It would've cost over $1 billion of taxpayer money to realistically get Watney home. Probably more with all the mistakes they made in the process. Yet the public is not upset by this one bit. Instead the filmmakers chose to depict people celebrating around the world. In reality, there would be large protests outside NASA everyday. Why did they choose to ignore that fact?
Does anyone question how much a Seal Team 6 rescue mission actually costs when they go and rescue a captive from terrorist hostage-takers, let alone protest it? I've never seen it. Perhaps you could link some examples, specific to my scenario, of a backlash that amounts to more than a handful of fringe nut-jobs to back up your assertions.
If NASA was able to do it without specifically asking Congress for more money (Teddy's "I'll find the funds" quote), it would never come up. If they did, and no one in Congress opposed it, then the matter would be pretty much settled.
Do you really think people would be out there with signs "Let Whatney Starve!! Don't spend my $3 taxpayer share on him!"
Think of this the other way, sure individuals who would have had momentary thoughts and not considered the situation well enough would voice their opinions as they do on every subject every day now, but which person in authority or the public-eye would publicly announce or request that Watney's life was beyond economic recovery? Their political or public life would end immediately, America loves its 'heroes' at all costs today and I can't see that changing any time soon.
Your suggestion that people would be upset about Watney's rescue is contradicted by both how NASA operates (budget wise), human morality, and the general perception of NASA by the population.
- Anyone who argues to not save a human being because of the financial cost, inherently puts a price on a human life. That is what you are literally doing when you get upset at the money that is being spent; you are arguing that the cost (a lot of money) is not worth the benefit (one more living human being). Therefore, that human life must be worth less than the money you are spending.
- Your questions assumes that the population has an idea of the cost of the rescue. Even if it is mentioned in the media, not everyone is listening, not everyone cares, and not everyone who cares will actually try to do anything about it.
- This unforeseen cost to save Watney would, logically speaking, come out of NASA's budget. No extra money will be spent, but NASA's current budget will be smaller as the costs of Watney's rescue are paid by their budget which was actually intended for other programs.
- The only complaint that people then could make, is not that they are paying more, but that they are getting less bang for their buck (since NASA will presumably have to cancel one or more programs to fund Watney's rescue). It is a recurring conversational topic that the population cares much too little for space exploration. There simply isn't a high expectation by the general populace for what NASA delivers, and therefore also no one to complain that they are not getting what they wanted to get out of it.
- It is possible for NASA's budget to be increased specifically to pay for Watney's rescue. However, the budget is decided by the US government, which operates on behalf of the people. Therefore, the government would only be able to increase NASA's budget because the people want the government to do that.
- If the government, for some unexplained reason, goes behind the people's backs and gives money to NASA that they should not have; then the people will be upset with the government, not NASA.
- You are also ignoring the impact Watney's rescue has on the population. Seeing humanity unite and work together to save a (near-unsaveable) human not only showcases the best of humanity, but it makes everyone feel safer in knowing that their fellow humans will always endeavour to save each other in times of need. Leaving Watney behind may be a PR nightmare, but rescuing him against all odds will usually mean NASA comes out on top and be perceived as doing the right thing for the right reasons.