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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.
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]
Originally posted by Chadwickus
reply to post by aspx
Why would you say that?
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.
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.”
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...
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?
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?
Originally posted by aspx
its all here dude
en.wikipedia.org...
i would say its something to do with magnetism
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.