Drobo

Can I take one disk out of Drobo and have it readable by an external drive enclosure?

Unfortunately this is not possible with Drobo or any storage technologies that writes data safely across multiple disks. In order for a storage array to efficiently utilize hard drive capacities and ensure data safety, data must be written using algorithms that place data on your disk differently than when you are using just a single drive or just a bunch of drives (JBOD).