The earth has thousands of satellites in orbit, and every one of them has an expiration date, so here's what happens to those satellites when they are retired.
The PATRIOT air defense system is used by the United States and its NATO allies to protect against missiles and other airborne threats. How does it work?
While we'd all like to use brand-new, fancy tools, sometimes it's much more cost-effective to keep using older or secondhand tools. Is it safe to do so, though?