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Space exploration: Where do we go from here?

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  • TalonsUpPuckDown
    replied
    Originally posted by LynahFan View Post
    Even on airplanes, fewer engines is better....down to a point. If you're flying over water, redundancy is nice. But fewer bigger engines is such a huge cost incentive that the regulating agencies have developed a certification called "ETOPS," (which officially stands for "extended twin operations" but is better known by running industry joke as "Engines Turn Or People Swim"). Without ETOPS, twin engine aircraft have to be within 60 minutes of flight time (on a single engine) of a suitable divert runway at all times. You can get ETOPS ratings to allow longer times, up to 330 minutes, which basically covers 100% of the earth's surface.

    So you can be a less nervous flyer, ETOPS certification is based not only on the design characteristics of the airplane ("how many redundant fuel pumps do you have?") but also on the actual service history of the planes, as maintained by the operator. So if United maintains their planes better and experiences fewer failures as a result, they may be able to get certified for more minutes of ETOPs than American can for the exact same type of aircraft. Going for an ETOPs cert therefore means that the airline has committed to collecting and documenting all the right failure rate data (in perpetuity, not just a one-time thing) to prove to the FAA that ETOPs is low risk - and going to all that trouble is still cheaper than adding a 3rd or 4th engine.
    Fun fact: The 777 was the first aircraft to be ETOPS certified at the time of first customer delivery. https://www.amazon.com/Twenty-First-.../dp/0684807211

    Leave a comment:


  • dxmnkd316
    replied
    Originally posted by MichVandal View Post

    Most of his money is in value of stock, and that can very much take a dump. And these huge rocket launches have to be incredibly expensive, moreso that they have to keep repeating them to reach ALL of the steps they need to reach before a real launch.

    We have to hope for the other launch businesses start taking business from X. Once there is real business for launches, their monopoly goes very much away.
    100% agree.

    Leave a comment:


  • MichVandal
    replied
    Originally posted by Handyman View Post

    He could never blow through his money...legitimately I am not sure it is possible.
    Most of his money is in value of stock, and that can very much take a dump. And these huge rocket launches have to be incredibly expensive, moreso that they have to keep repeating them to reach ALL of the steps they need to reach before a real launch.

    We have to hope for the other launch businesses start taking business from X. Once there is real business for launches, their monopoly goes very much away.

    Leave a comment:


  • Handyman
    replied
    Originally posted by MichVandal View Post

    Tesla died a a very poor man even though his innovations were more significant than Edison. So if elmo dies a poor, obscure person, well...

    It wasn't until much later that he got credit.

    If elmo keeps going like this, he will certainly blow through all of his money really quickly.
    He could never blow through his money...legitimately I am not sure it is possible.

    Leave a comment:


  • Jimjamesak
    replied
    Originally posted by dxmnkd316 View Post

    Honestly, and I don't mean to oversimplify this, this is the kind of remedial stuff you can learn in KSP. Which is why it's so infuriating that SpaceX is repeating these dumb... I'm trying to find a word because 'mistakes' isn't appropriate, these are fairly well-known concepts and it's like they're trying to prove them wrong. Which is... expensive.
    Muskrat hates Kerbal Space Program confirmed.

    Leave a comment:


  • MichVandal
    replied
    Originally posted by Handyman View Post
    Ego is part of it...in the need to be seen as the genius who revolutionized space travel and so on. If Elmo and crew just update what came before them they will be seen as heroes but not above those that came before. If you come up with something new now you are on the level of the greats.

    Elmo doesn't want to be some no named NASA engineer that is forgotten to history...he wants to be Edison or Tesla. A name that will always be known.
    Tesla died a a very poor man even though his innovations were more significant than Edison. So if elmo dies a poor, obscure person, well...

    It wasn't until much later that he got credit.

    If elmo keeps going like this, he will certainly blow through all of his money really quickly.

    Leave a comment:


  • LynahFan
    replied
    Even on airplanes, fewer engines is better....down to a point. If you're flying over water, redundancy is nice. But fewer bigger engines is such a huge cost incentive that the regulating agencies have developed a certification called "ETOPS," (which officially stands for "extended twin operations" but is better known by running industry joke as "Engines Turn Or People Swim"). Without ETOPS, twin engine aircraft have to be within 60 minutes of flight time (on a single engine) of a suitable divert runway at all times. You can get ETOPS ratings to allow longer times, up to 330 minutes, which basically covers 100% of the earth's surface.

    So you can be a less nervous flyer, ETOPS certification is based not only on the design characteristics of the airplane ("how many redundant fuel pumps do you have?") but also on the actual service history of the planes, as maintained by the operator. So if United maintains their planes better and experiences fewer failures as a result, they may be able to get certified for more minutes of ETOPs than American can for the exact same type of aircraft. Going for an ETOPs cert therefore means that the airline has committed to collecting and documenting all the right failure rate data (in perpetuity, not just a one-time thing) to prove to the FAA that ETOPs is low risk - and going to all that trouble is still cheaper than adding a 3rd or 4th engine.

    Leave a comment:


  • Handyman
    replied
    Ego is part of it...in the need to be seen as the genius who revolutionized space travel and so on. If Elmo and crew just update what came before them they will be seen as heroes but not above those that came before. If you come up with something new now you are on the level of the greats.

    Elmo doesn't want to be some no named NASA engineer that is forgotten to history...he wants to be Edison or Tesla. A name that will always be known.

    Leave a comment:


  • MichVandal
    replied
    Originally posted by dxmnkd316 View Post

    Honestly, and I don't mean to oversimplify this, this is the kind of remedial stuff you can learn in KSP. Which is why it's so infuriating that SpaceX is repeating these dumb... I'm trying to find a word because 'mistakes' isn't appropriate, these are fairly well-known concepts and it's like they're trying to prove them wrong. Which is... expensive.
    Exactly. Why reinvent the wheel? Even the wheels that you already developed.

    Seems more ego than logic driven.

    While the Soviets had to learn the hard way that so many engines is a real problem- they did it that way as it was the fastest solution given they had those engines developed for their ICBMs. Given NASA and the USAF were not the same body, and there was no way the USAF would want their ICBM engines public- NASA had to start from scratch.

    Leave a comment:


  • dxmnkd316
    replied
    Originally posted by aparch View Post
    Modularity is also why a space station waypoint or "gas station" on the Moon has always been considered for flights further into space: its easier to throw a bunch of smaller items into orbit/park on the Moon than it is to drag everything out to Mars with us.
    Easier and if an entire flight fails, you aren't starting from scratch. It's compartmentalizing the risk. You do this every time you bake a cake and crack eggs into a small bowl instead of adding directly to the mixing bowl.

    Leave a comment:


  • aparch
    replied
    Modularity is also why a space station waypoint or "gas station" on the Moon has always been considered for flights further into space: its easier to throw a bunch of smaller items into orbit/park on the Moon than it is to drag everything out to Mars with us.

    Leave a comment:


  • dxmnkd316
    replied
    Originally posted by MichVandal View Post

    There's also a "smarter, not harder" aspect, too. Looking back into history, NASA originally thought of the concept of a huge ship that lands and takes off from the surface of the moon. And then they calculated how much that would take in terms of thrust and fuel. IIRC, it took more than a lb of additional fuel to each lb of mass going to the moon, let alone the needed thrust. It was not a linear relationship. And going to Mars is even worse.

    That's why instead of a massive body to go to the moon and back, it was modular, and only the tiny command module was designed to get back to the earth's surface.

    It's a massive problem.

    Another "smarter" thing to do is to not have one single body launched. SpaceX has gotten proficient at orbital connection, right? So instead of one massive rocket, launch two smaller ones. Or even three. Have a command module, then a living module, and perhaps a rocket module launched separately. They could pretty easily do this in a day.

    And one more "smarter" is to add complete booster rockets. Like Space Shuttle did- and it's pretty common for launches outside of earth orbit these days. This is the one that is probably the most curious thing now- SpaceX has done this already. They have launched rockets where the two side booster rockets landed near the launch pad, and then the main segment landed on a barge in the Atlantic.

    Basically, there are multiple ways to the solution over the single out and back space craft.
    Honestly, and I don't mean to oversimplify this, this is the kind of remedial stuff you can learn in KSP. Which is why it's so infuriating that SpaceX is repeating these dumb... I'm trying to find a word because 'mistakes' isn't appropriate, these are fairly well-known concepts and it's like they're trying to prove them wrong. Which is... expensive.

    Leave a comment:


  • aparch
    replied
    I wonder if part of the problem is the volatility of the fuel used. The Apollo F1 and SpaceX Merlin Engines use Liquid Oxygen. Starship's Falcon engines use Liquid Methane.


    But overall, more powerful engines and less of them are much more successful than throwing a sh**ton of lower powered engines on a rocket.

    Leave a comment:


  • MichVandal
    replied
    Originally posted by Kepler View Post
    How do you do fewer engines and get the same thrust? More powerful engines? Or can you "work smarter, not harder"?
    There's also a "smarter, not harder" aspect, too. Looking back into history, NASA originally thought of the concept of a huge ship that lands and takes off from the surface of the moon. And then they calculated how much that would take in terms of thrust and fuel. IIRC, it took more than a lb of additional fuel to each lb of mass going to the moon, let alone the needed thrust. It was not a linear relationship. And going to Mars is even worse.

    That's why instead of a massive body to go to the moon and back, it was modular, and only the tiny command module was designed to get back to the earth's surface.

    It's a massive problem.

    Another "smarter" thing to do is to not have one single body launched. SpaceX has gotten proficient at orbital connection, right? So instead of one massive rocket, launch two smaller ones. Or even three. Have a command module, then a living module, and perhaps a rocket module launched separately. They could pretty easily do this in a day.

    And one more "smarter" is to add complete booster rockets. Like Space Shuttle did- and it's pretty common for launches outside of earth orbit these days. This is the one that is probably the most curious thing now- SpaceX has done this already. They have launched rockets where the two side booster rockets landed near the launch pad, and then the main segment landed on a barge in the Atlantic.

    Basically, there are multiple ways to the solution over the single out and back space craft.

    Leave a comment:


  • MichVandal
    replied
    Originally posted by Kepler View Post
    How do you do fewer engines and get the same thrust? More powerful engines? Or can you "work smarter, not harder"?
    F-1.

    If I do my calculation right, one of the Spaceship motors generates 515k lb of thrust each, the F1 makes 1,750k lb of thrust each.

    So instead of 30 motors to get right, you need 10.

    And there was an update "design" to the F1 that should make it easier to make. With X's experience, they should be able to do even better as well as make sure it's re-light able.

    Leave a comment:

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