u/Goregue

Rockets usually need two upper stage burns to enter orbit. A long one immediately following first stage cutoff to achieve a high apogee, and then a short circularization burn one hour later to increase the perigee and thus achieve a stable orbit. This is done for example on Falcon 9 Starlink launches, and also on the recent Ariane 6 Leo launch.

But during the recent Atlas V Leo launch, the upper stage was only fired once and it achieved its final circular deployment orbit. How is this possible and what are the advantages of doing it like this?