Chinese Testing EM Drive in Orbital Flight

[Jonfliesgoats]

The Chinese claim to be testing EM drives in flight.  Public announcements of something like this usually have more to do with politics and information campaigns than actual developments.  Still, I am sure this will generate some renewed discussion in the KSP community.  Personally, I am reserving my thoughts about the EM drive until we get more data from these and other experiments and better testing methods.

http://www.dailymail.co.uk/sciencetech/article-4052580/China-claims-built-working-version-NASA-s-impossible-engine-says-s-orbiting-Earth.html

http://www.ibtimes.co.uk/space-race-revealed-us-china-test-futuristic-emdrive-tiangong-2-mysterious-x-37b-plane-1590289

 

 

[Frozen_Heart]

Hopefully they manage to clear up if the thing works or not. Though i don't think that it does, i'd really like it to.

[insert_name]

Could we get a source a bit more  science related?

[rfmwguy]

https://www.reddit.com/r/EmDrive/comments/5jboig/microsoft_bing_offers_a_slight_better_translation/

And

https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http%3A%2F%2Fdigitalpaper.stdaily.com%2Fhttp_www.kjrb.com%2Fkjrb%2Fhtml%2F2016-12%2F11%2Fcontent_357004.htm

Edited December 21, 2016 by rfmwguy

[Jonfliesgoats]

Everything I see is an announcement of a test rather than an announcement of a result.  Still, they are flying one of these things, so we will know, once and for all, if can actually move something in space.

[magnemoe]

An issue with an space station test is electromagnetic forces between the engine and the huge metal station, vibration is also an issue. 
Purpose with an space test now is primarily to prove that it works, to get more funding and interest. Simplest way to do that would be an cubestat, 6u would be perfect, put em drive on one end but sideway, point solar panels towards sun and start the drive, if it works this will start to spin the satellite, soon the spin would have more torque than the reaction wheel could provide and they have proof. 
Rotation speed would be easy to measure and an very weak drive would work. 
Next step would be optimization for practical engines. 
 

[Steel]

My question: in anything other than deep space, how can you ever differentiate between a tiny thrust and the effects of the atmosphere, EM fields, irregularities in the earth's gravitational field, light pressure, slight incacuracies in reaction wheel manufacture e.t.c?

[p1t1o]

3 minutes ago, Steel said:

My question: in anything other than deep space, how can you ever differentiate between a tiny thrust and the effects of the atmosphere, EM fields, irregularities in the earth's gravitational field, light pressure, slight incacuracies in reaction wheel manufacture e.t.c?

I reckon that it is probably just as hard in LEO than in a lab, but you can leave your satellite in LEO for years, whereas keeping conditions stable in a lab setting for that long will be problematic.

Perhaps you dont have to filter out other forces at all, if you can simply point it in certain directions for long enough and see if you can deliberately control your orbit with it, then you know you are pointing thrust and not just sailing with the prevailing currents.

It may also be easier to perform tests with larger/more powerful versions in an LEO environment than in a lab?

[magnemoe]

6 hours ago, Steel said:

My question: in anything other than deep space, how can you ever differentiate between a tiny thrust and the effects of the atmosphere, EM fields, irregularities in the earth's gravitational field, light pressure, slight incacuracies in reaction wheel manufacture e.t.c?

This forces is very low even compared to em-drive, its also pretty well understood as we can predict orbital decay pretty well.
Drag on IIS or an huge satellite in low orbit would be higher than em-drive trust but scope is cube to micro ones, drag is the major here and it will always reduce your orbit. 

Correction, just by measuring the time an orbit takes it would be very easy to measure orbital changes. Was hanged up in that an real world satellite does not know its orbital data  but you only need the orbital time. 
You are primarily after proof that the drive works here, satellite experiment will not prove negative as defect drive would also give no trust and its no way to know. 
Benefit of orbital changes is that you could do follow up experiments like efficiency at various level of trust and hopefully the energy balance. 

An space station test would be more relevant for space qualifications. Here you want to prove that the engine can survive in space for an extended time and that they can do long term burns 

[Slam_Jones]

Awesome, it's about time someone sent one to orbit and find out what happens!

Regardless whether it works or not, I'm very excited to read what they find out!  Even if it turns out to produce 0 thrust, any knowledge gained is good!

[kerbiloid]

13 hours ago, Steel said:

how can you ever differentiate between a tiny thrust and the effects of the atmosphere, EM fields, irregularities in the earth's gravitational field, light pressure, slight incacuracies in reaction wheel manufacture e.t.c

Two clone probes near each other, both with EM drive. One — enabled, another — disabled. Measuring the difference.

The more probes to use - the more stable is average value.

Edited December 22, 2016 by kerbiloid

[DDE]

59 minutes ago, kerbiloid said:

Two clone probes near each other, both with EM drive. One — enabled, another — disabled. Measuring the difference.

The more probes to use - the more stable is average value.

That seems to fail to exclude any effect caused by the interaction with the magnetic field, et cetera. We need some sort of a dummy EmDrive imitator. Last time we tried that, it turned out a working EmDrive as well.

[kerbiloid]

4 minutes ago, DDE said:

That seems to fail to exclude any effect caused by the interaction with the magnetic field, et cetera.

They should push each other head to head. Enabled will push, disabled would be a ballast with no magnetic production.

[Jonfliesgoats]

I like the cube sat and formation cubesat test ideas.  

[Aethon]

An analysis EM thruster data by Tau zero scientist reviewers. 

" For those of you who are neither researchers nor funding sources, what should you do? First, before reposting an article, take the time to see if it offers new and substantive information. If it turns out to be hollow click-bait, then do not share it. If it has both new information with meaningful details, then share it. Next, as your read various articles, notice which sources provide the kind of information that helps you understand the situation. Spend more time with those sources and avoid sources who do not. "

 

http://www.centauri-dreams.org/?p=36830

[Jonfliesgoats]

Good post!

[PB666]

On 12/22/2016 at 0:50 AM, Jonfliesgoats said:

I like the cube sat and formation cubesat test ideas.  

Ideally NASA would test it in space, but its a rather big beaurocracy that takes time.

From the translation of the chinese news. "the maximum measured thrust of about 124 cattle". This of course is the favored relative measure in space because all those space ranchers are just waiting for a new device that can herd their space cattle.  Can chinese news actually be dumber than US based news reports. And to think I used to complain about science reports on the Beeb. 

 

[Jonfliesgoats]

Whether the state of Chinese science is healthy or not is debatable.  Certainly, there are some dubious things about research in China at the moment.  However, they are investing heavily in developing their scientific infrastructure.  It's easy in the West to forget that Standord and the US Army invested heavily in researching telepathy.  Those studies were well funded and very poorly designed.  China will achieve some great scientific breakthroughs. 

As for the translation, I saw the cattle references too.  I laughed.  Google translate is funny.  Imagine how tender steaks would be if they were from cattle raised in orbit!

The Beeb = BBC?

[Jonfliesgoats]

@PB666

Check this out for dumb, science news:

https://www.sciencenews.org/article/jet-lag-makes-hamsters-dumb

[SR]

Maybe they will prove once and for all EM drives are possible.

[Kryten]

I have not seen any Chinese source supporting the claim that they've actually launched an emdrive prototype, only that they have a programme. AFAICT, the claim is supposed to be have been from remarks given at a press conference on the programme, but I haven't been able to find a recording of this conference, any kind of official transcription, or even a direct quote of what was said. 

In short, it's dodgy.

 

[Jonfliesgoats]

Agreed on the dodginess.