I don't understand rolling Astrogation/Engineering until you succeed. Why bother rolling at all?
IMTU, unless there is something else going on (chased by pirates, avoiding a blockade, skirting customs, systems failure or damage) I don't bother with the roll. It's normal, standard process/procedure. It has to be safe or it wouldn't be worth the risk.
However, if something else is going on, they roll once and we see where things land. Maybe it'll be good ... maybe not so good ... but I guarantee everyone is holding their breath on that roll.
The chance to re-roll is not unique to Astrogation. If you fail any roll you can have another go. Most of the time you simply waste time (that you might not have). Some skills will have a negative effect if you fail such as the engineering check to jump, that is a one shot, you either succeed and jump or you fail and misjump to some degree. If you are trying to climb a low wall and fail you can have another go, if you try to climb a cliff and fail you might fall to your death. You can make multiple attempts to shoot someone, each costs a bullet etc.
If it offends you, you could always apply the effects of the previous roll as a negative modifier to the new roll or simply introduce a negative consequence of failing the roll, or introduce a house rule that if you get an effect -6 you have failed so badly that you cannot recover. However with an easy skill check it is hard to justify a serious negative impact with an effect that might only be -1.
It annoyed one of my players that they could make several attempts to gather rumours at a party (every 1D hours) , but got only one and done roll to graduate after 4 years at university.
Skill checks are advised when one of 4 conditions apply:
• The Travellers are in danger, - not on the routine journey out to the jump point.
• The task is especially difficult or hazardous - the task is specifically Easy and not hazardous (though a badly botched roll might make it so).
• The Travellers are under the pressure of time - not usually.
• Success or failure is especially important or interesting. - This should not apply unless specific circumstances require it and not for something where failure is a one in a million chance.
If being chased by pirates and you choose to have another go then there will be a consequence (presumably the pirates get closer or maybe get some shots off), that doesn't mean that you deny the player the option to take that consequence.
I wouldn't not roll if failure was possible, even as a remote chance as if you don't then you reduce a remote chance to no chance. Do that and players will learn to cut corners assuming there is no consequence. If the players can get the skill check down to the point failure is impossible but it is still part of a task chain they could fail then we'll still roll it (it takes a few seconds and is usually in the boring part of the trip anyway so it won't break the flow of the narrative). If they choose to try again after failing then usually there will be some inter-character banter which isn't a bad thing. If they choose to risk it and end up failing the chain then there will be plenty of intercharacter banter and adventure.
Astrogation is such a niche skill you need to roll it every chance you get
