Reliable Robotics Hardware Integration Engineer interview questions

I had a pleasant interview with the hiring manager and then a subsequent interview with the person in charge of the hardware systems team. I was then given a lengthy technical challenge with a flexible deadline (which I appreciated). After submitting the challenge, they responded within 2 days stating they would not be moving forward with the hiring process and offered me feedback upon my request. Looking back I will admit the position was meant to be filled by someone with more experience, but I appreciate they gave me a chance. The feedback listed many government publications I should have referenced with certain parameters in my design. If I had known that information up front I think I would have done better, but I think they're looking for someone that can demonstrate a certain level of experience. Overall it was a good experience, I learned a lot and I would consider applying again in a few years.