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Comment by mc32 | Hacker News Reader

Somewhat tangential, but does Space-X have the will or ability to develop heavy lift rocket engines which at the moment only the Russians seem to be capable of producing?

I think Boeing etc. have to procure their heavy lift rocket engines from Russia because they have no alternative supplier, at the moment.

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They are currently developing a larger engine, Raptor, which is intended for their Mars project and possibly for an upper stage for the Falcon family. But it's not a plug-and-play replacement for the Russian RD-180. (Nor is Blue Origin's BE-4, which is what ULA currently plans to use to effectively replace the RD-180 -- but only by building a substantially new Rocket, the Vulcan, around the BE-4, to replace their current Atlas V.)

BTW, as others have noted, "heavy lift" is more often used to characterize whole rockets than individual engines -- and the current American leader in that category (until SpaceX finally launches Falcon Heavy) is the Delta IV heavy, powered by three RS-68s, each of which nearly matches the thrust of an RD-180. (And yet isn't a drop-in replacement for numerous reasons, starting with use of different fuels.)

> which is intended for their Mars project

Space X is a for profit company right? What's the profit incentive of going to Mars? A marketing ploy? Does SpaceX not have any investors besides Elon Musk to answer to about spending?

Elon has done back of the envelope calculations and believes that Mars colonization can be profitable at a cost of around a half-million per ticket, with a free return for anyone who decides they want out.

At that price point, moving to Mars is something you can fund by selling your house. If enough people want to do it, he could make a lot of money that way. In addition to going down in history.

If he is wrong, well, it is his money. And every step along the way to building that capacity can be justified by ventures that are making money now.

If you invest $5K USD each year in an equities-heavy index fund, with compound interest and average market returns, you'll have your Mars ticket in ~25 years. Additional funds invested each year speed that up.

It's a privately held for-profit company. Who knows what the owners want...

Actually, since Musk owns half of it we can get a pretty good idea.

SpaceX is structured as a for-profit company, but the entire reason it exists is the Mars project, and Elon's vision of making humans a multiplanetary species.

Did some digging on Wikipedia.

Saturn V used 5x1 Rocketdyne F-1 at 1,746k pounds of thrust each. Made in the USA. https://en.wikipedia.org/wiki/Rocketdyne_F-1

Soyuz uses the 5x4 RD-107 engine at 229k pounds of thrust each. Made in Russia. https://en.wikipedia.org/wiki/RD-107

Falcon Heavy uses 9x3 of the Merlin 1D engines at 185k pounds of thrust each. Made in the USA. https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)#...

Boeing Space Launch System uses two solid rocket boosters and 4x1 RS-25D/E engines (the same ones the Space Shuttle used) at 512k pounds of thrust each. Made in the USA. https://en.wikipedia.org/wiki/Space_Shuttle_main_engine

1746k each? That's obscene.

For reference, the Space Shuttle SRBs were 2800k each at launch and bumped up over 3000k. This chart is a little nuts:

https://en.wikipedia.org/wiki/File:Srbthrust2.svg

It's true the SRBs were powerful, but I wonder how much of that was compensated by structural elements needed to live with their vibrations. I remember the original Ares I concept would vibrate the astronauts to death before the solid 1st stage burned out.

They are currently developing the methalox Raptor [1] engine that is planned to have 2300kN sealevel thrust. That would be more than six times powerful than the Merlin 1D+s in current Falcon 9. That would be solidly in the heavy lift rocket engine category, specifically as they intend to group them like they group engines in Falcon 9.

[1]: https://en.wikipedia.org/wiki/Raptor_(rocket_engine)

Do they need to? Should Falcon Heavy work as advertised they can get 50+ tons to LEO. Considering the Heavy is using a lot of F9 tooling and production lines (~same boosters and such) it probably saves plenty money not producing drastically different types of launch vehicles.

It seems as if for now Musk is betting on F9 + FH to milk the satellite industry for cash to fund his mars mission which requires a completely different vehicle setup including a new engine (Raptor) among other things.

http://www.spacex.com/falcon-heavy

Well, the Falcon Heavy doesn't use heavy lift engines. It just uses 27 medium-sized engines, 9 per core.

Right, but as Falcon Heavy demonstrates, you don't need "heavy lift engines" to build a heavy lifter. Going bigger than Falcon Heavy with the Merlin engines is probably getting a bit excessive, but the Falcon Heavy will already be one of the largest capacity rockets out there.

There has certainly been information out there about SpaceX's Raptor rocket engine...but I am unaware of how far they are along the development process: https://en.wikipedia.org/wiki/Raptor_(rocket_engine)

NASA's SLS, which is having its first test flight in 2018, will launch with a Block I config with 2 SRB of 3,600,000 lbf each, 4 RS-25D/E shuttle engines at 512,300 lbf each for stage one and RL10B-2 for stage two at 24,800 lbf OR a stage two Block 1B config of 4 RL10's at 99,000 lbf. So about 9m lbf in its heaviest configuration. The Saturn V produced 7m lbf for comparison.

Boeing also has the Delta IV which uses the home grown RS-68 series engines. The Heavy configuration of this rocket has 2m lbf.

Only the Atlas series uses the Russian RD-180. ULA just ordered 20 more RD-180s at the cost of a great deal of political capital. Its assumed this is the last batch until the replacement BE-4 engine is ready.

They are making an engine they call Raptor for their planned giant rocket: https://en.wikipedia.org/wiki/Raptor_%28rocket_engine%29

It is not a swappable substitute for the Russian ones, because it uses a different kind of fuel and probably for lots of more complicated reasons.

The Falcon 9 Heavy, which should launch later this year, will be the heaviest lift rocket since the Saturn 5.

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