The Gravitron is an aircraft used by the Epsilon Army. It has a similar appearance to Invaders, but instead of using dissolver beams, generate an anti-gravity field similar to that used by Libra which slows ground units in its wake and heavily damages approaching air units; ground units who are too close will be flipped to their doom. However, Gravitrons will always remain stationary even when being attacked, making them vulnerable to anti-air.
Another UFO, Yuri must have an obsession. Watch out, we don't know what it is. We're receiving readings of a strong gravity field manipulation around it though.
Gravitrons only appear in Earthrise as unbuildable, limited enemy units. They are scattered everywhere on the map, causing trouble to the player's Cosmonaut spamming tactics. However, they will remain stationary and will not actively move to attack the Soviet forces.