Shuttle cost

I just read a piece in this week's Nature that evaluates the cost per launch of the shuttle. Over the whole programme of 131 flights, the cost averages out at $1.5 billion a pop. Making the assumption that a post-doc costs approximately £100K per annum (including overheads), this means that a single shuttle launch (at today's exchange rate of £1:$1.64) works out at about 9150 post-doc years. Though I've always been a big shuttle fan (see image), I wonder if that's good scientific value for money? As I guess some of the $1.5 billion goes on things like researchers, it's not quite as either-or as I'm implying there for one thing. But it's still a whole lot of cash.