What a good question. I don’t think we have a real answer yet. SpaceX is also building a second Starship pad surprisingly close to the first one. From the rocket RUDs that we have seen, it seems that fire and flame stay relatively close to the pad. The latest Starship RUD shows some charring on a portion of the nearby tank farm. I suppose that the blast/overpressure could have a nasty effect much farther away than the fire damage.

All good questions. I have another to which I can’t find an answer – how big is this Diamant launch site? In addition to Latitude and PLD, Rocket Factory Augsburg and Isar have also expressed interest in building pads there. How close together can multiple pads safely be to one another? SpaceX is building a Starship pad less than a kilometer from its extant F9/FH pad at LC-39A and there is no evidence – at least yet – of any berm or blast wall separating the two. Perhaps berms or blast walls would allow multiple pads at Kourou’s ex-Diamant location to operate safely at minimal separations. Given SpaceX’s GSE misadventures these last few years, I worry a bit more about such things now than I used to.