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This is great but... what are they goig to do with so many Raptors? SpaceX is following a "fully reusable" strategy, I am not even sure if the BFR booster has

• jvanderbot 4y ago
  The bigger rockets use many engines, and for NASA applications, may not be coming home. So, deep space / Mars will be littered with raptors in 20 years, I bet.
  • adgjlsfhk1 4y ago
    I doubt it. Raptor isn't a great deep space engine. It's ISP is a good bit lower than hyrdalox engines.
    • bryanlarsen 4y ago
      Hydralox is worst of both worlds. To get out of gravity well thrust/weight is key, and Raptor is king at that. In deep space ISP is key, and ion thrusters are way more efficient than hydrolox at that. People don't realize that SpaceX is perhaps the world's largest manufacturer of ion thrusters since they use them on Starlink.
      • avmich 4y ago
        Storage time is also important, and it's likely easier to store long term (Earth-Mars flight time is months) mid-cryogenic LOX and liquid methane rather than deep-cryogenic LH2.
      • adgjlsfhk1 4y ago
        "To get out of gravity well thrust/weight is key" this isn't really true. TWR matters a lot for the first stage, but by the seccond stage, higher ISP and lower TWR is worth it as long as thrust is reasonable. ion thrusters are great for light unmanned probes but anything heavy needs higher thrust and hydralox is key for that. Ion propulsion is also pretty much worthless past jupiter since you can't get enough electricity.
        • bryanlarsen 4y ago
          Past Jupiter hydrolox is unusable because of boil-off issues. The best option past Jupiter is nuclear electric, aka ion propulsion. If you need both thrust & efficiency, a large number of ion thrusters is often a good option.
    • Me1000 4y ago
      ISP is like fuel milage, and the economics change drastically when there's infrastructure in place. Having an abundant source of propellant near a celestial body with a much smaller gravity well (Mars) could easily change the economics and practicality of which fuels make sense for different missions. Put another way, we might one day look at Starship as a big rig semi truck (though the ISP of Raptor is actually really good while a big rig's is very much not). The fuel efficiency isn't really that important. I think (or hope at least) we're far away from being able to really see how much space access is going to change if Starship actually pulls off what they're trying.
      • adgjlsfhk1 4y ago
        The big difference between ISP and millage is that ISP has exponential effects.
    • jvanderbot 4y ago
      Yes, but the economy of scale makes it much better than alternatives for now. (Cost wise).
• LanceJones 4y ago
  My opinion... they are going to drive down costs through economies of scale. Musk and Shotwell want to continue to drive donw the cost of getting payload to orbit.
• cryptoz 4y ago
  The Mars plans are medium-term, though, and they need many thousands of Starships+Boosters for that plan to work. In the short-term, SpaceX is 'behind' on launching Starlink, especially v2 which is needed to fulfill the promises of the network and be profitable (and v2 can only launch on Starship). In the short term, they need hundreds of full stage rockets, and in the medium term, thousands. That's tens of thousands of engines needed in the next ~10 years. I don't think 1/day is fast enough and I'm sure they will increase that rate as soon as possible. Also for testing, SpaceX doesn't want to be afraid of blowing up rockets and losing engines, so the first few hundred engines will likely not be reused.
  • tsimionescu 4y ago
    That plan will not work, as there is nothing that could possibly be gained by flying thousands of rockets to Mars: there is nothing worth having on Mars.
    • Moissanite 4y ago
      This is what baffles me about the current space-travel fetish. We know what's up there - basically nothing at all. Even if you go to another planet and mine for raw materials, bringing material back isn't even remotely economically feasible and is unlikely to become so in any of our lifetimes. Going to space in the 1960s made sense from the perspective of scientific advancement, and let's be honest, showing off. Now, we realize that the world has serious problems - but the people with influence are decidedly un-serious and so would rather continue to show off instead of fixing the mess they helped to create.
      • terafo 4y ago
        > even remotely economically feasible Depends on what exactly are you mining and whether it is possible to make fuel out there. And with launch cost falling drastically I expect to see this in my lifetime.
      • nickersonm 4y ago
        Why would you want to bring it back? There are literal gigatons of useful material 'up there', perfectly usable in-place (or anywhere that's not down a well) with low effort. Even with Starship, it's easier to use resources at the destination rather than boost them up.
• idontwantthis 4y ago
  For one thing, they are starting with expendable starships, so they can get Starlink V2 up faster.
• fabian2k 4y ago
  A full Starship will require 39 engines, and they will likely lose some during development. Even with a raptor a day that is less than 10 Starships a year. Of course if it is fully reusable and doesn't explode too often even 10 per year will be too much production (unless large-scale Mars colonization missions actually happen ). But it will take time, and for the meantime SpaceX does need to build up a fleet of Starships, and that takes a lot of engines.
  • mrtree 4y ago
  • prox 4y ago
    And that’s exactly the plan for SpaceX, a whole fleet of Starships. Mentioned by SpaceX and Elon Musk.
  • hinkley 4y ago
    “Fully reusable” is still a little wiggly. Cars are fully reusable and they still get replaced after 150k miles. Are we going to begrudge someone calling it reusable if they have a MTBF of 10 flights? Or at least, as long as partial failure results in a successful mission but a decommissioned engine or unibody? You’d use your whole manufacturing capacity then to do 90 missions a year.
    • zlsa 4y ago
      There's not a huge number of datapoints yet, but there are several Falcon 9 boosters that have flown >10 times (including two that have flown 14 times.) I'm quite confident in Super Heavy at least handily exceeding 10 flights MTBF.
      • hinkley 4y ago
        MTBF is mean time. So “a few over 14” isn’t anomalous if the mean is ~10. In fact it’s a bit low.
    • mlindner 4y ago
• anonporridge 4y ago
  > We only need so many launches, especially super heavy rocket launches before we run out of payload. Why do you believe this is true? It's entirely possible that there's a massive amount of unmet demand that's only economically feasible at lower price points that SpaceX is beginning to unlock with reusability and economies of scale. Even SpaceX themselves is a huge customer with Starlink. An extremely low cost of launch not only means that you can put drastically more satellites up, but you can put them in lower orbit where they will have a shorter lifespan, because they decay orbit and burn up exponentially faster, mitigating the risk of Kessler Syndrome. You can also iterate the satellites much faster as technology advances and waste less time making sure that the satellite is 'perfect' because you only have one shot at launching a JWST after 20 years of work. On that note, why is one Hubble or JWST enough? We probably need hundreds if not thousands of them if we want a sufficient observation coverage to be fully away of all extraterrestrial (asteroids and commets) threats that might be coming our way.
  • fabian2k 4y ago
    Starship will certainly enable some new things we could not do before, or that were simply not economically feasible. But even then there is likely still a severe limit to the demand for launching payloads. All those payloads cost serious money, and while you can save a significant amount by removing the necessity for very lightweight construction due to the enormous capacity of Starship, this might only move stuff from "extremely expensive" to "very expensive".
    • avmich 4y ago
      > But even then there is likely still a severe limit to the demand for launching payloads. The Starship is about changing the approach, not applying state of the art to a changed parameter. Currently there is a limit. After Starship is offered on the market, that limit may significantly change, as its main reason to exist is the high price of the launch services. > All those payloads cost serious money Right, but if you, say, are going to send off-the shelf - or, ok, almost off-the-shelf :) - Caterpillar to the Moon, the payload cost suddenly drops. This is exaggerration, of course, but the idea is that payloads may become much - orders of magnitude - cheaper to produce.
• joakleaf 4y ago
  So Elon Musk is aiming for 1000 starships towards Mars before 2050. 100/year over 10 year period (or something like that). Each booster uses about 33 Raptors, and each Starship uses 6. I assume the boosters can be reused between launches to some extend. So they might not need 100 boosters. But you'll need more than 100 ships active; I assume they wouldn't launch 100/year, but rather 200 every 2 years (due to the 26 month launch windows to Mars). Not sure about the return windows and strategy. That's at least 200 ships (1200 engines) you need active at any given time + boosters + refueling vessels (Each launch will require 6-9 refuels in orbit). Additionally, there is the whole Earth-to-Earth transport idea (i.e. New York to Tokyo in 50 minutes).
• armatav 4y ago
  Need thousands of Raptor engines over the next 5-10 years. Payload will not run out, demand is there (Starlink, military etc.)
• ugh123 4y ago
  I think NASA's point is that it's looking for reliability in manufacturing and reliability in the field. Being able to produce AND TEST the engines rapidly will drastically improve both of those fronts. If you're only able to make 4 a year (as does Rocketdyne, as mentioned in the article) then your ability to respond to failures during testing is abysmal at best. Also your ability to optimize and improve, simplify, harden, etc the manufacturing process and drive costs down also sucks. Slow iteration for testing and enhancing rocket engines has been the bane of the industry since inception.
  • biomcgary 4y ago
    As a kid, I read about Goddard and the early days of rocketry, which was a bit wild. Does anyone know of a good history that touches on the factors that contributed to the increasingly slow iterations in the field prior to SpaceX? My fuzzy knowledge of Mercury, Gemini, and Apollo missions suggest that they were fairly fast moving. Was the Space Shuttle era when iteration slowed down?
    • terafo 4y ago
      A lot of things happened. Apollo 1 disaster, end of space race, space shuttle not hitting enough launch volume and having unclear requirements, Challenger and Columbia incidents which skyrocketed shuttle between-flight maintenance, continued failure of NLS>Constellation>SLS.
      • bumby 4y ago
        This seems correct. Things move fast until something bad happens; then layers and layers of oversight are added to avoid bad things happening again. Years go by without bad things happening and people begin to wonder why we need so much oversight so they begin to peel them back. Rinse and repeat. In that context, a major mishap is a very big risk to SpaceX because it can erode their efficiency. One of the advantages of the CCP approach is that there is much less oversight, so things can move quicker. I'm not so sure NASA will be okay with that if they lose an astronaut.
• brandonagr2 4y ago
  What are they going to do with so many Raptors? Launch fleets of hundreds of starships at a time to colonize mars.
  • yamtaddle 4y ago
    In practice, I expect much of the answer will end up being "militarize space a whole bunch more". I don't think anyone's expecting anyone else to actually abide by all those space-related treaties if there's another Great Powers war. Which, this century, means only one pairing: the US and China. More surveillance, satellite kill vehicles with perhaps a little plausible deniability, dark, redundant GPS and comm sats, maybe some new, secret constellations at novel orbital heights for when all that debris gets spread around the lower orbits and screws everything up... maybe not actual space-based ground-targeting or anti-ICBM weapons, but then again, countries do cheat on treaties.
    • yamtaddle 4y ago
      I'd encourage anyone bothered by this post (evidently, someone was) to check out the stats on past and upcoming SpaceX contracts. The overwhelming majority are the US military and NASA, and the US military's share isn't far behind NASA. Seems clear to me the smart money is on "same stuff, but more of it" if they bring costs down even farther. And I'd say the US military's got more room in the budget to quickly put together useful payloads than NASA does, if the prices drop, which narrows it down to "mostly more military stuff". And especially if Starship gives them the ability to put large payloads in higher orbits on the cheap. I bet they've got filing cabinets and skunkworks warehouses full of shit they'd love to build/finish and launch as soon as the costs work out. But maybe I'll be surprised and military launches will remain about the same while StarLink competitors and elementary school students launching cubesats will eat up all that new, cheaper capacity.
• bdamm 4y ago
  Elon keeps hinting about competing with airliners for trans-oceanic flights. My bet is that Starship is going to become the suborbital trans-oceanic machine that shrinks the world in a way not seen since the airliner was invented.
  • deusum 4y ago
    Everyone be nice to Grandma! She pulled 9Gs out of Khazakstan just so she could see you on Christmas day. And she has to cruise back in the Morning! Talk about rocket lag
  • semi-extrinsic 4y ago
    If there is one thing we desperately need to avoid as a society, it's developing new technology that burns massive amounts of hydrocarbons to make rapid travel anywhere (somewhat) cheap and ubiquitous.
  • orbital-decay 4y ago
    So, basically Concorde, but worse and more restricted. Needs a launch site remote enough to not drive everybody crazy with the noise (Shuttle launches could have been heard dozens of miles away), and a secure trajectory to not kill anybody on the ground if things go bad. Not even talking about reliability, g-loads, and many other things. You can't jump from Mayfair, London to Manhattan with this system, at which point any flight time improvement becomes negligible.
    • adamsb6 4y ago
      High speed ferry to offshore platform? That should address both noise and safety. All the check-in gets handled on shore, then a fifteen minute ride out to the platform on a high speed ferry, 20 minutes to onboard, then 30 minutes to any other offshore platform in the world, followed by a 20 minute offboarding, and another fifteen minute ferry ride. The actual travel time would be less than the time you're expected to wait in the airport prior to boarding an international flight.
      • 4y ago
• Symmetry 4y ago
  Give some to ULA just to taunt Bezos? But seriously, I'm not sure why they aren't looking to sell them to other US rocket companies.
• kamaal 4y ago
  Asteroid mining is another very profitable and useful option. We are talking about many trillions to be made, many things to be built, and people who get up there first could end up controlling lots of things for the foreseeable centuries. Think of British East India Company, except the scope is way more than anything we can imagine. If you are a super power, a project like this is something you must absolutely consider.
• mlindner 4y ago
  > We only need so many launches, especially super heavy rocket launches before we run out of payload. And if they build as many rockets as they have engines for, where are they going to store them? What about the launch pads? Etc... The explicit goal, as has been stated several times by SpaceX leadership in the past, is for Starship to eventually cannabalize Falcon 9 and Falcon Heavy launches. They've said they'll keep launching them as long as there is demand for them, but there will be more and more incentive for companies/governments to stop buying Falcon 9 launches. Already SpaceX sells some launch contracts for "arbitrary vehicle" launches where SpaceX can elect to launch the spacecraft on Starship instead of Falcon 9/Falcon Heavy if SpaceX so wishes.