This was a pair of short stories (published in Analog, maybe late '80s?) set in a near future where man has spread out over the solar system. As for characters, there was a shuttle pilot (female?), and the prototypical absent-minded scientist (male, Scots name).
It opens with a discussion of why a high-gee spacecraft drive is not practical because of the effects on the crew/passengers. Said absent-minded scientist promptly goes out and invents one by positing that you could push a large disk of collapsed matter at high-gee, and move a crew capsule closer to it and farther away from it to balance the thrust, leaving the crew at 1 gee. Various implausible things happen when this system malfunctions while the capsule is snugged up against the disk, meaning you can't turn the drive off.
I actually had the magazine for the longest time, but can't find it now. The first story was the cover story on issue it appeared in, and said spacecraft was pictured on the cover, looking like a disk with a spike sticking out of it.