But there are no clouds in space and with the right orbit they are always facing the sun
The 1TW is the rated peak power output. It's essentially the same in space. The thing that changes is the average fraction of this sustained over time (due to day/night/seasons/atmosphere, or the lack of all of the above).
It's still the same 1TW theoretical peak in space, it's just that you can actually use close to that full capacity all the time, whereas on earth you'd need to over-provision substantially and add storage, so 1TW of panels can only drive perhaps a few hundred GW of average load.
You know how people sometimes dismiss PV by saying "what happens at night or in cloudy weather?"?
Well, what happens over the course of a year of night and clouds is that 1 TW-peak becomes an average of about 110 to 160 GW.
We're making ~1 TW-peak per year of PV right now.