SpaceX: propulsion update (VP Propulsion interview)

[Dr Mordrid]

News on the SpaceX propulsion front. Not official so exact numbers may change after the tests, but very close. This speedup is possible because of a hiring spurt - they're between 1,400 and 1,500 souls now and still growing. Seems resume's from engineers are staked up like cord wood, but they're picky.

1) Merlin 2 is a go and under active development. It will have a thrust of about 1,000,000 lb-ft (4,448,500 Newtons) - similar to the Rocketdyne RS-84 (which they have the rights to) and about 2.5x the thrust of the Space Shuttle Main Engine (!). Quite likely it'll be lighter, cheaper to build and simpler than either of those. Very possible it'll be an advanced staged combustion engine.

2) the Raptor liquid hydrogen/LOX second stage is also in active development. No details on it yet other than it'll be a staged combustion engine, but it would be used for high energy destinations like geostationary orbits, Mars, heavier lunar or asteroid missions..

3) a new variant of Falcon 9 is in the works that will replace the Merlin 1C engine cluster and MVac 2nd stage engine with the Merlin 2 and the Raptor. Very likely it'll also get higher capacity tanks up and down. A beast.

4) the Merlin 1C Block II engine is getting replaced with the Merlin 1D, which is now undergoing tests at their McGregor, Texas test site. Word is it's exceeding its goals.

This is a huge upgrade in that its weight has been reduced 33%, its part count drastically reduced (ex: down to a single servo from 13) and the whole thing made into a production line engine. All this and a major performance update too (see below)

The throttleability means that Falcon 9 will no longer have to shut down 2 of its 9 engines at maximum dynamic pressure (Max-Q), but simply ease up on the gas. This will also mean a very, very smooth ride for astronauts in the Dragon.

5) a new MVac 2nd stage engine is also in the works based on the new Merlin 1D for use in the Falcon Heavy

6) if a Merlin 2 version of Falcon Heavy would be built or if they'll go straight to a larger diameter core like Falcon X or Falcon XX is an open question.

[Dr Mordrid]

Just found out that the Merlin 1D's throw weight ratio of 160:1 breaks the record of 137:1 formerly held by the Russian NK-33 engine. The boys & girls at SpaceX are raising eyebrows among the propulsion jockeys.

[Dr Mordrid]

For those who like diagrams below is a leaked one that looks to be for the Raptor staged combustion liquid hydrogen 2nd stage engine -

[Dr Mordrid]

Finally - pics of Merlin-1D

In the composite: Merlin 1C (left) meets Merlin 1D (right). Merlin 1C is machined (very $$) while Merlin 1D is explosively hydro-formed (!= $$).

The Merlin 1D has developmental sensors and wiring taped to it that won't be in the production engine. It's much more powerful but has far fewer parts, which with the rapid explosive hydro-forming makes it a real live mass-production rocket engine. This means that instead of building just a few engines a year by hand like most companies, SpaceX can crank out several hundred Merlins a year just at the Hawthorne, California plant. They're going to need them - the Falcon Heavy will use 27 Merlin 1D's in the first stage cores and 1 M1DVAC in the second stage.

Still waiting for details on the new staged combustion engine, which rumors say burns methane or some methane/?? fuel blend.

[KRSESQ]

Keep it coming, Doc .

[Dr Mordrid]

From a Tom Mueller (SpaceX's VP of Propulsion Development) interview in LMU, the magazine of Loyola Marymount University. The red comments are....interesting.

http://magazine.lmu....2011/rocket-man

Rocket Man

In the coming months, Space Exploration Technologies Corp., known as SpaceX, will launch a supply ship carrying hundreds of pounds of astronaut provisions to the International Space Station. NASA is counting on the company, and another private firm, to take over the Space Shuttle’s resupply missions to the iss. only nine years old, SpaceX has technologically leapfrogged its competitors to lay claim to the world’s least-costly space flights. One of the brains behind SpaceX is Tom Mueller. He was interviewed by Doug McInnis.

Mankind’s dream of living and working in space seems to hinge on three factors — the ability to do it affordably, safely and reliably. So far, spacecraft have been made to work more or less reliably and safely, but not affordably. Has SpaceX cracked the cost barrier?

We’ve made a big improvement over the previous cost barrier. We can send a payload up for as little as one-fifth as much as other U.S. launch providers. But we would like to reduce that to 1/100 the current cost or less. The problem is that all rockets, including ours, are used just once. With expendable rockets, you pay for the full cost of the rocket each time you fly. With a reusable rocket, you could get the cost down. Ultimately, we want the whole thing to be like an aircraft flight — you don’t throw anything away except maybe some of the food trays you serve to the crew.

If cost is less of an inhibiting factor, is manned travel to the Moon, Mars and elsewhere coming?

Absolutely. I think that’s the next step in human exploration. Somehow we got trapped in low-Earth orbit for the past 40 years. That’s unfortunate. I think what mankind really wants to do is go to Mars. And certainly there are reasons to go back to the moon.

Do you think future SpaceX vehicles will go to the Moon or Mars, and do you think that someday SpaceX travel will be cheap enough to take tourists into space?

Yes, on both counts. We’ll be capable of going to the moon within five years and to Mars hopefully within 10. We’re also working really hard on reusability to get the price down, and I think that will open up space tourism. We’ve already announced our initial price for NASA astronauts: It’s about $20 million. But if we get reusability down and are able to cut that price dramatically, that would open it up for a lot more people.

What sorts of things have you done to create propulsion systems that work better and cost less to operate? was there a magic bullet or lots of small improvements?

There’s no real magic bullet. In order to keep the rocket’s engine simple, reliable and low cost, we picked fuels that were simple, low-cost and widely available. We picked an engine cycle that’s about 95 percent of maximum. It’s not like a Ferrari, as some other companies have done. It’s like a Chevy. It’s reliable and low-cost. We save money by making most of the parts. We do our own testing at our own sites. We have control of design and development through launch. We build the launch vehicle and the engine that powers it, so we don’t have to go to another company to interface. I just go to another office in the same building.

To create a new propulsion system, is it an advantage to start from scratch?

In the beginning, we would have liked to have bought an existing system to save all the development costs. But there was no system, not even the Russian system, that would do what we wanted. So we had to develop our own. That really allowed us to do a paradigm shift and get the costs down. We’re not looking to do an evolutionary change. We’re looking to do a revolutionary change.

Is your background from outside the box?

I come from a hands-on background. My dad was a logger, so I grew up around logging trucks and equipment, and chain saws. You learn a lot from that environment. I tend to have that rare gift where I can easily conceptualize what will work. If somebody were to give me specs for a different kind of engine, I could easily conceptualize what will work.

What were you like as a kid?

I got in big trouble when I took the lawn mower apart. My father came home and found the parts all over the yard. He was mad because he figured it wasn’t going to go back together. I had the pistons out and the valves out. But I put it back together, and the thing ran fine. At Christmas, I always went for the Erector Set–kind of stuff.

When did you become interested in space propulsion and how did you pursue those interests over the years?

I was always interested in rockets, even as a kid. I flew my own rockets. I read science fiction and was really into astronomy. The kid across the street from me was a real brain. He had a telescope. I would go over to his house and look at the stars. I loved reading about the stars, black holes, anything that had to do with space. But my junior high school guidance teacher decided I should be an aircraft mechanic. Then in my first year in high school, my math teacher asked if I was going to be an engineer. I said no. He was astounded. He asked, “Do you want to be the guy who fixes the plane or the guy who designs it?” If it hadn’t been for that math teacher, I probably would have been a mechanic or a logger. Thanks to him, I got the right courses to go to college.

SpaceX was the brainchild of Elon Musk, the legendary entrepreneur who also founded PayPal and electric carmaker Tesla Motors. What’s it like to work for him?

Elon says a company is the sum of all of its vectors. If you have a small company with all the vectors pointed in the right direction, he says it’s better than a large company with the vectors pointing in random directions. Here, everybody is moving in the right direction to build a very efficient machine that is super reliable.

You had a good job with TRW, a Fortune 500 company. Why did you give it up for SpaceX?

I was pretty happy there. The biggest problem probably was that rocket engines weren’t a core component of TRW’s operations. But when I met Elon, the rocket engine was key frontline technology for SpaceX. In addition, Elon’s business plan and the way he wanted to set up the company really appealed to me. And he had the capital to do it. So when Elon said (to me and another prospective employee), if you guys join, we’ll start the company, I signed on as one of the three cofounders.

SpaceX has a government contract to deliver unmanned supply vehicles to the space station. what other things do you have in the works?

Just over 50 percent of our work is commercial. We have, for example, a $550 million contract with Iridium Communications, a satellite communications company in McLean, Vir., to launch its next generation of telecommunications satellites into space. We also have a contract with NASA to develop a manned version of our Dragon spacecraft. And we are working to get more launches for the Department of Defense.

Do companies such as spacex indicate a shift from public to private space exploration?

Yes. To qualify that statement, government will always play an important role in space exploration. But NASA will be able to hire private companies to handle access to low-Earth orbit and eventually some points beyond. The government will need to lead efforts for deep space missions requiring farther-reaching technology (like ion and nuclear engines).

What’s next in space travel?

Until now, the trajectory has been all wrong. We went to the moon in 1969. Then we got stuck in low-Earth orbit with the space shuttle. And now we don’t even have that any more. I’m hoping that this is the beginning of a commercial revolution in terms of access to space. I think there are going to be a lot of startups. Hopefully, we’re going to bring spaceflight back so that it will be at the forefront of people’s attention. That’s what SpaceX is all about.