Is SpaceX's Raptor engine the king of rocket engines?

Because the assumptions made for one class of payload don't apply to another class of payload with vastly different mission specifications. A great place to start is this amazing video by The Everyday Astronaut: ▶ this video Notice how the type of fuel used itself is a consideration for the type of rockets we may send to Mars if we're considering In-Situ refueling.

in “Starship is threatening NASA’s moon contractors” · View on HN

NASA's big project for launch is a disposable rocket using Space Shuttle technology. It will cost at least a billion dollars per launch. SpaceX's project is a fully reusable rocket, with rapid turnaround because it uses methane fuel in the world's first clean-burning full-flow engine. They expect to be able to launch three times per day. On top of that the rocket is built of cheap stainless steel instead of carbon fiber. With that amount of reuse, each launch basically pays for fuel and ground support, each of which costs about a million dollars per launch. Given their payload of at least 100 tonnes, that's $20/kg. They've already done a single-engine hop test, and hope to reach orbit within six months. Here's a great video on what makes the new SpaceX engine revolutionary: ▶ this video

in “Ask HN: How would you bootstrap a space company?” · View on HN

SpaceX is making significant breakthroughs that you can appreciate if you understand the tech. > As of 2019, only three full-flow staged combustion rocket engines had ever progressed sufficiently to be tested on test stands; the Soviet Energomash RD-270 project in the 1960s, the US government-funded Aerojet Rocketdyne Integrated powerhead demonstration project in the mid-2000s,[6] and SpaceX's flight capable Raptor engine first test-fired in February 2019. [link] If you want to learn more ▶ this video

in “NASA – Artemis I Liftoff” · View on HN

Raptor is a breakthrough engine. If NASA with nation state resources and 23B is 6 years late, let’s cut SpaceX some slack for building a profitable launch business with multiple successful vehicles while also being very close with Starship. > As of 2019, only three full-flow staged combustion rocket engines had ever progressed sufficiently to be tested on test stands; the Soviet Energomash RD-270 project in the 1960s, the US government-funded Aerojet Rocketdyne Integrated powerhead demonstration project in the mid-2000s,[6] and SpaceX's flight capable Raptor engine first test-fired in February 2019. [link] If you want to learn more ▶ this video

in “NASA – Artemis I Liftoff” · View on HN

Starship is a pretty radical redesign with the main goal being reusability. Everything about it is with reusability and and thus scale in mind. A new engine was needed because while the Merlin is a great engine, it could never be reused the thousands of times Raptor is designed to be reused. You can think of engine design as the simultaneous, interdependent optimization across 10+ dimensions, but as an example of one of dimensions - Raptor uses Methane (rather than Kerosene) because it burns cleaner (does not leave residue) and can be manufactured on Mars more easily. Here's an in-depth video about Raptor: ▶ this video The rest of the rocket is similar, in that it is done with manufacturability, reusability and scale in mind. The Falcon design could never stretch to these demands.

in “We could see an orbital launch of SpaceX’s Starship this year” · View on HN

Both you and I agree that aerospace companies should do large scale vehicle simulations, which they do. In addition SpaceX does complex fluid dynamics simulations to design and test their engines. That's likely part of why they have successfully made the "holy grail" of Full-Flow staged combustion work in the Raptor. [0] None of the failures so far could have been detected through simulation since they were complex integration issues. At some point the cost of simulation is vastly larger than the cost of just creating a test article. Components like drogue chutes, explosive bolts, failsafe valves and abort systems are typically validated both analytically (by reviewing designs) and are often hard to fully validate by testing. Since validating components is so expensive, it leads companies that rely on analyitical validation (like Boeing) to become overly attached to previously analysed and working components because analysis is so time consuming and expensive. You end up with modern rockets built with space-shuttle engines as components (SLS) and old jets with new engines tacked on (747 Max). When you talk about explosive deconstruction of a test article after something new was learnt you fail to realise the learning (not the landing) was the goal. If SN9 had landed correctly, it is very likely they would have deconstructed it anyway. They just deconstructed SN12, 13 and 14 to make way for SN15 which has a very improved design. 0: ▶ this video "Is SpaceX's Raptor engine the king o

in “SpaceX SN9 Explodes on Landing” · View on HN