Well, apparently you can pick them up and do them later. But you must pick them up the day they are available.
On Tuesday I picked up Regnant Station (Rep) and completed it.
Wednesday I picked up Ardis Outpost Fortification (Rep). I couldn't not finish it due to that Comcast network error in my area. So I just left it in my log.
Thursday I picked up New Covar Ice Field (Rep) and completed it. Ardis Outpost Fortification (Rep) was still in my log, I made a few attempts but was to tired to complete it.
Friday I picked up Baros Ambush (Rep) and completed it. Then attempted Ardis Outpost Fortification (Rep) again an completed it. Still gave me the Operation reward and BH comms.
I received all the correct rewards each day. But I ended up completing Wednesdays mission on Friday. SO if you want to wait to do them in one day. I believe you still can, you just have to pick up the mission on that day which should be to bad. I'm sure you all are on your ship at least once a day.
Those are my findings. Give it a shot to see if it works for you.