Several missions are contingent on (and only completable during) particular BGS states, and some are even uncompletable outside of them. States can change every ~24 hours.
Odyssey in particular is affected by this.
- Wars/Conflict Zones essentially shut bases down for 4+ days. Almost any sort of mission targeting these bases cannot be completed while the war proceeds. This includes assassination, retrieval, covert theft, base restoration etc.
- Base Restoration is contingent on the target base being shut down, which occurs when the base is in particular (negative) BGS states such as (but not limited to) lockdown, infrastructure failure or natural disaster). If you take missions just before the base enters such a state, it can suffer the same issue per wars as above. If you take a restoration mission just before the owning faction leaves that state, it is impossible to complete; you can only abandon it.
Both these issues became apparent fairly quickly after Odyssey launched; people complaining about taking a restoration mission and being unable to complete it due to the base being online, or taking other missions and being unable to complete due to a warzone taking over, despite the short timeframe on Odd missions.
In space it's less bad due to most missions being contingent on USS, though there's one glaring (and similar) issue; CZ massacres. You can only find those targets in warzones. If the war finishes, there's no more targets. There's been numerous complaints about that occurring.
Another issue that affects both is the Retreat state; there's numerous cases now where a player hasn't been able to complete a mission where they took a half-billion worth of tourists out to <some destination 20,000Ly away> only to return and find the issuing faction is no longer present, because they were retreated out of the system during the month-long timer they were given to complete the mission. This also occurs with normal missions where the faction is retreated during the 24 hour window.
Equally, if assets change hands as a result of conflict and a mission targets a facility (e.g installation scan) targeting that faction, in control of that asset, these are now impossible.
Beyond all that, there's just all-round issues with synchronicity and "making sense"; taking a mission to "urgently source medical goods" for an outbreak, but if the timer is long/suspended during log-off, you might return days or weeks later with the "urgent goods" well and truly after the outbreak has ceased.
Outside that, long mission timers can be quite exploitable; whether it's for stacking, or "banking" completed missions to hand in at a time when they will be more impactful. States also affect the missions on offer... == different state effects for completing the mission, so banking those to an appropriate time for hand-in later is also viable. Banking works less these days given how the BGS works now, compared to old days, but it still has a place.
Of course, all these have
potential fixes, but that's also a
lot of potential effort simply to get "longer timers", and some of those fixes could look very clunky. Thus, back to my original post, I think the way missions work needs to be rejigged generally, though not towards longer timers, but rather to focus to rejig them to be committed activities to which you subscribe to one or two for that gaming session kinda like Odyssey does, rather than creating a "shopping list" like the current space game.