I think this is a great question, but a difficult one to answer with finality as there are a lot of variables at play. Including dice rolls!
My general rule of thumb--and this is just based on experience--is that a full party of adventurers can go through approximately 3 or 4 level-appropriate encounters in a day without dying, with each encounter using up around 20-30% of the party's daily resources (spells, abilities, HP, Stamina Points and Resolve Points [Starfinder] items and finally, one-use items). Some parties really like to push their abilities, some like to stop and rest every time the Arcing Surges have been expended.
If you are going to be keeping the PCs on the run under some sort of pressure or time constraint, then I'd suggest prepping scale-able encounters so that you can play it by ear. So things like:
Reinforcements arrive to help the gaggle of 1/2 CR critters and keep the PCs engaged in battle for longer. It needn't be reinforcements, it could just be a larger creature that finally arrives, or a weapon that's now ready to fire on the PCs. It's handy to have this kind of thing ready in the event that your PCs are running through encounters too quickly or easily. It also means you don't have to use these extras if the PCs are struggling--just save these prepped additions for next time.
Terrain can be used for advantage, to increase the difficulty but not the CR of an encounter. It can also be used to the baddies' disadvantage, depending on how the PCs are doing, i.e. security guards charging one at a time through a door as opposed to forcing the PCs to do so.
Role playing encounters also count as encounters and keep the game momentum moving. An encounter need not be hack-and-slash, but it can still use abilities, spells, and items to overcome. The security guards can be tricked, charmed, or circumvented entirely.
Add a Chase. This can be quite fun, fast paced, and generally relies more heavily on the PCs skills, with minimal use of limited resources. If you are looking to get PCs from point A to point B without killing them or having to roll too many random encounters, this could be a viable and engaging way to do so.