SpaceX test flight of Starship SN-5 [video]
youtube.com
youtube.com
- 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.
Would love to learn more about this, can you expand? What makes Raptor so unique?
https://everydayastronaut.com/raptor-engine/
* The Russians built one in the 60s but it never got past static fire tests
AFAIK it's the only flying, non-research example of such an engine.
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.
Another hurdle was that there was no material available for some of the parts. SpaceX - so we'll get some materials science people to develop a new alloy that does what we need. Not an easy sub-task but one that needed a solution, so they found one.
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].
To solve this, SpaceX had to develop special metal alloys that could withstand this incredibly corrosive environment for long durations.
SpaceX developed an incredibly advanced simulator to make it happen: https://www.youtube.com/watch?v=vYA0f6R5KAI
I don't think it's a stretch to imagine that Mars-based tankers supplying propellants and breathing oxygen would be commonplace through the solar system by the end of the century.
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.
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...)
If they were so inclined they cold even recover the helium from the tanks they are filling and use that to assist with pumping pressure.
You'd be surprised at how low of an acceleration is required for propellant settling and transfer. On the order of 0.0001-0.01m/s^2. At a 310s Isp for the ullage thruster, that's between 0.01kg and 1kg of propellant usage per second. Even if it takes an hour to transfer fuel (on the ground, fuel is transfered in about 20 minutes and in flight, all the propellant is transfered from the tanks to the engines in ~8 minutes), we're only talking about maybe 1% of the propellant needing to be used for ullage thrust and perhaps as low as 0.01%.
ULA has published a paper on the topic: https://www.ulalaunch.com/docs/default-source/extended-durat...
[slide] https://spaceflight101.com/spx/wp-content/uploads/sites/113/... [video] https://youtu.be/tdUX3ypDVwI?t=1411
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.
Adding another engine means, one more production line each with less production volume (i.e. less efficiency of scale).
I think they would be very happy to get a factor of 2 in one step. It would only 7 such steps to get that factor of 100.
Having said that, they aren’t aiming for the most modern rocket technology as that implies “less well tested”, and will be less reliable. They’re building T-34s, not Tiger tanks.
That much cryogenic hydrogen and massive temperature differences is as the limit of engineering possibilities.
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.
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.
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.
That'll be something to see haha N1
If a small number of rocket engines was required they would probably have a completely different design, perhaps an aerospike. Or maybe resurrecting Project Orion?
I think they push fluid through the bells, maybe other materials(like ceramic) for the larger nozzles... can they use magnetic field to contain heat... probably not assumes it's ionized or something ha... heat still goes through magnetism. I got it, active heat destructive interface ha.
https://en.wikipedia.org/wiki/NERVA
https://spacenews.com/momentum-grows-for-nuclear-thermal-pro... (2019)
The joke went entirely over your head boss.
[1]: https://en.wikipedia.org/wiki/N1_(rocket)#Block_A_first_stag...
It wasn't used in the Soviet lunar program; these are remnants of the Soviet Space Shuttle-like program (specifically the Energia rocket that lifted the Buran space plane).
edit: oh it's NK33/RD180 [0]
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.
It will probably circle the Moon before NASA SLS.
The future is exciting!
[0] Making Humans a Multiplanetary Species / Elon's original presentation from IAC 2016 - https://www.youtube.com/watch?v=H7Uyfqi_TE8
[1] Starship Update / 2019 - https://www.youtube.com/watch?v=sOpMrVnjYeY
* 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.
I'm also thinking on the flip side, say a Starship somehow gets irreparably damaged getting to Mars (but successfully gets there). With some basic gear they should be able to part it out and re-use the steel.
Like for a new door on all the Cybertrucks rollin' around up there. /s
But you have to plan for another mission to pick up the crew, unless you're on the Moon where you could use an electromagnetic catapult to achieve orbit, and then slowly ascend to the rocket that would take you home.
Electromagnetic catapult, huh. Sounds fun as hell.
On Mars, Moon or in space this constraint is reduced.
Welding thick to thin is nontrivial because of the different heat input required in each substrate. You tend to burn through the thin part.
Patching may be possible but thick patches don't make things any easier.
I would not be surprised if part of the reason for building these in a tent is so they can gain experience for building/repairing these rockets with as little infrastructure as possible.
That is, something you can have a fair chance of fixing while in orbit or on Moon or Mars.
https://en.wikipedia.org/wiki/SpaceX#Ownership,_funding_and_...
Most likely close to 0% of the SpaceX ownership stake is represented in Google's stock. Let's assume though for the sake of argument that some large part is, say $1.3 billion of the stake is represented (3% of $44 billion). That's equal to about 1.3% of Google's market cap (~$1t).
Whatever you do never buy a stock on that kind of premise. Risking the other 98.7% of your capital to get a meaningless piece of something else (which is already a big something else at a $44b market cap). If SpaceX doubles in value, you'll never notice it (you put $1,473 into Google, SpaceX doubles, max scenario you might make $20). It may be one of the worst reasons to ever buy a giant like Google. People commonly make this mistake when buying Berkshire Hathaway or certain other conglomerates, thinking they're getting a 1-to-1 direct exposure to the Berkshire portfolio (among their equity holdings, only a few matter at all, as with the Apple holding at $110b). I often see it pitched as a form of bonus diversification. Cash and equity holdings on the balance sheets of public companies are essentially never represented at full value in the market cap. The larger the company and the smaller the asset in question, the more likely it is to have something more toward zero representation.
It would be a mistake to invest in BH because, say, you're really bullish on Dairy Queen, but that doesn't seem like the mistake you're describing.
Is there actually a NASA proposal like that? As far as I know, orbital dynamics don't allow for this. One has to wait for a Hohmann transfer orbit window to return home.
"Opposition class missions" stay on the surface for 30 to 90 days. "Conjunction class missions" stay for 500 days or more.
That confirms the 30 days that you mentioned as a reasonable minimum.
[1] https://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf
https://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html
Of course, this in in the "resource-constrained" mode of thinking. If you allow for giant vehicles with on-orbit refilling, SpaceX-style, you just spend a bunch of energy to get there fast instead of monkeying around with Venus.
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.
Would it not be easier to build large structures in orbit or at one of the Lagrange points?
But I think my favourite idea is infrared scopes in the polar craters, some of the coldest places in the solar system. You don't need a complicated JWST-style extendable sun shield or limited helium supply. You are limited in terms of direction, but that's not a bad tradeoff.
With any luck, things you learn actually doing A, and then A' that is 10 times harder, and then A'' that is 100 times harder, will all turn out to be useful, even necessary, in tackling B. Failure is always an option, but there is no point in choosing it at the outset.
Under the sea starts out way more terraformed than Mars can ever be. It has water, gravity, and is warmer. Mineral wealth is right at hand.
The cloud tops of Venus start out way more terraformed than Mars can ever be. It has air pressure, gravity, water, carbon, sulfur, and shirtsleeve temperature.
What motivation does Mars provide that those don't?
The other option is the Moon, which has even less atmosphere and even bigger temperature swings than Mars.
But the point was, if you haven't even proven you can settle a mildly challenging environment, your odds on an actually difficult one don't look good.
Venus, you could only settle by bringing in everything from outside unless and until you can convert the atmosphere in a large way into building materials — Mars at least you only need to convert it into fuel, because you can do at least some of your construction from rocks.
On Venus, plastics, carbon fiber, water, buoyancy gas, and breathing air (I repeat myself) can be made directly from the air and clouds. Plastic and carbon fiber gives you building materials. Robots can gather minerals from the surface and deliver them by balloon to the cloud tops. Insolation provides abundant power, moreso than here; or, a lightweight, unshielded nuke plant may be suspended a mile or more below industrial plant, supported on its own balloon.
Mars will be much more unpleasant than Antarctica. We don't even know whether people can live for long in Mars gravity. We know that long weightlessness is quite harmful.
You might be right to do that — I’m no rocket scientist — but the target price would get a million people there for $200 billion, not your $5 quadrillion.
Yes, I also expect the first few thousand to be in easily damaged domes. I also expect them to bring some of The Boring Company equipment with them, as it is part-owned by SpaceX and the stated raison d'être of TBC being pointless in a future of fully self-driving cars.
Traffic jams with human drivers happen spontaneously when the cars get close enough that overcompensation turns into a negative spiral.
The roads are already there, electric cars are quiet, road trains are even more efficient.
I am no fan of American city design, having half encircled Davis CA on foot, having found the suddenly-terminating sidewalks in Salt Lake City, and having walked the really boring route from San Jose railway station to the hotel in the top left corner of the Apple Maps icon.
(NYC is surprisingly pedestrian friendly though).
But:
1. Musk doesn’t live in Europe, he set up TBC while stuck in a traffic jam in Los Angeles.
2. Solid car trains moving at full speed (whatever that is for the road, 20 kph for residential or much higher than the current rules for highways) use less land area than any other traffic, so some lanes can become bicycle only or whatever.
3. They can “perfectly” obey traffic lights and give way to pedestrians
4. Raised walkways are cheaper than tunnels
But the first starship missions will drop 100 tons each to the surface of Mars at a cost of a few hundred million dollars each. And they will send dozens of Starships that first trip, building an camp with over a hundred explorers and scientists the first synod.
They will have thousands of tons of equipment and supplies, and their habitats will have multiple redundancies and be easily repaired.
Mars is far easier to survive on than the Moon, for example. The temperature ranges are far milder, Mars reaches 70 degrees Fahrenheit at its equator during the day. The day is the same length as ours. There is adequate solar for power, tons of water, and a plethora of other easily accessible resources from CO2 to Iron.
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.
It's not just a discount - it is the reversed equivalent of banks charging interest for a loan due to failure risk. Private customers getting discounts accept the increased risk that some re-used part fails. Essentially SpaceX has managed to have their r&d subsidized by paying customers instead of having to borrow money, launch dummy payloads and pay the money back.
... 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_.
We ended up with a lot fewer nukes, and a lot less space. (Also fewer trippy alien wormholes.)
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.
Seems like a pretty good perdition of our future, really. UBI recipients with no labor of value to offer won't have power to change their government for long.
It's unfortunate that the authoritarian future of Star Trek probably wouldn't lead to paradise. Or at least, that's how our culture's view of the future has changed.
Both fictions are a product of their time. I still wish we had the optimism of Star Trek now.
If UBI was implemented as in The Expanse (food, shelter, and meds are free), I would expect the population of the earth to plummet. The UBI would allow for more people to pursue learning and educating others. It has been shown that when people feel safe from threat of violence and starvation, and when they are more educated, the desire to breed decreases.
On the flip side, perhaps knowing that you are off the hook for paying for the expense of many children would increase the desire to reproduce?
We have birth rate comparison between "first world" and "third world" countries plus migration experience studies (basically, even one generation after migration from a poor to a rich country, there is a massive drop in birth rate, and after something like 3 generations the birth rate is equal to the rest of the country).
Additionally, there is a noticeable drop in birth rates when a whole country gets richer.
I suspect that summarizing collectivism as authoritarian is like summarizing libertarianism as selfish: they go well together, but you can also get one without the other.
I don't know Star Trek very well, but as a utopia I guess they imagine a form of collectivism that largely preserves individual freedom? Of course most of the show centers on Starfleet, an authoritarian organisation like any military, which doesn't tell much about the whole society.
The 1890s demonstrated what a Libertarian regime would dissolve into, instantly: Absolute rule by the biggest dog. It has happened myriad times in human history, from all kinds of pre-conditions. We were lucky, 130 years ago, that the armed forces still believed in voting. Not sure they still do...
TOS-TNG: Klingons were Soviet-Russian, Romans were Chinese, the Federation was sexist (but much less so in TNG than in TOS) and pretended gay people didn’t even exist.
DS9: Lesbians and trans people exist, but only as exotic outsiders. Bajor feels inspired by Tibeten Buddhism and the final parts of the Northern Ireland Troubles.
VOY: ???
ENT: Nostalgia gone wrong followed by 9/11
DIS/PIC: Oh no Cold War enemies are a threat again / Oh no A.I.
There should really be no reason that people can't be trained or educated even if most of the skills are utterly useless in the face of automation.
If the negative aspect of the future portrayed in the Expanse are culturally absorbed, then there is a strong possibility that the people dreaming of and building the future could see that as a road sign to help them avoid that future.
E.g. it makes the point that we would need to work out ways to create better habitats in space and to concentrate on making a workable biosphere where enough food can be cultivated and raised (yes, cows in space) to survive.
Misleading road signs about the future may be worse than no signs at all.
And it doesn't matter how many Dyson spheres are made, if humans aren't dedicated to improving the collective opportunity to live life without suffering, there's little real 'significance' to extending the project of humanity compared to any other life-form.
You cannot eliminate suffering.
> Life will go on in other parts of the universe, and all life, no matter where they locate themselves, will have some kind of existential threat.
There's no guarantee or evidence that there is sentient life in the universe
!= improving the collective opportunity to live life without suffering
> There's no guarantee or evidence that there is sentient life in the universe
Do you at least consider a possibility that life originated only once?
There’s a lot of evidence that points to the fact that on a global scale, we can barely care about stuff geographically adjacent to us, or worse, socially (class) adjacent to us, but here we are claiming we care about generations beyond us.
Big old lie.
The second reason to get off-world is the more far-fetched one, but assuming we can establish that other worlds are dead or sterile then we are free to customize it as we please without having to feel bad about it. In the long run we could leave Earth completely, allowing whomever comes next to develop freely without our intervention.
I'm not saying there are no existential risks at all, but being on other planets would not make us any more likely to survive to them than to simply being very well isolated on Earth (which would cost 1000x less).
Developing space technology already has all sorts of benefits and it doesn't need this poor argument in its favor.
Mars would also offer cultural redundancy. Also, sometimes people choose to do things brcause they are hard.
If I were a betting person, I'm not sure I'd go all-in on a CEO-Emperor-King of Mars over existing nation-states on Terra
I see no immediate risks to life on Earth, and considering we're quite hard to get rid of, I suspect the human race will be here for quite some time yet. The ability to do a large-scale settlement on other planetary bodies on the other hand, might go away considerably sooner, and who knows if/when we will be able to do it again if we ever end up in a situation where it might be needed.
Regardless, there are other reasons, as you say. For one, space-based manufacturing would allow us to increase the standard of living on Earth without having to worry about things like CO2 levels and pollution. If we start commercializing space then I expect colonization to follow as a natural result of that and we won't have to worry about the more philosophical side.
Having a self-sustaining outpost somewhere other than earth is valuable not only for its own sake, but also due to the developed technology and industry and infrastructure implied by its existence.
If tomorrow you suddenly need a huge fleet of fully reusable ships for some reason, the right time to start working on them was 20 years ago, or as soon as basic science and technology level allow.
There are also political risks (we are all too close to each other).
Of course, this machinery can be medically disrupted by toxins and genetics (air pollution has an impact for example, lead ions, etc.), but there is a ‘healthy’ reason for depression (similarly there is a ‘healthy’ reason for ‘scabs’ and physical wound healing).
Most people in the modern era with ‘healthy’ depression are medicating away the effect (you will be shocked if you look into the rates of antidepressant usage in France for example), and this diversion can inadvertently prolong the depression as would be expected (e.g. dealing with symptoms and not cause).
Lots of interesting research in this area.
tl;dr yes, depression and depressive thoughts are useful for humans in certain cases, which is why we have them
Which isn’t to say a tempering perspective isn’t at all helpful, I just think in the absence of all optimism (& hope), there’s no room for constructive change
To illustrate, your viewpoint seems consistent with the statement: “There can be no great progress, no humanity taking root among the stars unless led by monstrous men.”
I hope you don’t consider this a straw argument, but it’s worth considering. To believe that statement is to either believe that a “good” future is necessarily one of stagnation and extinction (whether in 1000 years or 500 million years) OR to excuse the actions of monstrous men. A pessimistic, cynical perspective means no counter-movement, no inclusive cooperative with the goal of space settlement. This isn’t exactly motivating.
(And to be clear, from the perspective of history, I do not consider Elon—definitely not perfect—to be monstrous. Neither is SpaceX the work of one man. Gwynne Shotwell is as much the leader of SpaceX as Elon is—although you wouldn’t know it by reading headlines as she doesn’t care for the spotlight—plus thousands of passionate workers (who are co-owners) who believe in this vision and many of whom would be pushing for it even without Elon’s leadership.)
Regardless, unless we manage to come up with a new system that actually works, chances are that commercialization of space is one of the few ways for us to establish a presence off this planet.
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.
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.
The US uses over 20 million barrels of petroleum every single day. We have 44,000 airline flights every day.
I think 19 starship flights won’t even move the needle.
Let’s guess making the fuel takes 5,000,000 kg of oil (corrections welcome. I guess that’s a reasonable estimate. Less than 100% of fuel is methane, but the specific energy of methane is about 20% higher than that of oil, and creating liquid oxygen takes energy, too)
Multiply by 19 gives you 95,000,000 kg, or about 700,000 barrels. That’s 3% of the oil usage in the USA.
And that excludes construction, maintenance, and ground operations.
⇒ I think it would move the needle, more so given that we should work hard on getting that number down.
Also, separate point: Starship return flight to Mars requires large-scale manufacture of methane from atmospheric CO2, using solar (or technically nuclear, but I don’t see that happening in this case).
It’s the only way of getting back — their tanks are empty when they finish landing on Mars — but it works fine here too.
Methane is not made from oil. It's either directly pumped out of the ground as natural gas, or collected from organic decay processes. Methane is more carbon-efficient, as it has almost 2x more hydrogen per carbon compared to longer hydrocarbon fuels, and most of the energy in the molecule is in the hydrogen, to the tune of 40% more energy per ton of CO2. One ton of methane burnt produces ~2.7 tons of CO2 (and 2.2 tons of water), compared to one ton of octane producing 3.1 tons of CO2 (and 1.4 tons of water).
Of the propellant in the rocket, less than a quarter is methane, and more than 3/4ths are LOX. The stoichiometric ratio would be ~1:4 (by mass), but for various reasons most rocket engines are more fuel-efficient when burning fuel-rich, so the real ratio is probably somewhere between 1:3.6 to 1:3.8. The energy cost of producing LOX is really, really low, less than 1% of the energy content of similar mass of methane. Also, this process is done with electricity, and is very amenable to intermittent production. (So the CO2 impact is effectively zero).
Coming from the other direction, according to the department of energy, the US yearly CO2 emissions from all anthropogenic sources are ~6.7B tons of CO2 equivalents, while the launch of a single SS/SH produces about 2700 tons. If you were launching a thousand of them every year, they would account for 0.04% of emissions.
Currently we postpone many launches due to an abundance of caution. As spaceflight gets more routine we will increase our risk tolerance and launch in worse weather.
> Not just for the required fuel and environmental impact, but also given how often they just postpone basic launches due to weather.
The environmental impact of a rocket launch is roughly in the same category of the environmental impact of a airliner doing a single long-distance trip. (I did this calculation for F9, SS/SH would be higher but not more than two orders of magnitude higher.) Pre-covid, there were approximately 100 000 airliner flights a day. You do the math.
And that's before we consider that they are fueled with methane, and that there are sources of methane that are potentially not just GHG-neutral, but GHG-negative. (Collecting agricultural methane emissions and burning them is dramatically better than releasing them directly.)
As for weather, it is possible to launch rockets in very bad weather, for example the Russians frequently launch in literal blizzards where no winged aircraft could fly. It's just that ability to fly in inclement weather is something you need to design for -- rocket bodies are generally not strong against transverse loads, and this is made worse by having a high fineness ratio. SS/SH, being much more stubby than most current American rockets, will be much less impacted by weather than them.
- each starship burns 4600 tons of methalox fuel
- the mixture ratio of the propellent is 78% O2 and 22% CH4 [1]
- that means that each 100 tons of methalox results in 53.6 tons of CO2 and 2.5 tons of CH4
- generally in the climate science it is accepted that one ton of CH4 is equivalent to 25 tons of CO2
- overall, each 100 tons of propellent will produce 116 tons of CO2-equivalent emissions
- a single launch of 4600 tons propellent will result in 5.34 kT CO2 emissions
- if we get to 5000 launches per year we end up with about 25 MT of CO2-equivalent emissions
- the current worldwide level of emissions is 45 GT CO2-equivalent as of 2017 [2]
- that means 5000 launches will increase our global emissions by 0.06%
[1] https://twitter.com/elonmusk/status/1258580078218412033
[2] https://en.wikipedia.org/wiki/List_of_countries_by_greenhous...
> that results in CO2 and CH4
The chemical reaction of O2 + CH4 -> CO2 + CH4 does not compute.
More likely is the reaction 2 O2 + CH4 -> CO2 + 2 H2O.
So no methane emissions, that's the actual fuel. Only CO2 (and water) emissions.
The chemical reaction is indeed CH4 + 2 O2 -> CO2 + 2 H2O. So, for each 16 grams of CH4 you get 64 grams of O2, that's a stoichiometric mass ratio of 1:4.
The fuel ratio for the Raptor engine is 22:78, according to Elon Musk's tweet. So, for each 100 g of propellant mixture you get 19.5 g of CH4 to burn using 78 g of O2 and you are left with 2.5 g unburned CH4.
I simply neglected the H2O resultant from the reaction because, while H2O is a very potent greenhouse gas, it has a fast cycle in nature (rain, etc). Also, I have no idea how to account for it as a greenhouse gas.
Otherwise it would have been in a comment on an Eric Berger Ars Technica article.
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.
At 100t, that would be 400 a pop.
We can start looking at the infrastructure that makes moon or asteroid mining for fuel possible. 'Cheap' fuel in space is the dream because it means asteroid 'mining' for materials that get returned to earth can be profitable (massively profitable to the point of dwarfing any investment currently made).
But the amazing side effect is suddenly we also have materials in space that like the fuel now costs orders of magnitude less than if we were sending it up. It'll becomes viable to build more infrastructure in space and so (perhaps ironically) there will be more demand to get materials from earth to space.
Well, 1 million people ain't going to get to Mars by themselves[1].
But once you have that sort of capacity, at those sorts of prices, many things that are now unthinkable become very possible and possibly useful.
Asteroid mining has been mentioned. Putting huge telescopes into orbit or the Lagrange points. How about a nice and big radio-telescope on the far side of the moon, where there is no EM interference. Or maybe even further out? How about some very, very long baseline-interferometry[2]?
Put manufacturing in space. There appear to be some useful materials that can only be made in low-gravity environments, but currently the Price is not Right™[3]. Bezos wants to put large space habitats into orbit instead [4]
Others have mentioned Starlink, with up to 12000 satellites. Nowadays they're talking about 42K satellites.[5]
Space-based solar power might become feasible[6]. Maybe put up a sunshade[7] to control global warming.
How about some manned deep-space probes? Maybe with some Vasimir rockets[8], a nuclear reactor and lots of reaction mass.
We are so conditioned to think that anything space has to be small, super-lightweight and super-high-performance/expensive that it's really kind of hard to think about the consequences of those constraints no longer applying.
And of course tourism, like the already-announced circumlunar flight[9], space habitats etc.
Think big!
[1] https://www.syfy.com/syfywire/elon-musk-mars-colonization (or just google it)
[2] https://en.wikipedia.org/wiki/Very-long-baseline_interferome...
[3] https://en.wikipedia.org/wiki/Space_manufacturing#Materials_...
[4] https://www.businessinsider.com/jeff-bezos-proposes-floating...
[5] https://observer.com/2019/10/spacex-elon-musk-starlink-satel...
[6] https://en.wikipedia.org/wiki/Space-based_solar_power
[7] https://en.wikipedia.org/wiki/Space_sunshade
[8] https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magn...
Here's a writeup: https://exoplanets.nasa.gov/internal_resources/1375/
In general, once you get to LEO, you're half way to anywhere ... That is, getting to low earth orbit is half the battle. Spacex will remove that battle for everyone, making space expansion and exploration 2x easier.
My dream is earth-orbiting shipyards for outer planet missions and interstellar missions. There's nothing stopping us but will.
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.
But assembly enclosure for the first stage (Super Heavy) is being built already.
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! :)
I don't work overtime and I'm not a fan of Thai food
For example, here is a web development position in Hawthorne: https://boards.greenhouse.io/spacex/jobs/4682610002?gh_jid=4...
And a network position in Redmond: https://boards.greenhouse.io/spacex/jobs/4770694002?gh_jid=4...
Here is the job board for all software positions: https://www.spacex.com/careers/index.html?department=Softwar...
As a very experienced engineer, I can’t accept being judged on (historical) trivia.
[0] https://youtu.be/ywPqLCc9zBU?t=2733
[1] https://twitter.com/elonmusk/status/1208841343440568320?s=20
I prefer investing in Tesla/SpaceX instead of working there, and leave working extra hard to young people who have more energy than me.
The initial comment by bfieidhbrjr already answered that very nicely: out of the desire to actually do something that is important re work. Important being subjective to the person in question obviously.
I personally love working hard, which is why I only work with startups, which tend to have a higher personal ROI and more meritocracy oriented.
I'm also not a US citizen, so that's another cheap test I can't pass.
Unlike other "cheap tests", that one is imposed by US government regulations, not SpaceX's own decisions.
I imagine SpaceX would be quite happy if ITAR was loosened, but I doubt that will happen.
I honestly can't see why ITAR applies to citizens of friendly countries such as Canada or the UK. The point of ITAR is to stop unfriendly countries like China, Russia, Iran or North Korea getting access to technologies with sensitive military applications. The US trusts its closest allies in so many other ways (e.g. UKUSA "Five Eyes" intelligence sharing agreement, the 1958 Mutual Defence Agreement under which the UK and US share nuclear weapon design information), why not in this?
If the US can trust the UK with information on nuclear weapon designs and delivery systems, surely it can handle a few UK citizens working for SpaceX?
In the unlikely event that the UK and US had some falling out, the US government could always order SpaceX to lay off UK citizen employees.
Besides that, the risk of a US-UK breakup has always appeared to be low, and Brexit arguably makes it even less likely.
Bad example. The soviets got the bomb because of British spies in the Manhattan project. After that, there was very little collaboration to this day.
https://en.m.wikipedia.org/wiki/1958_US–UK_Mutual_Defence_Ag...
> The Americans disclosed the details of nine of their nuclear weapon designs: the Mark 7, Mark 15/39, Mark 19, Mark 25, Mark 27, Mark 28, Mark 31, Mark 33 and Mark 34. In return, the British provided the details of seven of theirs, including Green Grass; Pennant, the boosted device which had been detonated in the Grapple Z test on 22 August; Flagpole, the two-stage device scheduled for 2 September; Burgee, scheduled for 23 September; and the three-stage Halliard 3. The Americans were impressed with the British designs, particularly with Halliard 1, the heavier version of Halliard 3. Cook therefore changed the Grapple Z programme to fire Halliard 1 instead of Halliard 3.[85] Macmillan noted in his diary, with satisfaction that:
>> in some respects we are as far, and even further, advanced in the art than our American friends. They thought interchange of information would be all give. They are keen that we should complete our series, especially the last megaton, the character of which is novel and of deep interest to them.
> An early benefit of the agreement was to allow the UK to "Anglicise" the W28 nuclear warhead as the Red Snow warhead for the Blue Steel missile.[87] The British designers were impressed by the W28, which was not only lighter than the British Green Grass warhead used in Yellow Sun, but remarkably more economical in its use of expensive fissile material.
Wikipedia doesn’t appear to support your version of events. (Of course, Wikipedia is sometimes wrong; but if you think it is wrong, which of the above claims it makes is wrong specifically?)
Filtering on inane academic requirements up front is the exact opposite, and you end up rejecting half the real talent pool.
The US citizen (and/or permanent resident) thing is probably not negotiable, though, because SpaceX does a lot of Nat Sec stuff.
If you can't figure out how to move to a different state to pursue a dream, it's not much of a dream.
Measure what you do by the change in yourself and others, and how it makes society better.
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.
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?
My intent was not to imply that an employee can always utilize complete deterministic agency in their career path.
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.
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. ;)
This, overall, is an amazing achievement. I watch every F9 landing that I can, and it never ceases to amaze me. The FH two-booster landing looked like straight out of a SciFi movie. But this... this is next level again. The 20km flight will be truly incredible.
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.
It did the hop 'off balance' (the final version expects to have 3 raptor engines working together) so the engine out scenario for landing still seems pretty safe.
There is something like four more advanced vehicles in the warehouse section at various stages of completion. So scaling up making them seems to be working out.
It looks "small" in the images but when you see people working on it you can tell its grain silo big. That is a heck of a thing to fly overhead.
Rockets taking off and landing vertical has amazed me ever since I saw the DC-X do it once.
I don't think we have the advanced materials for that.
The Delta-X was an interesting design until NASA was involved.
> In a post-accident report, NASA's Brand Commission blamed the accident on a burnt-out field crew who had been operating under on-again/off-again funding and constant threats of outright cancellation.
That is the reason why SpaceX is so much more efficient and revolutionary, compared to what Boeing/ULA on US side and EADS/Ariane on EU are doing - they are cutting politics out of the equation and with it, a whole boatload of issues.
SpaceX isn't interested in a sweetheart subsidy deal. They are competing. That's why their contracts with NASA are fixed price: it gives SpaceX every incentive to keep costs down so as to maximize profit.
Surprise! SpaceX is doing better than the competition that gets sweetheart deals. It should really not be a surprise to anyone though, but it probably is to some.
I'm not convinced though that it ever really to achieve it's SSTO goals and still land it. With on orbit refueling perhaps (as could Starship in a similar scenario). It was also shooting for much lower mass to LEO.
Agree with this.
> If you make the rocket bigger, it's payload mass fraction increases.
Don't agree with this. The way I see it, as a rocket gets bigger, and stays in one piece, its payload mass fraction decreases. The inability to jettison heavy engines and structural components means those things become part of the 'mass fraction' that ends up in orbit. And the bigger you make those things, more and more of your mass fraction is being committed to carrying stuff and less is available for non-rocket payload. Hence its a decreasing mass fraction in terms of amount of payload.
Its fun to play around with this in Kerbal but its pretty much a hard limit.
Things that can affect the mass fraction in a positive way are things like more ISP in the engines. When you look at the evolution of the Falcon 9, the increase in mass to LEO was a result of two things, one upgrading the efficiency of the Merlin 1D engine and two developing a way to put more propellant and oxidizer in the same volume by super chilling it.
I need to check my math to be sure of how much you can scale that way, but that's one of the reasons Starship is such a BFR.
Elon talking about SSTO: https://www.youtube.com/watch?v=cIQ36Kt7UVg
This was the first flight of a vehicle which may someday take humans to mars.
They are only using one engine this test, but are testing the flight-design thrust puck (as opposed to some interim structure with a centre mount for the single engine).
This test article uses the same layout for engines, but with one engine instead of three. So that one engine is offset from the center.
Their flight software is already capable of handling the multiple engine out-scenario and compensating for it, so there's no real reason for them to center the engine for the test article.
The amount of kick to the side is almost certainly due to the offset engine, but they would definitely design the flight path (with that in mind) to clear the pad as fast as reasonable as well.
From what i remeber some Soviet rockets had after a string of pad destroing failures any abort commands disablee for the first 30 seconds of flight - regardless of what happens, it must not hit the pad, or Barmin (the chief designer of most Soviet launch complexes) will be angry and you don't want that.
I'm still worried about the overall design, specifically when it comes to landing. The current procedure is for it to fall into the atmosphere flat on its side, then continue to fall for a long time, and then only when it's near the ground it must reorient 90 degrees to upright and then do a final suicide burn to land. It seems like it has too many chances to fail with no recovery, but I'm no rocket scientist.
Doing it the thousandth time is starting to get old. Doing it the ten thousandth time is business as usual.
The place to improve from is not as good as you may think, "On the Demo-2 mission, NASA has estimated a 1-in-276 chance of losing the crew at some point." Once you have full re-usability, you can fly rockets several orders of magnitude more times. When you're flying that often, you have the ability to work out the kinks.
If instead you limit to what today feels the safest, you might limit yourself from full re-usability and eventually being much safer.
If you want to still go for full re-usability, adding a backup system might actually make things more dangerous: It's another thing that has failure modes. Redundancy can be a double edged sword.
Planes make 90 degree turns all the time! And in actuality this rocket could be less complex than a modern airliner as far as number of parts and processes.
They have taken huge leaps in engine technology with Raptor that allow for a lot of simplification across the rest of the rocket and which could make it airliner level safe someday.
I don't see much reason to be worried about changing orientation in the long term. It's not in a particularly exotic flight regime (subsonic, lower atmosphere) and so long as the vehicle has sufficient control authority (and it will) anything that would cause that maneuver to fail would cause any other maneuver, like landing, to fail as well. The F9 actually already does a (less dramatic) version of this, and has never had a problem in that phase of flight.
Is a much better video :)
Here they are:
https://www.youtube.com/watch?v=VwC6LG_z8zE
https://www.youtube.com/watch?v=NJR4gZBLMNw
And the last one is constantly streaming 3 live feeds of the SpaceX Boca Chica facilities 24/7:
https://www.youtube.com/watch?v=5QbM7Vsz3kg
EDIT: And by remarkable, I don't just mean technical capability but the really impressive non-traditional media community that has grown up around New Space the last 5-10 years. Here's amazing, close-up 4K video of the hop by yet another non-traditional space media person:
They are the only one to ever achieve this. It's a big deal because everyone else builds a $100M rocket and then throws it away because it can't land. Reusable rockets have the potential to make açcess to space much cheaper.
[1] https://en.wikipedia.org/wiki/SpaceX_Starship
[2] https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-f...
The first stage will be a bit longer than this & its build enclosure is already being uilt.
Curious how complex it is since it has to handle multiple engine failure scenarios etc...
https://www.reddit.com/r/spacex/comments/gxb7j1/we_are_the_s...
I thought SpaceX does these types of landings all the time. :)
Good article: inverse.com/innovation/spacex-mars-city-stunning-video
If Falcon 9 (the current rocket) was a motorboat capable of going from one port to a neighboring one on the same sea coast, this is the early prototype for a transatlantic liner.
It's designed to be much bigger, much faster and more powerful, while being fully reusable (like a plane) and extremely cost-effective, potentially 10 times cheaper than the Falcon 9, which is already the cheapest launch vehicle. That opens up all sorts of new possibilities.
And these hops are the first concrete steps toward that.
There are three big targets they need to hit:
1. Make Low Earth Orbit (LEO) cheap with a combination of launch cadence and reusability.
2. Reset the rocket equation in LEO by doing in-orbit fuel transfer.
3. Reset the rocket equation at Mars by generating fuel from the environment.
* The reasoning...
(1) A high launch cadence means you can switch from artisanal to mass production. You drastically reduce fixed costs of ground equipment and personnel. Experience translates to increased knowledge, reliability, and safety. You are less prone to schedule slip costs because there are more trains leaving the station.
(1) Reuse lets you get more life out of expensive components. It also helps you hit a higher launch cadence with less manufacturing capacity, further reducing costs.
(2) In orbit propellant transfer lets you start with a full tank again in LEO. It might take four tanker launches to refill one tank, but ultimately you can increase payload to non-LEO destinations by an order of magnitude. Being less mass constrained also makes things simpler and cheaper for payload development.
(3) Propellant production, aka in-situ resource utilization, lets you fully refuel at Mars or the moon. This lets you send non-trivial payloads in the return direction.
* The progress so far...
SpaceX has regular reuse of the 1st stage of their Falcon 9 and Falcon Heavy rockets. They have begun catching the fairings (nosecone) in giant nets mounted on ships and reusing those too. The 2nd stage is not reused. Doing so is difficult because it's much further downrange and has much larger velocity.
SpaceX has used their progress on reusability to drive down costs and capture a large part of the commercial launch market.
SpaceX is launching Starlink satellites to provide a global, low-latency, high-bandwidth internet access. Existing satellite internet is based on geosynchronous orbit satellites which have high-latency and low-bandwidth. SpaceX hoists 60 Starlink satellites per Falcon 9 launch. There are a couple hundred satellites in orbit already with several thousand planned. Their low orbit means they have a lifetime of just a few years and require regular replacement. If Starlink is a commercial success, then SpaceX will have found the "demand" needed to drive a high launch cadence.
* Why the SN-5 hop matters...
SN-5 is a prototype second stage for the "Starship" rocket. This rocket has both a massive payload capacity and _full_ reuse. In conjunction with Starlink this would solve (1). This prototype is demonstrating progress on the manufacturing process and viability of the design. There is still tons of work to be done.
SpaceX is already planning to do in-orbit propellant transfer using Starship, which then solves (2).
SpaceX has not begun on (3). However, the Mars 2020 rover mission actually has an experiment on board which does propellant production at demonstration-scale. The chemical reactions (sabatier process) are pretty straight forward, but providing sufficient energy and gathering the resources is a massive engineering challenge.
Ultimately, SpaceX has a coherent, achievable vision for reducing space transport costs by multiple orders of magnitudes and has made demonstratable progress towards that vision.
SpaceX has been flying cargo to the International Space System for some time using their Dragon capsule. A few days ago they completed their first manned mission on the Crew Dragon.
Three big items from this:
1. They have a reusable cargo/crew capsule for LEO operations.
2. They have gained experience in building human life support systems and associated ground operations.
3. They implemented autonomous docking for both the cargo and crew variants of Dragon. This is one of the keys to achieving in-orbit propellent transfer. Item (2) in my original post.
What do you mean by this? If you want to propel a mass M to delta-v V, you need a certain amount of initial mass. Dividing it into stages is already taken into account. If you split the lower stages into multiple trips, you might change the mass per trip, but you don't change any of the total early-stage mass required, right? Doesn't the rocket equation still apply in exactly the usual way?