Someone must have taken the ship off Mars.
5 seconds sound clip from the The Angry Red Planet movie soundboard.
You can hear this line at 00:02:30 in the Blu-ray version of the movie.
Quote context
[...]
- If there's enough fuel on board, we can send the ship homing for the Nevada base.
- If the fuel holds out through the re-entry deceleration, we can set her down safely.
- Here's another if: what if there is someone on board, alive?
- Major Ross, has communications established any contact? No, sir. None.
- Someone must have taken the ship off Mars.
- And how long will they last if we leave them out there?
- Then it's decided. We take off for Nevada at once.
- We're getting it now, sir, on the radar telescope screen. There she is.
- Yes.
[...]