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Mystery of the Slingshot Maneuver

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posted on Aug, 3 2010 @ 06:39 AM
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First let me say, this article talks about an interesting anomaly that happens when a spacecraft saves fule by using the so-called "slingshot fly-bys". That is when it uses a planet's gravitational pull to chance its trajectory, when the spacecraft does this, it experiences a slight acceleration. We haven't been able to attribute any known part of physics to explain this occurence, however we do speculate about it. This anomaly might point in the direction of a part of physics that we don't quite understand or haven't even discovered yet.


Experts are intrigued by the fact that while the acceleration is tiny and has no significant effect on NASA missions, it holds great interest because no explanation based on conventional physics and understanding has been found. The effect is so persistent that it could indicate some physics not considered in previous attempts to explain the motions of bodies in the universe.

In 1998, for example, NASA's NEAR Shoemaker spacecraft had its speed boosted by an additional 13.5 millimetres per second. There are many examples of this, but no explanation – which raises the tantalizing possibility that it could be a sign that a whole new branch of physics is waiting to be discovered.



Several ideas have been proposed in an attempt to explain why the anomaly occurs, ranging from tidal effects of the near-Earth environment, atmospheric drag, or the pressure of radiation emitted or reflected by the Earth, to much more extreme possibilities, such as dark matter, dark energy or previously unseen variations in General Relativity.

Anderson and colleagues are even looking at the possibility that Earth’s rotation may be distorting space-time more than expected, and affecting nearby spacecraft. But there is as yet no explanation how this could happen.


Source: The Spacecraft Flyby Mystery

It seems no one has got a clue as to what the explanation for this might be, but it certainly seems they're grasping at straws. However, it remains a peculiar and yet intruiging little detail that opens up for huge questions about our current understanding of physics.

The explanation that there's a ring of dark matter the spacecraft travels through that's causing the anomaly seems a bit weird though.

PS: Don't get angry if this has been posted before, I tried finding it with several search strings to no avail. I've also read about this several years ago, so it isn't exactly news, but there is some new information in the article that is very interesting.

[edit on 3/8/10 by Droogie]




posted on Aug, 3 2010 @ 06:55 AM
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Given the ability to use this mechanism with mathematical precision, I would say it is fully explained/understood. I surely don't have the chops to explain it here, as i haven't the education for it.

However, using Earth bound physics....if i have a rope with a small weight at the end, i can swing it in circles. It will swing evenly with the rope pulled tight.

But if i pull slightly on the rope, it will increase the speed that it revolves. It would seem that the energy pull in on the object, when juxtaposed with inertia/centrifugal force, has the energy displayed not by the change of course, but rather it is transferred into the speed of the object.

The same with the slingshot effect (being studied in depth via TiPS by the Dod). The gravity pulls in on the object. That energy is then transferred into the forward motion of the craft. Since it cannot be pulled down, it is pulled forward.

Yeah, i know i have slightly misrepresented the physics at play, as it isn't really a transferral of energy. It is more like the objects forward momentum is increased as the gravity pulls it downward/forward, and centrifugal force pulls it outward/forward. The two forces act in concert with the forward momentum of the object.

This isn't a mystery. The same effect is used in childrens toys, as well as "massaging" devices.



posted on Aug, 3 2010 @ 06:57 AM
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Interesting article!

Just to clear-up any possible confusion, there are two accellerations we see from a fly-by past a planet.

The first is very well known, and has been for a long time. A planet moves along in its orbit - The Earth, for example, orbits the Sun at over 66,000 mph. When a probe orbiting the Sun flies by the Earth heading in the same direction, the motion of the Earth adds to the velocity of the spacecraft, accellerating it so its trajectory takes it farther out into the solar system (the Cassini probe, to get to Saturn, flew past Venus once, the Earth twice and then past Jupiter to get enough velocity to get to Saturn). The article references several spaceprobe fly-bys from which this data comes.

The other accelleration, with is the subject of this article is much smaller, and its cause is unknown.



posted on Aug, 3 2010 @ 07:00 AM
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its all here dude

en.wikipedia.org...

i would say its something to do with magnetism



posted on Aug, 3 2010 @ 07:10 AM
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reply to post by aspx
 


Why would you say that?



posted on Aug, 3 2010 @ 07:18 AM
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Wait. You mean they really haven't figured this out? With all that brain power?

When an object is doing a "fly by" orbit, it has multiple forces acting on it. But we are going to only talk about three.


Forward momentum - It was moving forward before it ever reached the object it is going to fly by. This is the momentum we are measuring when we talk about an increase in speed.

Gravity - This is increasing its speed the entire time it approaches the object. Gravity is a force that pulls at you. There is no "terminal velocity" in space. Your speed continuously increases as you approach the body.

Centrifugal force - this is what counteracts gravity here. It pulls your away from the body. In a fly by, it is stronger than gravity in its effect, allowing the object to maintain escape velocity at its altitude.


Now, imagine that as the fly by begins the smaller body approaches at an increasing speed, due to gravity pulling at it. Then, as it begins it high orbital point, the center of mass is shared between the two items, allowing the object to circle around the larger body.

As it begins to circle around the larger body, the reality is that the gravity will pull down on it, while centrifugal force pulls out on it. But neither of these forces will win out, as the forward momentum is counteracting both of them.

But since the gravity is pull the object down, and centrifugal is pull it out (key word: they are pulling the object), then it ends up equating with the forward momentum benefitting from the energy created from these forces. Since they can neither be pulled down, or out, it is instead pulled forward.

Once you are away from the centrifugal force, you will see the gravity of the larger body begin to interact with the larger body once again. This is why the speed decreases rapidly at first, then slower as it gets further away.

This really, really seems like common sense. I don't get it.



posted on Aug, 3 2010 @ 07:23 AM
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OP, and all....what is being discussed here is the same effect as you would find in the tether propulsion programs being pursued planetwide (nice consonance, huh?
).


Tether propulsion systems are proposals to use long, very strong cables (known as tethers) to change the velocity of spacecraft and payloads. The tethers may be used to initiate launch, complete launch, or alter the orbit of a spacecraft. Spaceflight using this form of spacecraft propulsion may be significantly less expensive than spaceflight using rocket engines.

Tethers are kept straight by either rotating end for end, with very high tips speeds (several km/s), or by the difference in the strength of gravity over their length (tidal stabilisation). Tethers require strong, light materials. Some current tether designs use crystalline plastics such as ultra high molecular weight polyethylene, aramid or carbon fiber. A possible future material would be carbon nanotubes, which have an estimated tensile strength between 140 and 177 GPa (20.3-25.6 million psi), and a proven tensile strength in the range 50-60 GPa.

A momentum exchange tether is a rotating tether that would grab a spacecraft and then release it at later time. Doing this can transfer momentum and energy from the tether to and from the spacecraft with very little loss; this can be used for orbital manoeuvring. A rotating momentum exchange tether is known as a bolo.[1]


Tether Propulsion


Originally posted by Chadwickus
reply to post by aspx
 


Why would you say that?


Well, it is a known possibility, based on the tether dynamics already studied (from the above link, just for simplicity sake):


Another type of tether is an electrodynamic tether, this is a conductive tether that carries a current that can generate thrust or drag from a planetary magnetic field, in much the same way as an electric motor.


Regardless, OP, the change of momentum is a known principle in physics. It isn't an unsolved mystery. If it were, we would not be able to make planned flybys of other planets using the slingshot effect. We would end up with our satellite missing its target, as it would be unpredictable.



posted on Aug, 3 2010 @ 08:06 AM
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I'm not going to pretend that I understand all this, but from this article I gather that there is in fact an anomaly that can't be explained. I don't know if you read the entire article, but here's another excerpt that tells of something that further seemed to baffle scientists.


Scientists were hoping to gain more insight into the anomaly when the Rosetta spacecraft swung by Earth on Nov. 13 2009 to pick up a gravitational boost for its journey to rendezvous with a comet in 2014.

However, in a major disappointment – which had deepened the mystery — the Rosetta spacecraft did not experience the flyby anomaly during this swingby of Earth in 2009, even though the same spacecraft did experience the anomaly when it flew by Earth 2005, but didn’t in 2007.

“It’s a mystery as to what is happening with these gravity events,” said Trevor Morley, lead flight dynamics specialist working on Rosetta. “Some studies have looked for answers in new interpretations of current physics. If this proves correct, it would be absolutely ground-breaking news.”


I think it's intruiging that it happens sporadically, and unpredictably at this point. I'll be very interested in how they will explain it. You might very well be right about what you are describing bigfatfurrytexan, but it's curious that these scientists haven't figured it out.

[edit on 3/8/10 by Droogie]



posted on Aug, 3 2010 @ 08:12 AM
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reply to post by Droogie
 


In that case, you might find this interesting as a springboard for further research:

www.enterprisemission.com...

The great Werner Von Braun was stumped by orbital mechanics.


Something to consider: our highly electric atmosphere can have some unusual effects. Do we see similar anomolies on other celestial bodies?



posted on Aug, 3 2010 @ 08:12 AM
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reply to post by bigfatfurrytexan
 


Using a tether is slightly different, and can see the use of a planets magnetic force for that, but not for a 'typical' orbital slingshot.

I also saw no mention of magnetism in the wiki article, which is why I'm curious why aspx suggested it...



posted on Aug, 3 2010 @ 08:15 AM
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Please consider this as a total shot in the dark...
I have a radiation powered ball on my desk.the vanes are black on one side gold on the other. They spin in their little vacum.
What about that?
I would imagine that there are times when the light on one side of the object and the object is travelling into shadow...



posted on Aug, 3 2010 @ 08:19 AM
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Originally posted by Chadwickus
reply to post by bigfatfurrytexan
 


Using a tether is slightly different, and can see the use of a planets magnetic force for that, but not for a 'typical' orbital slingshot.

I also saw no mention of magnetism in the wiki article, which is why I'm curious why aspx suggested it...


See bolded above. They are synonymous.



posted on Aug, 3 2010 @ 08:23 AM
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reply to post by bigfatfurrytexan
 


Are you saying that a planets gravitational force is the same as it's magnetic force?

Or am I off target here?



posted on Aug, 3 2010 @ 08:24 AM
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reply to post by bigfatfurrytexan
 


Centrifugal force doesn't really exist. Centripetal force pulls "in", perpendicular to the direction of motion, otherwise the path would be uncurved. A constant force perpendicular to the direction of motion results in a circular path since a constant force results in constant acceleration. Gravity is the centripetal force, pulling the objects together while inertia resists the change in momentum.

Edit: Seem to be hitting "t" too oftetn.

[edit on 8/3/2010 by EnlightenUp]



posted on Aug, 3 2010 @ 08:28 AM
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reply to post by bigfatfurrytexan
 


Thanks for the suggestion and for the link! I will definitely have a thorough look at it



posted on Aug, 3 2010 @ 08:29 AM
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Originally posted by Chadwickus
reply to post by bigfatfurrytexan
 


Are you saying that a planets gravitational force is the same as it's magnetic force?

Or am I off target here?


I sure a heck hope he's not. Sheesh! Isn't there a slight difference in magnitude there?
That and bodies without magnetic fields do have gravity, I think.



posted on Aug, 3 2010 @ 08:38 AM
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Originally posted by Chadwickus
reply to post by bigfatfurrytexan
 


Are you saying that a planets gravitational force is the same as it's magnetic force?

Or am I off target here?


LOL, your off target. I am suggesting that the minor variation that is not consistent in any respect except in its inconsistency might be impacted by a multitude of forcces. Magnetism, while in our near area, would be one such force.

Not all planets have magnetic fields. but i bet the ones that do have novel effects on bodies that come near them.



posted on Aug, 3 2010 @ 08:39 AM
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Originally posted by aspx
its all here dude

en.wikipedia.org...

i would say its something to do with magnetism


I'd say it has to do with using natural gravity to increase velocity. Shoot the term gravity assist is in your link. Why do you say magnetism?



posted on Aug, 3 2010 @ 08:40 AM
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reply to post by EnlightenUp
 


yeah, they do seem to have some connection with each other (or, at least intrinsic interaction with each other), but they are not interdependent.



posted on Aug, 3 2010 @ 09:48 AM
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Regardless, OP, the change of momentum is a known principle in physics. It isn't an unsolved mystery. If it were, we would not be able to make planned flybys of other planets using the slingshot effect. We would end up with our satellite missing its target, as it would be unpredictable.


It is really rather meaningless to try and discuss this issue without describing it in terms of second or higher approximations of perterbational calculus. Become conversant with Leonhard Euler's work and then you are not constricted to dealing with it as a two body problem. It becomes a fairly straightforward question of multibody angular momentum integration.
As a sidenote, everyone who has difficulty with the issue is in good company. Newton, in Principia ran into the same problem since his calculus was pretty well limited to the two-body problem.




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