“the spacecraft will be traveling at one-fifth the speed of light”.
Stopping may become an issue.
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I don’t think that “stopping” would be part of the mission. It would be, in large measure, a “flyby” mission...a very high speed fly-by. I guess it would be possible to partially decelerate by using the craft’s “light sail” as a parachute resisted by the star’s radiation & solar wind.
If you could find some means to turn it around. Hard to do with gram like objects.