Ok, fine.  We&#x27;ll just stay on this planet and stop all space exploration because an accident may happen.<p>Besides, I&#x27;m pretty sure this has been addressed many times before.  It&#x27;s not that hard to secure nuclear material; we&#x27;ve dropped nukes in accidents before and they didn&#x27;t detonate because they were so well-built.  Even if you intentionally dispersed some nuclear fuel at high altitude, the concentration would be so low it wouldn&#x27;t make a difference.<p>And what do you mean about &quot;that much nuclear material&quot; anyway?  We safely launch <i>tons</i> of cargo all the time.  How much nuclear material do you think it takes to power a rocket?  Do you have any clue how <i>little</i> nuclear material is in a full-fledged bomb?