Final answer:
Sam Parkhill's situation is ironic because his extensive preparations for an influx of customers on Mars faces the harsh reality that there may be no customers at all, showcasing situational irony.
Step-by-step explanation:
In “November 2005: The Off Season,” the irony about Sam Parkhill's situation is that despite his preparations and expectations for millions of customers on Mars, the potential for such a customer base is nonexistent or highly unlikely. This is a classic example of situational irony, where the outcome is in stark contrast to what was expected or intended. Parkhill's investment of time, effort, and perhaps dreams in establishing a business infrastructure on Mars is met with an incongruous reality that there may be no one to serve or profit from, highlighting the unpredictable nature of colonization efforts and the complexities of space exploration.