Hubble Wide Field Camera is quite large - it's just 16 megapixel, though, and it does use a mirror:
https://www.nasa.gov/content/hubble-space-telescope-wide-field-camera-3
There are other different "cameras" onboard.
The largest camera I've seen and used (briefly) is a Sinar 8"x10" one. Here it is while attending a course about landscape photography with large format cameras, the lens and hood have not been attached yet, he was explaining the camera movements. Fully mirrorless, though. In the background the camera suitcase showing the wide angle bellows:
View attachment 180551
He has even a larger 20"x24" built I believe by Stenopeika (
https://www.stenopeika.com/prodotto/stenopeika-2024se2-folding-camera/), used for wet-collodion plates, but I've just seen the images and not the camera yet.