Det låter som om du beskriver " Den kalla ekvationen " av Tom Godwin.
Barton explains that her presence dooms the mission by exceeding the weight limit, and the subsequent crash would kill both of them and doom the colonists awaiting the medical supplies. After contacting her brother for the last moments of her life, Marilyn willingly walks into the airlock and is ejected into space.
Historien har anpassats upprepade gånger, men du beskriver förmodligen 1996 made-for-TV versionen eller Twilight Zone version som har en mer "rörig" känsla för det.