Earlier quoted context omitted.
The goal of cutting government spending is ultimately to reduce the amount of resources drained out of the economy through taxes/inflation. Balancing the budget is useful insofar as it reduces the resources that will need to be drained out of the economy in the future to pay interest on our growing debt (currently 11% of all Federal spending).
Tax money isn't drained out of the economy. The money used for NASA goes right back into the economy, since they use it to buy things. Even money to pay down debt isn't removed from the economy since the majority of that debt is held by US citizens who use that money to buy things.
You're fractionally engaging in the broken windows fallacy.
Every time we pay for something that wouldn't have got done otherwise it comes at our expense.
That's not to say that some of these things aren't worth doing. But there are a whole great many things the feds spend money on that aren't worth doing.
If two dollars go to invading some stupid sandbox and one dollar goes to Nasa and the NASA dollar pays back a buck fiddy we're half a dollar poorer at the end of the day.