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Uncertain Propulsion Breakthroughs?

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Re: Uncertain Propulsion Breakthroughs?

#31

Post by matheweis »

dom0 wrote: post #30
JumpCrisscross wrote: post #10

Earlier quoted context omitted.

Satellite orbits degrade overtime due to drag, among other things [1]. Operators counter this decay with periodic boosts. (The International Space Station is boosted, on average, once a month [2].) Boosting, even electric propulsion boosting, consumes propellant. If this works by impelling against the Earth's magnetic field, provided it is more efficient than a simple magnet, it could still have a market with satelli…

> If this works by impelling against the Earth's magnetic field That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.

But it would represent an improvement on what we have today, which is a finite amount of fuel use to keep the satellite in orbit that eventually runs out.

Re: Uncertain Propulsion Breakthroughs?

#32

Post by roywiggins »

JumpCrisscross wrote: post #10
cperciva wrote: post #8

Earlier quoted context omitted.

Being in space doesn't solve the problem of errant forces completely. You can push against the earth's magnetic field, for example.

Satellite orbits degrade overtime due to drag, among other things [1]. Operators counter this decay with periodic boosts. (The International Space Station is boosted, on average, once a month [2].) Boosting, even electric propulsion boosting, consumes propellant. If this works by impelling against the Earth's magnetic field, provided it is more efficient than a simple magnet, it could still have a market with satelli…

Electrodynamic tethers push off the Earth's magnetic field directly and don't need fuel.

Re: Uncertain Propulsion Breakthroughs?

#33

Post by stale2002 »

dom0 wrote: post #30
JumpCrisscross wrote: post #10

Earlier quoted context omitted.

Satellite orbits degrade overtime due to drag, among other things [1]. Operators counter this decay with periodic boosts. (The International Space Station is boosted, on average, once a month [2].) Boosting, even electric propulsion boosting, consumes propellant. If this works by impelling against the Earth's magnetic field, provided it is more efficient than a simple magnet, it could still have a market with satelli…

> If this works by impelling against the Earth's magnetic field That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.

The way science works is by doing experiments.

The people have been doing experiments on the EM drive and have been getting unexpected results.

Nobody really knows why yet, but that's kinda the point.

Is thermodynamics flawed? Is it pushing off of "dark matter"? Is it a completely new and novel scientific effect?

Any of these circumstances would be interesting.

Re: Uncertain Propulsion Breakthroughs?

#34

Post by stale2002 »

powera wrote: post #19

IMO the "rational" approach is to treat the claims as a bunch of pointless lies until there's a repeatable demonstration. Remarkable claims demand at least some evidence before wild speculation commences. As it is, Harry Potter is just as credible a theory of reality. After all, they've made the same claim repeatedly for 15 years after their first experiments were demonstrably not what they claimed.

This is what they are doing. They are sending something into space to demonstrate the effect.

Let the experiments decide what is right or wrong.

Re: Uncertain Propulsion Breakthroughs?

#35

Post by cjensen »

dom0 wrote: post #30
JumpCrisscross wrote: post #10

Earlier quoted context omitted.

Satellite orbits degrade overtime due to drag, among other things [1]. Operators counter this decay with periodic boosts. (The International Space Station is boosted, on average, once a month [2].) Boosting, even electric propulsion boosting, consumes propellant. If this works by impelling against the Earth's magnetic field, provided it is more efficient than a simple magnet, it could still have a market with satelli…

> If this works by impelling against the Earth's magnetic field That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.

The "premise" for the em-drive has been determined to be a thorough misunderstanding of the physics involved, so you cannot rule out any potentially contributing force in the experiment.

Yes you heard that right: guys who misunderstand physics go and design a reactionless thruster which, when measured in their shoddy experimental setup, produces a measurable thrust.

If there really is a measurable thrust, then the Laws of Motion are wrong and General Relativity is wrong. I'm disinclined to believe that long-held principles of physics will be upended by some guys who designed something based on a misunderstanding.

Re: Uncertain Propulsion Breakthroughs?

#36

Post by freehunter »

cjensen wrote: post #35
dom0 wrote: post #30

Earlier quoted context omitted.

> If this works by impelling against the Earth's magnetic field That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.

The "premise" for the em-drive has been determined to be a thorough misunderstanding of the physics involved, so you cannot rule out any potentially contributing force in the experiment. Yes you heard that right: guys who misunderstand physics go and design a reactionless thruster which, when measured in their shoddy experimental setup, produces a measurable thrust. If there really is a measurable thrust, then the La…

You sound very negative towards conducting more experiments on this, when the results have been unexpected every time it's been tested. You're displaying the kind of dogma that science has been fighting against since the dawn of time. Either it's true or it's not, but we can't tell until we test it. And so far, it's only been disproven in theory, not in practice. That's worth more experiments.

Re: Uncertain Propulsion Breakthroughs?

#37

Post by DanielBMarkham »

stale2002 wrote: post #33
dom0 wrote: post #30

Earlier quoted context omitted.

> If this works by impelling against the Earth's magnetic field That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.

The way science works is by doing experiments. The people have been doing experiments on the EM drive and have been getting unexpected results. Nobody really knows why yet, but that's kinda the point. Is thermodynamics flawed? Is it pushing off of "dark matter"? Is it a completely new and novel scientific effect? Any of these circumstances would be interesting.

Yes. Even if it's the most likely thing, experimenter error, for a half-dozen teams to all have errors and not spot them? That's quite interesting! It's the same situation we had with the FTL neutrinos a while back.

Re: Uncertain Propulsion Breakthroughs?

#38

Post by evo_9 »

cperciva wrote: post #8
anotheryou wrote: post #2

I hope we'll find out in practice: http://www.popularmechanics.com/science/energy/a22678/em-dri... (via lobster_johnson) "Proud to say that we have a partnership now - so the launch is already funded, and we hope to get a launch slot in 2017."

Being in space doesn't solve the problem of errant forces completely. You can push against the earth's magnetic field, for example.

So no proof will ever be enough for some? Are EM-Deniers going to be a 'thing' now?

Re: Uncertain Propulsion Breakthroughs?

#39

Post by jack9 »

powera wrote: post #19

IMO the "rational" approach is to treat the claims as a bunch of pointless lies until there's a repeatable demonstration. Remarkable claims demand at least some evidence before wild speculation commences. As it is, Harry Potter is just as credible a theory of reality. After all, they've made the same claim repeatedly for 15 years after their first experiments were demonstrably not what they claimed.

> until there's a repeatable demonstration

Not just repeatable, but in different physical configurations of the drive test bed. Right now the tests are using a rotating base that has little to no calibration, much less the hardware, if I understood the link correctly.

Re: Uncertain Propulsion Breakthroughs?

#40

Post by nonbel »

xupybd wrote: post #26
alasdair_ wrote: post #18

Earlier quoted context omitted.

Quite a few medicines (especially antidepressants) state something like "we don't really know why this stuff works, only that it does."

Very true. I'd not considered the medical world.

If people treated medical research with the same skepticism they treat this EM drive... the world would be a much healthier and safer place.
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