<i>you can&#x27;t stop the craft.</i><p>Zubrin and someone devised a way to use magsails to decelerate starships without using onboard fuel. That&#x27;s magic, as you&#x27;re not subject to the rocket equation. (Really, it was a failed attempt to develop a Bussard ramjet, but they figured out you&#x27;d never overcome the &quot;friction&quot; with the interstellar medium. So they were like, let&#x27;s go with the friction!)