I'm always amazed how small the financial help seems when compared to other spendings, especially the military.
The military spends millions on a simple helicopter or a tank that for the most part just sits there waiting to be used and such important scientific projects have to get by with a mere 600.000 dollars.
Boggles the mind sometimes to imagine what we could have achieved by now if the roles were switched.
Yes, but an extra guided missile frigate is surely worth a thousand times more than fusion engines - or something...
However, I'd say the size of the grant is more a reflection of how much money they need to test the prototype, not how much we'll spend in further development if the device shows lots of promise. Obviously getting a working prototype into orbit will cost several billion dollars, just to cover the R&D and launch.