This flight was launched with a Falcon Heavy, that is why it has more energy to reach high orbit than the previous launches with an Atlas V booster.

When you are in a highly eccentric orbit (meaning the point in the orbit farthest from Earth (apogee) is much higher than the lowest point (perigee)) like this one there are several maneuvers you can do to significantly change your orbit with relatively little energy. The article describes some of the things they are testing.

A small breaking burn at apogee will lower the perigee into the upper atmosphere and they can then do aerobreaking (use atmospheric drag to lose energy) to slow down enough to land.