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Space Discussion Thread

I'm really curious to what is actually producing these results.

Personally i see no mechanism how these drives can work, but at least they seem to even in vacuum. One problem is that the forces are very very small - with that setup running at 80 watts and 1.2 uN/W the resulting force is 100 uN on a device that looks like it weighs something in the order of a kilogram (10 N gravity).

Measuring this on earth is tricky, the change between off and on is 10 ppm or so. Literally dropping a speck of dust that weights only 1 milligram onto the device (or abalting that off) would offset the entire mesurement.

One these things are tested in space that may change, though it would have to be at a high altitude for effects from the atmosphere to be eliminated (this drive could not keep the ISS up in its orbit even if it had a gigawatt of power available).
 





Benm said:
I'm really curious to what is actually producing these results.

Personally i see no mechanism how these drives can work, but at least they seem to even in vacuum. One problem is that the forces are very very small - with that setup running at 80 watts and 1.2 uN/W the resulting force is 100 uN on a device that looks like it weighs something in the order of a kilogram (10 N gravity).

Measuring this on earth is tricky, the change between off and on is 10 ppm or so. Literally dropping a speck of dust that weights only 1 milligram onto the device (or abalting that off) would offset the entire mesurement.

One these things are tested in space that may change, though it would have to be at a high altitude for effects from the atmosphere to be eliminated (this drive could not keep the ISS up in its orbit even if it had a gigawatt of power available).
Click to expand...

My first guess was it was a type of photon pressure but this is orders of magnitude above the thrust of a photon rocket of the same power.

I'm hedging my bets that the thrust is produced by some effect on the Higgs Field or other Space/Time effect.
 
AaronT said:
My first guess was it was a type of photon pressure but this is orders of magnitude above the thrust of a photon rocket of the same power.

I'm hedging my bets that the thrust is produced by some effect on the Higgs Field or other Space/Time effect.
Click to expand...

I cannot be simply photon pressure indeed - you could achieve that by just opening up one side of the resonator cavity and microwaves would shoot out propelling you in the opposite direction. This would at best result in a force -far- lower than described.

I suspect it has to do with some interaction with atmosphere, even a very dilute one like in a good vacuum chamber. Launching off ionized air would easily make this amount of thrust possible, and if you design for it quite a lot more.

One example of such a device is this: https://www.youtube.com/watch?v=hv__Zln-h5Q

There is some BS about anti-gravity surrounding these contraptions, but they basically work by ionizing air and blasting the ions down at reasonable speed (25 kV or so), resulting in upwards forces many magnitudes larger than either photon rockets or this new EM drive concept.

These 'lifters' actually do work in a modest vacuum too. If you pull pressure down to 0.01 atm or something they still fly.
 
Benm said:
I cannot be simply photon pressure indeed - you could achieve that by just opening up one side of the resonator cavity and microwaves would shoot out propelling you in the opposite direction. This would at best result in a force -far- lower than described.

I suspect it has to do with some interaction with atmosphere, even a very dilute one like in a good vacuum chamber. Launching off ionized air would easily make this amount of thrust possible, and if you design for it quite a lot more.

One example of such a device is this: https://www.youtube.com/watch?v=hv__Zln-h5Q

There is some BS about anti-gravity surrounding these contraptions, but they basically work by ionizing air and blasting the ions down at reasonable speed (25 kV or so), resulting in upwards forces many magnitudes larger than either photon rockets or this new EM drive concept.

These 'lifters' actually do work in a modest vacuum too. If you pull pressure down to 0.01 atm or something they still fly.
Click to expand...

The paper quotes a vacuum spec of 8 x 10 -6 Torr "or better" for all testing

Outer space 1 × 10 −6 to < 1 × 10 −17
 
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At the pressure the 'lifters' stop working, but those a relatively low power devices producing a lot of force per watt of electrical input (those things in the video run off 25 kV, but probably draw in the order of 1 watt of power).

One concern i have it might be something else, even outgassing of atmosphere that adhered to the metal or even the metal evaporating from being heated by the micowaves.

The problem is that the thrust is just SO tiny for the amount of power produced. It's something that is quite bulky, uses as much power as a small drown, but produces an (additional to its own gravitational pull on earh) amount of force that lifts a grain of sugar.

I think this has to be proven in space, where one of these devices can operate for a long period of time. One test would be to set it just to keep increasing it's orbit, powered by solar panels. Downside is that this would have to be tested at a very high orbit (probably beyond geostationary) for the thrust to overcome the drag of the solar panels to power it.
 
Hey guys, just as a reminder, the Geminid meteor shower is going to peak December 13th. It's one of the best regular showers, but it will have some interference from moonlight.
 
Hey guys, Venus is at its greatest eastern elongation tonight, so you should have the best view of it right after nightfall.
 
It's quite bright indeed. Since i live high up and have a west and south view i'm quite used to seeing it by now.
 
Rivem said:
Another relevant Kurzgesagt video:

Click to expand...
That one seemed a little underwhelming. It just explained the problem, and didn't really propose any great solutions to it. It basically just said what we already know, which is that space travel is really, REALLY, REALLY hard.
 
Razako said:
That one seemed a little underwhelming. It just explained the problem, and didn't really propose any great solutions to it. It basically just said what we already know, which is that space travel is really, REALLY, REALLY hard.
Click to expand...

Pretty much. Though, I do like how it explains the basics of rocket science and why rockets are the way they are. That's pretty much the current nature of the field though. Not much huge innovation any more, and not any reasonable/foreseeable alternatives yet.

Edit: Just to throw in some advancement in rocket technology, one of the smallest orbital rocket launches was recently attempted. It ultimately failed due to communications errors, but success could have dramatically reduced costs for microsatellite launches.
Article: https://www.nasaspaceflight.com/2017/01/jaxa-ss-520-rocket-tricom-1-launch/
 
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I do wonder if electromagnetic launchers might eventually be useful for getting payload to orbit. Obviously the problems include the death and destruction of anything you launch due to the G-forces, but maybe they could be used to fling metals and other raw materials to orbit. Once in orbit they could be manufactured into the end-product on site.
 
Razako said:
I do wonder if electromagnetic launchers might eventually be useful for getting payload to orbit. Obviously the problems include the death and destruction of anything you launch due to the G-forces, but maybe they could be used to fling metals and other raw materials to orbit. Once in orbit they could be manufactured into the end-product on site.
Click to expand...

Honestly, if the commercial space industry ever really gets to the point where it's performing the vast majority of a much larger array of space operations without governments, people will probably be the only major cargo carried up to space. It would honestly be much more efficient if we could just manufacture all the long haul spacecraft in space from materials sourced in space.

Otherwise, I think any space construction up to that point will still be done with prefabricated components coming up from Earth instead of raw materials to be utilized up there.

Now, the EM launching is a possibly feasible launch method for other things. The main concern is as you say, the acceleration would have to be too high for most useful payloads.

That could be remedied by making the launcher extremely long at the expense of aim. I think there are actually reports out there talking about how long it would have to be for a safe human launch, and it's somewhere along the order of all the way from sea level to the peak of a very tall mountain.

Presumably, it's be much cheaper in the long run than rockets as long as it launched into useful orbits.
 
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