A person is lost in space when they move away from the spaceship, are unable to return, and their position is not tracked by others.
Regardless of whether they are eventually found or not.
@zzlk That assumes their starting position and velocity are well known, and that they do not undergo further acceleration as they travel.
And if determining those parameters required extensive analysis of telemetry it would count as being lost until the analysis was performed, wouldn’t it?
@lukres I think if they undergo acceleration after separating from some space craft then they seems like it would probably be intentional suicide rather than "getting lost". How would you count that situation?
I agree it could be hard if we don't know initial conditions but I think well into 2035 we will still be closely tracking space flights and missions, so I think it's very hard to go missing/get lost.
And I agree that they would be technically lost until we do the analysis and find them again but I guess it just wouldn't happen that way.