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A new way to orbit

Posted by: halman - Sun Mar 01, 2015 7:32 am
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A new way to orbit 
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Post A new way to orbit   Posted on: Sun Mar 01, 2015 7:32 am
Going into space has always meant taking off straight up. We don't have to do that any more, and we could make a lot more progress if we quit going into orbit that way. Taking off straight up means everything having to work right without fail. Taking off straight up means only launching in ideal conditions. Taking off straight up means aborting the launch at any sign of a problem.

Going into orbit means going [i]fast[i]. But we can not go fast while deep in our atmosphere. We have to get above most of it before we can start going really fast. Instead of using the atmosphere to our advantage, we are fighting it, trying to get past it as soon as possible. There is a better way.

By using a large wing, we can lift payloads to 15 kilometers. We can carry our spacecraft to the edge of the atmosphere before we start its engines, so that all of the fuel is used for accelerating. If the only payload that the spacecraft will carry is people, we can build a smaller, lighter spacecraft, one that does not need exotic fuels and advanced engines. We can build a spacecraft that lands on a runway, and is completely reusable. We can build the spacecraft that the engineers at NASA originally wanted to build.

Almost every aircraft that has ever been built has been designed to carry people and cargo from one place to another. The exception are the two White Knight aircraft, which were designed to carry something to altitude. The design we will need for our carrier wing will be as radically different as the White Knight is, only more so. A wing with no fuselage seems strange to most people, but the concept is proven.

The White Knight carries its spacecraft to altitude, and then drops it. So it must be able to straddle the spacecraft. But this won't work with a really large spacecraft, so our carrier wing will have to carry the spacecraft on its back. But this can be used to our advantage, as no altitude will be lost when the spacecraft launches. Also, this allows the weight of the spacecraft and the carrier wing to be concentrated on a small area. This is important because the carrier wing/spacecraft stack will not take off from a runway, but from a track which incorporates a linear motor.

Instead of relying solely on the power of the carrier wing to reach take-off velocity, we can catapult the stack up to a high enough speed that there will be no question of having enough lift. And using the track will eliminate the need for several kilometers of runway three meters thick, as well as an undercarriage which can support the weight of both the spacecraft and the carrier wing. An added bonus is the ability to abort a take-off without jeopardizing the crew or the vehicle.

15,000 meters up, the spacecraft lights up its engines, separates from the carrier wing, and begins accelerating. The lifting body shape provides lift, and the velocity causes the spacecraft to gain altitude. As it climbs, it can go faster, without any concern for max-Q, the atmospheric turbulence which the space shuttle had to throttle back to avoid.

By limiting the payload to passengers, and the maximum altitude to 400 kilometers, we can build our spacecraft small enough that the carrier wing can launch it. Cargo we can launch with step rockets. People are too valuable.

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Post Re: A new way to orbit   Posted on: Sat Mar 07, 2015 8:55 pm
I wonder if the wingcraft could be ran on fuel made with a supercritical solar gasifier, from algae at the launch site...

No supporting infrastructure needed....

Also, what kind of linear motor are you suggesting?

my own idea needs no wings.... but would require something like elon musks hyperloop, and an enormus laser array....

Basicly, you leave the tunnel at a high mach, and zip up the center of a laser induced plasma channel....

ride the lightning.....

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Post Re: A new way to orbit   Posted on: Tue Mar 10, 2015 10:52 pm
Your concept sounds very much like Zero-X from Thunderbirds are Go! (BTW great movie if you have not seen it).


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Post Re: A new way to orbit   Posted on: Wed Mar 11, 2015 10:06 pm
One of the most important aspects of my proposal is that it does not require the development of new technologies, only expansion on what is known. The linear motor is also called a 'rail gun' by some, basically a motor that is laid out flat, with the rotor being the moving payload. The Navy is investigating using them for launch catapults and weapons systems. The concept has been around for over 50 years, and has been developed by several researchers into portable weapons, launch catapults, and big weapons. The primary reason that I incorporate one into my proposal is to make up for the fact that turbofan engines are very inefficient at low speeds, so it would take a very long runway for the carrier wing to reach take-off velocity.

Propellents will undoubtedly evolve as we expand our sphere of activities, but what works right now is what I want to stick with, so that the investors are not spending money on research, but on building a launch system. Once it is up and running, there will be plenty of time and money for new techniques.

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Post Re: A new way to orbit   Posted on: Thu Mar 12, 2015 4:43 pm
I think the problem with your idea is that it will require a higher velocity to get to an altitude of 15km if you launch horizontally instead of vertically. If I understand correctly, your flying wing has no on-board power and gets all of its velocity from the rail gun. If you ignore air resistance you would need the same initial velocity to launch horizontally as you would vertically.

However, in real life you would need a much higher initial velocity to overcome the fact that you will be experiencing much higher air resistance. You will be fighting air resistance for a longer duration by starting out horizontally. Also, in a vertical launch the velocity is lower where the atmosphere is denser, and higher where the density is lower. A rail launch is the opposite, and less efficient.

EDIT: After re-reading your posts I may have misunderstood what you are proposing. So you're just proposing using a jet to carry a rocket to 15km, and using a railgun to launch the jet/rocket. I don't see the real advantage to the railgun unless the jet engine requires high velocity to work. If it's just an issue of jet-engine efficiency, I would lean toward carrying more fuel versus a railgun.


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Post Re: A new way to orbit   Posted on: Fri Mar 13, 2015 2:29 am
The reason I incorporate a rail gun (linear motor) in my proposal is that getting a very large mass moving using just jet engines takes a long time. Jet engines are not very efficient at low velocities. Also, I believe that a track will be necessary to support the weight of the carrier wing and spacecraft. I have used ballpark figures in my guestimates, but I think that 1 million pounds is a reasonable weight for the orbiter portion of the launch system, when fully fueled with payload. So the carrier wing is going to weigh somewhere around 2 million pounds, meaning that the total weight will be 3 million pounds. Even using Boundary Layer Control, leading edge slats, and all the other tricks for gaining lift, I still believe that the take-off velocity will be over 200 miles per hour, and an even higher speed would be desirable, so that there is no question of the wing being able to climb at lift-off.

Another important function of the catapult would be allowing aborted take-offs to be stopped quickly and safely, without having tires being destroyed, and the vehicle possibly damaged. The carrier wing and spacecraft stack would be slowed by the linear motor running backwards, until the velocity was down around 20 miles per hour. Hopefully, this launch system would be used on a daily basis, so there are bound to be aborts once in awhile. (Watching a pad abort with the shuttle was terrifying, as the main engines ran for about three seconds, and then shut down. When you are taking off straight up, everything has to work right.)

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Post Re: A new way to orbit   Posted on: Mon Mar 16, 2015 12:18 pm
halman wrote:
Another important function of the catapult would be allowing aborted take-offs to be stopped quickly and safely [...]


"Safely" is not a word I would expect in the same sentence as "Catapult".


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Post Re: A new way to orbit   Posted on: Wed Mar 18, 2015 10:05 am
IrquiM wrote:
halman wrote:
Another important function of the catapult would be allowing aborted take-offs to be stopped quickly and safely [...]


"Safely" is not a word I would expect in the same sentence as "Catapult".


'Catapult' is used in reference to the devices that accelerate aircraft to take-off speeds in a short distance, but does not adequately describe the machine that I am talking about. It would be a linear motor, reversible, that can accelerate 3 million pounds to 250 miles per hour in less than a mile, hold it at that speed for about 45 seconds, and then slow it back down if necessary. Because the carrier wing and orbiter would be riding on a cart that is attached to a big slug of magnetic material, the motor would be able to alter the cart's velocity.

This is a critical component of this launch system, because the catapult makes it possible to get a very large aircraft in the air without a long take-off roll. Also, it eliminates the need for a massive undercarriage, which would add tons to the carrier wing's weight. Rockets would work for accelerating the stack, but don't offer any help in slowing it down. And all the engines on the carrier wing would be running at full power, so that the wing would not slow down once it was released from the catapult.

Once this massive vehicle is in the air, everything gets much less complicated. By climbing at a slow, but steady rate, the wing can gain altitude while lining up on the desired orbital inclination. The orbiter can run its engines up while still attached to the carrier wing, and make sure that everything is ready before separation. The engines don't need to be super high powered, because the orbiter won't be climbing straight up, and it won't be carrying a heavy payload, and it won't be trying to reach an altitude above about 250 miles. By limiting the design requirements, we can allow some leeway with the performance specifications.

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