Light pollution from satellites puts new telescope operations at risk

Why can’t they close off the telescope (“LSST”) for the brief moment a bright satellite is in the field of view, during otherwise long and static exposures?

While the LSST is intended to image the entire sky each night, I don’t think it does so in one exposure. The article says 1000 exposures per night for ~8 hours of “night” is about 30s per exposure, and an LEO satellite might take a minute or two to cross the sky, and this telescope looks at a field of view of 40 moons or about 20° of view.

That’s a big field of view, but if space based solar telescopes are able to use a coronograph — a physical mask to block direct sunlight — in order to image dimmer parts of the sky, couldn’t a telescope like LSST in the article use a similar dynamic masking system?