I REALLY wish they would stop displaying ft, mi, lbs. It actually angers me.
Also feet happen to be the standard measurement of altitude in aviation, which rockets are part of, even in metric countries, I hate it but it's like that. Distances are nautical miles, a not so bad unit (it corresponds to 1 arcminute on earth), which make me hate the use of terrestrial miles in articles partaking to aviation even more. But it is a bit offtopic here because most of the article is metric.
Can someone from the industry confirm whether they use metric internally and the stream uses imperial just for the patriotic show or whether imperial units are used because some countries use different unit systems and this is normal?
On a related note, I don't think anyone is bothered buying screens (monitor/phone/...) labeled in inches, but orbital elevations and speeds? Weird.
Considering all these, you'd expect space sector to borrow from the aviation sector. But we use SI systems exclusively. Everything in metres, kilograms, seconds. Feet, miles, knots etc are unheard of (Well, we have heard of them. We just don't use them). SI units make calculations and our life a magnitude of order easier. I need to check up how it is with winged reentry vehicles. But they're also likely go with m/s rather than knots. The only time we face difficulty with esoteric units are when we use some rare sensors. You end up looking up the definition of 'BTU' and other similar atrocities.
There are two noteworthy exceptions to this trend though. It's when specifying engine thrust and specific impulse. Engine thrust is often specified in kilograms, (metric) tonnes etc. Of course they mean kgf and Tf (weight equivalent of that mass under 1g). Meanwhile mN, N, kN and MN are also used equally frequently. It's a perennial source of frustration and conflict, with younger generation preferring SI units and the seniors preferring kilograms and tonnes. Meanwhile, specific impulse is even weirder. If you were using SI units, you'd expect N.s/kg or m/s or something similar. Even if you were using imperial units, you'd expect something similar. But the unit everyone actually uses is seconds. For examples, a high end cryogenic engine may deliver an Isp in the range of 450s (SSME had a vacuum Isp of 452s). Sometimes, it's also expressed as 'effective velocity' of exhaust in m/s. There are logical explanations for all these weird units. But the reality is that none of them, including the SI units are strictly correct, because they all use some sort of scaling that isn't linear or an assumption that doesn't apply.
You can blame the US for all these inconsistencies in the space sector. The Americans have a habit of making up units on the spot. For example, the kT, MT yields of nukes were invented by the Manhattan project scientists. Similarly, the unit of nuclear criticality is dollars and cents - thanks to Louis Slotin. (Sadly, he passed away soon after the second criticality accident with the demon core). Anyway, the US also has shot themselves in the foot by mixing up units. The Mars Climate Orbiter crashed into the planet instead of entering its orbit due to the engineers mixing up the SI and imperial units. Moral of the story, if you plan to go to space, you better choose a measurement system and stick to it. Also, don't make a round scrubber for the command unit and a square scrubber for the lander. Make up your mind first!!
But miles has gone out of fashion. Pounds too..
Likewise, Liberia set up a transition program in 2018.
AFAIU both still use a bunch of traditional non US units too, like the UK.
After all, they’re the ones manufacturing the imperial screws, etc.
Some things are ridiculously better in the imperial system - like temperature: In Fahrenheit, 0 is roughly the coldest mean day in densely inhabited areas, and 100 is the hottest. In Metric, 0 is the freezing point of water at sea level in ambient temperatures and with a low barometer reading, 100 is boiling in the same conditions.
Since I measure weather much more frequently than I measure water temps, I am driven cukoo by the silly Centigrade system.
Also, The splitting into 12 used by the foot is more useful, in my experience, than the ten of the metric. In fact, I strongly decry that we teach our kids to use base 10 instead of the much more efficient and easier to divde into fractions of base 12. (You can teach kids to count joints on thier fingers [using the thumb as a pointer] to get to 12x12 on two hands, and give the kids a headstart on fractions, multiplication and division, but I digress..)
On the other hand, having both an Imperial Gallon and a US Gallon, etc, where the same word is used for different amounts, now THAT is insane.
But then I grew up with Celsius, so no wonder I'm used to it!
People confuse familiarity with intuitiveness all the damn time. It's a recurring theme in OS "ease of use" superiority debates as well as metric vs imperial. And date, time or number formats. And road signs.
I would say the nice thing about the metric system is as long as you convert into a base unit (i.e. Meters, Seconds, etc) then you can easily convert stuff around. But you can't! Metric uses Kilograms not Grams all the time for things like Force (Kg *m/s^2). So I still have the same problem as imperial units ...
It's just whatever your familiar with.
A <kilo>gram is 1000 times a gram, it's written in the word. Are you serious when you say you can't easily multiply or divide by 1000?
A mile is 5280 feet. I can't just convert 231 miles into feet like that, and that's assuming I remember "5280".
> Are you serious when you say you can't easily multiply or divide by 1000?
You have missed the point. Force is a mass * distance / time. So, if I have a 1 g weight I want to move 1 meter in 1 second then it takes 1 Newton of force. Except it doesn't because Force is actually kilo-mass * distance / time. If I need to look up (or memorize) stuff like this then the entire advantage of metric goes away because I can just memorize the imperial way as well.
It just comes down to what you're familiar with. There's certainly a benefit to everybody using Metric in the same reasoning as there's a benefit to everybody using Mandarin.
Hmmm... no?
With metric, once you know what a "meter" is, you have the distances. <milli>meter, <centi>meter, <deci>meter, ... It's one unit: the meter. And fractions of it that require trivial conversions.
With imperial, you have multiple units of distance: inches, feet, yards, football fields, miles.
The benefit of metric is that you have to memorise fewer units, period. Your example is a formula in physics. There you have to memorise F = m * a AND in which units those are (bonus if they are consistent between the formulas, of course). That's strictly equivalent between imperial and metric there.
> It just comes down to what you're familiar with.
Of course, if you're familiar with imperial and not metric, then you're better off with imperial!
> There's certainly a benefit to everybody using Metric in the same reasoning as there's a benefit to everybody using Mandarin.
That's an interesting example: Mandarin is known for being a lot harder than English. Obviously, if you grew up with Mandarin and no English, you will be more comfortable with Mandarin. But people speaking Mandarin don't insist on saying that Mandarin is not harder than English, in my experience :-).
I don't think the second point is particularly valid. The SI unit is a kg - which is weird, but always consistent. All Physics units in metric involve kilograms. I will grant that it's unusual that it has a prefix, but still - if you know the 7 base SI units (including the kg), the rest follows reasonably, and conversions are trivial compared to Imperial (orders of magnitude vs arbitrary multipliers).
Fundamentally yeah, what one's familiar with is the system that feels most intuitive, but I don't think these specific arguments against metric work super well
As someone who grew up with metric, my opinion is that nothing that imperial people claim is unintuitive with metric is, in fact, unintuitive to me. Nothing. And I tried hard. We're used to what we're used to :-).
> Some things are ridiculously better in the imperial system - like temperature
This says that you grew up with imperial, I'm convinced of it!
> In fact, I strongly decry that we teach our kids to use base 10 instead of the much more efficient and easier to divde into fractions of base 12.
What's the argument there? That because you can divide 12 by 2, 3, 4 makes it vastly easier than 10, because 10 you can only divide by 2 and 5? How does that make it easier to learn fractions? What about the fact that in metric, a centimeter is 1/100 of a meter, and a millimeter is 1/1000 of a meter? Those are fractions, right?
Just to make it clear: I am not claiming anything about imperial being ridiculous; I totally understand that if you grew up with it, then it's intuitive to you. What I don't understand, really, is all those imperial people who just cannot seem to apprehend the idea that maybe, just maybe, they are biased because imperial is what they know better. Is it that hard? It makes me concerned about cultural differences... do those people realise that others may have different cultures, and that it is okay and not ridiculous?
PS: I upvoted you because I don't find it fair that you get so many downvotes for an innocent opinion. I don't share your opinion, but it's not offensive or anything like that :-).
Most people don't seem to care about the units, what the haters care about (not you, but the general experience) is having an opportunity to proclaim how much better they are than other people, mostly over an accident of birth.
But I don't think that the rational answer is to try to convince everybody that your system is more intuitive because the other has "ridiculous" features. I answered to a comment that said: "ridiculously better in the imperial system".
Everybody hates swapping between units of measurement. You pick one and stick with it. It's natural having the need to move between two measurement systems irritates you.
>I measure weather much more frequently than I measure water temps,
In cold climates water temp is actually the most important thing to know about the weather by a long shot. The freezing point tells you if it's wet or dry, slippery or non-slippery.