ETA

ETA is a special object that exists just to help you get the times from now to certain events in a vessel’s future. It always presumes you’re operating on the current SHIP vessel:

structure ETA

Suffix	Type	Description
APOAPSIS	scalar, seconds	Seconds until SHIP hits its apoapsis.
PERIAPSIS	scalar, seconds	Seconds until SHIP hits its periapsis.
TRANSITION	scalar, seconds	Seconds until SHIP hits the next orbit patch.

ETA:APOAPSIS

Type:scalar, seconds Access:Get only

Seconds until SHIP hits its apoapsis. If the ship is on an escape trajectory (hyperbolic orbit) such that you will never reach apoapsis, it will return zero.

ETA:PERIAPSIS

Type:scalar, seconds Access:Get only

Seconds until SHIP hits its periapsis. If the ship is on an intersect with the ground, such that you’ll hit the ground first before you’d get to periapsis, it will still return the hypothetical number of seconds it would have taken to get to periapsis if you had the magical ability to pass through the ground as if it wasn’t there.

ETA:TRANSITION

Type:scalar, seconds Access:Get only

Seconds until SHIP hits its the end of its current orbit patch and transitions into another one, ignoring the effect of any intervening manuever nodes it might hit before it gets there.