The "script" is mine. I just gave some thought on hypothetical situation. Not even heard of the film Mars, where they leave behind a crew member.
I thought of the courage it takes to go out there exploring new worlds and the hazards coming with the "package".
It happened before during the Discoveries of the XVth century, it happenend with the Poles exploration, it will happen during space exploration.
Bottom line: What were the last thoughts of Katie?