Err, that wasn't quite my point about failures. (And sorry about the formatting above.) Just that by the time the rocket was ready to fire that stage, it was already at or near orbital speeds.
The primary problem with airbreathing engines would be that even the fastest of them can only get you about 1/4 of the speed needed for LEO. (2km/s vs 8km/s) The final design would probably use 1-2 stages to do the equivalent of the first stage of a typical booster. With a high enough launch rate, this should be cheaper...
As far as the simulations go, has NASA published the data from the X-43 project? Last I heard, hypersonic aerodynamics were rather poorly understood (and models would be very processor intensive).
You'd probably want to use titanium over steel. Especially for high temperature parts like the engine and nose. Even then, hull temperatures mach 5+ might well be high enough to warrent a somewhat shuttle-like TPS.
Recruiting hobbiest for these things does always help =)
Height is (almost) nothing for space travel. Speed is (almost) everything. If you haven't done so, play around with the rocket equation for a while. It gives a good idea of the challenge involved. At least a good ramjet stage could shave off a 1-2 km/s from what the rocket stage(s) need to do. (You talked about both supersonic and hypersonic designs when you brought up liquid hydrogen.)
As an example of how easy altitude is, the first rocket to get 60 miles up was launched around 1940. Rockets that could get *anything* up to orbital velocity weren't available until the mid-late 50s. (Does Von Barun count as an enthusiast who found a really good source of funding?;))
The wave rider prototype that the STAR group tested did beat the XB-70 by a few years. The latter was vastly more capable, though. (Supersonic strategic bomber. Yum.)
As far as the gravity fall-off goes, The difference between 6371 km and 6572 km isn't that much. (point mass assumed for hopefully obvious reasons)
>Sure, the thing you want to place in orbit has to maintain orbital velocity, but most payloads have rockets strapped to them to kick them into position and give them the speed to maintain it. The main rocket ONLY has to get to the correct height for all that to work.
It's worth looking at the records of launches where the upper most stage failed to fire. The rocket as already (or almost already) achieved orbit. Especially in the case of GEO launches, where altitude becomes somewhat important.
>Your kinetic energy figures are BS. Potential energy is along the vector pointing to the center of gravity of the Earth. Kinetic energy is along the vector orthogonal to that in which the object is travelling. The component of either that exists in the direction of the other is exactly zero - the definition of orthogonal vectors.
Energy is a scalar...
I wonder how well a ramjet would survive being shot out of a mini-babylon gun...
XP (classic) is behaving slightly differently. When I click on the bottom left corner, it actually moves the mouse up and to the right the few pixels so that it's on the start button. (And opens the start menut)
More or less. This gets into the classic E=mc^2. The problem is that fission only gets you about 0.3% of the mass converted into energy. Fusion is better (~0.7%), but to get truely amazing amounts, you need antimatter, or something similarly exotic.
Even so, a Nerva or Orion like space craft would have some nice capabilities.
Since I'm working at McDonalds this summer, I've noticed that the managers only get paid ~$10 an hour. I belive that it's ~$13 an hour for the store manager (who got to that position after working there for ~7 years).
Somehow, any entry level office job seems better. Similar (if not better) pay, less experience required, and much more comfortable working conditions. (you get a airconditioning and a chair for starters)
IIRC, you can make a ringworld with about 1 earth mass. Actually, you can make a dyson sphere with that little mass if you don't mind it being really thin. So for that 2.5% of earth's mass, call it a factor of 50. (Assuming that 90% of the work is in removing the mass. It shouldn't be too hard to aim it where you want for reassembly).
Yes, I'm unsure. At this level, intuition really doesn't work very well =/
Yes, it would have interesting effects.
Fortunately, were quite a few orders of magnitude away from those sorts of issues. (The moon is ~10% of the mass of the earth. If we can remove enough mass to affect tides on earth, we probably aren't all that far from building a ringworld or dyson sphere)
True nothing current can do the job, but things to not stand still.
You'd be surprised by how old the rockets are. The Delta and Atlas boosters date back to the 50s, the Soyuz and Proton to the 60s, and the Shuttle to the 70s.
Also, no one has built a booster that can meet or exceed the ~40 year old saturn V. (With the possible exception of the STS, if you include the shuttle itself as part of the payload)
It's not supposed to stop. It's not supposed to land anywhere. At the end of the mission, we just let it drift away. Thankfully, interplanitary (and even more so interstellar) space is large enough for us to get away with this for a *long* time.
A shuttle derived heavy lift vehical may make sense.
It's worth noting that no commercial launch vehical can lift more than ~25 tonnes into LEO. (and rather less on an earth escape trajectory) For a manned Moon or Mars mission, you need the equivalent of 100-150 tonnes to LEO, assuming that you are going with a lightweight (eg: Mars Direct) program.
Even if the Russians don't (or can't) bring back Energia, their Proton boosters are among the most powerful in use (beaten only by the new Delta-IV Heavy and very arguably the shuttle), and surprisingly cheap.
Is there any chance that a few (unmanned) shuttle C flights could be used to launch the remaining pieces of the ISS?
Or would it take too much time&money to build a few shuttle C orbiters? =/
Approximately 1/3 of astronauts get space adaption syndrome. Basically, when you're in microgravity, the fluid in your inner ear doesn't settle, and so doesn't give your body a proper sense of balance. This does cause nausea and disorentation (lasting for up to a few days) in some people. Since these sub-orbital hops only give a few minutes of weightlessnesss, this will hopefully not be an issue.
Or at least they're not supposed to be.
Rather, they give you the information that you need to then build a good air/spacecraft using similar ideas. (eg: The X-31's vectored thrust ideas being used in the F-22)
Okay, apparently exotic matter doesn't work, according to the article./lart self. It's interesting that the uncertainty principle can work on wormholes also...
Answer: we don't really know to travel into the past (although there are some guesses, mainly involving wormholes). AFAIK, there is nothing in relativity or quantum mechanics that explicitly prevents you from time traveling (and there are some possible ways to). You've hit upon a real problem, though.
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Err, that wasn't quite my point about failures. (And sorry about the formatting above.) Just that by the time the rocket was ready to fire that stage, it was already at or near orbital speeds.
The primary problem with airbreathing engines would be that even the fastest of them can only get you about 1/4 of the speed needed for LEO. (2km/s vs 8km/s) The final design would probably use 1-2 stages to do the equivalent of the first stage of a typical booster. With a high enough launch rate, this should be cheaper...
As far as the simulations go, has NASA published the data from the X-43 project? Last I heard, hypersonic aerodynamics were rather poorly understood (and models would be very processor intensive).
You'd probably want to use titanium over steel. Especially for high temperature parts like the engine and nose. Even then, hull temperatures mach 5+ might well be high enough to warrent a somewhat shuttle-like TPS.
Recruiting hobbiest for these things does always help =)
How about the composites in your car? Or the computer that you typed this on? (NASA did wonders for the IC market in the 60s and 70s)
Height is (almost) nothing for space travel. Speed is (almost) everything. If you haven't done so, play around with the rocket equation for a while. It gives a good idea of the challenge involved. At least a good ramjet stage could shave off a 1-2 km/s from what the rocket stage(s) need to do. (You talked about both supersonic and hypersonic designs when you brought up liquid hydrogen.) As an example of how easy altitude is, the first rocket to get 60 miles up was launched around 1940. Rockets that could get *anything* up to orbital velocity weren't available until the mid-late 50s. (Does Von Barun count as an enthusiast who found a really good source of funding? ;))
The wave rider prototype that the STAR group tested did beat the XB-70 by a few years. The latter was vastly more capable, though. (Supersonic strategic bomber. Yum.)
As far as the gravity fall-off goes, The difference between 6371 km and 6572 km isn't that much. (point mass assumed for hopefully obvious reasons)
>Sure, the thing you want to place in orbit has to maintain orbital velocity, but most payloads have rockets strapped to them to kick them into position and give them the speed to maintain it. The main rocket ONLY has to get to the correct height for all that to work.
It's worth looking at the records of launches where the upper most stage failed to fire. The rocket as already (or almost already) achieved orbit. Especially in the case of GEO launches, where altitude becomes somewhat important.
>Your kinetic energy figures are BS. Potential energy is along the vector pointing to the center of gravity of the Earth. Kinetic energy is along the vector orthogonal to that in which the object is travelling. The component of either that exists in the direction of the other is exactly zero - the definition of orthogonal vectors.
Energy is a scalar...
I wonder how well a ramjet would survive being shot out of a mini-babylon gun...
XP (classic) is behaving slightly differently. When I click on the bottom left corner, it actually moves the mouse up and to the right the few pixels so that it's on the start button. (And opens the start menut)
I just browsed through the JET website and saw nothing about break even mentioned. Why would something that major not be listed?
More or less. This gets into the classic E=mc^2. The problem is that fission only gets you about 0.3% of the mass converted into energy. Fusion is better (~0.7%), but to get truely amazing amounts, you need antimatter, or something similarly exotic. Even so, a Nerva or Orion like space craft would have some nice capabilities.
The R/L stuff is more of a Japanese thing anyway...
Since I'm working at McDonalds this summer, I've noticed that the managers only get paid ~$10 an hour. I belive that it's ~$13 an hour for the store manager (who got to that position after working there for ~7 years). Somehow, any entry level office job seems better. Similar (if not better) pay, less experience required, and much more comfortable working conditions. (you get a airconditioning and a chair for starters)
"Is everything shooting along while power generation creeps?" More like everything creeps along, while computers shoot ahead.
IIRC, you can make a ringworld with about 1 earth mass. Actually, you can make a dyson sphere with that little mass if you don't mind it being really thin. So for that 2.5% of earth's mass, call it a factor of 50. (Assuming that 90% of the work is in removing the mass. It shouldn't be too hard to aim it where you want for reassembly). Yes, I'm unsure. At this level, intuition really doesn't work very well =/
Yes, it would have interesting effects. Fortunately, were quite a few orders of magnitude away from those sorts of issues. (The moon is ~10% of the mass of the earth. If we can remove enough mass to affect tides on earth, we probably aren't all that far from building a ringworld or dyson sphere)
True nothing current can do the job, but things to not stand still. You'd be surprised by how old the rockets are. The Delta and Atlas boosters date back to the 50s, the Soyuz and Proton to the 60s, and the Shuttle to the 70s. Also, no one has built a booster that can meet or exceed the ~40 year old saturn V. (With the possible exception of the STS, if you include the shuttle itself as part of the payload)
It's not supposed to stop. It's not supposed to land anywhere. At the end of the mission, we just let it drift away. Thankfully, interplanitary (and even more so interstellar) space is large enough for us to get away with this for a *long* time.
A shuttle derived heavy lift vehical may make sense. It's worth noting that no commercial launch vehical can lift more than ~25 tonnes into LEO. (and rather less on an earth escape trajectory) For a manned Moon or Mars mission, you need the equivalent of 100-150 tonnes to LEO, assuming that you are going with a lightweight (eg: Mars Direct) program.
Even if the Russians don't (or can't) bring back Energia, their Proton boosters are among the most powerful in use (beaten only by the new Delta-IV Heavy and very arguably the shuttle), and surprisingly cheap.
Er, during which part of the Apollo program? I belive the (inflation corrected) funding is now up to ~65% of what it was in 1965.
Is there any chance that a few (unmanned) shuttle C flights could be used to launch the remaining pieces of the ISS? Or would it take too much time&money to build a few shuttle C orbiters? =/
Approximately 1/3 of astronauts get space adaption syndrome. Basically, when you're in microgravity, the fluid in your inner ear doesn't settle, and so doesn't give your body a proper sense of balance. This does cause nausea and disorentation (lasting for up to a few days) in some people. Since these sub-orbital hops only give a few minutes of weightlessnesss, this will hopefully not be an issue.
He still did okay, though.
But we threw it away. We stopped building Saturn Vs and we let Skylab burn up.
That would probably be part of a Mars Direct style program.
Or at least they're not supposed to be. Rather, they give you the information that you need to then build a good air/spacecraft using similar ideas. (eg: The X-31's vectored thrust ideas being used in the F-22)
Okay, apparently exotic matter doesn't work, according to the article. /lart self. It's interesting that the uncertainty principle can work on wormholes also...
Answer: we don't really know to travel into the past (although there are some guesses, mainly involving wormholes). AFAIK, there is nothing in relativity or quantum mechanics that explicitly prevents you from time traveling (and there are some possible ways to). You've hit upon a real problem, though.
I thought that all earlier calculations on wormholes showed that you needed something exotic to keep them from collapsing.