The SBIR program is not a loan. It's product development contract program. You tell the program manager what you want to build with their money, they give you t

The SBIR program is not a loan. It's product development contract program. You tell the program manager what you want to build with their money, they give you the money, you figure out how to build it. If you don't meet delivery expectations, you owe them nothing. If you deliver on the end product, they are likely to become your customer. If you look through the list of companies with SBIR funding, and what they are working on, you'd be really impressed. A lot of the ventures funded are a lot more high risk than any sane VC would invest in, but that doesn't make them any less cool.