Honestly man, all I see are challenges more than barriers. Barriers tend get broken anyhow and abiding by current science in a interstellar setting is silly to the point where even in this thread I think you're overdoing the whole realism thing and assuming the worst. For instance I thought interstellar space is so vast that you likely wouldn't hit a micrometer in the first place and even if its the ship causing the explosion I still believe it can be tanked because innovation.

I think you should tone it down to 80 or 90% hard sci-fi.