Seriously, 18 hour two-way mission from Earth to Sun ... I know it is a joke but still ... learn your orbital machanics :rofl:
Consider this [humor/satire]:
It takes light from the Sun roughly 8 minutes to reach the Earth at ~300km/s.
18 hours round trip for the Hero of North Korea = roughly 9 hours each way.
Take away 1 hour for exploration/sample gathering and one hour for Sun/Earth transfer burn, that leaves you with 16 hours round trip. 8 hours each way.
8 minutes for light vs. 8 hours for the chariot carrying the Pride of North Korea.
1 minute = 1/60 hrs, meaning you only need to go 1/60th the speed of light to achieve this time.
300km/s / 60 = 5000km/s. <-Much less than orbital velocity and many times less than escape velocity for Earth. Totally doable.
Congrats to the geniuses in the North Korean space program who figured all this out!!!
[/ humor/satire]