Could this be a better solution for our worst murderers?

If they could be isolated, on Alcatraz or an island which could be encircled so there would be no escape, would any here really object?

Robert Heinlein’s Coventry was already mentioned. Another fictional depictation of this idea was Robert Silverberg’s Hawksbill Station in which political prisoners were sent on a one-way trip millions of years into the past.

Okay, I get that. But I can’t go read those books tonight.

What are your opinions on a secure penal colony solution today (non-fiction), given today’s politcal realities?

IMO, such a solution would greatly alleviate prison overcrowding. These “life without parole” convicts will be there in our prison systems for a very long time. Given the number of such prisoners and the length of their lives (does anyone know the actual numbers?) their years incarcerated really adds up. Other prisoners are in and out.
One lifer’s cell, freed up, could be used a number of times for other criminals.

Humane vs Inhumane? In a penal colony they would have a freedom they would never have in a cell for life. What they would do with that freedom would be totally up to them. Theirs lives would no doubt be more productive than living in a cell waiting for their meals to be delivered.

{Cost ? Far less than the cost of housing in current prison, and building new prisons; 24/7 prison guards, cooks, medical, administrative personnel.