Raptor rocket engine firing
SpaceX’s Raptor rocket engine undergoes its first test firing. (Credit: Elon Musk via Twitter)

GUADALAJARA, Mexico – In advance of this week’s big reveal, SpaceX’s billionaire founder, Elon Musk, is dropping hints about the scale of his plans to send colonists to Mars.

Musk is scheduled to talk about what used to be known as the Mars Colonial Transporter in Guadalajara on Tuesday at the International Astronautical Congress.

The “late-breaking news” begins at 11:30 a.m. PT (1:30 p.m. CT) Tuesday. Streaming video of the talk should be available via SpaceX and YouTube as well as via the IAC and Livestream.

Musk has been building up to this presentation for months, arguably for more than a year. It’s the highlight of this year’s annual conference. Although he’s been coy about the details, Musk has let some hints slip out – for example, that the rocket should be capable of sending 100 tons of payload to Mars, or 100 passengers.

This month, he said in a tweet that the Mars Colonial Transporter “can go well beyond Mars, so will need a new name.” He then started referring to it as the interplanetary Transport System, or ITS.

Then, on Sunday night, he showed off pictures of the first firing of SpaceX’s Raptor interplanetary transport engine:

To the delight of SpaceX’s fans, Musk went on to provide technical details about the cryogenic methane-fueled engine:

He added that the chamber pressure would be about three times that produced in SpaceX’s workhorse Merlin engine.

That set off a flurry of questions, leading Musk to acknowledge that the rocket engine’s nozzle could get “pretty close” to 14 feet wide in some configurations. That’d be wider than the nozzles of the F-1 engines that powered NASA’s Saturn V rockets toward the moon.

Musk promised to go over the detailed specifications on Tuesday.

In his hourlong talk, Musk is also due to discuss the other challenges involved in creating a permanent, self-sustaining human presence on Mars. His previously stated timetable calls for sending out the first colonists in the mid-2020s. “It’s dangerous, and probably people will die – and they’ll know that,” he said in June.

SpaceX is planning to fund its own robotic missions to Mars, with the first launch coming as early as 2018. However, the description of Musk’s talk makes clear that he sees crewed missions as a collaboration between “industry, government and the scientific community.”

That suggests that there might have to be a debate over who pays for what when it comes to SpaceX’s Mars colonization plan. The total cost hasn’t been laid out, but it seems certain to amount to tens of billions of dollars over the next decade or two.

Musk’s big reveal comes less than a month after SpaceX suffered a serious blow: a launch-pad explosion that destroyed a Falcon 9 rocket and its satellite payload.

The blast and its aftermath have added to the pressure on Musk as he tries executing his long-term space vision. He also has another couple of ventures to worry about: the Tesla electric-car company and the SolarCity electricity-generating company, which are in the midst of a controversial merger.

But unless his money runs out, Musk isn’t likely to give up on the dream he’s held for well more than a decade: to make humanity a multiplanetary species and guarantee its long-term survival.

To reassure the skeptics, Musk could well repeat what he told me six years ago, before the launch of SpaceX’s first Falcon 9 rocket.

“People should take a look at my track record and realize that I always come through in the end,” he said back then. “It may take more time than I expected, but I’ll always come through.”

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