Today, Elon Musk, founder of SpaceX and CEO of Tesla Motors spoke at the All Things D conference. At the conference, Musk announced that the Supercharger, a quick charge unit for Tesla cars, would see a tripling by the end of next month.

By the end of 2013, Musk said, it will cover most of the metropolitan areas of the US, and Musk says that a drive from LA to NYC using only Superchargers will be possible. Both the density of Supercharger stations along routes and the overall geographic area are being increased. A map will be live tomorrow with the new coverage map.

“Starting an electric car company would have to be one of the dumbest things you could do to make money,” Musk said about starting Tesla, noting that he didn’t do it for the cash. Instead, he did it to show that an all electric car could be both viable commercially and aesthetically pleasing.

“It was clear that we were not going to see electric cars from incumbent manufacturers,” says Musk. For a while, he says, it seemed that there was going to be. General Motors created the EV1, but as soon as the government regulations were changed, GM recalled the cars and crushed them.

Musk notes that people showed up to hold candles and mourn over the cars’ disposal.

“If people are holding a candlelight vigil for your product, maybe you shouldn’t cancel it,” he joked.

In response to a question about whether he was worried about the majority of the electricity being used to charge the cars was generated by coal. Musk noted that the maximum extractable energy was much higher at the plant level than at the car level, including factors like cogeneration with coal and steam.

“When I was in college, I wanted to be involved in things that would change the world.”

One of those, he says, was the Internet, and so he founded PayPal. The other two areas, Musk says, were space exploration and sustainable energy. Hence SpaceX and Tesla.

Screen Shot 2013 05 29 at 8.13.50 PM Elon Musk: Tesla Supercharger network to triple by July, enable cross country travel by years end

“Every time you buy a gasoline car,” says Musk, “an enormous amount of subsidies occur.”

He’s referring to the upstream government subsidies from Federal and state taxes. Musk says that they’re much bigger, which is why you don’t see Chevy Volts and such flying off the shelf.

Musk expects a ‘$30,000′ Tesla in “three to four years”. Musk says that technologies take several generations to mature and he’ll be happy if by their third generation or so he’d feel great about that. This model will likely be 20% smaller than a Model S.

Musk says that he expects 25% gross margins outside of government credits by the 4th quarter.

On the subject of the much contested (by Musk) review of the Model S by the New York times, he said that the review contained factual errors and said that it was incorrect in “a very important way.”

Musk also spoke about SpaceX a bit, saying that the only way to ensure that the space program didn’t fade away was to simply begin and invest in projects like putting humans on Mars.

A low energy trajectory for travel to Mars would be about six months, but you could compress it down to three months, says Musk. “The big dream,” says Musk, “is to achieve a rapid, fully reusable rocket. If you think about any other form of transport — they’re all reusable.”

The space shuttle, Musk says, is not reusable and takes an army of people nine months to refurbish for another flight.

Musk then spoke about how we might be able to terraform Mars by using greenhouse gasses to warm it up. ”Mars is a fixer-upper of a planet, but we could make it work.” he added.

“Are there dangers, I heard there was radiation…?” asked Walt Mossberg.

“What could go wrong?” replied Musk.