16 ms·

Starship Update

438 points by adventured 7y ago

callumprentice 7y ago
Musk said at the start of his presentation that the magnitude of earth's gravity is such that we are right on the cusp of rocket flight possibility. If the magnitude were a little more, rocket flight would be impossible. If it were a bit less, it would all be a lot easier. Can anyone expand on that, assuming it's the truth..
- avs733 7y ago
  I'm gonna go with citation/mathematics needed. Spaceflight is about velocity and energy.
  - cbanek 7y ago
    https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation It's also about gravity, since gravity is what you are fighting against.
- allannienhuis 7y ago
  https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html https://www.nasa.gov/mission_pages/station/expeditions/exped...
  - duskwuff 7y ago
    Nice find! Near the end, the author directly addresses this question: > If the radius of our planet were larger, there could be a point at which an Earth escaping rocket could not be built. Let us assume that building a rocket at 96% propellant (4% rocket), currently the limit for just the Shuttle External Tank, is the practical limit for launch vehicle engineering. Let us also choose hydrogen-oxygen, the most energetic chemical propellant known and currently capable of use in a human rated rocket engine. By plugging these numbers into the rocket equation, we can transform the calculated escape velocity into its equivalent planetary radius. That radius would be about 9680 kilometers (Earth is 6670 km). If our planet was 50% larger in diameter, we would not be able to venture into space, at least using rockets for transport.
    - acidburnNSA 7y ago
      Not using chemical rockets. Nuclear propulsion would be able to do it with the ~1000000x energy density advantage of nuclear fuel over chemical fuel.
      - nine_k 7y ago
        The problem is that the super-dense energy of a nuclear blast also evaporates solids and rains gamma rays on everything around. Imagine how hard space exploration would be if the only practical rocket were a Project Orion.
      - Baeocystin 7y ago
        I remember seeing a simple demonstrator some years back of a laser pulsing against the backside of a spinning disc, the geometry of things causing the heat from the laser to provide thrust. I can't find the video I saw, but here's a general link on the topic: https://en.wikipedia.org/wiki/Laser_propulsion#Laser_energized_rocket https://en.wikipedia.org/wiki/Laser_propulsion#Laser_energiz... This comes with many problems, but it does bypass the rocket equation, while not requiring Project Orion levels of trouble.
        rocqua 7y ago
        I mean you still need to carry propellant: the stuff that is ablated away. It's just that the exhaust velocity is much higher.
        king07828 7y ago
        Air from the atmosphere may be the propellant [1]. If sufficient velocity can be achieved before leaving the atmosphere, then no propellant is needed to be carried up on the way to orbit. [1] https://www.youtube.com/watch?v=XhUasBcoj-Q https://www.youtube.com/watch?v=XhUasBcoj-Q
      - jccooper 7y ago
        Nuclear would be better, but it's not quite as good as it seems. Nuclear engines are rather heavier than chemical.
- deleted 7y ago
  [deleted]
- Already__Taken 7y ago
  if gravity were much more we'd be out of chemical reactions that produce the energy to beat the rocket equation.
  - api 7y ago
    This is a possible Fermi paradox answer, or at least factor. Maybe the vast majority of habitable worlds are larger than Earth. The inhabitants of those worlds might find space flight too hard or even impossible. They also might have less interest in it since they would make the natural anthropic assumption that worlds capable of supporting life are probably huge like theirs.
    - derekp7 7y ago
      That really makes a lot of sense. Because planets smaller than Earth cool a lot faster, so they lose their molten core and plate tectonics (which keeps land mass rising and out of the water), and also a magnetic shield that keeps the atmosphere from stripping away (like Mars).
      - JohnJamesRambo 7y ago
        I'm going to be hopeful and optimistic and point out that the large planets in our solar system aren't rocky and suitable for life as we know it anyway. Earth is the biggest one and the rest are gas planets. Maybe planets that harbor life (rocky, liquid water, goldilocks zone closer to the sun) usually have low enough gravity for aliens to escape it. This diagram has some exoplanets on it for size comparison- https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#/media/File:Diagram_of_different_habitable_zone_regions_by_Chester_Harman.jpg https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#/...
      - api 7y ago
        Earth might be right at this threshold of small enough for space flight to be practical (still hard, but practical) but big enough to hang onto water and atmosphere.
- uoaei 7y ago
  I assume he's relating 1) the force of gravity, composition and distribution of our atmosphere, and incredible velocity required for orbit, to 2) the chemical potential of fuels and the limits of structural strength for materials to carry cargo to orbit. I haven't run the numbers, but he's right: it's pretty hard to get something that can carry itself to orbit. It has to climb out of the atmosphere directly against gravitational force and atmospheric drag, and then as early as possible turn sideways and start accelerating to around 28000kph while making sure the rocket is pointed in the right direction and holding together. You need a lot of propellant to get to that state, which means you have to carry it around until you need it, which means the machine needs to be much bigger than just the cargo, which means that all of your challenges just magnified by many orders of magnitude.
  - TheSpiceIsLife 7y ago
    Would it be possible for the numbers to be a bit more difficult to work with so maybe we could go to low earth orbit, but never be able to make it to the moon?
    - JshWright 7y ago
      If you can make it to orbit, you can make it anywhere (it just may take multiple launches to assemble/fuel the spacecraft going elsewhere).
      - fireattack 7y ago
        Wait, really? So what's the deal of first and second cosmic velocity?
        cyphar 7y ago
        I guess the idea is that if you can make it to orbit (even if you waste all of your fuel), then you could in principle refuel in-orbit (by getting another unmanned rocket with just fuel into orbit) and thus escape the orbit. But yes, you still require more energy (exactly sqrt(2) times as much) to "escape" Earth's gravity entirely than to orbit it with a circular orbit.
- happytoexplain 7y ago
  I wonder how much this could be mitigated by extra-rocket energy delivered while the rocket is still close to the ground - e.g. a cartoonishly large slingshot.
  - drusepth 7y ago
    Or a comically large refueling hose hooked up until it hits orbit. I guess in that case you'd probably be fighting gravity even more trying to push fuel up the hose.
  - mey 7y ago
    Ground laser propulsion has been considered. https://en.m.wikipedia.org/wiki/Laser_propulsion https://en.m.wikipedia.org/wiki/Laser_propulsion
  - derekp7 7y ago
    There's also using chemical rockets for the first stage, then switching to nuclear for the second stage once clear enough of the ground to minimize fallout. Radiation pollution wouldn't be pleasant, but future advances could potentially minimize that also.
    - marktangotango 7y ago
      NERVA XE was damn near ready to fly during the Apollo era for Mars missions. Would've made a hell of 2nd stage engine. https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA
  - sdenton4 7y ago
    Unfortunately, drag force is proportional to the square of velocity... So the slingshot (or railgun or whatever) maybe gives you a nice acceleration at the start, but a LOT of that initial force will bleed off as drag early in the flight in the thick thick low atmosphere. (Consider the difference in difficulty of riding a bike at 15mph vs 16mph and 25mph vs 26mph... 25->26 requires a hell of a lot more effort, all due to drag.)
  - wahern 7y ago
- enjeyw 7y ago
  Ok so doing super-approximate maths: A fully fueled and loaded Saturn V weighs about 3,000,000 Kg, and has a payload of about 40,000 Kg to the moon. So that means once you've put all the bits of the rocket together that collectively give you sufficient thrust to get you to the moon, you've only got about 1.3% left for actual payload. S if earth's gravity had been ~1.3% stronger, then the weight of the "getting us there" bits of the rocket would have left no room for payload. Any more gravity, and we wouldn't even be getting to the moon. Equally, if the earth's gravity had been 1.3% weaker, we could have doubled our payload to the moon (or done things way easier). Contrast that with a Boeing 747 which has 50% of total mass as payload, and so is relatively insensitive to changes in gravity.
  - avmich 7y ago
    Some (funny) sources list Saturn-V payload as 140 tons on LEO :) so according to this logic to get to orbit one has plenty of margin. And as soon as the payload is in orbit it uses full value of accumulated speed, so it's used to get further and getting to the Moon is no harder than with Earth...
  - JohnJamesRambo 7y ago
    I recently realized that if we got in Jupiter's gravity well we could probably never escape it again. Someone correct me if I'm wrong. The thought made me feel really uneasy.
    - hossbeast 7y ago
      If that were true, it would be impossible to leave the solar system, since everything is currently in the Sun's gravity well, and the Sun is larger than Jupiter. But we have sent probes outside the solar system (did they fully leave the Sun's gravity well yet though? Not sure)
      - davidivadavid 7y ago
        But we didn't send the probes from the Sun.
- libtard 7y ago
  Well, it'd prevent rockets for sure, we'd only have nuclear pulse propulsion then to get into orbit and that's a lot harder to justify to people than a rocket.
  - wolfram74 7y ago
    There's a lot of alternatives, the main constraint is that it has to be built from the ground up, so space elevators are out. I think a dynamic structure such as a launch loop https://en.wikipedia.org/wiki/Launch_loop https://en.wikipedia.org/wiki/Launch_loop would work. Also inflatable towers for launch assist https://en.wikipedia.org/wiki/ThothX_Tower https://en.wikipedia.org/wiki/ThothX_Tower For even kookier options we've got lasers! https://en.wikipedia.org/wiki/Laser_propulsion https://en.wikipedia.org/wiki/Laser_propulsion https://en.wikipedia.org/wiki/Beam-powered_propulsion https://en.wikipedia.org/wiki/Beam-powered_propulsion
- sidorares 7y ago
  He was talking about rocket reusability, specifically reusing orbital stage. Just reaching the orbit is possible in stronger gravity, but returning back whole stage is already very close to the limits of current material science
- wmp56 7y ago
  I have another wild guess. Not only we have just right amount of fossil fuels to leave the planet, but also the sun has just right amount of energy to reach the stage when people can move to another solar system.
  - tdy721 7y ago
    My guess is the Sun probably has more... it’s really big. What if it’s just like fossil fuels and there’s enough energy there for us to smear ourselves out? Oh cool, kinda like fission then!
- duchenne 7y ago
  The rocket equation states that the amount of fuel that you need (to send a given payload into orbit) increases exponentially with the escape velocity of the planet: mass of the rocket with fuel = mass of the payload * exp(escape velocity / engine exaust velocity) That is because the faster you need to go, the more fuel you need to use, but now, you also need even more fuel to accelerate the fuel that you just added. So, it becomes exponential. So, if the earth was bigger, its escape velocity would increase, and the amount of fuel needed to power a space rocket would increase (exponentially) so much that it would become unpractical. Vice versa, with a smaller planet it would require exponentially less fuel to reach orbit. The only solution would be to have an engine with a higher exaust velocity. With the current technology, ion engines have very high exaust velocity but low thrust are very energy hungry. The thermal nuclear engines have both high exaust velocity and high thrust, working prototypes have been built, but all projects were boxed 60 years ago because of the fear of an accident.
- mpweiher 7y ago
  > earth's gravity [..] right on the cusp of rocket flight possibility He didn't actually say that. He was talking about "rapidly reusable orbital rockets" and "fully reusable orbital rocket[s]" being the "critical breakthrough" that's necessary, the "holy grail of space" and the "fundamental thing that's required". So fully and rapidly reusable. https://youtu.be/sOpMrVnjYeY?t=1234 https://youtu.be/sOpMrVnjYeY?t=1234
- sidcool 7y ago
  Gravity is taxing. It's possible that our galactic neighbors live on a larger planet with greater gravity which makes their escape from the planet next to impossible.
  - silasdavis 7y ago
    Can we swing by and drop them a ladder?
    - sidcool 7y ago
      If we get sucked by the gravity, we are stuck as well.
      - silasdavis 7y ago
        Presumably we'd need to lower it from geostationary orbit. This is a unique solution though I suppose there is some dependency on the mass of the planet where you might be too deep in the well. But you'd be in orbit so presumably some low thrust low propellant engine powered by sunlight ought to be an option?
- kromem 7y ago
  Hmmm... That's actually really interesting to think about from the anthropic principle perspective. Very interesting that the only intelligent species we are aware of is on a planet that we can leave. I wonder to what extent higher gravitational planets could sustain love that couldn't leave it. An interesting answer to Fermi's paradox.
  - htfu 7y ago
    Nah, again - nuclear. I doubt the safety profile would factor much once it's the only available option.
    - mrfusion 7y ago
      Don’t forget ground based propulsion too.
- hoorayimhelping 7y ago
  That is pretty much all there is: If earth was more massive, the chemical rockets we've been producing wouldn't have enough thrust-to-weight ratio to reach orbital velocity (about 25k km/h). We would have to load the rockets with so much fuel to break free of gravity that they would be too heavy to lift themselves. This is all assuming yields and fuels we have now. If we lived on a more massive earth and we were trying to escape its gravity, I'm sure we'd be using more exotic and dangerous fuels (like all those fun fluorine and boron fuels Dr. Clark mentions in Ignition![0]) to do the job. We just happened to have the capability in the middle of the century to use a fuel we were already making (refined petroleum) for jet engines. [0] https://www.amazon.com/Ignition-Informal-Propellants-University-Classics/dp/0813595835 https://www.amazon.com/Ignition-Informal-Propellants-Univers...
superkuh 7y ago
The most surprising thing to me was nixing the transpiration cooling with methane and switching back to heat shielding tiles for half of it.
- mabbo 7y ago
  It was such a cool idea, but I imagine it was going to be very hard to make it work.
  - superkuh 7y ago
    Reusable heat shielding tiles are also very hard.
    - lukebuehler 7y ago
      Could it be easier compared to other rockets/shuttle since the space ship is made out of steel?
      - nickik 7y ago
        It makes it a bit easier because as Elon mentioned the steel structure can get much hotter without it being an issue. This makes it easier to connect the tiles directly to the ship. However still the primary problem is still to have some surface that can handle the heat without deterioration over multiple flights.
  - geuis 7y ago
    Exactly. Say you land on the Moon and your ship sticks around for a few months. Micrometeorites can impact and cause minor damage to the surface cooling system. You’re baked at that point. But given the hull is stainless steel repairs are much easier. Any experienced welder can spot repair divots and holes or weld in much larger patches. No need to worry about the specially constructed parts required for evaporative cooling. Fix the hull then install replacement tiles.
- SEJeff 7y ago
mabbo 7y ago
"We could see people flying next year". O_O This is "Elon Time" at its best, but worth keeping in mind how fast Starship development has actually gone. Elon Time is becoming more realistic.
- smashem 7y ago
  Why has it taken so long to get people on-board the Dragon Crew Capsule? Isn't it mostly because of all the safety testing that has to be done? Didn't get the chance today to hear about Starship's safety mechanisms.
  - thunderbird120 7y ago
    NASA requirements + lack of full reusability. It's a lot easier to vet safety through large numbers of tests if you can launch much more often and at a much lower cost which is what they want from Starship.
  - tus88 7y ago
    Because one blew up.
    - TheCraiggers 7y ago
      I doubt it. Everyone knows that this shit is dangerous. It's not a question of if something bad will happen, it's a question of how often. There's some pretty gnarly diminishing returns on proofing these beasts, but SpaceX has a huge advantage over the boosters that NASA used- they're reusable so getting a few extra 9's of safety is not necessarily a waste. Of course, the non-reusable boosters had an advantage too where they were only subjected to the insane stress of a launch once, but I'm guessing that's a smaller advantage than what I said above or else we wouldn't have modern airlines.
- eugenhotaj 7y ago
  I have not seen the presentation yet. Still, I am willing to bet anyone a non-trivial amount of money that we do not see people flying next year.
gouggoug 7y ago
What a painful presentation to watch. Musk really needs to either work on his public speech or delegate them to someone comfortable. His product reveals could be so much more impactful and inspiring did he not jump between points he's trying to make and stutter his way through the entire presentation.
- zaroth 7y ago
  Yeah, he’s given hundreds of these presentations but he “needs to work on it”? Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires.
  - umeshunni 7y ago
    > Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires. That's how you get WeWork.
    - dmix 7y ago
      There's hundreds of millions of smooth talkers. Only a few WeWork type companies...
  - gouggoug 7y ago
    > he’s given hundreds of these presentations but he “needs to work on it” Giving "hundreds of these presentations" is not a measure of one's ability to present well. So, yes. On delivering them. He's really hard to follow. Musk is a bad speaker. That fact doesn't diminish in any way what he has accomplished. > Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires. Well, sure. I'd rather have more Musk than more Neumann; but that literally has nothing to do with the opinion I was expressing.
    - kjksf 7y ago
      His presentation was great. You're just judging him by the most superficial attribute: the cadence of his speech. An attribute that he cannot change, btw, because that's how he speaks. The content was great. He knows what's he's talking about, he's direct, he doesn't bullshit and what he talks about is inspiring. Starship presentation was 10x better than, say, the polished and perfectly delivered Apple keynote full of cliches like "this is the best Foo we've ever done".
strainer 7y ago
I do find this to be actually legendary. At a target rate of about one per month, he is set to produce stainless steel, rapidly reusable, 150-ton-capable Mars transports. And is doing this using currently "about 5%" of the resources of his own commercially built satellite launch company, grown from scratch in a decade or so and out-performing every other nations satellite launch programs - by a large margin. His presentation is noticeably a little self-concious, but not so much as to obscure his enjoyment to be standing in front of the first massive shimmering yet wielded and dented together rocket ship, which is due to demonstrate lift off and landing in a month or so.
- lettergram 7y ago
  I had the same thoughts watching that.m - it’s been 17 years, but the company is amazing. Each rocket contains as much pressurized space as the ISS. I do however think the “rapid reusability” thing is going to be a challenge. He mentioned 20 flights a day for the booster and 6 (or so) for the starships. I expect 1 per day tops, still exceedingly impressive, but once one of these blow up (or hopefully before) they’ll have heavy pre-flight inspections. Starting off id hope for heavy inspections, then following a period of no error inspections could be reduced.
- aiyodev 7y ago
  Let's hope Musk can produce something other than investment theater.
  - grey-area 7y ago
    He has, at multiple companies.
  - tdy721 7y ago
    Go watch the landing fail reel, or Crew Dragon blow up. I guess you’re on team Starliner goes first? An electric car in solar orbit? He’s actually trying to conquer space! Go stink on the Solar City deal, but leave the rockets alone. He produced a real working reusable ICBM booster!
stevebmark 7y ago
It's time for Elon to step down as the face of SpaceX. He ruins every presentation he's involved in. I can't imagine how awkward it was to be there in person and be help prisoner by a completely unprepared, rambling, lazy talk for over an hour.
- agildehaus 7y ago
  Most of the SpaceX community thinks it's awesome to not have some polished person up there who knows next to nothing about what they're talking about, and he's been doing it during the entire duration of SpaceX's unbridled success. So, no?
- russdill 7y ago
  SpaceX has plenty of flashy speakers and uses them appropriately.
- jordanthoms 7y ago
  You're not the target audience for this presentation. It's goal was to provide an information dump for the people who have been closely following the project, and it achieved that extremely well. It's not aimed at the kind of person who prefers a flashy presentation over substance, which in this case is extremely rapid progress towards the most capable rocket humanity has ever built.
  - jakeinspace 7y ago
    Considering the amount of time he spent explaining rudimentary spaceflight concepts (getting to LEO is about speed not altitude, who knew?), I wasn't sure how technical this was going to be.
- remontoire 7y ago
  Totally agree, no one has ever been inspired by this man! In fact, he has actively put spaceflight back 50 years by making everyone disinterested in going to mars. What we need are more people in suits who give us made up numbers.
- 7y ago
SomeOldThrow 7y ago
Is there a transcript somewhere?
- _Microft 7y ago
  Sure, go to the video on Youtube [0], click the three dots menu on the right hand side below the video and open the transcript from there. This loads all of it at once, so you can even search through it with your browser's in-page search function! Clicking a line in the transcript jumps to the correct position in the video. It might be the most amazing feature that Youtube has. [0] https://www.youtube.com/watch?v=sOpMrVnjYeY https://www.youtube.com/watch?v=sOpMrVnjYeY
  - deleted 7y ago
    [deleted]
  - SomeOldThrow 7y ago
    There is a transcript that youtube provides.
snrji 7y ago
SpaceX always beats my expectations, unlike Tesla.
growlist 7y ago
A couple of takeaways for me: 1. oldspace and its supporters, if they have a clue, should be even more terrified than before by the scale of the vision. Even if only a percentage is achieved the disruption should be shattering 2. the unspoken juxtaposition between Musk on the one hand - on the face of it unpolished and light-hearted to the point of flippancy about a topic no less grand than the destiny of humanity, yet in reality visionary, fiercely determined and stunningly successful, and proceeding with at least as stated altruistic goals; and oldspace on the other - polished, solemn, pompous, claiming the sole capability and privilege to act as gatekeepers to space, yet in reality outdated, inefficient, outclassed, and acting like a resentful dog-in-the-manger in response to SpaceX. There's something tragicomic, almost Shakespearean about it all
- Lanzaa 7y ago
  I don't think any of "oldspace" are terrified by the Starship. I would bet they are almost as excited as SpaceX. SpaceX's improved launch capabilities will not kill off "oldspace" companies. Mainly because access to space is a national/military security issue. The launch providers for China, Russia, India, and the EU will continue to exist, if only because those entities don't want to be beholden to SpaceX for their access to space. If anything I would expect an increase in funding to some of those "oldspace" launch providers as countries try to catch up with SpaceX's technology.
  - growlist 7y ago
    > I don't think any of "oldspace" are terrified by the Starship. I would bet they are almost as excited as SpaceX. Not so sure about that - ESA's saltiness suggests they are not thrilled: 'Asked about how the Ariane 5 compares to lower-cost alternatives on the market today, such as SpaceX's Falcon 9 rocket, Stefano Bianchi, Head of ESA Launchers Development Department, responded with a question of his own. “Are you buying a Mercedes because it is cheap?” Ranzo, sitting nearby, chimed in and referenced the India-based maker of the world’s least expensive car. As he put it, “We don’t sell a Tata.”' You are correct that it won't kill off oldspace, but the pressure to change will be inexorable: it's not difficult to foresee a scenario where commercial work all goes to SpaceX, apart from situations where companies are forced to use a national provider; but even then, those companies will thus be forced to eat the cost of subsidising an inefficient provider, which will lower their profits making them less competitive, etc. There could be a similar pressure when one considers military payloads, i.e., the cheapness of launching with SpaceX offers the US a game changing capability to put materiel in orbit. https://arstechnica.com/science/2018/07/as-the-spacex-steamroller-surges-european-rocket-industry-vows-to-resist/ https://arstechnica.com/science/2018/07/as-the-spacex-steamr...
sveit 7y ago
"One of the really interesting interesting things to contemplate is the total mass to orbit capability of a large reusable system where you have a significant fleet in operation. If you've got something like Starship where you've got maybe 150 tons capable to orbit and the ship can fly, is capable of say theoretically flying four times a day but you know they call it like 75 percent uptime so theoretical three times a day, three hundred sixty-five days a year. So that's like about a thousand flights a year for the ship. The booster can do a lot more than that. This is obviously max theoretical. You've got, you know, 150 tons that service, 150,000 tons to orbit per year per ship. If you've got say ten ships you'd have [...] one and a half million tons to orbit per year. Twenty ships you've got three million tons to orbit per year. I think the total rest of world capacity, if you take all rockets on earth including Falcon, the total capacity to orbit I think is around two to three hundred tons currently. Total Earth capacity to orbit is about two to three hundred tons if all rockets launched at max rate. So we're talking about something that is with a fleet of starships a thousand times more than all earth capacity combined. All other rockets combined would be 0.1% including ours." How is this not massively disruptive to the entire space launch industry?
- jccooper 7y ago
  It is, and is supposed to be. Elon loves to talk about Mars, but the real story behind this architecture is complete ownership of spacelift until someone else catches up. Then the story becomes enabling actual space industry.
- ddalex 7y ago
  It is. Three orders of magnitude leaves everybody else in the dust. I wonder if this applies to pricing as well. If we get to single-digit dolar prices pe kg to orbit, a tourist ticket would be easily a couple thousand dollars - equivalent to a business class plane ticket. One more order of magnitude and you can start shipping ready-to-be assembled habitats and fuel factories to Mars. And Boston Dynamics robots to assemble them. At these prices you can start sending empty nuclear reactors for power, and lift heavily shielded nuclear fuels as well. Not puny RTG generators for a couple hundred watts but 1000MW generators that will sustain cities. So many possibilities!
- 7y ago
tibbydudeza 7y ago
It looks like something from Fallout or Rocketeer ... the space nerd in me is disappointed at the "look" but I really really hope it works.
snoshy 7y ago
I didn't notice this being mentioned in the webcast or in any of the follow-up articles I've read on the presentation: while the timelines for 6-months-to-orbit seem insane, I believe the underlying drive for an aggressive schedule here largely derives from Mars launch windows. [1] We have a launch window to Mars open from July 2020 - September 2020, the tail end of which is almost exactly one year away. Starship will have to be orbit capable well before this window, such that the flight and maneuvering characteristics are understood well enough to reasonably justify taking a crack or two at an unmanned cargo Mars mission within the 2020 window. Musk might not have explicitly mentioned it in the presentation, but I would bet that the Starship teams are internally being driven to these targets. FTA, Musk is quoted in 2017, saying SpaceX was targeting uncrewed Mars missions in 2022, but given his ambitions and depending on the progress of the Starship/Super Heavy, I can see them actually aiming for 2020 such that any failures would still guarantee a path to making the 2022 window. All of this is my own amateur speculation, would love to hear corrections or other ideas. [1] https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_windows https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_win...
- Lanzaa 7y ago
  I don't think the schedule is aggressive enough for a 2020 Mars launch with the Starship. It is likely that Starship will be capable by then, but the wow factor is missing. I don't think an interesting mission would be ready. Don't forget that Musk's Tesla was already launched to "Mars". So it would be safer and just as impactful to have an interesting mission planned using Falcon Heavy. The only mission I can think of which might be viable is Starship landing on Mars. However I don't think SpaceX would have proven Starship enough to get approval for that.

438 points by adventured 7y ago

Musk said at the start of his presentation that the magnitude of earth's gravity is such that we are right on the cusp of rocket flight possibility. If the magnitude were a little more, rocket flight would be impossible. If it were a bit less, it would all be a lot easier. Can anyone expand on that, assuming it's the truth..

avs733 7y ago
I'm gonna go with citation/mathematics needed. Spaceflight is about velocity and energy.
- cbanek 7y ago
  https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation It's also about gravity, since gravity is what you are fighting against.
allannienhuis 7y ago
https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html https://www.nasa.gov/mission_pages/station/expeditions/exped...
- duskwuff 7y ago
  Nice find! Near the end, the author directly addresses this question: > If the radius of our planet were larger, there could be a point at which an Earth escaping rocket could not be built. Let us assume that building a rocket at 96% propellant (4% rocket), currently the limit for just the Shuttle External Tank, is the practical limit for launch vehicle engineering. Let us also choose hydrogen-oxygen, the most energetic chemical propellant known and currently capable of use in a human rated rocket engine. By plugging these numbers into the rocket equation, we can transform the calculated escape velocity into its equivalent planetary radius. That radius would be about 9680 kilometers (Earth is 6670 km). If our planet was 50% larger in diameter, we would not be able to venture into space, at least using rockets for transport.
  - acidburnNSA 7y ago
    Not using chemical rockets. Nuclear propulsion would be able to do it with the ~1000000x energy density advantage of nuclear fuel over chemical fuel.
    - nine_k 7y ago
      The problem is that the super-dense energy of a nuclear blast also evaporates solids and rains gamma rays on everything around. Imagine how hard space exploration would be if the only practical rocket were a Project Orion.
    - Baeocystin 7y ago
      I remember seeing a simple demonstrator some years back of a laser pulsing against the backside of a spinning disc, the geometry of things causing the heat from the laser to provide thrust. I can't find the video I saw, but here's a general link on the topic: https://en.wikipedia.org/wiki/Laser_propulsion#Laser_energized_rocket https://en.wikipedia.org/wiki/Laser_propulsion#Laser_energiz... This comes with many problems, but it does bypass the rocket equation, while not requiring Project Orion levels of trouble.
      - rocqua 7y ago
        I mean you still need to carry propellant: the stuff that is ablated away. It's just that the exhaust velocity is much higher.
        king07828 7y ago
        Air from the atmosphere may be the propellant [1]. If sufficient velocity can be achieved before leaving the atmosphere, then no propellant is needed to be carried up on the way to orbit. [1] https://www.youtube.com/watch?v=XhUasBcoj-Q https://www.youtube.com/watch?v=XhUasBcoj-Q
    - jccooper 7y ago
      Nuclear would be better, but it's not quite as good as it seems. Nuclear engines are rather heavier than chemical.
deleted 7y ago
[deleted]
Already__Taken 7y ago
if gravity were much more we'd be out of chemical reactions that produce the energy to beat the rocket equation.
- api 7y ago
  This is a possible Fermi paradox answer, or at least factor. Maybe the vast majority of habitable worlds are larger than Earth. The inhabitants of those worlds might find space flight too hard or even impossible. They also might have less interest in it since they would make the natural anthropic assumption that worlds capable of supporting life are probably huge like theirs.
  - derekp7 7y ago
    That really makes a lot of sense. Because planets smaller than Earth cool a lot faster, so they lose their molten core and plate tectonics (which keeps land mass rising and out of the water), and also a magnetic shield that keeps the atmosphere from stripping away (like Mars).
    - JohnJamesRambo 7y ago
      I'm going to be hopeful and optimistic and point out that the large planets in our solar system aren't rocky and suitable for life as we know it anyway. Earth is the biggest one and the rest are gas planets. Maybe planets that harbor life (rocky, liquid water, goldilocks zone closer to the sun) usually have low enough gravity for aliens to escape it. This diagram has some exoplanets on it for size comparison- https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#/media/File:Diagram_of_different_habitable_zone_regions_by_Chester_Harman.jpg https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#/...
    - api 7y ago
      Earth might be right at this threshold of small enough for space flight to be practical (still hard, but practical) but big enough to hang onto water and atmosphere.
uoaei 7y ago
I assume he's relating 1) the force of gravity, composition and distribution of our atmosphere, and incredible velocity required for orbit, to 2) the chemical potential of fuels and the limits of structural strength for materials to carry cargo to orbit. I haven't run the numbers, but he's right: it's pretty hard to get something that can carry itself to orbit. It has to climb out of the atmosphere directly against gravitational force and atmospheric drag, and then as early as possible turn sideways and start accelerating to around 28000kph while making sure the rocket is pointed in the right direction and holding together. You need a lot of propellant to get to that state, which means you have to carry it around until you need it, which means the machine needs to be much bigger than just the cargo, which means that all of your challenges just magnified by many orders of magnitude.
- TheSpiceIsLife 7y ago
  Would it be possible for the numbers to be a bit more difficult to work with so maybe we could go to low earth orbit, but never be able to make it to the moon?
  - JshWright 7y ago
    If you can make it to orbit, you can make it anywhere (it just may take multiple launches to assemble/fuel the spacecraft going elsewhere).
    - fireattack 7y ago
      Wait, really? So what's the deal of first and second cosmic velocity?
      - cyphar 7y ago
        I guess the idea is that if you can make it to orbit (even if you waste all of your fuel), then you could in principle refuel in-orbit (by getting another unmanned rocket with just fuel into orbit) and thus escape the orbit. But yes, you still require more energy (exactly sqrt(2) times as much) to "escape" Earth's gravity entirely than to orbit it with a circular orbit.
happytoexplain 7y ago
I wonder how much this could be mitigated by extra-rocket energy delivered while the rocket is still close to the ground - e.g. a cartoonishly large slingshot.
- drusepth 7y ago
  Or a comically large refueling hose hooked up until it hits orbit. I guess in that case you'd probably be fighting gravity even more trying to push fuel up the hose.
- mey 7y ago
  Ground laser propulsion has been considered. https://en.m.wikipedia.org/wiki/Laser_propulsion https://en.m.wikipedia.org/wiki/Laser_propulsion
- derekp7 7y ago
  There's also using chemical rockets for the first stage, then switching to nuclear for the second stage once clear enough of the ground to minimize fallout. Radiation pollution wouldn't be pleasant, but future advances could potentially minimize that also.
  - marktangotango 7y ago
    NERVA XE was damn near ready to fly during the Apollo era for Mars missions. Would've made a hell of 2nd stage engine. https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA
- sdenton4 7y ago
  Unfortunately, drag force is proportional to the square of velocity... So the slingshot (or railgun or whatever) maybe gives you a nice acceleration at the start, but a LOT of that initial force will bleed off as drag early in the flight in the thick thick low atmosphere. (Consider the difference in difficulty of riding a bike at 15mph vs 16mph and 25mph vs 26mph... 25->26 requires a hell of a lot more effort, all due to drag.)
- wahern 7y ago
enjeyw 7y ago
Ok so doing super-approximate maths: A fully fueled and loaded Saturn V weighs about 3,000,000 Kg, and has a payload of about 40,000 Kg to the moon. So that means once you've put all the bits of the rocket together that collectively give you sufficient thrust to get you to the moon, you've only got about 1.3% left for actual payload. S if earth's gravity had been ~1.3% stronger, then the weight of the "getting us there" bits of the rocket would have left no room for payload. Any more gravity, and we wouldn't even be getting to the moon. Equally, if the earth's gravity had been 1.3% weaker, we could have doubled our payload to the moon (or done things way easier). Contrast that with a Boeing 747 which has 50% of total mass as payload, and so is relatively insensitive to changes in gravity.
- avmich 7y ago
  Some (funny) sources list Saturn-V payload as 140 tons on LEO :) so according to this logic to get to orbit one has plenty of margin. And as soon as the payload is in orbit it uses full value of accumulated speed, so it's used to get further and getting to the Moon is no harder than with Earth...
- JohnJamesRambo 7y ago
  I recently realized that if we got in Jupiter's gravity well we could probably never escape it again. Someone correct me if I'm wrong. The thought made me feel really uneasy.
  - hossbeast 7y ago
    If that were true, it would be impossible to leave the solar system, since everything is currently in the Sun's gravity well, and the Sun is larger than Jupiter. But we have sent probes outside the solar system (did they fully leave the Sun's gravity well yet though? Not sure)
    - davidivadavid 7y ago
      But we didn't send the probes from the Sun.
libtard 7y ago
Well, it'd prevent rockets for sure, we'd only have nuclear pulse propulsion then to get into orbit and that's a lot harder to justify to people than a rocket.
- wolfram74 7y ago
  There's a lot of alternatives, the main constraint is that it has to be built from the ground up, so space elevators are out. I think a dynamic structure such as a launch loop https://en.wikipedia.org/wiki/Launch_loop https://en.wikipedia.org/wiki/Launch_loop would work. Also inflatable towers for launch assist https://en.wikipedia.org/wiki/ThothX_Tower https://en.wikipedia.org/wiki/ThothX_Tower For even kookier options we've got lasers! https://en.wikipedia.org/wiki/Laser_propulsion https://en.wikipedia.org/wiki/Laser_propulsion https://en.wikipedia.org/wiki/Beam-powered_propulsion https://en.wikipedia.org/wiki/Beam-powered_propulsion
sidorares 7y ago
He was talking about rocket reusability, specifically reusing orbital stage. Just reaching the orbit is possible in stronger gravity, but returning back whole stage is already very close to the limits of current material science
wmp56 7y ago
I have another wild guess. Not only we have just right amount of fossil fuels to leave the planet, but also the sun has just right amount of energy to reach the stage when people can move to another solar system.
- tdy721 7y ago
  My guess is the Sun probably has more... it’s really big. What if it’s just like fossil fuels and there’s enough energy there for us to smear ourselves out? Oh cool, kinda like fission then!
duchenne 7y ago
The rocket equation states that the amount of fuel that you need (to send a given payload into orbit) increases exponentially with the escape velocity of the planet: mass of the rocket with fuel = mass of the payload * exp(escape velocity / engine exaust velocity) That is because the faster you need to go, the more fuel you need to use, but now, you also need even more fuel to accelerate the fuel that you just added. So, it becomes exponential. So, if the earth was bigger, its escape velocity would increase, and the amount of fuel needed to power a space rocket would increase (exponentially) so much that it would become unpractical. Vice versa, with a smaller planet it would require exponentially less fuel to reach orbit. The only solution would be to have an engine with a higher exaust velocity. With the current technology, ion engines have very high exaust velocity but low thrust are very energy hungry. The thermal nuclear engines have both high exaust velocity and high thrust, working prototypes have been built, but all projects were boxed 60 years ago because of the fear of an accident.
mpweiher 7y ago
> earth's gravity [..] right on the cusp of rocket flight possibility He didn't actually say that. He was talking about "rapidly reusable orbital rockets" and "fully reusable orbital rocket[s]" being the "critical breakthrough" that's necessary, the "holy grail of space" and the "fundamental thing that's required". So fully and rapidly reusable. https://youtu.be/sOpMrVnjYeY?t=1234 https://youtu.be/sOpMrVnjYeY?t=1234
sidcool 7y ago
Gravity is taxing. It's possible that our galactic neighbors live on a larger planet with greater gravity which makes their escape from the planet next to impossible.
- silasdavis 7y ago
  Can we swing by and drop them a ladder?
  - sidcool 7y ago
    If we get sucked by the gravity, we are stuck as well.
    - silasdavis 7y ago
      Presumably we'd need to lower it from geostationary orbit. This is a unique solution though I suppose there is some dependency on the mass of the planet where you might be too deep in the well. But you'd be in orbit so presumably some low thrust low propellant engine powered by sunlight ought to be an option?
kromem 7y ago
Hmmm... That's actually really interesting to think about from the anthropic principle perspective. Very interesting that the only intelligent species we are aware of is on a planet that we can leave. I wonder to what extent higher gravitational planets could sustain love that couldn't leave it. An interesting answer to Fermi's paradox.
- htfu 7y ago
  Nah, again - nuclear. I doubt the safety profile would factor much once it's the only available option.
  - mrfusion 7y ago
    Don’t forget ground based propulsion too.
hoorayimhelping 7y ago
That is pretty much all there is: If earth was more massive, the chemical rockets we've been producing wouldn't have enough thrust-to-weight ratio to reach orbital velocity (about 25k km/h). We would have to load the rockets with so much fuel to break free of gravity that they would be too heavy to lift themselves. This is all assuming yields and fuels we have now. If we lived on a more massive earth and we were trying to escape its gravity, I'm sure we'd be using more exotic and dangerous fuels (like all those fun fluorine and boron fuels Dr. Clark mentions in Ignition![0]) to do the job. We just happened to have the capability in the middle of the century to use a fuel we were already making (refined petroleum) for jet engines. [0] https://www.amazon.com/Ignition-Informal-Propellants-University-Classics/dp/0813595835 https://www.amazon.com/Ignition-Informal-Propellants-Univers...

superkuh 7y ago

The most surprising thing to me was nixing the transpiration cooling with methane and switching back to heat shielding tiles for half of it.

mabbo 7y ago
It was such a cool idea, but I imagine it was going to be very hard to make it work.
- superkuh 7y ago
  Reusable heat shielding tiles are also very hard.
  - lukebuehler 7y ago
    Could it be easier compared to other rockets/shuttle since the space ship is made out of steel?
    - nickik 7y ago
      It makes it a bit easier because as Elon mentioned the steel structure can get much hotter without it being an issue. This makes it easier to connect the tiles directly to the ship. However still the primary problem is still to have some surface that can handle the heat without deterioration over multiple flights.
- geuis 7y ago
  Exactly. Say you land on the Moon and your ship sticks around for a few months. Micrometeorites can impact and cause minor damage to the surface cooling system. You’re baked at that point. But given the hull is stainless steel repairs are much easier. Any experienced welder can spot repair divots and holes or weld in much larger patches. No need to worry about the specially constructed parts required for evaporative cooling. Fix the hull then install replacement tiles.
SEJeff 7y ago

mabbo 7y ago

"We could see people flying next year". O_O This is "Elon Time" at its best, but worth keeping in mind how fast Starship development has actually gone. Elon Time is becoming more realistic.

smashem 7y ago
Why has it taken so long to get people on-board the Dragon Crew Capsule? Isn't it mostly because of all the safety testing that has to be done? Didn't get the chance today to hear about Starship's safety mechanisms.
- thunderbird120 7y ago
  NASA requirements + lack of full reusability. It's a lot easier to vet safety through large numbers of tests if you can launch much more often and at a much lower cost which is what they want from Starship.
- tus88 7y ago
  Because one blew up.
  - TheCraiggers 7y ago
    I doubt it. Everyone knows that this shit is dangerous. It's not a question of if something bad will happen, it's a question of how often. There's some pretty gnarly diminishing returns on proofing these beasts, but SpaceX has a huge advantage over the boosters that NASA used- they're reusable so getting a few extra 9's of safety is not necessarily a waste. Of course, the non-reusable boosters had an advantage too where they were only subjected to the insane stress of a launch once, but I'm guessing that's a smaller advantage than what I said above or else we wouldn't have modern airlines.
eugenhotaj 7y ago
I have not seen the presentation yet. Still, I am willing to bet anyone a non-trivial amount of money that we do not see people flying next year.

gouggoug 7y ago

What a painful presentation to watch. Musk really needs to either work on his public speech or delegate them to someone comfortable. His product reveals could be so much more impactful and inspiring did he not jump between points he's trying to make and stutter his way through the entire presentation.

zaroth 7y ago
Yeah, he’s given hundreds of these presentations but he “needs to work on it”? Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires.
- umeshunni 7y ago
  > Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires. That's how you get WeWork.
  - dmix 7y ago
    There's hundreds of millions of smooth talkers. Only a few WeWork type companies...
- gouggoug 7y ago
  > he’s given hundreds of these presentations but he “needs to work on it” Giving "hundreds of these presentations" is not a measure of one's ability to present well. So, yes. On delivering them. He's really hard to follow. Musk is a bad speaker. That fact doesn't diminish in any way what he has accomplished. > Take this as inspiration that’s its not just all smooth talking bullshit artists who get to become billionaires. Well, sure. I'd rather have more Musk than more Neumann; but that literally has nothing to do with the opinion I was expressing.
  - kjksf 7y ago
    His presentation was great. You're just judging him by the most superficial attribute: the cadence of his speech. An attribute that he cannot change, btw, because that's how he speaks. The content was great. He knows what's he's talking about, he's direct, he doesn't bullshit and what he talks about is inspiring. Starship presentation was 10x better than, say, the polished and perfectly delivered Apple keynote full of cliches like "this is the best Foo we've ever done".

strainer 7y ago

I do find this to be actually legendary. At a target rate of about one per month, he is set to produce stainless steel, rapidly reusable, 150-ton-capable Mars transports. And is doing this using currently "about 5%" of the resources of his own commercially built satellite launch company, grown from scratch in a decade or so and out-performing every other nations satellite launch programs - by a large margin. His presentation is noticeably a little self-concious, but not so much as to obscure his enjoyment to be standing in front of the first massive shimmering yet wielded and dented together rocket ship, which is due to demonstrate lift off and landing in a month or so.

lettergram 7y ago
I had the same thoughts watching that.m - it’s been 17 years, but the company is amazing. Each rocket contains as much pressurized space as the ISS. I do however think the “rapid reusability” thing is going to be a challenge. He mentioned 20 flights a day for the booster and 6 (or so) for the starships. I expect 1 per day tops, still exceedingly impressive, but once one of these blow up (or hopefully before) they’ll have heavy pre-flight inspections. Starting off id hope for heavy inspections, then following a period of no error inspections could be reduced.
aiyodev 7y ago
Let's hope Musk can produce something other than investment theater.
- grey-area 7y ago
  He has, at multiple companies.
- tdy721 7y ago
  Go watch the landing fail reel, or Crew Dragon blow up. I guess you’re on team Starliner goes first? An electric car in solar orbit? He’s actually trying to conquer space! Go stink on the Solar City deal, but leave the rockets alone. He produced a real working reusable ICBM booster!

stevebmark 7y ago

It's time for Elon to step down as the face of SpaceX. He ruins every presentation he's involved in. I can't imagine how awkward it was to be there in person and be help prisoner by a completely unprepared, rambling, lazy talk for over an hour.

agildehaus 7y ago
Most of the SpaceX community thinks it's awesome to not have some polished person up there who knows next to nothing about what they're talking about, and he's been doing it during the entire duration of SpaceX's unbridled success. So, no?
russdill 7y ago
SpaceX has plenty of flashy speakers and uses them appropriately.
jordanthoms 7y ago
You're not the target audience for this presentation. It's goal was to provide an information dump for the people who have been closely following the project, and it achieved that extremely well. It's not aimed at the kind of person who prefers a flashy presentation over substance, which in this case is extremely rapid progress towards the most capable rocket humanity has ever built.
- jakeinspace 7y ago
  Considering the amount of time he spent explaining rudimentary spaceflight concepts (getting to LEO is about speed not altitude, who knew?), I wasn't sure how technical this was going to be.
remontoire 7y ago
Totally agree, no one has ever been inspired by this man! In fact, he has actively put spaceflight back 50 years by making everyone disinterested in going to mars. What we need are more people in suits who give us made up numbers.
7y ago

SomeOldThrow 7y ago

Is there a transcript somewhere?

_Microft 7y ago
Sure, go to the video on Youtube [0], click the three dots menu on the right hand side below the video and open the transcript from there. This loads all of it at once, so you can even search through it with your browser's in-page search function! Clicking a line in the transcript jumps to the correct position in the video. It might be the most amazing feature that Youtube has. [0] https://www.youtube.com/watch?v=sOpMrVnjYeY https://www.youtube.com/watch?v=sOpMrVnjYeY
- deleted 7y ago
  [deleted]
- SomeOldThrow 7y ago
  There is a transcript that youtube provides.

snrji 7y ago

SpaceX always beats my expectations, unlike Tesla.

growlist 7y ago

A couple of takeaways for me: 1. oldspace and its supporters, if they have a clue, should be even more terrified than before by the scale of the vision. Even if only a percentage is achieved the disruption should be shattering 2. the unspoken juxtaposition between Musk on the one hand - on the face of it unpolished and light-hearted to the point of flippancy about a topic no less grand than the destiny of humanity, yet in reality visionary, fiercely determined and stunningly successful, and proceeding with at least as stated altruistic goals; and oldspace on the other - polished, solemn, pompous, claiming the sole capability and privilege to act as gatekeepers to space, yet in reality outdated, inefficient, outclassed, and acting like a resentful dog-in-the-manger in response to SpaceX. There's something tragicomic, almost Shakespearean about it all

Lanzaa 7y ago
I don't think any of "oldspace" are terrified by the Starship. I would bet they are almost as excited as SpaceX. SpaceX's improved launch capabilities will not kill off "oldspace" companies. Mainly because access to space is a national/military security issue. The launch providers for China, Russia, India, and the EU will continue to exist, if only because those entities don't want to be beholden to SpaceX for their access to space. If anything I would expect an increase in funding to some of those "oldspace" launch providers as countries try to catch up with SpaceX's technology.
- growlist 7y ago
  > I don't think any of "oldspace" are terrified by the Starship. I would bet they are almost as excited as SpaceX. Not so sure about that - ESA's saltiness suggests they are not thrilled: 'Asked about how the Ariane 5 compares to lower-cost alternatives on the market today, such as SpaceX's Falcon 9 rocket, Stefano Bianchi, Head of ESA Launchers Development Department, responded with a question of his own. “Are you buying a Mercedes because it is cheap?” Ranzo, sitting nearby, chimed in and referenced the India-based maker of the world’s least expensive car. As he put it, “We don’t sell a Tata.”' You are correct that it won't kill off oldspace, but the pressure to change will be inexorable: it's not difficult to foresee a scenario where commercial work all goes to SpaceX, apart from situations where companies are forced to use a national provider; but even then, those companies will thus be forced to eat the cost of subsidising an inefficient provider, which will lower their profits making them less competitive, etc. There could be a similar pressure when one considers military payloads, i.e., the cheapness of launching with SpaceX offers the US a game changing capability to put materiel in orbit. https://arstechnica.com/science/2018/07/as-the-spacex-steamroller-surges-european-rocket-industry-vows-to-resist/ https://arstechnica.com/science/2018/07/as-the-spacex-steamr...

sveit 7y ago

"One of the really interesting interesting things to contemplate is the total mass to orbit capability of a large reusable system where you have a significant fleet in operation. If you've got something like Starship where you've got maybe 150 tons capable to orbit and the ship can fly, is capable of say theoretically flying four times a day but you know they call it like 75 percent uptime so theoretical three times a day, three hundred sixty-five days a year. So that's like about a thousand flights a year for the ship. The booster can do a lot more than that. This is obviously max theoretical. You've got, you know, 150 tons that service, 150,000 tons to orbit per year per ship. If you've got say ten ships you'd have [...] one and a half million tons to orbit per year. Twenty ships you've got three million tons to orbit per year. I think the total rest of world capacity, if you take all rockets on earth including Falcon, the total capacity to orbit I think is around two to three hundred tons currently. Total Earth capacity to orbit is about two to three hundred tons if all rockets launched at max rate. So we're talking about something that is with a fleet of starships a thousand times more than all earth capacity combined. All other rockets combined would be 0.1% including ours." How is this not massively disruptive to the entire space launch industry?

jccooper 7y ago
It is, and is supposed to be. Elon loves to talk about Mars, but the real story behind this architecture is complete ownership of spacelift until someone else catches up. Then the story becomes enabling actual space industry.
ddalex 7y ago
It is. Three orders of magnitude leaves everybody else in the dust. I wonder if this applies to pricing as well. If we get to single-digit dolar prices pe kg to orbit, a tourist ticket would be easily a couple thousand dollars - equivalent to a business class plane ticket. One more order of magnitude and you can start shipping ready-to-be assembled habitats and fuel factories to Mars. And Boston Dynamics robots to assemble them. At these prices you can start sending empty nuclear reactors for power, and lift heavily shielded nuclear fuels as well. Not puny RTG generators for a couple hundred watts but 1000MW generators that will sustain cities. So many possibilities!
7y ago

tibbydudeza 7y ago

It looks like something from Fallout or Rocketeer ... the space nerd in me is disappointed at the "look" but I really really hope it works.

snoshy 7y ago

I didn't notice this being mentioned in the webcast or in any of the follow-up articles I've read on the presentation: while the timelines for 6-months-to-orbit seem insane, I believe the underlying drive for an aggressive schedule here largely derives from Mars launch windows. [1] We have a launch window to Mars open from July 2020 - September 2020, the tail end of which is almost exactly one year away. Starship will have to be orbit capable well before this window, such that the flight and maneuvering characteristics are understood well enough to reasonably justify taking a crack or two at an unmanned cargo Mars mission within the 2020 window. Musk might not have explicitly mentioned it in the presentation, but I would bet that the Starship teams are internally being driven to these targets. FTA, Musk is quoted in 2017, saying SpaceX was targeting uncrewed Mars missions in 2022, but given his ambitions and depending on the progress of the Starship/Super Heavy, I can see them actually aiming for 2020 such that any failures would still guarantee a path to making the 2022 window. All of this is my own amateur speculation, would love to hear corrections or other ideas. [1] https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_windows https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_win...

Lanzaa 7y ago
I don't think the schedule is aggressive enough for a 2020 Mars launch with the Starship. It is likely that Starship will be capable by then, but the wow factor is missing. I don't think an interesting mission would be ready. Don't forget that Musk's Tesla was already launched to "Mars". So it would be safer and just as impactful to have an interesting mission planned using Falcon Heavy. The only mission I can think of which might be viable is Starship landing on Mars. However I don't think SpaceX would have proven Starship enough to get approval for that.