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  1. - Top - End - #61
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    You mean like England was where all the stuff was? Because it mostly was.

    A lot of (mostly fairly small) colonies failed, with no survivors.

    That was a different situation, but there are some similarities at least. There are a lot of people who want to go. There are a lot of people who don't want to go, but giving them a veto over other people going seems excessive to me.



    Space tourism is probably a good thing, I'm not at all sure that Virgin's almost space tourism is good since they don't get to orbit and their craft probably can't be sensibly or economically be converted to get to orbit. Satellites which are profitable are great.

    This book was published in 1971:



    https://www.amazon.com/Frontiers-Spa.../dp/B0010P5H16

    It's full of spacecraft that might have been built in the then future. None of them were (they didn't have the shuttle as such, and didn't cover basic rockets). That the Apollo missions were the peak of space travel does make me slightly angry.
    I think we both know there is a difference between colonizing "The New World" and "An Actual New World" when it comes to potential issues and profitability. For one thing we already know that el dorado cant be found on mars. Or the moon for that matter. Secondly, the cost to profit ratio of sending things by sail boat from north america to the british isles is far more economically viable than mars to earth. The tech to travel to the new world and establish a colony was already in existence, well tested, well established. And the initial outlay of doing so was far lower. Sure you generally had to talk to the king or queen to get funding for it, but better them than every king or queen in europe needing to sign on to pay for it all with not even the most positive of estimates showing a profit to be made for the first century.
    "Interdum feror cupidine partium magnarum Europae vincendarum"
    Translation: "Sometimes I get this urge to conquer large parts of Europe."

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Traab View Post
    I think we both know there is a difference between colonizing "The New World" and "An Actual New World" when it comes to potential issues and profitability. For one thing we already know that el dorado cant be found on mars. Or the moon for that matter. Secondly, the cost to profit ratio of sending things by sail boat from north america to the british isles is far more economically viable than mars to earth. The tech to travel to the new world and establish a colony was already in existence, well tested, well established. And the initial outlay of doing so was far lower. Sure you generally had to talk to the king or queen to get funding for it, but better them than every king or queen in europe needing to sign on to pay for it all with not even the most positive of estimates showing a profit to be made for the first century.
    Sailing is easy now, it wasn't back then. Finding the same place twice was difficult. We could find Alpha Centauri now, navigation is almost solved.

    Quote Originally Posted by Kato View Post
    You wanting space colonies to be a thing doesn't mean it can be a thing. We cannot get everything we want. And living in space might be one of the things that doesn't work out. That doesn't mean it's anyone's fault or people want to keep others from their dreams. Maybe you'll get your wish one day, maybe one of your descendants will. Or maybe it turns out we're stuck on this rock for one reason or another.
    We are coming up on the fiftieth Aniversary of the Apollo missions, and we haven't done anything better since. Skylab was nice, it was more or less part of Apollo, then it went down. The ISS is nice, so NASA wants to scrap it.

    I was a child when the first Apollo mission was live on TV, and I watched it. Fuzzy as heck, but important. Since then, not much.

    Space colonies almost certainly could be a thing, if there was sufficient political will.
    The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.

  3. - Top - End - #63
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Traab View Post
    For one thing we already know that el dorado cant be found on mars. Or the moon for that matter.
    Of course not. They(plural) are in the asteroid belt.
    Quote Originally Posted by Harnel View Post
    where is the atropal? and does it have a listed LA?

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by LordEntrails View Post
    We will need new satellites. Partly because old ones die; they run out of fuel for station keeping, their batteries degrade, their solar panels degrade, parts stop working. Second, existing satellites use existing technologies; hence they are limited and as we want them to do more, handle more data/bandwidth, provide higher resolution images, different EM spectrums, etc, they need to be replaced (since they are not designed to be upgraded in place.)
    Yeap, there were plans to give satellites the ability to be refueled, but I'm guessing most operators ran the numbers and decided it wasn't worth the cost of refueling a 20+ year old satellite to stay in orbit for another few decades, especially considering the advances in technology.

    For example, each the three Viasat-3 satellites that will be launched over the next few years will have as much network capacity as all other communications satellites combined.

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    Default Re: How to make space exploration profitable.

    I wonder how much money you could make setting up a service to remove orbital debris? I mean, its a serious issue for launches as well as collisions with satellites. We have a lot of junk floating around our planet of all shapes and sizes, so the idea of sending up a device meant to basically collect, or deflect the debris in such a way that, if small enough, it safely burns up on reentry, or is collected like a space faring roomba and brought back down that way.
    "Interdum feror cupidine partium magnarum Europae vincendarum"
    Translation: "Sometimes I get this urge to conquer large parts of Europe."

    Quote Originally Posted by Nerd-o-rama View Post
    Traab is yelling everything that I'm thinking already.
    "If you don't get those cameras out of my face, I'm gonna go 8.6 on the Richter scale with gastric emissions that'll clear this room."

  6. - Top - End - #66
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    Default Re: How to make space exploration profitable.

    Colonies were immediately profitable, those that weren't struggled immensely in their early period and had to argue that they probably would be one day. They generated net resources for the home countries, increasing the food supply and resources faster then they increased in population. They also took very little upkeep, Massachusetts for instance dealt with its own military struggles and protected the surrounding colonies until about 1700.

    A space colony can't just be a wood boat with some brave people, it takes constant maintenance and supplies from Earth. We struggle to feed and house people on a planet we were custom designed to live on by 400+ million years of trial and error, space habitation would be a monstrous injustice to those people unless it can be self-sufficient (or better yet be a net profit.)
    Quote Originally Posted by The Glyphstone View Post
    Vibranium: If it was on the periodic table, its chemical symbol would be "Bs".

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Traab View Post
    I wonder how much money you could make setting up a service to remove orbital debris? I mean, its a serious issue for launches as well as collisions with satellites. We have a lot of junk floating around our planet of all shapes and sizes, so the idea of sending up a device meant to basically collect, or deflect the debris in such a way that, if small enough, it safely burns up on reentry, or is collected like a space faring roomba and brought back down that way.
    Removal of debris is a business enterprise that is wanting on technological developments to happen. There is active research in this area to figure out how to remove debris without producing more debris at the same time in an economical way. Figure that this is something that will happen, on at least the small scale, sometime in the current century.
    Resvier: a P6 homebrew setting

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Mechalich View Post
    Removal of debris is a business enterprise that is wanting on technological developments to happen. There is active research in this area to figure out how to remove debris without producing more debris at the same time in an economical way. Figure that this is something that will happen, on at least the small scale, sometime in the current century.
    I agree that it will happen, but I don't think it will be done in a commercial manner. After all, why would a commercial company pay for it? They will just chose another parking orbit. IMO it will be consortiums and or governments that will finance the endeavors. King of like roads and road cleanup.

    I guess if it gets bad enough, a commercial company might pay to have one of its old satellites removed so it can replace it with a new one. But, maybe I'm pessimistic and think it will be up to non-commercial entities to clean things up first.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    Sailing is easy now, it wasn't back then. Finding the same place twice was difficult.
    Actually, no, finding the same place is easy, even back then--you just sail westward along a constant line of latitude. We've been able to find our latitude for hundreds of years to a fair degree of accuracy, because you can do it by measuring the sun's altitude above the horizon at its highest point. It's longitude that was impossible to measure before the invention of sufficiently accurate naval chronometers.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Traab View Post
    I wonder how much money you could make setting up a service to remove orbital debris? I mean, its a serious issue for launches as well as collisions with satellites. We have a lot of junk floating around our planet of all shapes and sizes, so the idea of sending up a device meant to basically collect, or deflect the debris in such a way that, if small enough, it safely burns up on reentry, or is collected like a space faring roomba and brought back down that way.
    There's a decent hard science fiction manga/anime series about this called Planetes.
    Quote Originally Posted by Harnel View Post
    where is the atropal? and does it have a listed LA?

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    Space tourism is probably a good thing, I'm not at all sure that Virgin's almost space tourism is good since they don't get to orbit and their craft probably can't be sensibly or economically be converted to get to orbit. Satellites which are profitable are great.
    They do have plans for an orbital rocket, and personally I think air launched is the correct direction for large scale exploitation of space. The complexity of an air launched vehicle currently outweighs the benefits, but that complexity is mostly a R&D problem, that only needs done once. The falcon 9 separates at about Mach 6 in return to pad mode, and that is within reach of a standard ramjet (just). Building a ramjet aircraft that could carry the 100 ton falcon 9 second stage up to Mach 6 and execute the high G pull up (~3) to get enough 'airtime'* would be highly non trivial, but does not require anything particularly exotic tech wise. Anything better than 123 tons of fuel to do the manoeuvre is an improvement, and should be doable with current tech (and lots of $$ for R and D).

    Of note is that the high altitudes and thin atmosphere mean that you don't get the same drag reducing benefits of size, so smaller rockets are possible. Not starting on the ground means that thrust to weights less than 1 are also viable, though it places higher stresses on the loft trajectory. That means less of the expensive rocket engines are required for the same fuel tank volume.

    Granted this doesn't look much like their current design, but the experience in air launching and supersonic flight (including high G pullups) will make moving in this direction quite natural. A 3 stage design using a drone version of their current craft could easily launch a small final stage capable of putting a few cubesats into orbit, and would require just the final stage to be designed. As a way to further the technology without people on board it is a natural direction.

    * The airtime is required partly to let the rocket point prograde rather than angling up, and partly because getting into extremely thin air will make separation simpler. One non obvious advantage to this approach is in terms of structure of the final stage. The falcon 9 second stage has to be able to deal with the accelerations from the first stage with it's own structure, that it then carries to orbit. It will produce similar accelerations on it's own, but will have much less fuel by the time it does. The forces that the structure has to deal with stay lower.

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    Quote Originally Posted by monomer View Post
    Yeap, there were plans to give satellites the ability to be refueled, but I'm guessing most operators ran the numbers and decided it wasn't worth the cost of refueling a 20+ year old satellite to stay in orbit for another few decades, especially considering the advances in technology.

    For example, each the three Viasat-3 satellites that will be launched over the next few years will have as much network capacity as all other communications satellites combined.
    One thing that really matters here is the orbit. For LEO (low Earth orbit), things tend to fall back down in a few years without fuel keeping them up. I think it only takes a few hundred kph to decelerate something at ISS level so that it falls back down in a single orbit (getting it down in a week presumably takes a lot less).

    Out in Geosync land, things are different. Such satellites are required to boost themselves into the "graveyard orbit" where they won't interfere with other satellites. Another reason they may replace a 20+ year old (or less) satellite is simply to keep the valuable orbital position, and have more communication bandwidth to/from that position.

    Not to say there aren't other, funky orbits (polar orbits for Earth observation, sun synchronous orbits for doing same while always in sunlight). My favorite being a Molniya orbit. This "hovers" over one spot on the globe for nearly 12 hours, then dips down across the equator and back up and then hangs over the opposite side of the planet (but equally above/below the equator, not directly across) for another 12 hours. I think you could cover the East coast of the US and China, and the West coast of the US and India, but haven't really looked at the numbers.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Fat Rooster View Post
    They do have plans for an orbital rocket, and personally I think air launched is the correct direction for large scale exploitation of space. The complexity of an air launched vehicle currently outweighs the benefits, but that complexity is mostly a R&D problem, that only needs done once. The falcon 9 separates at about Mach 6 in return to pad mode, and that is within reach of a standard ramjet (just). Building a ramjet aircraft that could carry the 100 ton falcon 9 second stage up to Mach 6 and execute the high G pull up (~3) to get enough 'airtime'* would be highly non trivial, but does not require anything particularly exotic tech wise. Anything better than 123 tons of fuel to do the manoeuvre is an improvement, and should be doable with current tech (and lots of $$ for R and D).

    Of note is that the high altitudes and thin atmosphere mean that you don't get the same drag reducing benefits of size, so smaller rockets are possible. Not starting on the ground means that thrust to weights less than 1 are also viable, though it places higher stresses on the loft trajectory. That means less of the expensive rocket engines are required for the same fuel tank volume.

    Granted this doesn't look much like their current design, but the experience in air launching and supersonic flight (including high G pullups) will make moving in this direction quite natural. A 3 stage design using a drone version of their current craft could easily launch a small final stage capable of putting a few cubesats into orbit, and would require just the final stage to be designed. As a way to further the technology without people on board it is a natural direction.

    * The airtime is required partly to let the rocket point prograde rather than angling up, and partly because getting into extremely thin air will make separation simpler. One non obvious advantage to this approach is in terms of structure of the final stage. The falcon 9 second stage has to be able to deal with the accelerations from the first stage with it's own structure, that it then carries to orbit. It will produce similar accelerations on it's own, but will have much less fuel by the time it does. The forces that the structure has to deal with stay lower.
    NASA's X series of planes were interesting too, but so far they haven't reached orbit and craft launched from planes don't look particularly likely to do so in say the next five or ten years. Rockets may be sort of crude, but they work now. In a contest between perfect and good enough, at this time for me the rocket wins by a pretty large margin. It may be that at a later time the economies inherent in launching to orbit from planes will make sense, but now it's not a working technology, and doesn't seem likely to become one in the forseeable future.

    Quote Originally Posted by factotum View Post
    Actually, no, finding the same place is easy, even back then--you just sail westward along a constant line of latitude. We've been able to find our latitude for hundreds of years to a fair degree of accuracy, because you can do it by measuring the sun's altitude above the horizon at its highest point. It's longitude that was impossible to measure before the invention of sufficiently accurate naval chronometers.
    With what level of accuracy?

    If I remember rightly there were whole colonies lost and not rediscovered. Once a settlement got established and running things took off, but the early colonies were very precarious indeed.
    Last edited by halfeye; 2019-02-15 at 01:26 PM.
    The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    With what level of accuracy?

    If I remember rightly there were whole colonies lost and not rediscovered. Once a settlement got established and running things took off, but the early colonies were very precarious indeed.
    Colonies failed or were abandoned, but not literally 'lost'. They might run out of supplies or suffer some disaster, and a ship heading to bring them said supplies could easily sink or be driven off course by a storm, but it's not because people just forgot how to get to their location.
    Last edited by The Glyphstone; 2019-02-15 at 02:23 PM.
    Quote Originally Posted by Red Fel, on quest rewards View Post
    "Is a stack of ten pancakes too many pancakes to give to the party, even if most of them fell on the floor and one or two were stepped on? I wanted to give my party pancakes as a reward but I'm unsure if it's too much. The pancakes are also laced with blowfish poison so the party would have to get an antitoxin before they could eat the ones which weren't pulverized by shoes."

    I don't think anyone would want those pancakes even if you paid them to eat them.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post


    We are coming up on the fiftieth Aniversary of the Apollo missions, and we haven't done anything better since. Skylab was nice, it was more or less part of Apollo, then it went down. The ISS is nice, so NASA wants to scrap it.

    I was a child when the first Apollo mission was live on TV, and I watched it. Fuzzy as heck, but important. Since then, not much.
    I think it's silly to discount the last ~40 years of space of exploration just because there was no meatbag on board.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    If I remember rightly there were whole colonies lost and not rediscovered. Once a settlement got established and running things took off, but the early colonies were very precarious indeed.
    I'm assuming you're probably thinking about the Lost Colony of Roanoke? As The_Glyphstone points out, they never lost track of where that was located, they just lost track of all the people, who vanished from the colony in between supply shipments. Once you actually reach land then you can use landmarks to figure out where you are.

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    Default Re: How to make space exploration profitable.

    They did in fact lose Vinland and Greenland after the first crusade, so it isn't impossible to do. Some of the Conquistador expeditions went places they couldn't retrace due to just treking around the woods as well.
    Quote Originally Posted by The Glyphstone View Post
    Vibranium: If it was on the periodic table, its chemical symbol would be "Bs".

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Hackman View Post
    I think it's silly to discount the last ~40 years of space of exploration just because there was no meatbag on board.
    Exploration is not colonisation.

    I also disagree that what has been done by robots is all exploration, which is about making maps and measuring distances. What the robots have done is mostly science, and it's hugely worthwhile, but except for the tiny percentage that has applications on Earth, until people follow, it's pretty pointless.
    The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by halfeye View Post
    We are coming up on the fiftieth Aniversary of the Apollo missions, and we haven't done anything better since. Skylab was nice, it was more or less part of Apollo, then it went down. The ISS is nice, so NASA wants to scrap it.
    NASA doesn't want to scrap the ISS, and in fact they have a number of crucial experiments on the long-term health affects of living in free-fall for extended periods which they think need to run until at least 2028. (NASA ISS Audit PDF)

    The issue is that the current ISS funding runs out in 2024, and Congress hasn't agreed on any continued funding after that. NASA is currently spending about $3.4B each year on ISS, including maintenance, operations, cargo/crew transportation, and experiments (international partners also contribute, but NASA's share is far and away the most), and with the station approaching end-of-life, maintenance costs will only increase. So if NASA doesn't get a budget increase, they will start having a hard time paying for other exploration projects. While I would be disappointed to lose our only permanent space habitat, imagine what they could do in LEO with $3B and a fleet of Falcon Heavys.

    There is a "plan" to sell the ISS to private industry in 2025, but no one wants it since there isn't likely to be a business case where commercial enterprises could actually make a profit with it. Sure, a private company could probably shave some costs off of the current $3.4B, but there will still a huge annual cost there that they would have to make up. And it doesn't help that the ISS' orbit is at an inclination of 52 deg, which is only easy to get to for the Russians while everyone else has to make a fuel-inefficient dogleg to get there. So yeah, I doubt anyone will be banging on the doors for the chance to buy a worn-out space station in a wonky orbit.

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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by monomer View Post
    Sure, a private company could probably shave some costs off of the current $3.4B,
    Doubtful. It's a very specialized project with lots of things involved pretty much no private company currently has, including a suitable rocket (or good enough contacts with someone else who has those), a suitable launch site, space craft with the right docking equipment, trained astronauts, trained ground crews, lots and lots of knowledge on the sysyems, etc. Setting all of that stuff up for a few years of operation is expensive.

    It's one of my pet peeves for things politicians say (that isn't directly political so I can discuss it here): privatization does not automatically under all circumstances equal less costs.
    Last edited by Lvl 2 Expert; 2019-02-16 at 02:53 AM.

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    Quote Originally Posted by Lvl 2 Expert View Post
    It's one of my pet peeves for things politicians say (that isn't directly political so I can discuss it here): privatization does not automatically under all circumstances equal less costs.
    I agree, but I think it is directly political.
    The end of what Son? The story? There is no end. There's just the point where the storytellers stop talking.

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    Quote Originally Posted by Fat Rooster View Post
    They do have plans for an orbital rocket, and personally I think air launched is the correct direction for large scale exploitation of space. The complexity of an air launched vehicle currently outweighs the benefits, but that complexity is mostly a R&D problem, that only needs done once. The falcon 9 separates at about Mach 6 in return to pad mode, and that is within reach of a standard ramjet (just). Building a ramjet aircraft that could carry the 100 ton falcon 9 second stage up to Mach 6 and execute the high G pull up (~3) to get enough 'airtime'* would be highly non trivial, but does not require anything particularly exotic tech wise. Anything better than 123 tons of fuel to do the manoeuvre is an improvement, and should be doable with current tech (and lots of $$ for R and D).
    Some issues with air launch:

    You really can't "grow" your rocket if you use air launch without a much more expensive program to grow your aircraft.

    Stratolaunch Launch Systems died with Paul Allen. It is possible that out of the wreckage of the smallsat market (not a problem with launching smallsats, but there are *way* too many companies trying to compete there) that somebody will swoop down and by the Stratolaunch plane (at post-bankruptcy prices) and enough small rockets to build something.

    Ramjet to mach 5 - sounds great in theory, but the details get hairy. Probably the biggest issue is that you probably want to jettison the ramjets *after* leaving the atmosphere, presumably making them side-mounted boosters (so the main rocket can get them out of the atmosphere). During the SR-71 drone testing (launching a drone rocket from a SR-71), Launch Control Officer (LCO) Ray Torick died after ejection and this pretty much canceled the program.

    There's also the issue of recovering your boosters. Both SpaceX and Blue Origin favor propulsive landings and you can't do that with a ramjet. Of the other programs, only the Chinese and Indians appear to have the ambitions needed to cut costs enough by things like recovery, but aren't married to propulsive recovery.

    For a more ambitious look at this see the X-43 program and the followup X-51 program. Unfortunately these are both dead, and the only source of funding seems to be in idiotic "hypersonic weapons programs" (hint: these threaten to do what weapons that were fielded to do in the mid-cold war did, only inefficiently and badly).

    Also don't completely forget about air-augmented rockets. The idea is to add outside air to the rocket exhaust and just it for propulsion much like you make a hydrogen rocket fuel rich to allow additional hydrogen exhaust. As far as I know, it was only planned on the USSR Gnom missile, which was scrapped before building a rocket. These wouldn't get nearly the Isp of a ramjet, but would get the thrust of a rocket and allow propulsive landings (pretty much like the boosters on a falcon heavy). They may well be the first step in low fuel launches (presumably replacing the first stage in things like the Super Heavy Booster, or the New Armstrong, assuming you can work around the airflow issues of the subsequent stage[s]).

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    Quote Originally Posted by wumpus View Post
    Some issues with air launch:

    You really can't "grow" your rocket if you use air launch without a much more expensive program to grow your aircraft.

    Stratolaunch Launch Systems died with Paul Allen. It is possible that out of the wreckage of the smallsat market (not a problem with launching smallsats, but there are *way* too many companies trying to compete there) that somebody will swoop down and by the Stratolaunch plane (at post-bankruptcy prices) and enough small rockets to build something.

    Ramjet to mach 5 - sounds great in theory, but the details get hairy. Probably the biggest issue is that you probably want to jettison the ramjets *after* leaving the atmosphere, presumably making them side-mounted boosters (so the main rocket can get them out of the atmosphere). During the SR-71 drone testing (launching a drone rocket from a SR-71), Launch Control Officer (LCO) Ray Torick died after ejection and this pretty much canceled the program.

    There's also the issue of recovering your boosters. Both SpaceX and Blue Origin favor propulsive landings and you can't do that with a ramjet. Of the other programs, only the Chinese and Indians appear to have the ambitions needed to cut costs enough by things like recovery, but aren't married to propulsive recovery.

    For a more ambitious look at this see the X-43 program and the followup X-51 program. Unfortunately these are both dead, and the only source of funding seems to be in idiotic "hypersonic weapons programs" (hint: these threaten to do what weapons that were fielded to do in the mid-cold war did, only inefficiently and badly).

    Also don't completely forget about air-augmented rockets. The idea is to add outside air to the rocket exhaust and just it for propulsion much like you make a hydrogen rocket fuel rich to allow additional hydrogen exhaust. As far as I know, it was only planned on the USSR Gnom missile, which was scrapped before building a rocket. These wouldn't get nearly the Isp of a ramjet, but would get the thrust of a rocket and allow propulsive landings (pretty much like the boosters on a falcon heavy). They may well be the first step in low fuel launches (presumably replacing the first stage in things like the Super Heavy Booster, or the New Armstrong, assuming you can work around the airflow issues of the subsequent stage[s]).
    The aim was not for it to grow. I was looking towards the limit point in terms of a large mature industry, which means that R&D costs are ignored. The 737 for example has had more than 10,000 built. Once a system is doing 100,000 launches plus, saving 50 tons of fuel per launch starts to justify substantial R&D. Current commercial systems are not even used enough to justify specialised engines for each stage, which shows how far away we are from that.

    The D21 system did cause one crash, but otherwise it worked! It's not like staging has never been a problem in modern rockets. What's more, it worked in atmospheric flight, which is even harder than what I am suggesting. The technology for a Mach 3 air launch is more than 50 years old. The concept I am suggesting is a zoom climb at ~Mach 3 using a 'conventional' jet, using the hang time to switch mode to ramjet mode (you probably don't want to be messing with significant airflow too much at those speeds, hence leaving the atmosphere to do it. Diving back also lets you maintain a more consistent angle of attack, improving efficiency and simplifying things). You then Dive into the atmosphere, fire up the ramjet, and zoom climb back out again at Mach 5. You effectively get an energised bounce (Neil Armstrong did something very similar, only without extra power, and by mistake). You then get to separate above any substantial atmosphere, which is no different from any other staging event. You reenter the atmosphere with the engine in conventional mode, using a stalled intake to increase drag until you get to the point where it will actually work, and then fly back and land. The ramjet stays with the first stage, and is recovered with it. Later stages are recovered however you would with any other rocket. Should be doable with about 15% takeoff weight in fuel*, meaning 15% payload capacity is enough to improve on current efficiency, even neglecting the hundreds of tons of oxidiser not needed. Getting 35% should be doable, and would half the total fuel used.

    *Assuming 2000s up to Mach 3, based on the SR71, and 1300s for the ramjet acceleration (Quick look didn't find good real data on ramjets). Lift to Drag of 6 for the pullup, and a couple percent added on for gravity drag. Probably a little conservative, as 4000s should be possible up to Mach 1.8ish, and for much of the gravity drag.

    The aircraft would be the bastard child of the Valkerie, X15, and D21. While those aircraft are awesome, they are also all extremely old. The specification of this aircraft would be closest to the X15, in that sustained high speeds are not actually required. It just needs to be able to sprint, and behave at extreme altitude.

    Simple this is not, and the number of disciplines involved is impressive. It is also extremely natural for rocket engineers to say "Why not just use a rocket? We know they can do it, and we already have these rockets". That doesn't make it the best way when the first stage problem is considered in isolation and scale is a non factor. The atmosphere can be used for large gains in terms of fuel efficiency, when that starts to become important. Currently it isn't, but when it becomes so Virgin Galactic will have a head start in terms of relevant expertise.

    Air augmented rockets look like a dead end, by playing to the strengths of neither. Rockets really want to work in a Vacuum, and work fast. That means aero drag is more important than gravity drag for rockets (Rockets exist that break Mach 6 within 2 KM). Air breathers need much lower flatter trajectories, and want to spend as much time as possible gobbling air. That means lift to favourably trade gravity drag for aerodynamic drag is really useful. An SSTO would want to abuse the benefits of both, but those are stupid. More sensible is to use the atmosphere until it is not useful, and then stage into a rocket (ditching all the heavy but efficient atmospheric stuff). You would also likely lose any gains if you tried to land propulsively, as the extra hardware would have to be landed again, and propulsive landings are all about keeping the empty weight down to a far greater extent than is usual for first stages. If you want a lifting landing, you might as well use the lift on takeoff and use a more efficient engine.

    Scramjets generally push what the atmosphere can do a little too far I think, though the 2000s theoretical specific impulse at orbital speeds looks really shiny. 50% weight hydrogen could get you orbital if you got anywhere near theoretical limits, but oxygen is basically free and a hydrogen rocket can get about 50% of that performance per hydrogen anyway. When you consider that your typical rocket is throwing stuff out the back at about 3km/s, and that at Mach 6 the stuff entering an engine is going just shy 2km/s, you start to appreciate how hard getting useful thrust out of these things is. Given that they also don't even really start to work until Mach 5, really need bulky hydrogen to make sense (terrible for atmospheric drag) and the inlet design is radically different from a more conventional engine (making diverting as appropriate impractical), I don't see them having a place. Super cool though, and supersonic combustion might have a place in very hot burning rockets as afterburners, so the tech might not go to waste.

    Recovery of a rocket propulsively makes sense, as it uses the hardware available, while recovery of a lifting stage using the lift also makes use of the existing hardware. I'm still not sold on propulsive landings for upper stages though, as heat shields scale pretty well with the mass of the craft, and spreading one out to a wing is not that much of a tax. SpaceX's active shielding might work out lighter, but you can still shape it into a wing. Getting expertise in propulsive landings is well worth doing even if it wasn't the most efficient though, as there is no other way to land on the moon or mars, which is their ultimate goal.

    I'm torn on the stratolaunch, as the aircraft is magnificent. The problem is that it doesn't give much improvement in terms of delta V for a first stage, as you need to fit the engines on the plate which means small nozzles anyway, and it just adds complexity. Horizontal launches require that you either keep your thrust to weight above 1 (actually higher than ground launches), or deal with lateral forces from a lifting surface while in flight. It doesn't look designed to zoom climb, which is really required. Rockets like to go the direction you point them, and that really should be up. An air breathing stage could be built; possibly a ramjet to Mach 5 after a solid booster to Mach 2, but then you have built 3 stages to get the point that can be done in 1 fat rocket stage. If you are building a recoverable air breathing stage, then you might as well use the recovery system as a launch system, and skip the stratolaunch and the rocket.

    The stratolaunch is a good example of how not to do airlaunch. Slow and level is bad. Fast and rapidly climbing is good. See the ASM-135_ASAT. It is not orbital, but illustrates the point.

  24. - Top - End - #84
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    Quote Originally Posted by Fat Rooster View Post
    The aim was not for it to grow. I was looking towards the limit point in terms of a large mature industry, which means that R&D costs are ignored. The 737 for example has had more than 10,000 built. Once a system is doing 100,000 launches plus, saving 50 tons of fuel per launch starts to justify substantial R&D. Current commercial systems are not even used enough to justify specialised engines for each stage, which shows how far away we are from that.

    The D21 system did cause one crash, but otherwise it worked! It's not like staging has never been a problem in modern rockets. What's more, it worked in atmospheric flight, which is even harder than what I am suggesting. The technology for a Mach 3 air launch is more than 50 years old. The concept I am suggesting is a zoom climb at ~Mach 3 using a 'conventional' jet, using the hang time to switch mode to ramjet mode (you probably don't want to be messing with significant airflow too much at those speeds, hence leaving the atmosphere to do it. Diving back also lets you maintain a more consistent angle of attack, improving efficiency and simplifying things). You then Dive into the atmosphere, fire up the ramjet, and zoom climb back out again at Mach 5. You effectively get an energised bounce (Neil Armstrong did something very similar, only without extra power, and by mistake). You then get to separate above any substantial atmosphere, which is no different from any other staging event. You reenter the atmosphere with the engine in conventional mode, using a stalled intake to increase drag until you get to the point where it will actually work, and then fly back and land. The ramjet stays with the first stage, and is recovered with it. Later stages are recovered however you would with any other rocket. Should be doable with about 15% takeoff weight in fuel*, meaning 15% payload capacity is enough to improve on current efficiency, even neglecting the hundreds of tons of oxidiser not needed. Getting 35% should be doable, and would half the total fuel used.

    *Assuming 2000s up to Mach 3, based on the SR71, and 1300s for the ramjet acceleration (Quick look didn't find good real data on ramjets). Lift to Drag of 6 for the pullup, and a couple percent added on for gravity drag. Probably a little conservative, as 4000s should be possible up to Mach 1.8ish, and for much of the gravity drag.

    The aircraft would be the bastard child of the Valkerie, X15, and D21. While those aircraft are awesome, they are also all extremely old. The specification of this aircraft would be closest to the X15, in that sustained high speeds are not actually required. It just needs to be able to sprint, and behave at extreme altitude.

    Simple this is not, and the number of disciplines involved is impressive. It is also extremely natural for rocket engineers to say "Why not just use a rocket? We know they can do it, and we already have these rockets". That doesn't make it the best way when the first stage problem is considered in isolation and scale is a non factor. The atmosphere can be used for large gains in terms of fuel efficiency, when that starts to become important. Currently it isn't, but when it becomes so Virgin Galactic will have a head start in terms of relevant expertise.

    Air augmented rockets look like a dead end, by playing to the strengths of neither. Rockets really want to work in a Vacuum, and work fast. That means aero drag is more important than gravity drag for rockets (Rockets exist that break Mach 6 within 2 KM). Air breathers need much lower flatter trajectories, and want to spend as much time as possible gobbling air. That means lift to favourably trade gravity drag for aerodynamic drag is really useful. An SSTO would want to abuse the benefits of both, but those are stupid. More sensible is to use the atmosphere until it is not useful, and then stage into a rocket (ditching all the heavy but efficient atmospheric stuff). You would also likely lose any gains if you tried to land propulsively, as the extra hardware would have to be landed again, and propulsive landings are all about keeping the empty weight down to a far greater extent than is usual for first stages. If you want a lifting landing, you might as well use the lift on takeoff and use a more efficient engine.

    Scramjets generally push what the atmosphere can do a little too far I think, though the 2000s theoretical specific impulse at orbital speeds looks really shiny. 50% weight hydrogen could get you orbital if you got anywhere near theoretical limits, but oxygen is basically free and a hydrogen rocket can get about 50% of that performance per hydrogen anyway. When you consider that your typical rocket is throwing stuff out the back at about 3km/s, and that at Mach 6 the stuff entering an engine is going just shy 2km/s, you start to appreciate how hard getting useful thrust out of these things is. Given that they also don't even really start to work until Mach 5, really need bulky hydrogen to make sense (terrible for atmospheric drag) and the inlet design is radically different from a more conventional engine (making diverting as appropriate impractical), I don't see them having a place. Super cool though, and supersonic combustion might have a place in very hot burning rockets as afterburners, so the tech might not go to waste.

    Recovery of a rocket propulsively makes sense, as it uses the hardware available, while recovery of a lifting stage using the lift also makes use of the existing hardware. I'm still not sold on propulsive landings for upper stages though, as heat shields scale pretty well with the mass of the craft, and spreading one out to a wing is not that much of a tax. SpaceX's active shielding might work out lighter, but you can still shape it into a wing. Getting expertise in propulsive landings is well worth doing even if it wasn't the most efficient though, as there is no other way to land on the moon or mars, which is their ultimate goal.

    I'm torn on the stratolaunch, as the aircraft is magnificent. The problem is that it doesn't give much improvement in terms of delta V for a first stage, as you need to fit the engines on the plate which means small nozzles anyway, and it just adds complexity. Horizontal launches require that you either keep your thrust to weight above 1 (actually higher than ground launches), or deal with lateral forces from a lifting surface while in flight. It doesn't look designed to zoom climb, which is really required. Rockets like to go the direction you point them, and that really should be up. An air breathing stage could be built; possibly a ramjet to Mach 5 after a solid booster to Mach 2, but then you have built 3 stages to get the point that can be done in 1 fat rocket stage. If you are building a recoverable air breathing stage, then you might as well use the recovery system as a launch system, and skip the stratolaunch and the rocket.

    The stratolaunch is a good example of how not to do airlaunch. Slow and level is bad. Fast and rapidly climbing is good. See the ASM-135_ASAT. It is not orbital, but illustrates the point.
    Hm. I'm reminded of Bloodhound:

    https://en.wikipedia.org/wiki/Bloodh...sile)#Variants

    That's one of the very few uses of ramjets I'm aware of. Again, needs to be launched to operating speed by other means.
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  25. - Top - End - #85
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by LordEntrails View Post
    As of today. It is likely their will be international laws regulating such endeavors soon after such becomes possible. Again, I refer youto the Mars series, it addresses this issue directly.
    Eh, I seriously doubt that will be a relevant issue. The distance makes effective governance by a terrestrial authority next to impossible.

    Quote Originally Posted by Mechalich View Post
    Sure you can do all the heavy industry you want on Mars - but the tyranny of the rocket equation means that anything you produce is only going to be profitable within Mars' gravity well. As a result, in order to make heavy industry on Mars worth bothering with you need to have a Mars colony in place first, only there's no reason to build a permanent colony unless you're trying to make it an economic success in the first place. That's the fundamental Catch-22 of space development.

    Remember, space has no raw materials that are not available on Earth, since raw materials ultimately just boils down to the periodic table (and space isn't good at providing long-chain hydrocarbons anyway). So a space extraction or industrial process can only have supplies that are more convenient than those of Earth. Now, that convenience can be pretty impressive, there are some asteroids out there that are pretty much solid blocks of metal ore and don't represent a gravity well of any consequence. However, in order to utilize them you still have to haul at least a power source, a fabber, and some feedstock out to them, and once you have your extracted metals you then have to bring them back to some location where people want to use them, and if those people are on a planet that means you have to put them down into a gravity well without them either burning up or leaving big craters.

    It's worth noting that it's not all that difficult to imagine a profitable series of space industries servicing other people in space, because once you're talking about moving things from one microgravity location to another you're just transferring orbits and most of the expensive rocketry can be avoided. If you can build a space elevator, then, you can start to bring planets and moons into the mix in a limited way, but that breakthrough's a ways off if it's possible at all.
    You don't need rockets to get to orbit on Mars. The gravity there is lower than on earth. Low enough that we could build practical space elevators with modern materials.
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by druid91 View Post
    You don't need rockets to get to orbit on Mars. The gravity there is lower than on earth. Low enough that we could build practical space elevators with modern materials.
    As was discussed earlier, modern materials might have a bit of trouble surviving the impact of Mar's moon Phobos as it does it's twice-daily intersection with the equator plane at sub-geostationary heights, or surviving the dance necessary to keep the tether from impacting said moon.

    Also, it is disingenuous to claim "You don't need rockets to get to orbit on Mars" when you do, in fact, need a rocket until such time as there is a space elevator.

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    Quote Originally Posted by woweedd View Post
    I would say that's the dumbest theory Grey Wolf's heard, but, let's be honest: It's Grey Wolf. They've probably heard dumber theories today. Point is, neat idea, but it's a real stretch.
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Grey_Wolf_c View Post
    As was discussed earlier, modern materials might have a bit of trouble surviving the impact of Mar's moon Phobos as it does it's twice-daily intersection with the equator plane at sub-geostationary heights, or surviving the dance necessary to keep the tether from impacting said moon.

    Also, it is disingenuous to claim "You don't need rockets to get to orbit on Mars" when you do, in fact, need a rocket until such time as there is a space elevator.

    Grey Wolf
    A mass driver could probably work too. Doesnt need all that much room due to significantly lower escape/orbital velocity. Even shortet if its mainly for cargo with conventional, reusable launch vehicles for people.

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    Quote Originally Posted by Chen View Post
    A mass driver could probably work too. Doesnt need all that much room due to significantly lower escape/orbital velocity. Even shortet if its mainly for cargo with conventional, reusable launch vehicles for people.
    I'd imagine the rarified atmosphere would also help, not to mention you could probably build it up the very gentle slope of the solar system's largest mountain.

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    Quote Originally Posted by woweedd View Post
    I would say that's the dumbest theory Grey Wolf's heard, but, let's be honest: It's Grey Wolf. They've probably heard dumber theories today. Point is, neat idea, but it's a real stretch.
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    Default Re: How to make space exploration profitable.

    Quote Originally Posted by Chen View Post
    A mass driver could probably work too. Doesnt need all that much room due to significantly lower escape/orbital velocity. Even shortet if its mainly for cargo with conventional, reusable launch vehicles for people.
    Escape velocity on Mars isn't as low as you maybe think it is--it's about 5km/s (compared to 11km/s for Earth). You would need a lot of acceleration in your mass driver to achieve that speed, and a very robustly designed craft to survive going through even the thin Martian atmosphere so fast.

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    Quote Originally Posted by factotum View Post
    Escape velocity on Mars isn't as low as you maybe think it is--it's about 5km/s (compared to 11km/s for Earth). You would need a lot of acceleration in your mass driver to achieve that speed, and a very robustly designed craft to survive going through even the thin Martian atmosphere so fast.
    Half the escape velocity means 1/4 the length which is a significant savings. Not to say it wouldnt still be a huge task, but we’re talking about it in the context of building a space elevator which is also a huge task. Hell you even have Olympus mons there to run your mass driver up which gets you past most of the atmosphere anyways.

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