Rocket-silo requests are normally only created when the logistics network has enough to fill a rocket, so in normal circumstances, although it may take a long time, the rocket should eventually launch.
However, if the resource is spoilable (or perhaps otherwise being removed from the logistics network), it's possible to run out of a material for a rocket-launch request. Even if 0 of the material remain in the logistics network (because it all spoiled), the rocket launch order is never never canceled.
In this event, the Rocket-silo will remain unavailable for all future logistics deliveries until the resource is returned to the logistics network, and worse, it freezes the space-platform in the "Waiting for rocket to arrive" state, even if all departure conditions are satisfied.
- automatic-rocket-silo-request-with-red-logistics.png (138.53 KiB) Viewed 205 times
In my particular save, this deadlocked a space-platform that ferried Biter-eggs from Nauvis to Gleba and Bioflux from Gleba to Nauvis. Nauvis had enough Biter-eggs to trigger a rocket launch, but some must have spoiled before finishing. However, this held up the rocket that was supposed to deliver more Bioflux. So despite the "Time passed" condition permitting departure, the Nauvis-Gleba shuttle was stuck in the "Waiting for rocket to arrive" state.
----
I think this is an extreme, but probably commonly reached, edge case, related to the discussion at viewtopic.php?p=645225
In general, the game cannot determine if a rocket delivery is merely "slow" or never coming. However, I think in at least the specific case of
- the Space-platform is ready to depart, but cannot because it is in the "Waiting for rocket to arrive" state
- and the logistic-network does not have enough capacity for the delivery (the resource icon is "red" -- meaning, if the delivery hadn't already been attempting, it would not be started again at this point)
- and the delivering rocket-silos itself is empty,
I think even the first two conditions may be enough to cancel the request with a timeout, but if the request is impossible and robots have not made any progress whatsoever in fulfilling it I think it is definitely safe to cancel.
In addition, there does not appear to be any way to see whether or not a rocket-silo is in this blocked state; a rocket-silo with a logistics request but no contents does not appear differently when mousing-over, so it is essentially impossible to find the misbehaving rocket silo in a large save:
- rocket-with-unsatisfiable-logistics-but-no-marker.png (130.85 KiB) Viewed 205 times
----
I attached a save file showing a rocket-silo/space-platform stuck in this state. It is easy to reproduce, for example, by injecting just enough of a quickly spoiling item like bacteria to start the delivery, but with few enough logistics-robots that the rocket is not successfully filled before all of the material spoils.
----
TL;DR: Automatic rocket requests should be automatically cancelled if they are preventing a space platform to depart and there is 0 of the material in the rocket & 0 in the logistics network
