- Tech Insider/Recode/NASA
Tech billionaire Elon Musk is convinced that humans must colonize Mars with a million people if humanity is to survive long term.
To that effect, he almost went broke funding his aerospace company SpaceX in 2008 to keep developing next-generation rockets.
The big announcement is scheduled for Tuesday afternoon at the 67th International Astronautical Congress in Guadalajara, Mexico. (Watch it live at the end of this post.)
But ahead of that highly anticipated speech, Musk shared on Twitter early Monday morning the first photo of a powerful rocket engine, dubbed Raptor, designed to be part of his “Interplanetary Transport System,” or ITS, to get to Mars:
SpaceX propulsion just achieved first firing of the Raptor interplanetary transport engine pic.twitter.com/vRleyJvBkx
— Elon Musk (@elonmusk) September 26, 2016
A methane rocket engine for Mars
This isn’t the first the world has heard about the Raptor engine. It is, however, definitely the first photo we’ve seen of Raptor spitting out fire.
The image shows a static fire test, which is when a cone-shaped rocket engine is hooked up to a fuel source, ignited, and pushed to the limits to measure its performance.
The Raptor’s fuel is almost certainly methane burned with liquid oxygen, based on SpaceX’s prior intimations about its Mars rocket system. (The ITS was previously called the “Mars Colonial Transporter,” or MCT, and before that a self-descriptive “Big F—ing Rocket,” or BFR.)
Why methane, which isn’t the most powerful or readily available rocket fuel, instead of the RP-1 kerosene that SpaceX has traditionally used?
- NASA/Susan Twardy
In a December podcast interview with SpaceNews, Jeff Thornburg – a former SpaceX propulsion engineer who previously led Raptor’s development – said methane was an affordable and dense fuel that may be readily available for harvest on Mars:
“You’re kind of looking at two things: What does the fuel cost, and if you want to use and develop and exploration architecture for Mars or the solar system, where can you live off the land? … Now that you don’t need to take your propellant to get home as part of your camping gear and you can make it on Mars or you can make it somewhere else, now you can take a whole bunch more stuff.”
But Thornburg left SpaceX in November, according to his LinkedIn profile, and aside from a $33.6 million contract with the US Air Force to develop Raptor, we’ve heard precious little about it until Musk’s tweets on Monday.
Musk shared a few of the Raptor’s test-firing details, as well as a beautiful image of the rocket engine firing. “Production Raptor goal is specific impulse of 382 seconds and thrust of 3 MN (~310 metric tons) at 300 bar,” Musk wrote on Twitter.
How does a methane-powered Raptor engine compare to the kerosene-powered Merlin engines used on SpaceX’s signature Falcon 9 rocket – the one that delivers supplies to the International Space Station?
“Chamber pressure is almost 3X Merlin, so engine is about the same size for a given area ratio,” Musk wrote on Twitter.
This means the Raptor, which can spit out about 675,000 pounds of thrust, is roughly three times as powerful as the Falcon 9’s Merlin engines, each of which can push with a force of about 200,000 pounds.
The Falcon 9 uses nine Merlin engines in its recoverable booster and one in its upper stage:
So presumably, SpaceX engineers will be attaching a cluster of Raptor engines to the bottom of a very big and yet-to-be-announced multistage rocket.
The first major goal, as Musk said in 2015, is to get 100 people and 100 tons of gear to Mars.
What about the rocket?
- Skye Gould/Tech Inside
Beyond that, the world knows next to nothing else about the BFR, MCT, ITS, or whatever Musk decides to call it next.
What we do know is that it must be very big and very powerful and lean on SpaceX’s history of rocket development.
Musk has acknowledged that permanently colonizing Mars and saving humanity is a long-term goal.
He’d first like to land one of his Red Dragon spacecraft on Mars in 2018:
Planning to send Dragon to Mars as soon as 2018. Red Dragons will inform overall Mars architecture, details to come pic.twitter.com/u4nbVUNCpA
— SpaceX (@SpaceX) April 27, 2016
That timeline may be more difficult to achieve now, though.
Following a recent launchpad explosion of a Falcon 9 rocket, presumably caused by a faulty helium system – a failure Musk has dubbed “the most difficult and complex” in SpaceX’s history – the company now faces launch delays for $10 billion worth of business, plus the first launch of its significantly more powerful Falcon Heavy rocket (which will precede a Mars mission).
“During a special keynote entitled ‘Making Humans a Multiplanetary Species,’ Musk will discuss the long-term technical challenges that need to be solved to support the creation of a permanent, self-sustaining human presence on Mars. The technical presentation will focus on potential architectures for colonizing the Red Planet that industry, government and the scientific community can collaborate on in the years ahead.”
When the time comes, you can watch SpaceX’s livestream either below or on YouTube.