SpaceX Merlin 1C engine development completed

In the media package attached to that press release is a high resolution version of the Merlin 1C firing (suitable for use as wallpaper on a portrait screen).

It's a beautiful engine.

Posted by Daniel Schmelzer at 11/12/07 10:19:58

a positive development…this should definitely put them ahead of any future COTS competitors.

Posted by Al Park at 11/12/07 10:43:19

Congrats to the SpaceX team.

I don't understand why the media doesn't talk more about the way that SpaceX operates. They build things. They test them. They take that experience and build new versions of them (three Merlin generations and two Kestel). SpaceX is doing this to make engines that are easier to make or that have better performance (or both).
The old time space companies would never do this, once they build something they use it for decades without changes. Cost is not a factor for them, because somebody else has to pay.
SpaceX is trying to drive down the cost of space launch, so they have the need to spend time improving their designs. It also makes them a great company to work for, they really build things (not just making Powerpoint presentations).
It's fun to watch them and I wish them only the best of luck in the future.

Posted by tc at 11/12/07 12:34:51

SpaceX is a hungry little mammal and evolving fast.

Posted by Mike Puckett at 11/12/07 16:17:08

I have not heard any plans of spacex to build a saturn V class vehicle or a F1 class engine recently.

I think the troubles with getting the Falcon 1 off the ground humbled them a bit. Which might be good in the long run. I think it makes much more sense to mass produce a relatively small engine and to gradually make it as reliable as an aircraft engine.

Posted by anonymous at 11/12/07 16:53:28

SpaceX is a "humble" "hungry little mamal" with no plans to build a saturn V class vehicle? I guess you have not been following them that long. They have wanted to go to Mars from the start. The press gave them a bad time for expressing grandiose plans, so they quit talking, and started doing their homework. I can't imagine 500 engineers being described as a "hungry little mamal". But it's more a slam against the "big dinosaurs" of aerospace I guess.

Musk has always seemed very "humble" in is media interviews. I wonder if he is a good boss to work for. One thing is for sure. They seem to be testing the heck out of the new engine and Musk is also involved with the Tesla electric car. The man has vision, no doubt about it.

Why isn't Boeing making an electric car? Or fully streamlined electric motorcycle for that matter, with aerodynamic controls and a prop or jet engine? 40 million chinese have electric motorcycles already. The majority of chinese may well skip the fossil fuel powered car.

Twenty years ago a division of Boeing in Virgina was working on "People Movers" essentially light rail for airports. It's as if there has to be some commercial aviation connection before Boeing feels like it can be invlolved. This phrase "core competency" is over used by big aerospace management.The essence of being an engineer is being able to apply new technology to new designs.

If the Bussard Fusion Reactor is rebuilt succesfully by Dr. Nebel at LANL, do you think Boeing or SpaceX will be first to make a rocket from it? I am betting on Musk!

Posted by Tony Rusi at 11/12/07 18:16:35

Watching Merlin 1C fire, I can almost see the stars in its plasma. There's something magical about SpaceX - something that overcomes skepticism and makes you feel the future approaching. I could believe quite easily that Elon will become a legend to all mankind. But the proof will not be in Falcon 1 or even 9, but in 20 years (or less?) when he takes the next step. Build us a road that never ends, rocket man, and write your name in the heavens.

Posted by Brian Swiderski at 11/12/07 21:51:57

Re: Tony Rusi

I have seen some interviews where Elon Musk came over very arrogant. But I have no problem with that since he is actually building hardware with his own money, so he can be as arrogant as he wants.

And being humble is a good thing. They have a decent chance to build a saturn V class vehicle in the future, but that is not necessary and IMHO not even the best approach to go to mars.

Their near-term goal should be to replace the soyuz as the cheap workhorse of world space flight.

Posted by anonymous at 11/13/07 06:40:00

Regarding the Polywell Fusion Reactor (Bussard's concept) being used as a propulsion system:

This is something that I don't see as a technology to be used for Earth-to-Orbit propulsion (I might be surprised, however), but is something that once a large infrastructure is in place around the Earth. I'm talking Bigelow habitats and regular commercial passenger flights to/from the Earth in a manner like commercial airlines.

Basically, that is something which would be of incredible value for a genuine space SHIP which is designed for point to point travel in space, particularly because it can provide nearly constant thrust for a long period of time. That requires energy, and fusion reactors can provide that magnitude of energy if it is necessary. Earth to Mars in just a few weeks may be something possible with this system. Certainly a much shorter journey than London to Boston in the 18th Century.

All this to the side, I think a strong congratulations is in order to SpaceX for their continued work on their engines. Neither launch of their Falcon I seemed to be a problem from their engines, and this certainly looks like what is becoming a mature design for them. Comparisons with the F1 engine I hope is not a just PR hot air but something truly comparable. If so, SpaceX has a real winner and can start to think about the next generation of rockets after the Falcon 1/9 series.

I just hope that SpaceX is on track for their 1st Quarter 2008 launches of the Falcon I. I'm looking forward to the show.

Posted by Robert Horning at 11/13/07 06:54:43

Why would SpaceX be so different from North American, Convair, Martin, Douglas or Pratt & Whitney in the launcher business? What is so drastically different about Falcon 1 or 9?
Orbital at first promised Pegasus for 6 million too. Reality set in after it started operating...

I like that they are building stuff. I just don't think that it's reusable enough.

The engine is completely conventional. It's continuing the Navaho - RS-27 - H-1 - F-1 heritage. A normal straight forward high performance gas generator kerosene engine, with pretty low margins as far as I know.

Then they will notice that recovery is expensive (requires a lot of crew and ship time), the booster is not in very good condition, the engine isn't either and it will cost as much to refurbish it as to build a new one.

I would like for them to succeed in lowering spaceflight price significantly, I just don't find it that likely.

On the other hand, if they went for a good dry landing of the first stage, then it would be much much easier to make the propulsion system reusable, in a "fuel and go again" style.
They could have much lower performance (which would enable margins) if they made the first stage just bigger.

This is what the "second wave" of new space is trying to do. Armadillo, XCor and friends. Start from low performance but low operations cost. Then extend performance while absolutely keeping operations cost in check. I find that a much more believable approach. A low operations cost space launch system doesn't spring from the forehead of a Master Designer. It's a long path with lots of dead ends that you can't see beforehand until you've visited them.

Posted by mz at 11/13/07 07:25:22

"Watching Merlin 1C fire, I can almost see the stars in its plasma. There's something magical about SpaceX - something that overcomes skepticism and makes you feel the future approaching. I could believe quite easily that Elon will become a legend to all mankind. But the proof will not be in Falcon 1 or even 9, but in 20 years (or less?) when he takes the next step. Build us a road that never ends, rocket man, and write your name in the heavens."

Posted by Brian Swiderski at 11/12/07 21:51:57
-----------------------------
I second that Brian.
Elon's falcon is my 2nd favourite.
I See mach diamonds in his eyes.
I think Elon will be the one who will bring about this industry.
I think his design is absolutely fabulous. Like Wildfire it is a very masculine looking rocket...very pleasing to the eye, I would ride either to the cosmos. I can't wait.
go Elon!

Posted by Mufftie at 11/13/07 08:30:28

Re: mz

I agree completely that water recovery will never lead to a truly reusable design. But the conservative approach of spacex has already netted them quite a few private customers and government contracts.

There is nothing about the Merlin 1C engine that prevents it from being used in a real reusable VTVL vehicle. For the next generation of Falcon launch vehicles, maybe SpaceX can contract out a powered vertical landing system to Armadillo or Masten Space Systems.

Posted by anonymous at 11/13/07 11:27:14

"build real hardware with his own money"

At some point he said SpaceX has been cash flow positive for several years now. That sounds like an awful lot of other people's money too, most of it probably from the government.

Mind you I am impressed with him too
and have no problem with him being arrogant either, but it's better to keep the facts straight

Posted by nork_2 at 11/13/07 12:20:28

But making it really an expendable design has probably (I don't really know) made Merlin really that, an expendable engine. It even originally had an ablative chamber that screams cheap expendability philosophy.

It's harder to make it reusable if it's not designed to be like that from the start. I don't really know what it's like on the inside and what it can take... some expendable engines like RL-10 seem to be fine with very long burn durations.
But it might not be reliable or would require a huge amount of refurbishment and inspections, even when not landing at sea. Like the SSME.

You accept lower performance and use bigger margins when designing for reusability, reliability, low maintenance and low operating cost.

So I bet there actually is a lot in the Merlin 1C that prevents it being used in a real reusable VTVL vehicle, or that would at least make it very inconvenient and expensive. But we don't know.

Posted by mz at 11/13/07 12:28:21

Re: mz

The press release states that one of their engines has run a total of 3000 seconds with 125 restarts. A single mission is 170s, so that would be good for at least 17 launches.

The whole thing is a relatively simple design, so it is definitely not as high maintenance as the SSME.

I think that they even have redundant torch igniters on the Falcon 1, which would make the engine restartable. The 1h countdown recycle during the last launch seems to confirm this.

Last I heard, they are planning to use TEA/TEB hypergolic igniters on the Falcon 9 though. A regression if you ask me.

One thing that is probably worth more than the engine itself is that they now have an experienced engine design team. The news about the merlin improvements seems to confirm that they will keep this team together for the time being.

Posted by anonymous at 11/13/07 12:45:30

We don't know how much they changed parts between those runs, but that certainly is encouraging.

Posted by mz at 11/13/07 14:14:11

MZ would be well advised to read Elon's critique of Pegasus. It was very specific. Also, it boggles the mind that anyone reading an alt.space blog would be unaware that the flight rate is the primary driver of the cost. For the reasons outlined by Elon, Pegasus would not be anywhere near Falcon-1, but if it flew every other day, it could be much cheaper than it ended being.

Elon was asked about the value of recovering an ablative engine once. He replied that he's mostly interested in two things: data which can be obtained by examining the structure post-flight, and the truss structure between the engine and the tank (if it survives the splashdown). But once again, the cost savings from the reuse is the second order to the flight rate increase.

Posted by Pete Zaitcev at 11/13/07 15:14:16

"... I bet there actually is a lot in the Merlin 1C that prevents it being used in a real reusable VTVL vehicle, or that would at least make it very inconvenient and expensive..."

VTVL needs an engine that can throttle down by an amount equal to the product of the t/o thrust/weight times the vehicle mass ratio (to/land). So if the vehicle is 60% fuel at T/O (very modest for a launch vehicle) and it takes off at a relatively low 1.25 t/w, then you need to throttle down at least 1.25 * 1/.4, or 3.1:1. Now while that is easily done with a pintle (that is if the 1C is still a pintle) if it is designed in at the beginning, it is NOT something that can be easily "retrofit" later. Note that Delta-V goes as the fuel fraction (log actualy) which drives one to high fuel fraction, and up with T/W (low gravity loss). So for a VTVL deep throttle is a prime performance driver.

In terms of reuse, kersone is hard since it tends to break down and coke at elevated termperatures. That makes both regen chamber and gas generator design very sensitive to temperature. It CAN be done, but again, you have to start at the known coking limits and do careful design to keep the relevant temperature below that point. Not something that is easy to "retrofit", and generally not without performance penalty. This is rocket science, there are no free lunches.

Posted by Earl at 11/13/07 18:47:21

Re: Earl

while using the main engine for landing might work with a suborbital hopper like the armadillo or masten design, it is not very practical for something like a falcon first stage with a propellant mass fraction of 0.95 or so.

You would need an engine that can be throttled to less than 5% in order to have positive acceleration on launch while still being able to produce less than 1g acceleration during landing.

I think it would be more practical to have separate landing engines. These might be pressure-fed and would not be using the main propellant tank.

About coking: If the engine is capable of running 3000s during certification, obviously there is no significant coking going on.

Posted by anonymous at 11/14/07 02:43:56

Earl, Anonymous,
Yeah, while our pintle injector engines turned out to be throttleable down to at least 30% without any problems (or any real effort to make them deep throttleable), you would definitely want to go with a mains/verniers kind of approach for the powered landing.

~Jon

Posted by Jonathan Goff at 11/14/07 15:09:27

you don't want mains/verniers, or at least it's
a challenging trade, if you want reliability.

If you have different size engines, you need either
a whole lot of them, so you can handle failures,
or you need to have some amazing gimbal angle.

throttle is a very enabling tool, but it's hard to do.
Unless you are very clever

Posted by anonymous at 11/14/07 16:16:31

Anonymous,
<i>you don't want mains/verniers, or at least it's a challenging trade, if you want reliability.</i>

Yeah, preferably you want enough thrust on the "verniers" that a main engine failure doesn't doom the vehicle. And there are other details. While we may not have spent as much money on trade studies at some, we've at least looked at the problem and have a few ideas we want to try out for fixing them.

<i>If you have different size engines, you need either a whole lot of them, so you can handle failures, or you need to have some amazing gimbal angle.</i>

It all depends very strongly on the details. Stuff like relative size of mains to verniers, what kind of volume is available (ie how big can the verniers be), where the CG is at any given time, etc, etc.

<i>throttle is a very enabling tool, but it's hard to do. Unless you are very clever</i>

Why thank you! While admittedly it's a lot easier to throttle a pressure-fed vehicle, and while our throttling isn't as great yet as we want it to be, it was a fun challenge. :-)

~Jonathan Goff

Posted by Jonathan Goff at 11/15/07 08:17:20

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