Thanks to my boss, who brought in a vintage 1996 CD-ROM drive, I'm now happily upgrading my NeXTStation to OpenStep 4.2. This drive has no problem reading the CD-R that failed on the other mechanism, so I'll chalk it up to a dusty lens or some other age-related failure.
This upgrade is really just to prove the drive can read the disc for long periods of time; I have a much larger, quieter SCSI drive I eventually want to be the main drive for this system. At a whopping 4gigs, it will need to be carefully partitioned to avoid running into OpenStep's myriad limitations of 1 and 2 gigabytes, depending on the phases of the moon and which patch level you're running.