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Thread: Reusable Rockets

  1. #31
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    Quote Originally Posted by cannongray View Post
    As for me, a reusable spacecraft is not quite safe cause it can lead to unforeseen consequences, which, unfortunately, will only be detected at startup.
    Do you apply the same reasoning to aircraft and insist on planes that haven't been test flown?
    The effects of wear and tear can be measured, quantified, and predicted based on real world performance. Issues that happen on startup are most likely to happen on first startup, and a vehicle that has already flown can be expected to have far fewer such issues.


    Quote Originally Posted by cannongray View Post
    Btw, these days most parts are automated, which means it can be much cheaper to make them from scratch.
    An old claim that's looking rather foolish at this point. SpaceX has managed to reduce production costs to levels their competitors can't match, and still sees immediate benefits in cost from booster reuse, in addition to the logistical benefits allowing much higher launch cadence. China, Russia, and the EU are all working on reusable systems in an attempt to catch up.

  2. #32
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    Quote Originally Posted by cannongray View Post
    As for me, a reusable spacecraft is not quite safe cause it can lead to unforeseen consequences, which, unfortunately, will only be detected at startup. Btw, these days most parts are automated, which means it can be much cheaper to make them from scratch.
    Automation covers a wide range of technologies, traditional ones use expensive tooling so that economy only comes with very large numbers.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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  3. #33
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    Quote Originally Posted by Nicolas View Post
    Bathtub theory says that new = unproven hardware is more likely to fail than flight proven. Spacex prices show that reuse is cheaper than new. And they even use 3d printing in their manufacturing.
    I think bath tub Theory applies to mass produced components which allow a probability to be measured. For example bathtub theory is extensively used in production electronics to predict reliability of assemblies of resistors and diodes and so on. It allows burn in time to be used for quantity production in order to avoid the first steep part of the curve, and then predicts when the rate of failure will start to increase with time.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  4. #34
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    If you want to have statistically valid data to base your specific product curve on, certainly. I was naming it in the more general sense that a product is most likely to fail either really early in its life or really late, which speaks against single-use rockets.
    With sufficient thrust, water towers fly just fine.

  5. #35
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    Quote Originally Posted by cannongray View Post
    As for me, a reusable spacecraft is not quite safe cause it can lead to unforeseen consequences, which, unfortunately, will only be detected at startup.
    And yet the empirical evidence says you are wrong. Most recent problems SpaceX have encountered have been with newly made boosters and second stages. After a 100 flightst I think SpaceX have got the consequences of reuse dialled in.

    Btw, these days most parts are automated, which means it can be much cheaper to make them from scratch.
    Which is why SpaceX uses such processes to mass produce parts, in fact they come much closer to having a true production line environment than any of their rivals. Also you are literally missing the big picture. However cheap the individual parts may be when you are throwing away the entire rocket on every flight those manufacturing costs mount up.

    Honestly your argument reads like it was written ten years ago when reuse was still theoretical.

  6. #36
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    I agree with Garrison that it is difficult to argue against the benefits from shifting to reusable rockets today, especially now that they have become routine for SpaceX with others working to catch up.

    In an interview with Harvard Review, one economist, Sinead O'Sullivan commented:
    ".... I mean letís look at the primary cause of the explosion in this market. And it has been a reduction in launch costs. So, whereas it now costs $2,000 Ė roughly looking at SpaceX numbers, $2,500 to launch one kilogram into space. It used to cost upwards of $50,000 with a very, very long lead time. So, with very cheap access to space, people are putting a lot of satellites into space because itís making it, the availability of data much higher and the price of that data much cheaper."

    https://hbr.org/podcast/2019/05/unde...-space-economy

    This is consistent with what I have seen elsewhere. As more and more reusable rocket. launches are carried out the gap with throw away launches is only going to get bigger....

  7. #37
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    Quote Originally Posted by Nicolas View Post
    If you want to have statistically valid data to base your specific product curve on, certainly. I was naming it in the more general sense that a product is most likely to fail either really early in its life or really late, which speaks against single-use rockets.
    Well fair point , there is no way to predict reliability of new components except for field test. But any flight project has all kinds of tests on components, including proof testing where you deliberately exceed predicted loads. So there is no basic argument against multi use, if you can show on the ground, that components survive the loads. In this way rockets are not that different from airframes where components are allocated hours or take off limits, etc, and replaced accordingly. The triumph is that some very hot components used to be assumed single use, or so few minutes survival that reuse cannot be entertained. Then of course the traditional view that lowering a rocket from height onto a controlled point was too difficult. But SpaceX just said “why not?”
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  8. #38
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    I think that someone forgot to tell them it was impossible.

    Quite some players have nailed the trick with suborbital powered landings, but comig back from orbit this way is still a lonely place to be. Certainly the huge cost difference to test orbital return vs suborbital return is a major factor here, where SpaceX had the advantage that they could test basically for free as they had customer paid orbital launches.
    With sufficient thrust, water towers fly just fine.

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    "Europe’s lack of rocket ‘audacity’ leaves it scrambling in the space race"

    A 2014 there was a point they could have gone for reusable rockets but instead chose to go the Ariane 6 route.

    https://www.politico.eu/article/euro...et-space-race/

    Europe knows it needs a booster to keep up with the space race.

    The European Commission wants to rally governments behind France-based Arianespace in the face of competition from upstarts such as Elon Musk’s SpaceX, which has upended the space industry by slashing the cost of launching satellites thanks to its breakthrough in developing reusable rockets.

    Europe is in a tough spot because seven years ago it passed on the chance to develop those kinds of launchers itself, instead opting for conventional technology with its new Ariane 6 rocket. Now the EU is scrambling to regain its footing by pressing European governments to stick with Arianespace for their launches as part of a new alliance between industry and governments.
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  10. #40
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    Quote Originally Posted by selvaarchi View Post
    A 2014 there was a point they could have gone for reusable rockets but instead chose to go the Ariane 6 route.
    Wouldn’t have happened. They had to see it before they could accept it. Heck, I remember reading comments from European “experts” that were saying there was no point in reusability. I distinctly remember at least one was from Arianespace. As I recall, the argument was that it reduced payload too much, there would be too much operational complexity, the hardware would need to be extensively inspected after flight reducing the cost advantage, and given the limited number of launches, it would reduce manufacturing too much to maintain institutional knowledge and manufacturing efficiencies. There was a claim too that demand was highly inelastic so lower costs wouldn’t create more demand.

    So SpaceX made some of their own demand, and it wasn’t as inelastic as thought anyway (they are doing plenty of building), they studied the returned rocket stages and changed the bits that wore out easily, reducing inspection requirements, and used their landing ships to reduce return fuel needs for the missions that required it, and streamlined operations.

    Basically, incorrect assumptions were being made. For one thing, SpaceX went from the block 1 to the block 5 booster design in just a few years. I would bet Arianespace operates much more like American old space manufacturers than SpaceX. Imagine how long it would take and how expensive it would be to iterate SLS like Falcon 9.

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  11. #41
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    Quote Originally Posted by Van Rijn View Post
    Wouldn’t have happened. They had to see it before they could accept it. Heck, I remember reading comments from European “experts” that were saying there was no point in reusability. I distinctly remember at least one was from Arianespace. As I recall, the argument was that it reduced payload too much, there would be too much operational complexity, the hardware would need to be extensively inspected after flight reducing the cost advantage, and given the limited number of launches, it would reduce manufacturing too much to maintain institutional knowledge and manufacturing efficiencies. There was a claim too that demand was highly inelastic so lower costs wouldn’t create more demand.

    So SpaceX made some of their own demand, and it wasn’t as inelastic as thought anyway (they are doing plenty of building), they studied the returned rocket stages and changed the bits that wore out easily, reducing inspection requirements, and used their landing ships to reduce return fuel needs for the missions that required it, and streamlined operations.

    Basically, incorrect assumptions were being made. For one thing, SpaceX went from the block 1 to the block 5 booster design in just a few years. I would bet Arianespace operates much more like American old space manufacturers than SpaceX. Imagine how long it would take and how expensive it would be to iterate SLS like Falcon 9.
    That’s right but the difference is risk. Especially when the first to consider a daring innovation is not spending a personal budget. To embark on a reused booster, means a spend with risk of failure, and the estimates are difficult. Rather like aiming for the moon, you need a person who can say “that’s the goal, let me worry about the budget” . As soon as a committee controls decisions, those risks are not taken.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by cjameshuff View Post
    Do you apply the same reasoning to aircraft and insist on planes that haven't been test flown?
    The effects of wear and tear can be measured, quantified, and predicted based on real world performance. Issues that happen on startup are most likely to happen on first startup, and a vehicle that has already flown can be expected to have far fewer such issues.




    An old claim that's looking rather foolish at this point. SpaceX has managed to reduce production costs to levels their competitors can't match, and still sees immediate benefits in cost from booster reuse, in addition to the logistical benefits allowing much higher launch cadence. China, Russia, and the EU are all working on reusable systems in an attempt to catch up.
    I even drive a reusable car!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  13. 2021-Jan-19, 08:49 PM

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    Moved to another thread

  14. #43
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    Paper cups can be disposable. Baby wipes can be disposable. Toothpicks. Popsicle sticks. (Though even much of what we once habitually threw away is now recycled.)

    But a multi-million dollar spacecraft the size of a skyscraper? Nah.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Wrong thread? LauncherOne isn't reusable.

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    Quote Originally Posted by cjameshuff View Post
    Wrong thread? LauncherOne isn't reusable.
    Have moved it to Small Rocket launches as only the 747 is reusable...

  17. #46
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    Quote Originally Posted by DavidLondon View Post
    Have moved it to Small Rocket launches as only the 747 is reusable...
    So the modified 747 is not a rocket, but does the booster job, and the payload is relatively small. But the combination is not a small rocket from a ground pad. Is it then a class of its own? Noting the 747 can be flown from any suitable airstrip in the world, not like small or big rockets. With the low (ish) cost of small satellites, the successful demo may be quite significant in the near future.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  18. #47
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    China's commercial company iSpace is making progress in reusable launchers.

    https://spacenews.com/chinas-ispace-...ing-leg-tests/

    Last week iSpace also announced progress in developing the reusable first stage of its Hyperbola-2 liquid methane-liquid oxygen propellant launch vehicle.

    The firm carried out tests of struts for landing legs of the first stage, including structural, dynamic and vibration tests, as well as performance in high and low temperatures.

    The components are designed to help absorb the impact of landing following powered descent. iSpace tested telescopic deployment arms for the landing legs in November (Chinese).

    iSpace is planning to conduct hop tests, similar to those of the SpaceX Grasshopper tech demonstrator, in 2021, starting at the level of meters, followed by one-kilometer and 100-kilometer-altitude vertical launch and landing tests.
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  19. #48
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    Quote Originally Posted by profloater View Post
    So the modified 747 is not a rocket, but does the booster job, and the payload is relatively small. But the combination is not a small rocket from a ground pad. Is it then a class of its own? Noting the 747 can be flown from any suitable airstrip in the world, not like small or big rockets. With the low (ish) cost of small satellites, the successful demo may be quite significant in the near future.
    At most, air launch makes the booster a few tons lighter, it doesn't come close to replacing it. The 747's just a flying launch platform, and I'm not aware of any orbital launch vehicle using a non-reusable launch platform.

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    Quote Originally Posted by cjameshuff View Post
    At most, air launch makes the booster a few tons lighter, it doesn't come close to replacing it. The 747's just a flying launch platform, and I'm not aware of any orbital launch vehicle using a non-reusable launch platform.
    I took a further look at alternative threads and concluded that, although the 747 is reusable, clrjameshuff is right re it technically not being a ‘reusable rocket’ and so it should be moved to ‘Small Rocket Launches’ thread where Virgin Orbit’s activity has been covered already. The 747 is launching a small - non reusable but still potentially competitive - rocket which is competing eg in the small satellites market along with its competitors covered in that thread.

    A bit technocratic maybe but thread creep can be a problem.
    Last edited by DavidLondon; 2021-Jan-20 at 07:23 PM. Reason: Correction and clarification

  21. #50
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    Quote Originally Posted by Noclevername View Post
    Paper cups can be disposable. Baby wipes can be disposable. Toothpicks. Popsicle sticks. (Though even much of what we once habitually threw away is now recycled.)

    But a multi-million dollar spacecraft the size of a skyscraper? Nah.
    It really is amazing just how long it took for someone to embrace the idea that simply throwing 100s of millions of Dollars of hardware into the Ocean was a bad business strategy...

  22. #51
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    And how nobody saw the chicken and egg in "with throwaway rockets, it will cost you a midsize country to launch a satellite into orbit, but there is little launch demand so why bother making them reusable". Well, part of the argument likely was that the only example of a reusable rocket was the STS, which due to a variety of reasons was still very expensive and cumbersome. And if you use a single datapoint to draw your conclusions...

    Now, as the amount of satellites is about to increase exponentially, there needs to be extra focus on end-of-life and space debris issues. But that's another discussion, another thread.
    With sufficient thrust, water towers fly just fine.

  23. #52
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    Quote Originally Posted by Nicolas View Post
    And how nobody saw the chicken and egg in "with throwaway rockets, it will cost you a midsize country to launch a satellite into orbit, but there is little launch demand so why bother making them reusable".
    Oh, it was seen. It was even called a chicken and egg problem. I read arguments about it probably thirty years ago. One big issue was that per conventional wisdom it was extremely expensive to build a new rocket, so it was thought that to make a reusable rocket economically competitive required an extremely high flight rate. SpaceX built Falcon 9 for a fraction of the cost it likely would have been if built by an old space company, so doesn’t need as high a flight rate to pay for itself. There is also more demand than there was twenty or thirty years ago, and newer technology gives more ways to reduce rocket cost. And as I mentioned elsewhere, they created some of their own demand with Starlink.

    It generally was thought that demand would grow slowly, so eventually (maybe mid century) reusables would become competitive. It was not believed that demand was currently elastic - they didn’t think lower cost launch would create much additional demand.

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  24. #53
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    Quote Originally Posted by Van Rijn View Post
    Oh, it was seen. It was even called a chicken and egg problem. I read arguments about it probably thirty years ago. One big issue was that per conventional wisdom it was extremely expensive to build a new rocket, so it was thought that to make a reusable rocket economically competitive required an extremely high flight rate. SpaceX built Falcon 9 for a fraction of the cost it likely would have been if built by an old space company, so doesn’t need as high a flight rate to pay for itself. There is also more demand than there was twenty or thirty years ago, and newer technology gives more ways to reduce rocket cost. And as I mentioned elsewhere, they created some of their own demand with Starlink.

    It generally was thought that demand would grow slowly, so eventually (maybe mid century) reusables would become competitive. It was not believed that demand was currently elastic - they didn’t think lower cost launch would create much additional demand.
    My bold, because it has achieved a pretty high flight rate anyway!
    Also, throwaway boosters were largely developed by large aerospace companies for the government. If you make a profit on each one, there's no incentive to reuse.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

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    "'Major reusable launch breakthrough' by private rocket firm i-Space prior to IPO"

    https://www.globaltimes.cn/page/202101/1213057.shtml

    Beijing-based private rocket launch company i-Space announced a key breakthrough in its reusable launch system ahead of a planned IPO, a boost for the nation's commercial space sector, experts said.

    I-Space successfully completed a landing buffer test of its reusable rocket Hyperbola-2, marking an important breakthrough in reusable launch technology, the company said on its official WeChat account on Friday.
    I am because we are
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  26. #55
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    It would be nice if they explained what the breakthrough was supposed to be. Also, they havenít had a test flight yet, which strikes me as important.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." ó Abraham Lincoln

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  27. #56
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    Quote Originally Posted by Van Rijn View Post
    It would be nice if they explained what the breakthrough was supposed to be. Also, they haven’t had a test flight yet, which strikes me as important.
    Do not know but my guess they might tried the 1st of the "SpaceX Grasshopper tech demonstrators". They have been making progress on the landing legs.
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  28. #57
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    Quote Originally Posted by selvaarchi View Post
    "'Major reusable launch breakthrough' by private rocket firm i-Space prior to IPO"

    https://www.globaltimes.cn/page/202101/1213057.shtml
    Yeah when a company announces a big breakthrough right before an IPO I would be very cautious about it, especially when they are being rather vague.

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