> Even the most reliable launch vehicles (Falcon 9, Atlas V) are probably not more than ~99% likely to succeed.

Falcon 9 is it at this point. All of the remaining stock of Atlas Vs and Ariane 5s have been sold.

Of course Vulcan and Ariane 6 will come online soon; buy they don't have anywhere close to the safety record that Falcon 9 does.

I'm not a statistician, but I wouldn't be surprised if Falcon 9 had better than 99% chance of success. It has more than a 150 long success streak. And no rockets in the current configuration have ever failed.

> Can we convince this segment of the population that launching a small device (with necessarily less shielding) is safe?

This isn't obviously no to me. NASA has launched a bunch of RTGs in the past. Those have the same sort of safety concerns in the event of a failed launch. Probably less material, though.