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#1
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Mojave airport is not a spaceport
The Mojave Airport is a perfect place to test
airplanes and sounding rockets, but it is probably the worst place on Earth to locate the space rocket launch site -- Manhattan would be better. There is no ocean to the east of Mojave, so you cannot make cheap pressure-fed rockets, splash them down and reuse them. A big city (Los Angeles) is just 100 km south of Mojave. The nearest pacific coast is 130 km south west, next to Ventura, California. If you launch the real thing, you will have to launch it in the south west direction and hope it will not fall on Los Angeles. NASA should make the Kennedy Space Center available to independent rocket makers. |
#2
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Mojave airport is not a spaceport
In article ,
Andrew Nowicki wrote: The Mojave Airport is a perfect place to test airplanes and sounding rockets, but it is probably the worst place on Earth to locate the space rocket launch site -- Manhattan would be better. Hardly. Mojave *is* out in the middle of nowhere, which is why a lot of aircraft testing already gets done there. The biggest hazards from rocketry are in the immediate vicinity of the launch site. There is no ocean to the east of Mojave, so you cannot make cheap pressure-fed rockets, splash them down and reuse them. You couldn't do that from Mojave Spaceport anyway, because (last I heard) their spaceport license is for horizontal-takeoff-horizontal-landing launch vehicles only. They've decided to cater to one particular type of vehicle, rather than covering the whole spectrum. If you're going to build vehicles resembling artillery rockets, where pieces deliberately fall off during ascent and make uncontrolled landings, then quite likely you are going to have to launch over water. That's not the only design option. A big city (Los Angeles) is just 100 km south of Mojave. Orlando is about the same distance from the Cape, and Vandenberg is not much farther away from L.A. If you launch the real thing, you will have to launch it in the south west direction and hope it will not fall on Los Angeles. No, you launch eastward, and establish sufficiently low probability of casualties by good design and proper testing. (Operating only over largely uninhabited areas certainly *helps* -- it means you can achieve the required level of safety even with a relatively high estimated probability of failure, which is easier to justify -- but it is not actually required.) Note that there is no launch site on Earth where your debris footprint will be on water throughout ascent. Even launching from the Cape, some possibility of hitting Africa must be accepted. NASA should make the Kennedy Space Center available to independent rocket makers. The Cape is already available to commercial rocket builders, and has been for quite a while. The bureaucratic hurdles are considerable -- and they would not get easier at KSC, because the USAF is in charge of range safety either way -- and the overhead costs are high, but it is available. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#3
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Mojave airport is not a spaceport
Andrew Nowicki wrote:
There is no ocean to the east of Mojave, so you cannot make cheap pressure-fed rockets, splash them down and reuse them. If you're going to reuse them in any significant fashion, "cheap" is a loaded term. You want them to be economical to use, certainly, but that's not the same thing as being inexpensive to build (or buy) in the first place. I've always agreed with the idea that dropping machinery in sal****er and fishing it back out isn't a great thing to do if you want to use it again without significant refurbishing. What's wrong with spending the bit of extra effort required to simply *land* the things and reuse them? Appropriate up-front engineering can lower the operational costs of staging. A lot of cost can be saved if your first stage rocket comes back to the launch site by itself, and if it basically just needs to be brushed off and recharged/refueled before it's ready to have an upper stage vehicle latched on for the next launch. (For that matter, what's wrong with spending the next bit of extra effort required to make "first-stage rockets" as quaint as capsule splashdowns? The ultimate reduction in the operational costs of staging is to remove staging completely.) |
#4
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Mojave airport is not a spaceport
"Alan Anderson" wrote in message ... (For that matter, what's wrong with spending the next bit of extra effort required to make "first-stage rockets" as quaint as capsule splashdowns? The ultimate reduction in the operational costs of staging is to remove staging completely.) To eliminate staging, you need to provide: 1. Enough extra wing to land the big "first stage" tanks. 2. Enough extra shielding to re-enter tanks and wing. 3. Enough extra fuel to deorbit tanks, wings, and shielding. 4. Enough extra fuel to get tanks, wings, shielding, and extra fuel into orbit in the first place. 5. A larger "first stage" tank to hold the extra fuel for requirements 1-4. 6. And so it cycles. These requirements don't go away with a "bit of extra effort" at the design and manufacturing stage. Maybe eliminating staging saves enough operationally to make sense. But maybe we should be trying to cut those operational costs without resorting to fundamentally wasteful expenditure of resources lifting and returning things that we don't use while we are "up there". |
#5
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Mojave airport is not a spaceport
Alan Anderson wrote:
I've always agreed with the idea that dropping machinery in sal****er and fishing it back out isn't a great thing to do if you want to use it again without significant refurbishing. What is wrong with it? You can keep an unpainted titanium rocket in the sal****er for many years without any adverse effects except biofouling (things growing on it). There are paints which prevent biofouling. Unpainted aluminum rocket can be kept in the salt water for a few days without any signs of corrosion. (Many large ships and tankers are made of painted aluminum. The Coast Guard is replacing its steel buoys with aluminum buoys.) What's wrong with spending the bit of extra effort required to simply *land* the things and reuse them? The pressure-fed rocket has almost no moving part. It can be made in a shipyard. The rocket-plane is at least one order of magnitude more expensive. It has lots of moving parts which can fail. Look at the russian Baikal: http://www.spacedaily.com/news/rocketscience-03j.html It has foldable wings, jet engines, landing gear... Appropriate up-front engineering can lower the operational costs of staging. A lot of cost can be saved if your first stage rocket comes back to the launch site by itself, and if it basically just needs to be brushed off and recharged/refueled before it's ready to have an upper stage vehicle latched on for the next launch. If the rocket-planes do not crash upon landing, they may be feasible. Anyway, the idea of a reusable first stage is more important than its implementation. The range safety is more important -- I doubt anyone can get a permit to fly his rocket launcher over a populated area. |
#6
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Mojave airport is not a spaceport
Andrew Nowicki wrote:
AN There is no ocean to the east of Mojave, AN so you cannot make cheap pressure-fed rockets, AN splash them down and reuse them. Henry Spencer wrote: HS You couldn't do that from Mojave Spaceport anyway, HS because (last I heard) their spaceport license is HS for horizontal-takeoff-horizontal-landing launch HS vehicles only. They've decided to cater to one HS particular type of vehicle, rather than covering HS the whole spectrum... you launch eastward... Single stage rocket launchers do not exist. Does it mean that the spent first stage is dropped near Phoenix, Arizona, and the spent second stage is dropped on Texas? |
#7
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Mojave airport is not a spaceport
In article ,
Andrew Nowicki wrote: HS You couldn't do that from Mojave Spaceport anyway, HS because (last I heard) their spaceport license is HS for horizontal-takeoff-horizontal-landing launch HS vehicles only... Single stage rocket launchers do not exist. Neither do the pressure-fed launchers you're talking about. Does it mean that the spent first stage is dropped near Phoenix, Arizona... No, its pilot turns it around and flies it back to base. Or, possibly, glides it down to a landing at some suitable airstrip, from which it is trucked or flown back to Mojave, although that's rather less convenient. What part of "horizontal-takeoff-horizontal-landing only" is so hard for you to grasp? Your pressure-fed artillery rockets will *never* operate out of Mojave, and it's got nothing to do with where the pieces falling off would land. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#8
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Mojave airport is not a spaceport
In article om,
Perplexed in Peoria wrote: ...Maybe eliminating staging saves enough operationally to make sense. But maybe we should be trying to cut those operational costs without resorting to fundamentally wasteful expenditure of resources lifting and returning things that we don't use while we are "up there". The question is whether it is less trouble to take them along, or to have them fall off and be recovered separately. The answer is not immediately obvious. Recovering stuff that falls off halfway to orbit is not easy. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#9
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Mojave airport is not a spaceport
Andrew Nowicki wrote:
Single stage rocket launchers do not exist. Does it mean that the spent first stage is dropped near Phoenix, Arizona, and the spent second stage is dropped on Texas? Actually, single stage rocket launchers do exist. As do rockets with entirely reusible stages throughout. Single stage *orbital* launchers do not, but nobody's flying those out of Mojave any time soon so that's a non-issue. |
#10
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Mojave airport is not a spaceport
"Perplexed in Peoria" wrote:
To eliminate staging, you need to provide: 1. Enough extra wing to land the big "first stage" tanks. Wet wings can help here. But who says you need wings in the first place? 2. Enough extra shielding to re-enter tanks and wing. You're talking thermal protection, right? If the vehicle is big and light at reentry, dealing with the heating problem should be *easier*. 3. Enough extra fuel to deorbit tanks, wings, and shielding. 4. Enough extra fuel to get tanks, wings, shielding, and extra fuel into orbit in the first place. 5. A larger "first stage" tank to hold the extra fuel for requirements 1-4. Fuel is cheap. 6. And so it cycles. If you start with something large enough to meet the requirements in the first place, you don't have to iterate making it larger. These requirements don't go away with a "bit of extra effort" at the design and manufacturing stage. Maybe eliminating staging saves enough operationally to make sense. But maybe we should be trying to cut those operational costs without resorting to fundamentally wasteful expenditure of resources lifting and returning things that we don't use while we are "up there". Those "resources" are essentially propellant. Wasting something that isn't all that expensive is not a large problem. |
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