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by binarycoffee 1898 days ago
Just to be clear, for most anyone with low-thrust measurement experience, thermal drift had been suspect nr 1 from the moment Eagleworks published their work. Here is a comment I made back at that time:

https://news.ycombinator.com/item?id=12962579

But then, nobody had Tajmar's perseverance; kudos to his team!
2 comments
unityByFreedom 1898 days ago
Lol at the lone reply you received. You called it and that's what you got. I hope we can learn to look at all points from more perspectives in the future.
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IshKebab 1898 days ago
I mean, most people didn't believe that this was real. It's not like he was the lone voice saying "nah this is surely bollocks...".
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unityByFreedom 1897 days ago
That wasn't clear at the time.

This post shows how hard it was for scientists to prove it's bollocks. And the above comment shows how the general population doesn't want their hopes dashed.

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IshKebab 1896 days ago
It really was clear at the time. Even then people pointed out that the measurements didn't behave in the way you'd expect if it actually worked (e.g. thrust didn't correlate with power).

There were plenty of people saying "But imagine if it did work! We could get to other stars in a few years!" but you always get crazy optimists that ignore all the evidence with stuff like this (c.f. solar roadways).

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unityByFreedom 1895 days ago
The post shared by the above poster shows the upvoted crazy optimists,

https://news.ycombinator.com/item?id=12957537

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waheoo 1898 days ago
Day made. Good chuckle that.
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Sebb767 1898 days ago
Sorry if this is a stupid question, but what is thermal drift in this context?
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binarycoffee 1898 days ago
Not a stupid question -- sorry for the jargon.

It is what is mentioned in this fragment of the article:

"When power flows into the EmDrive, the engine warms up. This also causes the fastening elements on the scale to warp, causing the scale to move to a new zero point"

Basically, thermal expansion of the thruster and the measurement device causes the rest position of the thrust balance to drift with time, which is hard to differentiate from the actual thrust generated. This is most critical when the thrust-to-weight ratio is low, as is the case here.

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