Yes. that is do-able. Consider a space elevator that goes out past Geosynchronous orbit. Put a lightweight sat about 4000km past the GSO point and release it. It will be flung (at the cost of a minuscule portion of the Earth's angular momentum) to an apogee about Lunar distance.
Now the neat trick is using a Lunar Space Elevator. from the nearside the tether would simply 'lay across' the L1 point.
And the Earth Moon-L1 point can get you to the EML2 point. From there, you can catch a manifold from EML2 to the Earth Sun L1/L2 points.
As Burdell said, it's not a matter of altitude for the most part, it's velocity.
So, consider a cannon on a tall mountain. The cannon functions just like a rocket, except all of the fuel is burned right at launch, providing a fixed amount of acceleration.
Say you put a unit of propellant in the cannon (gunpowder, C-4, rapidly heated liquid Nitrogen, anything exothermic) and you find your projectile (cannonball, shell, capsule, Sputnik) will follow a parabolic arc, landing some distance away.
However, consider if the Earth's surface didn't stop it, and the projectile passed ghostlike (or passed through a ghostlike planet). It would follow a elliptical path down, passing some distance from the Earth's center of mass, and then back up, to collide with your cannon.
Okay, if you fire this cannon with successively larger amounts of power, the shell impacts the Earth's surface (also called 'landing' or 'Lithobraking') further down range. Eventually the shell is landing at spots over the horizon. And with enough power it will hit the back of your cannon. If you moved the cannon out of the way (and assuming they there are no mountains/buildings in the projectile's path) it would circle the Earth.
This is an orbit--falling down with enough sideways velocity that you don't hit the ground.
Now the nice little picture I just gave you of mountains, cannons and projectiles is ignoring the Earth's atmosphere. An object passing through the atmosphere experiences drag--slowing it down. So to launch a object into orbit we need to both, have enough change in velocity (delta-v) to go fast enough to not hit the Earth, and to push through the Earth's atmosphere, and fight gravity losses (because Gravity is pulling you down at 9.8 m/s^2 as you are going up.).
Orbital velocity for an altitude of about 300 km is about 7500m/s, an you have to add about 1500â"2000 m/s for gravity/atmospheric drag losses.
If you happen to use a PC, and some flavor of windows, try Orbitersim (http://www.orbitersim.com). It's a free spaceflight sim. Just take the exercise to get into Orbit and more will be clear to you
Also, launching from a high altitude--good Idea, hard to do in practice for a larger rocket, as you have to either build a launch site on top of a very large, remote peak, or suspend a rocket from a balloon (limited payload), or an aircraft (also limited payload--see the Pegasus launcher)
Well, lets break down the base problem of getting TO the bit of Cosmos 200km above our heads.
This requires delta-v. And the more mass you are taking up, the more delta-v you need
Which means (given propulsion/engines of a fixed impulse), more fuel.
Which means a larger rocket, or more throwaway booster stages.
So, this method of taking advantage of these boundary conditions allows a satellite to use less fuel to get from the Earth-Sun L1/L2 orbit to another planet's L1/L2 point, and then from there a small set of timed maneuvers (and even aerobraking if there's enough atmosphere).
Less fuel for the Trans-planetary injection maneuver= less satellite mass=a relatively cheaper launch.
You could imagine multiple satellites being launched for the same cost as a single as one--using a constellation of satellites to explore the magnetosphere and moons of Jupiter rather than a lone satellite
Also, in the realm of 'more advanced', if you can build a satellite at the L1/L2 point, you can reduce the vehicles mass further (as it doesn't have to handle a 10 minute multi-g acceleration/vibration-fest into LEO). and with very little delta-v 'push' it into the correct manifold to a target body.
Admittedly, this is only for unmanned satellites (or cryogenically preserved passengers)
BTW, Geoff, I'd love having you back at Norwescon one of these years. You were a great Science GoH.
Of course I was making some generalizations. The paragraph about NASA would have gotten rather unwieldy very shortly.
SpaceX did not integrate every possibly lesson from every possible launch vehicle program by all of the various groups.
They did not take into account that hot, humid, salty sea air + aluminum nut with a scratch it its paint = possible failure of said nut.
For two flights they are almost to a walk from a crawl is my view (for what it's worth). Elon has a flight manifest that is pretty full, a near working launch vehicle, and two other models on the way. He has a passion for this in sinking his fortune into it.
He has stated "When people ask me why I started a rocket company, I say, 'I was trying to learn how to turn a large fortune into a small one.' " (http://www.spacex.com/media.php?page=42). I think he has the right attitude, that he could go broke doing this. The development of the railroad network across North America in the 19th century certainly cost a number of men and shareholders their wealth, but the result was the powerhouse that America's industries became.
I should have appended IANARS (I am not a rocket scientist) or IANAE (economist) either, but it's a subject that I have some knowledge about and quite a bit of passion, more on those two counts than many people I know and meet.
You are absolutely right.
If you look to much earlier rocketry development programs, ie Dr. Robert Goddard and Dr. Werner Braun (ignoring any politics of either, just the pure research, engineering and development effort) Developing Rockets are Hard.
SpaceX lost their first rocket because of a corroded aluminum nut securing a fuel line.
I think it is worth pointing out a number of facts with this accident.
The Falcon 1 launch vehicle have an in flight rapid disassembly event (explosion for those desiring a non-obfuscated tone). The nut failed, fuel spewed from the line, combusting when it reached into the rocket's plume, this caused a fire in the region of the Falcon 1's fuel pumps, gutting control wiring and other fuel lines. Result-- the engine simply shut down. The rocket fell onto the reef offshore and was destroyed.
As a result SpaceX reviewed the engine design and one of the changes was to replace all aluminum nuts with stainless steel. Equivelent mass, not prone to corrosion and cheaper as an additional benefit.
The second flight's failure was due to the wrong flight profile being loaded into the first stage's engine's computer(s). As a result the fuel/oxidizer mix fed to the engine wasn't quite optimal, resulting in the first stage engine cutoff (MECO) occured at a lower altitude than intended. At that point in flight the Falcon 1's orientation, with respect to it's trajectory (it's 'angle of attack') was enough that aerodynamic forces from the dynamic pressure (the atmospheric pressure at altitude considering the vehicle's velocity through it) caused the Falcon 1 first stage as it was jettisoned to pitch more than expected.
This resulted in the first stage coming into contact with the second stage's engine bell.
This resulted in the second stage in being rotated about it's center of mass a bit.
The second stage Kestral engine pivoted to correct the second stage's orientation onto the correct vector.
This resulted in an increasing oscillation that toward the end of the second stage's burn, as the mass of the vehicle was less and less.
This resulted in the remaining fuel in the propellant tanks sloshing away from the fuel tank's sump.
The Second stage engine cut off prematurely, below orbital velocity and the vehicle reentered.
Lessons and modifications taken from this. Confirm that the proper engine software is loaded onto the vehicle, and the installation of an anti-slosh baffles in the propellant tanks.
In this case the vehicle engines or structure did not fail catastrophically.
The upcoming flight is takes the lessons learned from all of this, and is a flight test for the new Merlin 1C engine, which will be used on the Falcon 9 when it flies.
Spaceflight is hard. SpaceX is standing on the shoulder's of giants, and still there is much to learn, old lessons to apply, and new breakthroughs to be made.
But the goal is worthwhile.
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Yes. that is do-able. Consider a space elevator that goes out past Geosynchronous orbit. Put a lightweight sat about 4000km past the GSO point and release it. It will be flung (at the cost of a minuscule portion of the Earth's angular momentum) to an apogee about Lunar distance. Now the neat trick is using a Lunar Space Elevator. from the nearside the tether would simply 'lay across' the L1 point. And the Earth Moon-L1 point can get you to the EML2 point. From there, you can catch a manifold from EML2 to the Earth Sun L1/L2 points.
As Burdell said, it's not a matter of altitude for the most part, it's velocity. So, consider a cannon on a tall mountain. The cannon functions just like a rocket, except all of the fuel is burned right at launch, providing a fixed amount of acceleration. Say you put a unit of propellant in the cannon (gunpowder, C-4, rapidly heated liquid Nitrogen, anything exothermic) and you find your projectile (cannonball, shell, capsule, Sputnik) will follow a parabolic arc, landing some distance away. However, consider if the Earth's surface didn't stop it, and the projectile passed ghostlike (or passed through a ghostlike planet). It would follow a elliptical path down, passing some distance from the Earth's center of mass, and then back up, to collide with your cannon. Okay, if you fire this cannon with successively larger amounts of power, the shell impacts the Earth's surface (also called 'landing' or 'Lithobraking') further down range. Eventually the shell is landing at spots over the horizon. And with enough power it will hit the back of your cannon. If you moved the cannon out of the way (and assuming they there are no mountains/buildings in the projectile's path) it would circle the Earth. This is an orbit--falling down with enough sideways velocity that you don't hit the ground. Now the nice little picture I just gave you of mountains, cannons and projectiles is ignoring the Earth's atmosphere. An object passing through the atmosphere experiences drag--slowing it down. So to launch a object into orbit we need to both, have enough change in velocity (delta-v) to go fast enough to not hit the Earth, and to push through the Earth's atmosphere, and fight gravity losses (because Gravity is pulling you down at 9.8 m/s^2 as you are going up.). Orbital velocity for an altitude of about 300 km is about 7500m/s, an you have to add about 1500â"2000 m/s for gravity/atmospheric drag losses. If you happen to use a PC, and some flavor of windows, try Orbitersim (http://www.orbitersim.com). It's a free spaceflight sim. Just take the exercise to get into Orbit and more will be clear to you Also, launching from a high altitude--good Idea, hard to do in practice for a larger rocket, as you have to either build a launch site on top of a very large, remote peak, or suspend a rocket from a balloon (limited payload), or an aircraft (also limited payload--see the Pegasus launcher)
Well, lets break down the base problem of getting TO the bit of Cosmos 200km above our heads. This requires delta-v. And the more mass you are taking up, the more delta-v you need Which means (given propulsion/engines of a fixed impulse), more fuel. Which means a larger rocket, or more throwaway booster stages. So, this method of taking advantage of these boundary conditions allows a satellite to use less fuel to get from the Earth-Sun L1/L2 orbit to another planet's L1/L2 point, and then from there a small set of timed maneuvers (and even aerobraking if there's enough atmosphere). Less fuel for the Trans-planetary injection maneuver= less satellite mass=a relatively cheaper launch. You could imagine multiple satellites being launched for the same cost as a single as one--using a constellation of satellites to explore the magnetosphere and moons of Jupiter rather than a lone satellite Also, in the realm of 'more advanced', if you can build a satellite at the L1/L2 point, you can reduce the vehicles mass further (as it doesn't have to handle a 10 minute multi-g acceleration/vibration-fest into LEO). and with very little delta-v 'push' it into the correct manifold to a target body. Admittedly, this is only for unmanned satellites (or cryogenically preserved passengers)
Geoffrey Landis commented on my post??
Cool!
BTW, Geoff, I'd love having you back at Norwescon one of these years. You were a great Science GoH.
Of course I was making some generalizations. The paragraph about NASA would have gotten rather unwieldy very shortly.
SpaceX did not integrate every possibly lesson from every possible launch vehicle program by all of the various groups.
They did not take into account that hot, humid, salty sea air + aluminum nut with a scratch it its paint = possible failure of said nut.
For two flights they are almost to a walk from a crawl is my view (for what it's worth). Elon has a flight manifest that is pretty full, a near working launch vehicle, and two other models on the way. He has a passion for this in sinking his fortune into it.
He has stated "When people ask me why I started a rocket company, I say, 'I was trying to learn how to turn a large fortune into a small one.' " (http://www.spacex.com/media.php?page=42). I think he has the right attitude, that he could go broke doing this. The development of the railroad network across North America in the 19th century certainly cost a number of men and shareholders their wealth, but the result was the powerhouse that America's industries became.
I should have appended IANARS (I am not a rocket scientist) or IANAE (economist) either, but it's a subject that I have some knowledge about and quite a bit of passion, more on those two counts than many people I know and meet.
Thank you for your time.
You are absolutely right. If you look to much earlier rocketry development programs, ie Dr. Robert Goddard and Dr. Werner Braun (ignoring any politics of either, just the pure research, engineering and development effort) Developing Rockets are Hard. SpaceX lost their first rocket because of a corroded aluminum nut securing a fuel line. I think it is worth pointing out a number of facts with this accident. The Falcon 1 launch vehicle have an in flight rapid disassembly event (explosion for those desiring a non-obfuscated tone). The nut failed, fuel spewed from the line, combusting when it reached into the rocket's plume, this caused a fire in the region of the Falcon 1's fuel pumps, gutting control wiring and other fuel lines. Result-- the engine simply shut down. The rocket fell onto the reef offshore and was destroyed. As a result SpaceX reviewed the engine design and one of the changes was to replace all aluminum nuts with stainless steel. Equivelent mass, not prone to corrosion and cheaper as an additional benefit. The second flight's failure was due to the wrong flight profile being loaded into the first stage's engine's computer(s). As a result the fuel/oxidizer mix fed to the engine wasn't quite optimal, resulting in the first stage engine cutoff (MECO) occured at a lower altitude than intended. At that point in flight the Falcon 1's orientation, with respect to it's trajectory (it's 'angle of attack') was enough that aerodynamic forces from the dynamic pressure (the atmospheric pressure at altitude considering the vehicle's velocity through it) caused the Falcon 1 first stage as it was jettisoned to pitch more than expected. This resulted in the first stage coming into contact with the second stage's engine bell. This resulted in the second stage in being rotated about it's center of mass a bit. The second stage Kestral engine pivoted to correct the second stage's orientation onto the correct vector. This resulted in an increasing oscillation that toward the end of the second stage's burn, as the mass of the vehicle was less and less. This resulted in the remaining fuel in the propellant tanks sloshing away from the fuel tank's sump. The Second stage engine cut off prematurely, below orbital velocity and the vehicle reentered. Lessons and modifications taken from this. Confirm that the proper engine software is loaded onto the vehicle, and the installation of an anti-slosh baffles in the propellant tanks. In this case the vehicle engines or structure did not fail catastrophically. The upcoming flight is takes the lessons learned from all of this, and is a flight test for the new Merlin 1C engine, which will be used on the Falcon 9 when it flies. Spaceflight is hard. SpaceX is standing on the shoulder's of giants, and still there is much to learn, old lessons to apply, and new breakthroughs to be made. But the goal is worthwhile.