Space

SpaceX Mars mission will fly on methane

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Artist's concept of SpaceX Mars landing (Image: SpaceX)
Artist's concept of SpaceX Mars landing (Image: SpaceX)
The SpaceX Falcon Heavy rocket (Image: SpaceX)
Artist's concept of SpaceX Mars landing (Image: SpaceX)
Elon Musk (Image: Royal Aeronautical Society)
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Elon Musk, founder and CEO of SpaceX, says that the missions to Mars by his company will use rockets powered by methane, which can be manufactured on the Red Planet. The announcement came last as the South-African born entrepreneur was giving a lecture in November to the Royal Aeronautical Society in London, where he was presented with the Gold Medal – the society’s highest award.

In his talk, Musk said that he foresees the first Mars mission as a collaboration of private industry and government, but is prepared for the possibility that it will be just commercial. His vision is to see a manned landing on Mars within 15 years as the prelude to colonization. With this in mind, he said that the only way to make such a program economical is to keep transport costs as low as possible.

Elon Musk (Image: Royal Aeronautical Society)

His target is to keep the price of passage at US$500,000, which he said is was within reach of people in developed countries. "Most people in their mid-forties could put together enough money to make the trip,” he said. “Half a million dollars, that's a normal middle-class couple in California."

Part of keeping these costs down is the choice of fuel. "The cheapest fuel is methane,” said Musk. “So it's going to be methane. Also, the great thing about methane is that you can create it on Mars because Mars has a CO2 atmosphere and there's a lot of water ice also. Conceivably, you could extract water vapor from the atmosphere. With water you've got H2O plus CO2 and bingo, you can replace propellant."

The SpaceX Falcon Heavy rocket (Image: SpaceX)

Musk was referring to the Sabatier reaction, which uses a nickel catalyst to convert water and carbon dioxide into methane gas and water. It has been proposed as a means of creating rocket propellants on Mars, with one possibility being to send automated factories to the Red Planet to process fuel in anticipation of a manned landing.

Musk also pointed out that methane performs almost as well or better than kerosene or hydrogen, but has certain advantages – especially over hydrogen. “Methane is much easier to deal with. It's not a cryogen and hydrogen likes to get into all sort of places, making metal brittle and creating invisible high-temperature fires and that sort of thing. Methane is just much easier to deal with."

As to kerosene, Musk said, “The energy cost of methane is the lowest and it has a slight (specific impulse) advantage over kerosene and it does not have the pain-in-the-ass factor that hydrogen has.”

Artist's concept of SpaceX Mars landing (Image: SpaceX)

Musk added that the Russians have made advances in methane-powered rockets, so the technology is there. Another factor he cited is that the Mars ship needs to be not only cheap, but large, since making the over two-year journey in Dragon would result in the astronauts “coming back mad, if at all.” This makes inexpensive propellant even more important.

As part of this long-term planning, SpaceX will be using methane in its future rockets, beginning with the Raptor upper-stage engine. The technology will then migrate through the rest of the flight systems as development proceeds.

The video below is of Musk's complete lecture and Q&A session.

Source: Royal Aeronautical Society via Flight Gobal

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12 comments
inchiki
musk is changing the space game so rapidly, he is a remarkable man and these are exciting times for space.
solutions4circuits
Yes - Earth is not enough. Let's start polluting another planet before we even set foot on it.
D U M B.
Hydrogen/oxygen, or nothing Elon.
Slowburn
re; ugosugo
This is not a vacation trip it is akin to the pioneers taking a covered wagon across the American great plains back when it was called the Great American Desert you had to cash out your life and buy the necessary equipment for the journey and making a new life on the frontier. A middle aged person of the middle class Should be able to put together half a million dollars in a few years if he is willing to leave no property behind and forgo immediate gratifications that so much of our money gets spent on. The people unable to do this would not make a good homesteader anyway.
re; solutions4circuits
Assuming that you are talking about Mars the atmosphere is about 95% carbon dioxide, 3% nitrogen, 1.6% argon, and traces of free oxygen, carbon monoxide, water and methane, among other gases, for a mean molar mass of 43.34 g/mol. And the methane manufactured on Mars gets its carbon from the atmosphere. So what pollutant are you thinking of? On earth by the time you have generated the hydrogen and liquified it you will have generated more C02 than launching with methane. Liquid hydrogen is lousy fuel.
Just as an aside. If you use methane as your fuel it would be easy to convert the fuel tank into living space.
Derek Howe
Can't wait until he reveals his design for the Mars spaceship. I will be eagerly awaiting his future artist renderings of that big beautiful beast.
Kaido Tiigisoon
From the Isp point of view Methane is not a very good propellant. However from the in situ resource usage point of view it's irreplaceable. Another option would be to burn magnesium or aluminum in CO2 which is not a very bright idea.
As of not being cryogenic - normally it is cryogenic, but it's critical point is: Critical temperature : -82.7 °C Critical pressure : 45.96 bar So from this perspective one can play a little with temperatures (ranging ~68 degrees downwards `til it is cryogenic) and with a pressures in order to find a sweet spot.
Stewart Mitchell
Put a station on a mars moon and tether to the atmosphere. Parachute to the ground. No rocket landing required.
Fritz Menzel
I'm a huge fan and eager supporter of current robotic missions and their amazing quests and findings. I'm even tolerant of near-earth/orbital manned missions. That's real, practical science worth societal investment.
And as long as it's just multimillionaires' & billionaires' assets (and lives) being risked on incredibly ignorant flights of fancy, I'll watch in amusement in the same manner that the world watched, gasped and laughed at early unscientific attempts to fly.
However, if they feast on the ignorance of naive adventurer-wannabees or dare to hawk their snake-oil in order to raid taxpayer assets to subsidize this silliness, watch out!
Slowburn
re; Kaido Tiigisoon
Listen to the video again. it almost as good as hydrogen with far fewer disadvantages.
Stephen N Russell
If usable, expand methane for use in Space, why not. Or use some Biofuel for space use.
Rich Brumpton
Everyone bashing on methane should pay attention to the stuff they use in some rockets and missiles.
It could be potassium perchlorate and kerosene or one of the other toxic brews that have been used. Methane (which can be manufactured out of the air, on Earth or Mars) can be compared to biofuel in that you could manufacture biofuel at your camp to return (if you were patient enough, and have a few basic requirements) after a long safari where you only took enough diesel for the outbound leg.
This could well be a big thing for earth-based space as well, very interesting.
P.S. Stewart Mitchell should direct a horror film, on his Mars, NOBODY LEAVES! ;)