This month’s issue of Popular Mechanics has a feature by me about Space Exploration Technologies, the startup that might just end up building America’s next orbital spaceship–and provide charter flights to NASA.

I told the SpaceX story in my book Rocketeers, but I’ve been angling for years to land a magazine story to cover it. In particular, I wanted to go deeper into the meeting of minds between company financier Elon Musk and propulsion chief Tom Mueller. The two met in a workshop where Mueller was building the world’s biggest amateur liquid fueled rocket engine, and Musk asked Mueller, “Can you build something bigger?”

Read the story online at http://www.popularmechanics.com/science/air_space/4328638.html.

The online version of the story includes an innovative feature that I pushed hard for: a pencast of Mueller explaining the inner workings of the workhorse engine he and his team designed and built for SpaceX.

If you don’t know what a pencast is, you’re in for a treat. Livescribe, a Silicon Valley startup, has created what I call the Super Pen (actually known as the Pulse), which allows handwritten notes, doodles, sketches, or anything else you can make with a pen, to be linked with audio being recorded by the pen at the same time.

This has quickly become an indispensable tool in my work as a journalist. When someone I’m interviewing says something I know I’ll want to play back later, I just jot a quick reference note, and then later, whenever I tap the pen to that place in my notebook, the recording of that particular place in the interview plays back.

You can also upload pencasts to the Web, which allows you to hear an interview playing back in a Web browser and watch the sketches and notes being drawn and written out in real time. This gives you a you-are-there immediacy I don’t believe can be captured any other way. Check out the Mueller pencast here and tell me if you agree.

If you want to see more of these pencasts included with Popular Mechanics stories, let the editors know by adding a comment to my story at http://www.popularmechanics.com/science/air_space/4328638.html.