But should you be tempted to purchase in advance a ticket-to-ride on Musk’s escapist enterprise, you might want to consider these facts first. Mars’s atmosphere has next to no oxygen, the planet’s average temperature is -81 degrees Fahrenheit, and its distance from Earth is 133 million miles. Best not to get locked out of your doomsday bunker there, nor expect a frontier scout or an underpaid but dedicated EMT to arrive from afar to save your day.