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Old 02-26-2009, 04:06 PM   #51
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Default Can the space shuttle take off from a runway?

Someone got sold on the idea that because it's shaped like a airplane that it can be used as such. Land, roll it back to the launch pad, prop it up, and shoot it off again. In essence a "free" space craft after the first time around.

The reality is a 450+ million launch, and I'm not sure that even includes all the refit and inspection after a landing.
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Old 02-26-2009, 08:41 PM   #52
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Default Can the space shuttle take off from a runway?

Quote:
Originally posted by: Rubycon
Quote:
Originally posted by: Modelworks

I'll stick with what a NASA engineer said " The shuttle is a rock in a controlled free-fall to the ground"
I've heard the same thing said by another NASA physicist too.

Also the SSME Rocketdyne motors are not designed for horizontal operation across the ground? Would the pumps and gimbal mounts even work correctly like this?
During the latter half of the reentry, it glides down to earth just like any other glider.
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Old 03-03-2009, 09:57 PM   #53
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Default Can the space shuttle take off from a runway?

Quote:
Originally posted by: KillerCharlie
Quote:
Originally posted by: Rubycon
Quote:
Originally posted by: Modelworks

I'll stick with what a NASA engineer said " The shuttle is a rock in a controlled free-fall to the ground"
I've heard the same thing said by another NASA physicist too.

Also the SSME Rocketdyne motors are not designed for horizontal operation across the ground? Would the pumps and gimbal mounts even work correctly like this?
During the latter half of the reentry, it glides down to earth just like any other glider.

actually its more like the last 3 minutes. Most of the re-entry is S turned purposefully designed to create drag and slow the craft to around 600 MPH. Flying brick is truly an accurate description.

The cold fuel engine cooling system would be the biggest challenge to horizontal operation, gravity would pull the fuel/combustion down, and would lead to a non-uniform burn, could melt the directional housing.
Also the engine swivels would present an interesting challenge.
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Old 03-11-2009, 03:57 AM   #54
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Default Can the space shuttle take off from a runway?

If you (by any means) apply enough propelling force to the shuttle for taking off from a runway, it would probably go underground rather than taking off i think.
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Old 03-11-2009, 01:06 PM   #55
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Default Can the space shuttle take off from a runway?

Quote:
Originally posted by: sao123
Quote:
Originally posted by: KillerCharlie
Quote:
Originally posted by: Rubycon
Quote:
Originally posted by: Modelworks

I'll stick with what a NASA engineer said " The shuttle is a rock in a controlled free-fall to the ground"
I've heard the same thing said by another NASA physicist too.

Also the SSME Rocketdyne motors are not designed for horizontal operation across the ground? Would the pumps and gimbal mounts even work correctly like this?
During the latter half of the reentry, it glides down to earth just like any other glider.

actually its more like the last 3 minutes. Most of the re-entry is S turned purposefully designed to create drag and slow the craft to around 600 MPH. Flying brick is truly an accurate description.
Bear with me I am trying to remember the crap from space camp 20 years ago

I think it's more like horizontal loops IRC. I remember a series of 2-3 hard banking loops to decelerate.

Also the OHMS engines (bulbous upper rear engines) are used to slow the craft down enough for gravity to pull the orbiter back to earth. Once the Orbiter ditches its rusty external tank, it no longer has any fuel for substantial lift. The ET alone can only provide enough lift to propel the orbiter up after the SRBs have pushed it into a weaker gravity where less lift is required.

Once the orbiter goes into reentry it does of course act as a glider but like everyone has already said, a pretty inefficient one. This is why it needs such a high rate of speed to not tumble to the ground. The air strips to land the orbiter are so large to accommodate the high speed landing (along with decel chutes).

The Shuttle is really a very inefficient and overly complex and expensive system to get things into space. A friend of mine who worked on the SRBs and now the new constellation project and ares platforms. He's always bashing the space shuttle program on how ridiculous having that kind of reentry vehicle is for this early stage of space flight. He says we can have 3-4 launches for the cost of 1 shuttle launch.

Look at the X plane projects. Those are the closest thing we have to runway launched space vehicles.

For the record, the space shuttle orbiter has taken off from a runway several times. On the back of the SCAs.
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Old 12-10-2012, 10:47 PM   #56
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Checkmate: http://www.youtube.com/watch?v=g_MjTjEXi7I

With a cargo-bay fuel tank feeding the main engines, it's absolutely doable. My only reservation was whether it could achieve the necessary angle of attack while on the runway, but Buran doesn't seem to have a problem. Might need a slightly taller nose wheel assembly, is all.
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Old 12-11-2012, 03:48 AM   #57
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To escape earth's gravity, the space shuttle has to travel at 11.4 km/s (6.9 miles/sec), that's why people build rockets, the escape velocity becomes lower as the altitude increases, yes space shuttle does have a fuel tank- that's for coming down- which is easy.

More here: http://en.wikipedia.org/wiki/Escape_velocity
This is entirely misleading.

a) Escape velocity is the instantaneous velocity you'd have to give an object to escape the gravity well with no further propulsion. For instance, if you were launching an object from a railgun/linear accelerator then this is the velocity you'd need to fire at. But rockets have ongoing propulsion counteracting other forces, so never actually need to reach escape velocity. If you could design a rocket which travelled away from the earth's surface at a constant 1m/s (not that it's a good idea), it would still eventually escape the gravity well.

b) The shuttle is designed to go into orbit, not escape the gravity well, so this is entirely irrelevant anyway.

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Old 12-11-2012, 07:24 AM   #58
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Necro-shuttle thread. Appropriate since the shuttles are dead now. Interesting reading though.
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Old 12-11-2012, 10:59 AM   #59
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Checkmate: http://www.youtube.com/watch?v=g_MjTjEXi7I

With a cargo-bay fuel tank feeding the main engines, it's absolutely doable. My only reservation was whether it could achieve the necessary angle of attack while on the runway, but Buran doesn't seem to have a problem. Might need a slightly taller nose wheel assembly, is all.
It should be mentioned that in that video the Buran is actually using convential jet engines and not rockets. Those jet engines were designed to assist with landing. Buran doesn't actually produce thrust on launch, whereas the Space Shuttle and it's three SSMEs produce a significant amount of thrust in conjunction with the twin SRBS. Maneouvering is accomplished by changing thrust vector for all 5 rockets.

The Shuttle is purpose built to launch vertically. If you were to use even one SSME whlie the shuttle was on the ground on a runway, not only would the Shuttle have inadequate means to control it but in the extremely rare circumstance that the shuttle could get airborne without flipping end over end or getting torn apart, transition into a vertical profile would need to be aggressive or acceleration would quickly force the shuttle beyond structual limits destroy it.

One of the benefits of launching vertically is that as you accelerate and get lighter, the air pressure is also decreasing. A horizontal launch adds all sorts of new challenges.

In addition, the hypergolic OMS engines would be a poor choice for this use. They are designed to assist the shuttle with orbital insertion in a near zero G environment. By their nature, they wouldn't have near the thrust needed for atmospheric use and their high profile would mean shifting the CG way back, which is counterintuitive if your adding fuel to the cargo bay which would push the CG forward. OMS engines only produce ~26 kN compared to the ~2000 kN of the SSME, and thats in a vacumn. OMS engines aren't even rated for atmospheric use so I'm not even sure what the danger would be.
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Old 12-13-2012, 10:16 AM   #60
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It could be done but it wouldn't happen with the current 8000LB thrust engine or the mains.

You would also need to move the main landing gear forward and set the nose very high like the F7U cutlass or it will simply sit on the ground and roll very fast without generating enough lift to take off.

The first car towed lifting body test confirmed the gear location issue causing it to porpoise up as it lifted because the wheels were too far aft of the center of gravity.



Speaking of shuttle........that rig that demates the shuttle from the 747 is taxing to climb if you sprinted up and down it's stairs without being in shape.......twice......after standing on the runway for 10 hours in the sun and working on cars.

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Old 12-13-2012, 10:35 AM   #61
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Meh, shuttle gone, concorde gone. It feels like we're moving backwards instead of forward.
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Old 12-13-2012, 01:59 PM   #62
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Meh, shuttle gone, concorde gone. It feels like we're moving backwards instead of forward.
Semiconductors never fail to disappoint.

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Old 12-13-2012, 02:07 PM   #63
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Semiconductors never fail to disappoint.
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Old 12-13-2012, 05:18 PM   #64
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I have to wonder how many people here are pilots. There are some remarkable posts here, indicating remarkable thought processes. ( Private pilot single engine land )

There is a term called Wing loading: pounds of aircraft per square foot of wing:

Cessna 150: docile trainer. 10 pounds per square foot
Bede 5: squirrely hyper unstable death trap: 22.5 pounds per square foot
Shuttle: 225 pounds per square foot.

Mosler safe is not listed, but it can't be far from the shuttle.
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Old 12-14-2012, 03:40 AM   #65
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Of course the shuttle can take off from a runway - it can after all life off vertically.
You would need to modify the stack a little bit, toughen up the gear, or have it run on rails...But a system that has enough thrust to take off vertically, and reach orbital velocity has enough thrust to use it to lift off after rolling along a runway.

In the sum of forces acting to lift the shuttle, the wing's contribution will probably not be the largest factor. That's not what they are designed for. Maybe close to supersonic speeds the lift provided will become sufficient that it can maintain altitude just from aerodynamic lift, without a vertical component in the thrust vector.
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Old 12-15-2012, 08:16 AM   #66
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It should be pretty obvious that wings provide lift, and there is no real difference between 'gliding' and 'providing lift'. Otherwise, what you have is a rock on a ballistic trajectory.... Whats missing is thrust to make the wings remotely useful. The shuttles only power is really inertia from launch...
Inertia is not a source of power. That's only the tip of the iceberg that sunk your post. Others have pointed out the rest.
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Old 12-15-2012, 08:25 AM   #67
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Originally Posted by furball4 View Post
Checkmate: http://www.youtube.com/watch?v=g_MjTjEXi7I

With a cargo-bay fuel tank feeding the main engines, it's absolutely doable. My only reservation was whether it could achieve the necessary angle of attack while on the runway, but Buran doesn't seem to have a problem. Might need a slightly taller nose wheel assembly, is all.
lol @ checkmate. More like check your facts and figures at the door, mate.

That's like saying a Mazda Miata can beat a Lambo Aventador 0-60.

Sure if you just happen to shove the Aventador's engine into the Miata along with quite a few other modifications.
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Old 12-15-2012, 08:31 AM   #68
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I'll stick with what a NASA engineer said " The shuttle is a rock in a controlled free-fall to the ground"
And it's takeoff is one giant controlled stall.

Well the NASA engineer didn't say that, I just did.
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Old 12-15-2012, 09:47 AM   #69
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Inertia is not a source of power. That's only the tip of the iceberg that sunk your post. Others have pointed out the rest.
I think you meant "source of energy." Power is the rate at which you "use" energy. But, inertia most certainly can be used as a source of energy. Take a physics course which discusses physics after the 1800's. There's this formula that you might not have ever heard about: E=mc^2. :>)

(Inertia = mass, I think the poster meant "momentum." )
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Old 12-15-2012, 10:27 AM   #70
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lol @ checkmate. More like check your facts and figures at the door, mate.

That's like saying a Mazda Miata can beat a Lambo Aventador 0-60.

Sure if you just happen to shove the Aventador's engine into the Miata along with quite a few other modifications.
It's a video of an aerodynamically similar craft achieving controlled take-off with less thrust than the shuttle's main engines would provide, were they modified to work in this application. It answers 90% of the significant questions raised here, by working example. It confirms that thrust is not a deal-killer, that basic aerodynamics and lift are not deal-killers, and even that control is perfectly achievable, whether or not our shuttle happens to have just the right control configurations by default. I'm sure Buran as configured has many distinguishing features, but the example still covers all the basics. It refutes AD5MB, for example, who proposed an objection based on calculated wing load, appearing to suggest that there was some kind of practical limit to controlling any craft of this type. Obviously that isn't correct.

I'm guessing that despite all the mud one can find to sling at specific thought experiments, anything that can maintain a controlled glide can take off from a runway if it configures its landing gear to an appropriate AoA and it has the needed thrust. The only objections that would seem to hold water are ones relating to the structural integrity of the craft at the speed necessary to achieve a positive rate of climb (thrust absorption by the airframe, etc.) and its internal fuel capacity.
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Old 12-15-2012, 12:05 PM   #71
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Inertia is not a source of power. That's only the tip of the iceberg that sunk your post. Others have pointed out the rest.
just so you know you're responding to a post from 2009. Either way, it's not too difficult to see what he means. All of the energy the shuttle has is from its initial vertical climb. After that, all of the energy it has is from its own momentum. It uses this energy during the landing on to its landing strip to provide plenty of horizontal motion so that its tiny wings can generate enough lift to not have the whole thing smash into the ground.

http://www.youtube.com/watch?v=YOxZsbyjSb8

if you watch this video it's apparent the shuttle is generating lift, since it just about hovers in the vertical axis, however you will notice it has a pretty high angle of attack to generate that lift. I don't have enough knowledge to say whether or not it can actually take off without any custom work done on it.
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Old 12-15-2012, 03:53 PM   #72
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I think you meant "source of energy."
Yes I meant energy. Thanks for the correction.
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Old 12-15-2012, 07:46 PM   #73
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Meh, shuttle gone, concorde gone. It feels like we're moving backwards instead of forward.
The shuttle was not an improvement over traditional rocket launches. It was a huge sidestep that cost umpteen billions to show us that no, space planes make no sense.

We are actually seeing huge steps in space launches now, with SpaceX promising to send stuff into orbit at a fraction of the cost of the old rockets.
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Old 12-16-2012, 09:59 PM   #74
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I've always wondered why they can't just create a giant solonoid, put the rocket in it (rebuild it in thick steel / possibly some lead for shielding the inside). Apply billions of volts for a few seconds to the solonoid, WHAM, in space.

They'd need doctors at the space station to rectify the whiplash of all people onboard though, and the aim better be good.

But seriously, if done properly, would that concept work? Save on shitload of fuel. (probably brown out every single power plant in the contry in the process though)
It's called a mass driver.

The difference is in a rocket/shuttle you have constant acceleration. In a mass driver the only acceleration is on the ground in the "gun barrel". Once it exits, it's decelerating from then on out like a bullet, so the initial muzzle velocity required to achieve orbit is several orders of magnitude greater. Air resistance also becomes several orders of magnitude greater due tot he higher initial velocities needed. It would be a challenge in and of itself just to prevent the launch vehicle from bursting into flames from air resistance alone when it hits the atmosphere as soon as it leaves the "barrel" at ground level.

Last edited by exdeath; 12-16-2012 at 10:20 PM.
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Old 12-17-2012, 01:02 AM   #75
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did you even read his explanation? air resistance != lift
It's like the blind leading the blind in this thread. (Yes, I know 2009, but still. It's still idiotic)

EVERY wing generates 'lift'. In fact, even a barn door generates lift. However, this only occurs when the wing is at the correct angle of attack. Air doesn't magically go faster over the top than the bottom. That's the age-old easy and pretty much incorrect answer.

A wing is curved on top not to generate lift, but to prevent turbulence. Because of the angle of attack, air coming in toward the bottom of the wing is deflected downward. The effect of the mass of the air striking the underside of the wing creates a force with an upward vector. The same way air hitting the spoiler on the rear of a race car creates downward force. It's also the reason wings have camber.

At the same time, the the air just above the top edge of the wing tries to move straight past the wing. This creates a low pressure zone extending along the length of the wing. This gives the air a velocity vector downward, because it needs to fill the vacuum. Combining the horizontal vector of the air velocity with its new downward vector results in an 'increase' in speed. However, the old pictures of a wing that is completely horizontal and has arrows over the top suggesting the air magically accelerates is a farce.

A wing without the angle of attack will not work very well at all. Without the curve on the top of the wing, the turbulence will cause a stall.

Seriously. Get educated, and 3 of you. Grow up. This is highly technical, not 'guess and hope you get it right'.
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