Welcome to the 40th episode of the Inc. Uncensored podcast!

This week, Burt Helm rings in the holiday season with the story behind Inc. 5000 honoree Tipsy Elves, a company that makes ugly sweaters. The niche retailer was born just before Christmas in 2010 when founders Evan Mendelsohn and Nick Morton were invited to a holiday party where everyone wears those ugly sweaters your grandmother buys you. The company, which has grown almost 2,000 percent in three years, brought in $6.5 million in revenue last year.

Will Yakowicz talks about NASA's planned manned mission to Mars in 2030. The bad news is that a recent audit finds that NASA is not prepared to deal with the risks associated with sustaining life in deep space. Private space companies like Jeff Bezos' Blue Origin are making progress in the quest to send humans to space, but building permanent colonies on the Red Planet is going to take a lot more help, both private and public.

Check out a video featuring photos taken by NASA's Curiosity Rover on Mars. 

Christine Lagorio-Chafkin discusses one of the country's largest solar panel companies, Solar City, and how Elon Musk is building his home-and-car battery factory in the Nevada desert. It may not sound sexy, but the battery is the last mile in sustainable solar energy and could be the key to ending reliance on fossil fuels.

You can listen to individual episodes of the Inc. Uncensored podcast, which is part of the Panoply network, on Soundcloud, or on iTunes--where you can also subscribe. We hope you enjoy. Stream the 40th episode above.