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SpaceX Fires Mars-Bound Raptor Engine (extremetech.com)
Elon Musk took to Twitter Sunday evening to announce the "first firing of Starship Raptor flight engine." While SpaceX has fired individual components before and experimented with various designs, this is the first time the now-completed design has been assembled and fired in its intended spaceflight configuration. ExtremeTech reports: Raptor has gone through a number of design changes -- originally, SpaceX planned to mount it to the ITS launch vehicle back in 2016 (powered by 42 Raptor engines), before changing gears and unveiling its BFR rocket concept (officially known as "Super Heavy" for the first stage, and Starship for the second). The Super Heavy mounts 31 Raptor engines, while the Starship has seven. The engine has been designed with a priority on lowering overall wear and tear and removing failure points that could limit its reusability or increase long-term operating costs. Unlike SpaceX's Merlin engine, which runs on a mixture of RP-1 and LOX, the Raptor engine is fueled by cryogenic liquid methane and LOX. The Raptor uses subcooled methane (subcooling refers to keeping the temperature of the liquid well below its boiling point). Subcooling the methane allows SpaceX to increase the amount of propellant stored in the rocket. It increases specific impulse and reduces cavitation.
The actual test burn only goes on for a few seconds, but yields tremendously valuable information about the actual performance of the rocket and its ability to ignite in a controlled fashion. The green glow in the exhaust near the end of the firing indicates the copper liner in the engine chamber burned by accident. While this should not have happened, it's precisely to find these pain points that engineers conduct test firings in the first place. There is no substitute for this kind of test-firing and, as Ars Technica notes, "any 'first' test firing of a new, full-scale rocket engine that doesn't end in an uncontrolled explosion is a good thing." Ars also states that this specific engine may be deployed for "hopper" flights this year when SpaceX attempts to fly the Starship roughly 5km high, then land it again.
The actual test burn only goes on for a few seconds, but yields tremendously valuable information about the actual performance of the rocket and its ability to ignite in a controlled fashion. The green glow in the exhaust near the end of the firing indicates the copper liner in the engine chamber burned by accident. While this should not have happened, it's precisely to find these pain points that engineers conduct test firings in the first place. There is no substitute for this kind of test-firing and, as Ars Technica notes, "any 'first' test firing of a new, full-scale rocket engine that doesn't end in an uncontrolled explosion is a good thing." Ars also states that this specific engine may be deployed for "hopper" flights this year when SpaceX attempts to fly the Starship roughly 5km high, then land it again.
Nobody is going to the moon or Mars on a tourist trip in your lifetime, try to stop being an idiot before you die.
Funny though Virgin Galactic's whole business model is based around Space Tourism and they are only planning Sub Orbital. I think Anonymous Cowards should try having dreams rather than crushing them.
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I doubt they could get 100 people on a spacecraft for 7 days, just due to the logistics. Food, water, waste management, and of course providing some entertainment because much of that time is just uneventful travel through the void. Even just the need for people to exercise and move around presents a challenge you wouldn't get on an airliner - can't expect people to stay mostly seated for a week.
There would also be issues with regulators interested in passenger safety. It's not like if someone gets sick or they lose an engine they can just divert to the nearest airport.
const int one = 65536; (Silvermoon, Texture.cs)
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The main attraction of methane is that you can make it on Mars, and only have to send up hydrogen. Secondarily, pumping fuel is a big part of rocket engine deign, and that's just easier with cryogenic fuels than fuels that are liquid at room temperature. It also has slightly better ISP, and you get less coking, than RP-1, but I'm not sure those differences are compelling.
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