Falcon or Crew Dragon manufacturing teams, and the vast majority of the design and engineering currently happening for Starship has long been completed for Crew Dragon.
Let’s also remember that NASA is hardly the only company that pays SpaceX, they have other income sources and what they do with that income is ultimately their choice. Unless they are using NASA money to build Starship there should be no problem.
"Musk said in 2018 that SpaceX was “all hands on deck for Crew Dragon,” and it would be making trips to the ISS by December 2018.
After that, he said, “most of our engineering resources will be dedicated to BFR, and I think that will make things go quite quickly,” he said. BFR was the earlier name for Starship."
"All hands on deck" is not some subjective term, it is naval and means get everyone on deck now to repel boarders.
[1]https://kfor.com/2019/09/28/nasa-administrator-tells-elon-mu...
Elon responded saying he would do whatever it took to go faster, but there was nothing he could do.
Almost certainly the top minds at spacex are focussed on starship, and the 5% number might only be kinda-true because starship is being built with a lot of contractors.
FWIW SpaceX is exactly the kind of phenomenon that might spur state investment.
The Artemis thing is like a joke for real, though. After the last 30 years of bullshit we've seen from the US government's manned space exploration efforts I think I'll be living in a SpaceX-manufactured igloo on Titan before Richard Shelby and his obstructionist, pork-slinging ilk manage to put footprints on the moon.
We're talking about rockets here, which should be a million miles away from any discussion of Brexit.
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.
DHS would like your location...
I wish he could have gotten into the space industry vs oil refineries. The latter is much harder on a person.
I'm a mediocre amateur welder and I totally understand why.
[1] https://www.thefabricator.com/article/safety/the-invisible-r...
It's hard on people regardless. And the oil industry is not known for being prudent in looking after their workers' health.
They got real pissed when he filed a workers compensation claim for a hearing aid before he retired. Thankfully he had support from his union.
And the number of stories he's told me where he was nearly killed...
I've no sympathy for the industry.
puts sunglasses on
Yeaaaahh!!!!!!
Somehow my Dad managed to swipe that thing around like he was painting or something. It was impressive.
The tales I heard from my father were X-ray scans of their finished, grinded, polished welds and they had to be perfect. Not a hair-sized infraction would be permitted.
The https://www.spacex.com/careers/list ? There are currently several entries for Welder (Starship) and Tank Fabricator/Welder.
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
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!
According to NASA the space shuttle was ~$450 million per launch, or $16,364 per kg to LEO. The Delta 4 Heavy is $12,156 per kg. For some launches it's even higher- the Air Force paid $15,109 per kg for four launches.
The Falcon 9 is $62 million, or $2,719 per kg to LEO. The Falcon Heavy is $2,351 per kg when expendable or $1,411 when reused.
The BFR is supposed to have 2.5x the payload for 8% of the cost: $46 per kilogram. Even fully expendable it's $2,233 per kg. That's INSANE. It's space elevator money:
> For a space elevator, the cost varies according to the design. Bradley C. Edwards received funding from NIAC from 2001 to 2003 to write a paper, describing a space elevator design. In it he stated that: "The first space elevator would reduce lift costs immediately to $100 per pound" ($220/kg).[1]
If the BFR actually becomes reality it turns a journey to orbit into an airplane ride. A $10,000 airplane ride that will shake your fillings loose, but make no mistake: that completely changes everything about space. It makes putting satellites in orbit around Jupiter as hard as visiting the north pole. Fucking TV hosts will be able to go for a quick jaunt around the moon.
If the BFR happens, we'll have a mars base just because it would be so cheap it's a no-brainer. Building a new ISS would be about as hard as building a new Sealab.
And though Musk isn't a fan, this could even make solar power satellites economical. The monolithic designs from the 1970s would be absurdly expensive, but modern designs like SPS-Alpha get economies of scale by using lots of small identical parts that self-assemble in orbit. According to the book The Case for Space Solar Power, a 2GW satellite would deliver electricity at 15 cents/kWh at pre-SpaceX launch costs. I plugged BFR's $50/kg into its cost breakdown and got 4 cents/kWh, which is pretty good for zero-carbon baseload. Ground solar is cheaper by itself, but probably not after including storage.
The basic idea is geosynchronous orbit, microwave power transmission with a phased array device that requires a reference signal from the target location, and a wire mesh collector several miles wide. Over 24 hours, a solar panel in geosynch collects 5.4 times as much light as one on Earth. At the time the book was written, the power transmission had been tested over a couple dozen miles, and was 40% efficient.
Longer-term, if we collect fuel from the moon to go from LEO to GEO, we could make it even cheaper.
Firstly, you have 24/365 production, always at peak power. All things equal, you need a lot less capacity for equivalent power generation.
Then, I am fairly certain that the amount of power that can be collected depends a lot on antenna size, just like standard wireless transmission: the antenna needs to be "tuned". And a few hundred meters of steel cable would likely absorb a lot more energy than an 80 L water bag.
And finally (but related), microwaves are likely a lot less dangerous than UV: it isn't ionizing, because individual photons cary a lot less energy. That also means that they penetrate more "cooking" (increasing temperature) more deeply the objects in its path. Instead of getting your skin burnt from the energy, you feel slightly warmed up (and would likely be able to dissipate the small extra heat in the atmosphere). A sizeable portion of this energy would likely end up in the ground, if no antenna is present to collect it.
This technology is interesting, as it offers a lot of new possibilities: it's easy to relocate, for instance. We might also be able to split the beam to power multiple places simultaneously, reducing grid losses (and load balancing at the satellite).
(I used to work in a lab there next to some of the equipment and one day I asked my good friend about it - he had been there for decades.)
It’s likely to be really hard to make it efficient to transmit the power, because either it will be microwaves or it will be lasers; lasers can be blocked by clouds, microwaves need an huge antenna at each end (the numbers I’ve seen say that the one on the ground has to be big enough that people will ask why you’re not just using building a PV solar array on the ground instead of the antenna). If the antenna isn’t big enough, transmission losses from beamed power is proportional to distance squared, whereas resistance loss in wires is only proportional to distance (P = I²R, R = distance * some_design_specific_number Ω/m).
And that’s without the geopolitical implications of anyone worrying if the enormous directed microwave/laser source could be weaponised. Just saying “trust us” isn’t going to be good enough.
Why people don't have to trust us: because the technology isn't physically capable of maintaining even that low energy density at the target, without the reference signal from the ground.
Why put the PV in space instead of on the ground: because there's 5.4X as much energy available and it's 24/7.
There's real engineering behind this design, detailed in the book and the SPS-Alpha final report to NASA: https://www.nasa.gov/pdf/716070main_Mankins_2011_PhI_SPS_Alp...
I'm not aware of any real engineering studies for things like transmitting power via LEO satellite relays from the Sahara. Personally I don't find it plausible, but if you can provide such a study I'm willing to change my mind.
From what I see that’s a design choice not a fundamental aspect of reality, but even if it isn’t: what stops a hostile actor creating their own guide signal, either to direct the power towards an vulnerable location, or to directed away from the receiver, causing wide-scale power outages in the process?
> I'm not aware of any real engineering studies for things like transmitting power via LEO satellite relays from the Sahara. Personally I don't find it plausible, but if you can provide such a study I'm willing to change my mind.
This is because beamed power in general is a bad idea compared to simple wires, however the Sahara is a lot closer than Geostationary orbit and therefore any technology that works for Geostationary orbit will also work for the Sahara, and at guaranteed lower cost regardless of the technology.
Changing the beam target would require a repointing of the satellite in addition to the new guide signal. If you somehow do that militarily, it's still a pretty weak weapon; it'd slightly increase people's body temperature and they'd have to evacuate unless the guide transmitter could be found quickly. It probably wouldn't be hard since it's sending a signal that can be detected 36,000 miles away.
I'd like to see a real engineering cost estimate of transmitting power from one side of the planet to the other, by wires or any other method. I really doubt it can be done for four cents/kWh. And it would certainly introduce a possibility for hostiles to cause wide-scale power outages.
I can believe either-or, not both. If a guide signal is important, antenna orientation isn’t; if orientation is important, guide signals are not.
> I'd like to see a real engineering cost estimate of transmitting power from one side of the planet to the other, by wires or any other method. I really doubt it can be done for four cents/kWh. And it would certainly introduce a possibility for hostiles to cause wide-scale power outages.
Do I have to? Geostationary is 36,000 km, pole-to-pole is 20,000 km over the surface. All I am claiming here is that any tech you use would also be able to solve my alternative more easily.
The advantage of transmitting power from space instead of the other side of the planet is that there's a straight line with no planet in the way. To go around the planet you need relay stations or wires. Plus there's the 5.4X more energy collected by each square meter of panel. So yes, some supporting evidence would be nice. Maybe even take a quick look at the NASA report I provided, too.
Which is why I said 20,000 km not 12,000 km. Even if the circuit approximates the Earth as a square and goes up 6,000 km, turns 90 degrees at one relay, goes 12,000 km, makes another 90 turn at a second relay, and then 6,000 km down, that’s still a shorter path (though I’d expect the important distance in that instance to be 12,000 km not 24,000 km because it’s related to the inverse square law between any two antennas not over the whole distance).
> Maybe even take a quick look at the NASA report I provided, too.
I did. Now that I no longer at work I have time for a more detailed (though still brief) look at the contents rather than just skim read.
• That research was an attempt to turn a TRL-1/2 into a TRL-3.
• It is suggesting that — with further work — it could deliver electricity rate of 9 cents per kilowatt hour, whereas the Lazard 2017 price estimate for utility-scale ground mounted PV electricity was about half that (4.3-5.3) and the record (unless it’s been beaten since) is 2.4 cents/kWh.
• What I have read about the Retro Directive Phased Array is that it is it an assistant for good actors, not that it is a safety mechanism. By analogy, it seems that saying it makes this system “safe” is like claiming the passive aerodynamic stability of a 747 will prevent it crashing into a building — not the claim made by the inventor.
RDPA looks to me like a nice improvement to a traditional phased array antenna. Phased arrays can be re-aimed dynamically without physical rotation — which is, I think, why it’s being used in this design.
• The link itself suggests using its own wireless power transmission tech as a substitute for wires (page 50)
• Their own estimate for an initial full-scale (1 GW) is “far term (20-30 years)” (page 65) whereas their “mid- to far-term” market opportunities are the $0.5-$3.0 per kWh range (page 51)
$0.5/kWh is worse than combining batteries (~$0.18/kWh) with 5.4 times as much ground-based PV.
• The construction costs for the 2 GW plant “With aggressive tech advances“ are estimated at $16 per Watt (page 83), compared to current ground mounted costs of $0.103-$0.278 per Watt according to PV EnergyTrend on October 31 last year.
• Check out that risk-impact matrix for the 2 GW “mature” design on page 95
• The ground receiver is estimated to cost $10/m^2 on page 79; Unfortunately page 70 says “Determination of the actual power received will require additional, more detailed analysis“, which makes me wonder what the claimed costs per kilowatt hour even refer to. (Transmission? But there are estimates of beamed power efficiency…)
I’ve not seen estimates for the size of the ground station in that document, I’m going to have to handwave this one and say that the ground station is a 10 km diameter circle (because that’s the value that I’ve seen in other analyses of space-based solar power), which gives 2 GW / (π (5000m^2)) ≈ 25 W/m^2, which is both a bit higher than I’d be comfortable with and simultaneously so low that at $10/m^2 = 2.5 W/$ = $0.4/W, even the ground station alone is significantly more expensive than PV ($0.13/W).
Meanwhile, the comparable cost from solar is the total required for dispatchable power 24/7, not just the cost of PV alone.
If a non-engineer is in charge of a space company, they'll look at the popular science articles and assume that single launch is the only way to do things. They'll also assume that we just need to get the material science right to be able to do space elevators. They'll assume that the only way to get into space is to get bigger and bigger space budgets. That will increase shareholder profits after all.
When you have an actual engineer running the company, they can question all those assumptions. They can take everything apart and put it back together again in different ways and question the assumptions of the "thought leaders" in the space.
In a way, this outside "thought leadership" by research institutes has hindered science by leading researchers given grants to carefully conserve and develop their pet solution to a problem that they are an authority on. If their idea falls out of favor, then they will lose their grant money. It's the extreme version of the innovator's dilemma. An entrepreneurial engineer just wants to get the job done. If they can't deliver a great product, they'll lose their revenue stream. If they can leapfrog the competition by capitalizing on their innovator's dilemma, then they'll move to true greatness.
SpaceX is standing on the shoulders of giants.
But then Musk took over and once again a brilliant, innovative engineer was in charge, and so we are back to making real progress in space travel.
By the way, I am not talking about the space probe designers. They have been brilliant, and have produce an astounding series of scientific advances. But the rocket industry has stagnated.
Sure there are lots of brilliant engineers in the years after but these guys were not making top level decisions.
You can see that in all industries. MBA guys have kicked out engineers as leaders. I have seen the same while working in software engineering. Business thinking dominate over engineer thinking. You end up with these really short sighted decisions and there is an inflated fear of trying anything new.
Look at the SLS disaster: stuck on coupling together a whole bunch of old tech to the point that it creates its own complexity.
It's going to hand them the biggest bonanza they have ever seen. All that launch capacity Starship brings online will have to be used to launch stuff, and these guys are going to be building the stuff. They're not just rocket manufacturers, but have huge satellite manufacturing arms. If I had the money, I'd be investing in space technology stocks like crazy right now.
> 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?
With napkin math is't easy. Adding one zero here, one zero there, and you can easily show that you're increasing world's capacity by two orders of magnitude. Elon is known for big over-simplification in his vision statements.
> 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.
That's just day-dreaming, that support will tend towards zero. Even if it's design for rapid reuse, and they deliver on it, support is a almost always biggest cost of running any complicated machinery.
How will so many more launches impact the space junk problem?
From what I understand, there's already a catastrophe waiting to happen if some space junk collides with a satellite and causes a chain reaction of more space junk destroying more satellites, etc... until there's an impenetrable debris field around the earth.
Will having that many more launches and the potential accidents therefrom significantly increase the odds of such a catastrophe?
"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.
> "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’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?
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.
Does this preclude them from doing so in the future? They certainly will within the next year or so (crew dragon).
The moon has been out of reach of humans for 47-ish years mostly because we haven't had the orbital capacity to get there. Humanity has not had a super-heavy-lift launcher since the Saturn V (excluding the Shuttle and Energia, as they're mostly launching inert structural mass, rather than the fuel necessary to get elsewhere and back).
Certainly it's challenging, and their timelines are incredibly optimistic, but I've been watching SpaceX for about a decade, and they generally do the things they claim they will (on delayed timelines).
Certainly it doesn't preclude them from doing so, but a healthy dose of skepticism never hurts. Talking about the moon and mars when they have not yet successfully put someone in LEO is a little bit like putting the wagon before the horse.
5 years ago, you could have said the same about SpaceX and reusable rockets, and look where they are now.
I don't know whether the surface of Mars (.378 g) or the Moon (.165 g) will prove any less destructive to human health.
But is that because it's hard to put people on the moon or because only one country tried? (Sure, the USSR tried too, but they stopped trying before succeeding to put a large enough rocket into LEO).
There is a very unique challenge in landing on the moon, and most moon landings still fail. But that can be perfected with unmanned landings, and Space X has the unique advantage of having plenty of experience with powered landings, and not requiring a separate lander.
You might even argue that it's already obsolete, as despite it still potentially being the most capable rocket for some subset of missions, the per-launch costs are so high it might arguably be better to re-architect those missions to use multiple launches of a cheaper vehicle rather than launch on SLS. (You can launch 10 reusable Falcon Heavys for the cost of a single SLS launch.)
NASA/Congress has been stubbornly continuing to develop SLS despite that, but how much longer will they be able to hold out? Surely they won't be able to justify continued spending on SLS once there's another operational rocket that's both more capable in every respect, and a couple orders of magnitude cheaper to operate?
So at what point will they finally give up? Are they going to wait until after Starship hops? Until after it reaches orbit? Until after it achieves in-orbit refueling? Until after it lands on the Moon? Until after it lands on the moon, with crew? When?
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.
[1] like this old-fashioned warehouse https://en.wikipedia.org/wiki/File:Pl_gdansk_zuraw_dlugiepob... or the more modern style https://www.acklandsgrainger.com/en/category/Jib-Cranes/Cran...
The weight of the crane isn't a big factor, you open a hatch and lower stuff to the ground.
... and so programmed to crash just like Golgafrinchan Ark Fleet Ship B?
The largest rolling mills in the world are ~4 meters wide[1]. They require backup rollers[2], ie rollers that push down the rollers that push down the rollers that push down the metal. Bending deflection increases with width^2. A 28 meter wide rolling mill does not exist AFAIK and cannot be built in three months.
[1]: https://www.aleris.com/company/rolled-products/
[2]: http://www.yourarticlelibrary.com/metallurgy/types-of-rollin...
No real indication he means a spiral.
There are a lot of problems with a spiral. Thin sheets of steel, even hot rolled, are very affected by the rolling process. There's also the weld line going up in a spiral. That will cause uneven heat diffusion and expansion, which is a recipe for disaster given that the skin will be cold enough to liquify helium on one side and boiling hot on the other. Then red hot during reentry. Straight lines don't have the same problems.
It's been 12 hours and I only skimmed the video, so I might be misremembering what he said. My understanding was this: Mk1 is welded from plates so at each layer of the stack you have n-1 welds holding the n plates together. My understanding of his comment was that the steel coils will wrap around the major axis of the rocket but instead of each layer containing n-1 welds to join n plates, there will just be one weld in each layer to join the beginning and end of that coil. That would still leave you with welds joining the different layers of coils but only one "seam" weld along the rocket's major axis.
Single helical weld.
This of course matters if the seam is weaker than the rest of the metal.
I've been assured time and again that you can make welds that are stronger than the rest of the metal, but my lizard brain thinks they're all liars.
Same exists for most goods - try to buy a dustsheet to cover your room, and you can't buy one wider than 5 meters without a seam
https://twitter.com/FarryFaz/status/1170535411678101504/phot...
https://pbs.twimg.com/media/ED6Tva7XYAESQJJ?format=jpg&name=...