12г - более тупой перевод придумать трудно. - https://ru.wikipedia.org/wiki/Перегрузка_(летательные_аппараты)

Космонавт при взлете докладывает в ЦУП:
The fuel is go. 1.2g. Cabin pressure at 14 psi. Oxygen is go.
И кто ж поверит, что доклад его окажется таким:
Топливо идет/поступает. 1.2 g. Давление в кабине 14 psi. Кислород идет/поступает. ???

А что именно вам не нравится?

Смысл именно такой, а в красноречии упражняйтесь сам, если хотите. Вот только космонавту нужна краткость, а не красноречие

Alex, please look at the first definition here: https://idioms.thefreedictionary.com/all+systems+go GO is used in aeronautics to confirm that individual flight systems, or "all systems," are ready for takeoff.

1.2g means that it's AFTER the takeoff

I won’t pretend to know what 1.2g means, but GO means ready.

See the link to wiki above

According to that article, an object can register a g-force of 1 even when sitting on the ground: “The standard gravitational force at the Earth's surface produces g-force only indirectly, as a result of resistance to it by mechanical forces. It is these mechanical forces that actually produce the g-force on a mass. For example, a force of 1 g on an object sitting on the Earth's surface is caused by the mechanical force exerted in the upward direction by the ground, keeping the object from going into free fall. The upward contact force from the ground ensures that an object at rest on the Earth's surface is accelerating relative to the free-fall condition. (Free fall is the path that the object would follow when falling freely toward the Earth's center).”

Yes, 1, not 1.2. Big difference.
Возможно речь идёт о готовности следующей ступени.

Ох уж эти гуманитарии!

According to this, the g-force of a rocket at launch is around 3g: “Astronauts normally experience a maximum g-force of around 3gs during a rocket launch. This is equivalent to three times the force of gravity humans are normally exposed to when on Earth but is survivable for the passengers.” https://www.spaceanswers.com/space-exploration/what-g-force-do-astronauts-experience-during-a-rocket-launch/

It doesn't matter what happens "normally".
1.2g means that the rocket is flying and either accelerating or braking. Period.
3.0g is "a maximum g-force"- and, possibly, at the last stages when the weight is smaller. "The g-force of a rocket launch is limited by the cargo it is carrying" - your link. Big amount of fuel and extra stages at the start are a "cargo".

"staging allows the thrust of the remaining stages to more easily accelerate the rocket to its final speed and height. " - https://en.wikipedia.org/wiki/Multistage_rocket

http://lovefreenovels.com/Newest-Books/The_Calculating_Stars__Lady_Astronaut___1_/page_28.html

Confirm liftoff. Manual clock is started.”
I picked up my pencil and poised it over the graph paper.
“This is Hercules 7. The fuel is go. 1.2g. Cabin pressure at 14 psi. Oxygen is go.”
As the rocket roared into the air, ...

I am not sure, but I read this as the phrase in question was said after the liftoff.

I think you’re right. I know nothing about aeronautics, but I do know that GO means ready.

Мне, как обычно, нужен толковый русский перевод, а не толкование. Может, кто и попробует с таковым мне помочь?

варианта два - см. выше и выбирайте.
Мой, думаю, больше подходит по смыслу.
Второй - более обтекаемый и, вроде, включает в себя более точное значение.
И вы так и не ответили на вопрос. Нехорошо.

for the record:
"второй" вариант был "в норме" - если мне не изменяет память.