I'm wondering if what they mean is,
that's the total tension required on the cables or something like that.
When one refers to a tightrope walker, that rope has to be really, really tight.
I've forgotten how to do the calculations (high school, ~1955), but I know that even a small weight on a "tight" "rope" will deflect the rope substantially no matter how "tight" the rope is.
So it seems to me that large number (900 tons)
might refer to the suspension cable tensions rather than the weight of the module.
Hawkmoon, what do you think?
Terry, 230RN
Pic credits in properties. The tightrope walker may not be an actual image.