dazza 38 Posted August 18, 2015 Share Posted August 18, 2015 Having previously worked in High Rise Construction for 13 years. All I am thinking of is what would the height and site allowance be? $$$$ Link to comment Share on other sites More sharing options...
Litespeed Posted August 18, 2015 Share Posted August 18, 2015 For a good read on space elevators - See Kim Stanley Robinson- Mars trilogy. Red Mars, Green Mars, Blue Mars. Excellent series and puts it all in perspective or our planet, politics and corporate power. Link to comment Share on other sites More sharing options...
Litespeed Posted August 18, 2015 Share Posted August 18, 2015 For a good read on space elevators - See Kim Stanley Robinson- Mars trilogy. Red Mars, Green Mars, Blue Mars. Excellent series and puts it all in perspective or our planet, politics and corporate power. Link to comment Share on other sites More sharing options...
Marty_d Posted August 18, 2015 Share Posted August 18, 2015 Having previously worked in High Rise Construction for 13 years. All I am thinking of is what would the height and site allowance be? $$$$ Only job in construction where both parachute and oxygen are part of the kit. Link to comment Share on other sites More sharing options...
Marty_d Posted August 18, 2015 Share Posted August 18, 2015 Having previously worked in High Rise Construction for 13 years. All I am thinking of is what would the height and site allowance be? $$$$ Only job in construction where both parachute and oxygen are part of the kit. Link to comment Share on other sites More sharing options...
Guest ozzie Posted August 18, 2015 Share Posted August 18, 2015 Elevator music taken to new heights. do do doo do dodada dodo dooodo dodada dada....ding Link to comment Share on other sites More sharing options...
Guest ozzie Posted August 18, 2015 Share Posted August 18, 2015 Elevator music taken to new heights. do do doo do dodada dodo dooodo dodada dada....ding Link to comment Share on other sites More sharing options...
Maritime_Ev Posted August 18, 2015 Share Posted August 18, 2015 You need about 22,000 MPH to escape gravity. If you take off in an easterly direction at the equator you already have 1,000 MPH. It pays to get up out of the atmosphere to benefit from it. Nev As Nev already mentioned to, the problem of getting to space is not to get up that high (although that is hard enough in itself), you also need to get to escape velocity (around 8km/sec in proper metric units). So a 20km high tower doesn't really gain you all that much of an except maybe a lower air resistance, but it would probably cheaper to carry your rocket up by aeroplane a la white knight. I guess if you made your tower so high that it reached to geostationairy orbit Randall Munroe of XKCD fame explains it much better than I can: https://what-if.xkcd.com/58/ You got to love a place where you can discuss space flight on the same forum as the latest Rotax engine Link to comment Share on other sites More sharing options...
Maritime_Ev Posted August 18, 2015 Share Posted August 18, 2015 You need about 22,000 MPH to escape gravity. If you take off in an easterly direction at the equator you already have 1,000 MPH. It pays to get up out of the atmosphere to benefit from it. Nev As Nev already mentioned to, the problem of getting to space is not to get up that high (although that is hard enough in itself), you also need to get to escape velocity (around 8km/sec in proper metric units). So a 20km high tower doesn't really gain you all that much of an except maybe a lower air resistance, but it would probably cheaper to carry your rocket up by aeroplane a la white knight. I guess if you made your tower so high that it reached to geostationairy orbit Randall Munroe of XKCD fame explains it much better than I can: https://what-if.xkcd.com/58/ You got to love a place where you can discuss space flight on the same forum as the latest Rotax engine Link to comment Share on other sites More sharing options...
Marty_d Posted August 19, 2015 Share Posted August 19, 2015 As Nev already mentioned to, the problem of getting to space is not to get up that high (although that is hard enough in itself), you also need to get to escape velocity (around 8km/sec in proper metric units).So a 20km high tower doesn't really gain you all that much of an except maybe a lower air resistance, but it would probably cheaper to carry your rocket up by aeroplane a la white knight. I guess if you made your tower so high that it reached to geostationairy orbit Randall Munroe of XKCD fame explains it much better than I can: https://what-if.xkcd.com/58/ You got to love a place where you can discuss space flight on the same forum as the latest Rotax engine That is a good explanation. So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. Link to comment Share on other sites More sharing options...
Marty_d Posted August 19, 2015 Share Posted August 19, 2015 As Nev already mentioned to, the problem of getting to space is not to get up that high (although that is hard enough in itself), you also need to get to escape velocity (around 8km/sec in proper metric units).So a 20km high tower doesn't really gain you all that much of an except maybe a lower air resistance, but it would probably cheaper to carry your rocket up by aeroplane a la white knight. I guess if you made your tower so high that it reached to geostationairy orbit Randall Munroe of XKCD fame explains it much better than I can: https://what-if.xkcd.com/58/ You got to love a place where you can discuss space flight on the same forum as the latest Rotax engine That is a good explanation. So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. Link to comment Share on other sites More sharing options...
ayavner Posted August 19, 2015 Share Posted August 19, 2015 yeah and now i am in the rabbit hole.. i'm up to /103 now... Link to comment Share on other sites More sharing options...
ayavner Posted August 19, 2015 Share Posted August 19, 2015 yeah and now i am in the rabbit hole.. i'm up to /103 now... Link to comment Share on other sites More sharing options...
Maritime_Ev Posted August 19, 2015 Share Posted August 19, 2015 That is a good explanation.So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. The only way to avoid that is to build your tower to geostationary orbit (which is what a real space elevator would do), if you built it on the equator you'd be able to just push your spaceship off from the tower and it's in orbit. Only problem is that you need to be roughly 1500x as high as this proposed tower: 35750km I may not be smart enough to be a rocket scientist but I do play Kerbal Space Program occasionally when I need my flying fix and I'm on the boat or the weather doesn't cooperate, amazing how much of the elementairy stuff about orbital mechanics you pick up from that. https://kerbalspaceprogram.com Link to comment Share on other sites More sharing options...
Maritime_Ev Posted August 19, 2015 Share Posted August 19, 2015 That is a good explanation.So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. The only way to avoid that is to build your tower to geostationary orbit (which is what a real space elevator would do), if you built it on the equator you'd be able to just push your spaceship off from the tower and it's in orbit. Only problem is that you need to be roughly 1500x as high as this proposed tower: 35750km I may not be smart enough to be a rocket scientist but I do play Kerbal Space Program occasionally when I need my flying fix and I'm on the boat or the weather doesn't cooperate, amazing how much of the elementairy stuff about orbital mechanics you pick up from that. https://kerbalspaceprogram.com Link to comment Share on other sites More sharing options...
cscotthendry Posted August 19, 2015 Share Posted August 19, 2015 That is a good explanation.So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. There is a height (forget the figure just now) where a geostationary orbit is possible. If the tower went to that height it should be possible to just step off at the top and you're in orbit. The trouble I think is the forces on all the stuff below that height. If I knew more about orbital dynamics I could explain ... but I don't, so I can't. Ooops, just noticed the post above. Link to comment Share on other sites More sharing options...
cscotthendry Posted August 19, 2015 Share Posted August 19, 2015 That is a good explanation.So even if you got your tower high enough so the top was in space, you still haven't got the speed to maintain orbit when you launch off it. Sounds like any vehicle taking off from it is still going to use a high proportion of the fuel load they would have used launching from sea level, just to attain orbit. There is a height (forget the figure just now) where a geostationary orbit is possible. If the tower went to that height it should be possible to just step off at the top and you're in orbit. The trouble I think is the forces on all the stuff below that height. If I knew more about orbital dynamics I could explain ... but I don't, so I can't. Ooops, just noticed the post above. Link to comment Share on other sites More sharing options...
willedoo Posted August 19, 2015 Author Share Posted August 19, 2015 I guess the cheapest way is to keep hitching a ride with the Russians. All this sounds a bit expensive. 1 Link to comment Share on other sites More sharing options...
willedoo Posted August 19, 2015 Author Share Posted August 19, 2015 I guess the cheapest way is to keep hitching a ride with the Russians. All this sounds a bit expensive. Link to comment Share on other sites More sharing options...
Marty_d Posted August 19, 2015 Share Posted August 19, 2015 The forces are the thing. As Maritime_Ev said, if you need to go 36,000k into space to have a true "step off and you're there" thing... I think one problem is there's no material currently available that could go that far and have the strength to handle those forces. Link to comment Share on other sites More sharing options...
Marty_d Posted August 19, 2015 Share Posted August 19, 2015 The forces are the thing. As Maritime_Ev said, if you need to go 36,000k into space to have a true "step off and you're there" thing... I think one problem is there's no material currently available that could go that far and have the strength to handle those forces. Link to comment Share on other sites More sharing options...
Phil Perry Posted August 19, 2015 Share Posted August 19, 2015 haha plus i can just imagine a rotating runway... " XYZ downwind, runway 29 for a full stop. Oops make that 30. sorry... 31.. bugger..." If you reckon that's a hard job,. . .what about the poor Navy rating who has to repaint the flight deck runway numbers every time the damn carrier turns into wind ? ? ? ? ? 3 Link to comment Share on other sites More sharing options...
Phil Perry Posted August 19, 2015 Share Posted August 19, 2015 haha plus i can just imagine a rotating runway... " XYZ downwind, runway 29 for a full stop. Oops make that 30. sorry... 31.. bugger..." If you reckon that's a hard job,. . .what about the poor Navy rating who has to repaint the flight deck runway numbers every time the damn carrier turns into wind ? ? ? ? ? Link to comment Share on other sites More sharing options...
Mike Borgelt Posted August 31, 2015 Share Posted August 31, 2015 The energy advantage of launching at 65000 feet or at say 40000 feet isn't all that significant. What a launch at 65000 feet mainly gets you is the ability to optimise the engine bell for vacuum instead of having to optimise for sea level or close to it. The extra specific impulse gets you a lot. Look up "rocket equation" and plug in some numbers. It can make a significant difference to the mass delivered to orbit on an SSTO (Single Stage To Orbit) vehicle or even make one feasible. Link to comment Share on other sites More sharing options...
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