so these 2 rockets (starship/new glenn) are both using liquid oxygen+methane for their propellant, which the article mentions in two paragraphs :
Now there is a race on to develop alternatives to existing fuels like RP-1 and UDMH, and liquid methane appears to be in the lead. Several new rocket engines, including SpaceX’s Raptor and the European Space Agency’s Prometheus engine, have been designed to use this gas as a fuel because it has a higher performance than other fuels, meaning the rocket can be smaller and produce less soot when it’s launched. Its lower cost means the price of a rocket launch can be reduced, too.
Methane, however, is controversial because it is one of the worst gases as far as global warming is concerned. It is around 80 times more warming than carbon dioxide over its lifetime.
in the second paragraph Piesing implies that the methane is released raw into the atmosphere in a rocket launch, you can hopefully see that’s not true right? the fuel in a rocket is burnt with the oxidiser, in this case forming water vapour and co2. I think water vapour is a pretty potent greenhouse gas in the upper atmosphere but i mean it’s water and not all of it is deposited in the upper atmosphere
it is true that the fuel+oxidiser isn’t exactly burnt in the perfect stoichiometric ratio and in this case there is a slight surplus of methane, but that methane is likely burned with the oxygen in the air (given that it’s next to a stream of hot rocket exhaust) and turned into co2+water.
also it’s very untrue that methane+oxygen has better performance than other fuels, hydrogen+oxygen stages are usually more efficient (but less dense) and rp1+oxygen stages are usually less efficient but more dense, and it’s all a tradeoff. if methane was just superior there wouldn’t be any reason to use any other fuel.
anyway the statement made in this article about the soot is also extremely misleading, the soot produced from the engines are mostly based on the engine cycle, e.g. in a open cycle (like the spacex merlin, rocketdyne f-1) there’s a lot of soot produced from the turbopump (a little rocket engine used to spin a turbine to pump the fuel) due to it being fuel rich rp-1, but there’s other rp-1 engines like the rd170 (soviet design) that uses a closed cycle and a oxygen rich turbopump, which don’t produce the same soot.
also iirc most pollution from rockets come from the ammonium percolate solid rocket boosters, used by things like the space launch system, bosters on the vulkan, most chinese rockets, some indian rockets and some japanese rockets. these boosters aren’t used (and aren’t going to be used in the foreseeable future) for these 2 rockets
i think you can see how I feel about this article when there’s this much misinformation in 2 paragraphs
that is one of the articles of all time lmao
so these 2 rockets (starship/new glenn) are both using liquid oxygen+methane for their propellant, which the article mentions in two paragraphs :
in the second paragraph Piesing implies that the methane is released raw into the atmosphere in a rocket launch, you can hopefully see that’s not true right? the fuel in a rocket is burnt with the oxidiser, in this case forming water vapour and co2. I think water vapour is a pretty potent greenhouse gas in the upper atmosphere but i mean it’s water and not all of it is deposited in the upper atmosphere
it is true that the fuel+oxidiser isn’t exactly burnt in the perfect stoichiometric ratio and in this case there is a slight surplus of methane, but that methane is likely burned with the oxygen in the air (given that it’s next to a stream of hot rocket exhaust) and turned into co2+water.
also it’s very untrue that methane+oxygen has better performance than other fuels, hydrogen+oxygen stages are usually more efficient (but less dense) and rp1+oxygen stages are usually less efficient but more dense, and it’s all a tradeoff. if methane was just superior there wouldn’t be any reason to use any other fuel.
anyway the statement made in this article about the soot is also extremely misleading, the soot produced from the engines are mostly based on the engine cycle, e.g. in a open cycle (like the spacex merlin, rocketdyne f-1) there’s a lot of soot produced from the turbopump (a little rocket engine used to spin a turbine to pump the fuel) due to it being fuel rich rp-1, but there’s other rp-1 engines like the rd170 (soviet design) that uses a closed cycle and a oxygen rich turbopump, which don’t produce the same soot.
also iirc most pollution from rockets come from the ammonium percolate solid rocket boosters, used by things like the space launch system, bosters on the vulkan, most chinese rockets, some indian rockets and some japanese rockets. these boosters aren’t used (and aren’t going to be used in the foreseeable future) for these 2 rockets
i think you can see how I feel about this article when there’s this much misinformation in 2 paragraphs
The use LNG because it’s cheap. As the total cost of the vehicle goes down through reuse, suddenly the cost of fuel becomes more relevant.
And because you can make it on Mars!