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That site indicates they're attempting to launch a human on a suborbital trajectory. What does that have to do with either orbital flight or going to the moon?

by nknight 15y ago

rbanffy 15y ago
If you can get to space, even a suborbital flight, you must have gotten most of the life support right. If you reach orbit, you got your rocket right. If you can change orbits, you got manevering right. If you can stay a week in space, the rest of your life support is OK. All you need now is a second booster to launch you to the Moon. You can either circle it in a free return trajectory, or brake an enter orbit. The orbit part seems the most complicated.
- nknight 15y ago
  Wow. Just wow. Every single system you name is made up of a large number of complex sub-systems designed and built to exacting requirements, and any one of them can still break at any time. Thinking you "got it right" just because it didn't break one time in one set of circumstances is unbelievably naïve. There's a reason all man-rated launch systems have redundant backup systems, and even the fallbacks don't always work right. By the way, let me know when you get micrometeoroid shielding "right" -- every space agency on Earth will want to talk to you. You might even win a Nobel Prize. You're also completely ignoring navigation. Just because you can fire up a rocket doesn't mean shit if you're at the wrong point in your orbit, or pointed in the wrong direction. You're also failing to distinguish between "I can get THIS rocket into orbit" and "I can get a rocket big enough to carry people and a useful payload into orbit and/or to the moon". Think you can just "scale up"? You're wrong. Effects that were too small to measure before will suddenly kill you. Materials that could handle the strain of the smaller rocket will crumble under the increased forces. Oh, by the way, every time the weight or configuration of your spacecraft changes, you're gonna have to rework your navigation assumptions. Might I suggest playing with Orbiter for a while? Once you've done that, spend a few minutes thinking about the fact that you've just been overwhelmed by a vastly simplified simulation in which nothing ever goes wrong. Now picture the real world. Oh, by the way, your heat shield is cracked, but nobody noticed because your budget didn't allow for more than one guy to inspect it, and he was too drunk. Have fun getting home.
  - rbanffy 15y ago
    The original point is that, once you achieve LEO, a free-return tragectory to the moon is just a question of delta-v. And not that much - the Soyuz-based moon roundtrip being offered for US$ 100M is a Soyuz docked with a mini-bus-sized booster stage. Micrometeorites? Did Apollo have that? I am not implying it's easy - I'm implying LEO is the hardest part when it comes to a moon-orbit trip. And in the case of an unmanned craft, it's easier: you don't have to bother with life support, atmospheric braking and most of the radiation shielding.
    - nknight 15y ago
      Except that wasn't the original point at all. It started with Jd saying: "If you want to go to the moon you need a f'ing spaceship and not emacs and an open source notebook. Spaceships are big. They take a lot of people to run, and they have to be smart people. One mistake and you are smithereens at Cape Canaveral." Followed by sedachv saying some guys who are trying to launch humans on suborbital flights would disagree. Nothing you've said explains what suborbital flights have to do with going to the moon. On the contrary, you seem to be admitting they have nothing to do with going to the moon, so I still have absolutely no idea what sedachv's point was.
      - rbanffy 15y ago
        Well... I maintain that the hardest part of going to the Moon is achieving Earth orbit. The rest is, comparatively, easy. But, then, this discussion is completely unrelated to the point regarding emacs and an open source notebook (whatever that is). In general, Jd's rant felt confusing. I am not sure how Lisp and spacecraft are related, BTW. He (or she) implied somehow that you couldn't go to space with something simple and elegant like Lisp, but I can't be sure.
        Jd 15y ago
        Re: open source notebook see: http://stallman.org/stallman-computing.html http://stallman.org/stallman-computing.html I'll make the relation very clear. There is a segment of the Lisp community, which most certainly includes Paul Graham, that maintains that projects with large team sizes are bad. There is a certain logic here, as it is hard to maintain a high average intelligence distributed across a large number of people. Most true geniuses were loners. Regardless, projects of a certain scope (i.e. building a space shuttle) require large teams. You simply can't do it with two guys in a basement. In a certain sense the computer language employed is irrelevant, except that the lisp community has never, largely because of the facts that should be obvious but are apparently not to the introverted "genius" types they pray on, produced good and extensive enough libraries to be viable for most real world tasks. In case you didn't notice, for example, it took what, 4 years for Hacker News to get HTTPS support. I don't want to rib anyone too badly, because I am a strong supporter of what YCombinator is doing in general and in the incorporation of lambdas and closures in newer languages, but I think generally speaking it is clear that the Lisp culture is not to cooperate but to position one's self as some sort of genius and thus to create one's own dialect, etc. I'll give you an example that will probably irritate some people, but is relevant here. Microsoft Word is, in my opinion, one of the greatest architectural marvels of modern civilization. The feature set of that single app is truly extraordinary, and there are all sorts of wonky ways that you can do lots of tasks that makes millions (and potentially even billions) of people's lives better every day. I understand that there is a point to OpenOffice and "fighting the man" and whatever since Microsoft certainly crushed some competitors in mean ways, but realistically there is nothing in the world that competes. Now you might say, oh sure but I can just use vim and use latex for formatting (or even google docs). And in a certain sense you might be right too, but sooner or later you will find a feature that is not accessible to you (I recently noticed that change tracking still absolutely blows in Google Docs compared to Word). Why do I bring this up? Well, even if you are right that "the hardest part of going to the Moon is achieving Earth orbit," you still have to have all of those other things. You need life support or you dead; this is non-negotiable, just in the way that mail merge is not negotiable for millions of people at millions of office worldwide. And if you want life support (or mail merge), you need to work with the people who design these other systems. By the way, I'm not saying you need to like any of this. I'm simply saying that if you want to build something great, you have to at times slog through the mud. My experience with Lispers is they are frequently afraid to get their hands dirty. And that doesn't cut it except in a pretty-ditty fantasy castle.

That site indicates they're attempting to launch a human on a suborbital trajectory. What does that have to do with either orbital flight or going to the moon?

by nknight 15y ago

That site indicates they're attempting to launch a human on a suborbital trajectory. What does that have to do with either orbital flight or going to the moon?

rbanffy 15y ago

If you can get to space, even a suborbital flight, you must have gotten most of the life support right. If you reach orbit, you got your rocket right. If you can change orbits, you got manevering right. If you can stay a week in space, the rest of your life support is OK. All you need now is a second booster to launch you to the Moon. You can either circle it in a free return trajectory, or brake an enter orbit. The orbit part seems the most complicated.

nknight 15y ago
Wow. Just wow. Every single system you name is made up of a large number of complex sub-systems designed and built to exacting requirements, and any one of them can still break at any time. Thinking you "got it right" just because it didn't break one time in one set of circumstances is unbelievably naïve. There's a reason all man-rated launch systems have redundant backup systems, and even the fallbacks don't always work right. By the way, let me know when you get micrometeoroid shielding "right" -- every space agency on Earth will want to talk to you. You might even win a Nobel Prize. You're also completely ignoring navigation. Just because you can fire up a rocket doesn't mean shit if you're at the wrong point in your orbit, or pointed in the wrong direction. You're also failing to distinguish between "I can get THIS rocket into orbit" and "I can get a rocket big enough to carry people and a useful payload into orbit and/or to the moon". Think you can just "scale up"? You're wrong. Effects that were too small to measure before will suddenly kill you. Materials that could handle the strain of the smaller rocket will crumble under the increased forces. Oh, by the way, every time the weight or configuration of your spacecraft changes, you're gonna have to rework your navigation assumptions. Might I suggest playing with Orbiter for a while? Once you've done that, spend a few minutes thinking about the fact that you've just been overwhelmed by a vastly simplified simulation in which nothing ever goes wrong. Now picture the real world. Oh, by the way, your heat shield is cracked, but nobody noticed because your budget didn't allow for more than one guy to inspect it, and he was too drunk. Have fun getting home.
- rbanffy 15y ago
  The original point is that, once you achieve LEO, a free-return tragectory to the moon is just a question of delta-v. And not that much - the Soyuz-based moon roundtrip being offered for US$ 100M is a Soyuz docked with a mini-bus-sized booster stage. Micrometeorites? Did Apollo have that? I am not implying it's easy - I'm implying LEO is the hardest part when it comes to a moon-orbit trip. And in the case of an unmanned craft, it's easier: you don't have to bother with life support, atmospheric braking and most of the radiation shielding.
  - nknight 15y ago
    Except that wasn't the original point at all. It started with Jd saying: "If you want to go to the moon you need a f'ing spaceship and not emacs and an open source notebook. Spaceships are big. They take a lot of people to run, and they have to be smart people. One mistake and you are smithereens at Cape Canaveral." Followed by sedachv saying some guys who are trying to launch humans on suborbital flights would disagree. Nothing you've said explains what suborbital flights have to do with going to the moon. On the contrary, you seem to be admitting they have nothing to do with going to the moon, so I still have absolutely no idea what sedachv's point was.
    - rbanffy 15y ago
      Well... I maintain that the hardest part of going to the Moon is achieving Earth orbit. The rest is, comparatively, easy. But, then, this discussion is completely unrelated to the point regarding emacs and an open source notebook (whatever that is). In general, Jd's rant felt confusing. I am not sure how Lisp and spacecraft are related, BTW. He (or she) implied somehow that you couldn't go to space with something simple and elegant like Lisp, but I can't be sure.
      - Jd 15y ago
        Re: open source notebook see: http://stallman.org/stallman-computing.html http://stallman.org/stallman-computing.html I'll make the relation very clear. There is a segment of the Lisp community, which most certainly includes Paul Graham, that maintains that projects with large team sizes are bad. There is a certain logic here, as it is hard to maintain a high average intelligence distributed across a large number of people. Most true geniuses were loners. Regardless, projects of a certain scope (i.e. building a space shuttle) require large teams. You simply can't do it with two guys in a basement. In a certain sense the computer language employed is irrelevant, except that the lisp community has never, largely because of the facts that should be obvious but are apparently not to the introverted "genius" types they pray on, produced good and extensive enough libraries to be viable for most real world tasks. In case you didn't notice, for example, it took what, 4 years for Hacker News to get HTTPS support. I don't want to rib anyone too badly, because I am a strong supporter of what YCombinator is doing in general and in the incorporation of lambdas and closures in newer languages, but I think generally speaking it is clear that the Lisp culture is not to cooperate but to position one's self as some sort of genius and thus to create one's own dialect, etc. I'll give you an example that will probably irritate some people, but is relevant here. Microsoft Word is, in my opinion, one of the greatest architectural marvels of modern civilization. The feature set of that single app is truly extraordinary, and there are all sorts of wonky ways that you can do lots of tasks that makes millions (and potentially even billions) of people's lives better every day. I understand that there is a point to OpenOffice and "fighting the man" and whatever since Microsoft certainly crushed some competitors in mean ways, but realistically there is nothing in the world that competes. Now you might say, oh sure but I can just use vim and use latex for formatting (or even google docs). And in a certain sense you might be right too, but sooner or later you will find a feature that is not accessible to you (I recently noticed that change tracking still absolutely blows in Google Docs compared to Word). Why do I bring this up? Well, even if you are right that "the hardest part of going to the Moon is achieving Earth orbit," you still have to have all of those other things. You need life support or you dead; this is non-negotiable, just in the way that mail merge is not negotiable for millions of people at millions of office worldwide. And if you want life support (or mail merge), you need to work with the people who design these other systems. By the way, I'm not saying you need to like any of this. I'm simply saying that if you want to build something great, you have to at times slog through the mud. My experience with Lispers is they are frequently afraid to get their hands dirty. And that doesn't cut it except in a pretty-ditty fantasy castle.