So what did the 40k for your research cover? It sounds like you are probably discounting the cost of your own salary as a graduate student supported by the gran

So what did the 40k for your research cover? It sounds like you are probably discounting the cost of your own salary as a graduate student supported by the grant, which is usually the bulk of the direct cost for NSF grants like this and probably runs 100k/year, with the grant covering maybe 3 years of your time.