Methane. CH4. It is an odorless, colorless gas and a tetrahedral molecule with four equivalent C-H bonds. Methane has four main reactions; steam forming, syngas, halogenation, and of course combustion. It is the principal component of natural gas.
So why should we want methane. What good could it possibly do?
Methane is prevalent in space. It can be harvested on planets such as Mars, Titan, Jupiter, and many other planets & moons. Deep space exploration needs to think about that. And they have.
It started out years ago. In 2007 at NASA’s Marshall Space Flight Center there was a test of a LOX/methane engine as a design for the future.
Consider what is currently used. Liquid Hydrogen fuel which must be stored at -252.9 Celsius as opposed to methane’s -161.6 Celsius. Tanks would not require so much insulation. Oh, and they could be smaller. Liquid methane is denser than liquid hydrogen; Which means money saved 2 ways – from the size necessary and the weight.
Consider the handling of the fuel. Some rocket fuels are potentially toxic, not methane. Methane is a ‘green propellant.’
Now consider this, NASA could fly to Mars, weighing less, confident that while Mars is not methane rich, methane can be manufactured there. It’s a simple recipe – mix some CO2 with some H, add heat and produce CH4 & H2O. It is called the Sabatier process.
Of course if NASA were to go to Titan, it is literally raining liquid methane. PLUS there are lakes and rivers of methane and other hydrocarbons.
Anyway - fast forward to 2012 and NASA’s project Morpheus launch. A methane powered launcher, a vertical launch system to send robonauts to the moon. Hey! What about Mars?
Enter SpaceX and the Raptor. The Raptor is the first member of a methane-fueled rocket engine family developed by SpaceX. The Raptor engine will have over six times the thrust of the Merlin 1D vacuum engine; a reusable methane staged-combustion engine that is the planned method for the exploration & colonization of Mars.
So if this is so good why hasn’t anyone else thought of it? Actually they have. Since the 1990s a number of Russian Rockets have been proposed, one using a methane/LOX variant of the RD-191. In 2013, China announced that it had completed a first ignition test for a new LOX methane rocket engine.
Okay, I’m sold; Mars here we come!