What I’ve Been Up To Lately

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If you’re wondering why blogging has been so light as of late, let’s just say we’ve been a bit busy at work these past few weeks. Things are picking up momentum at MSS, with us nearing the completion of our first engine design. I’ve lost track of the number of firings we’ve done, but we’re over 200 by now, with many of them in the 10, 15 and even 40 second range. All in all, we’ve met or exceeded several of our design goals for the engine (including having a slightly higher Isp than our target, as well as having a much better throttling range), and are getting quite familiar with the system. We will be testing a flightweight chamber-saddle-jacket version of the engine in the near future (hopefully Saturday), and then we will start putting together the actual vernier module and finish up the engine control programming. I’ll post some pictures when we get there, but it looks like we’ve just about reached another major milestone with this company. There aren’t very many companies in the world right now that have a 3:1 throttleable, in-air restartable, fully regen-cooled liquid bipropellant engine.

Now we just have to finish putting that vehicle together…..

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
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9 Responses to What I’ve Been Up To Lately

  1. Iain McClatchie says:

    There aren’t very many companies in the world right now that have a 3:1 throttleable, in-air restartable, fully regen-cooled liquid bipropellant engine.

    There is of course one, in particular: Armadillo.

    Both Masten and Armadillo recently fired regeneratively cooled 1600 pound engines. Yours is LOX/isopropyl, theirs is LOX/ethanol. I’m not aware that Armadillo has said what throttle range they have, or whether the thing is air-startable. But it’s clear the two engines are of similar performance and intended for similar applications (though yours is a vernier and theirs is the main engine IIRC).

    Care to tell us the important differences you see between the two approaches?

    Oh, and how do you folks pick your fuels? Alcohols? Is there something wrong with unleaded gasoline?

  2. Jon Goff says:

    Iain,
    Actually there are a few differences. First, our engine is only 500lbf. Theirs is a lot bigger. Second, ours is regen cooled while Armadillo (IIRC) is using an phenolic ablative chamber and a radiation cooled graphite throat. I don’t know what their throttle range is, but I imagine it on the same order as ours. Ours has a much higher chamber pressure so we’re getting a much higher Isp than Armadillo had been previously posting (though their numbers may have gone up since last time they posted about it).

    But, yeah, Armadillo is serious competition. Still, even counting them, there still aren’t a lot of companies that have throttleable biprop engines. Especially not ours or Armadillo’s size.

    I still think we have reason to be proud that we’ve gone from none of us having fired a biprop engine of any size or style as of last November to now having a regen cooled engine that is stable over a wide range and that has good performance.

    As for why we chose IPA? Mostly just because it’s very forgiving, and burns better than gasoline. In the future we may try Kerosene, Methane, or Subcooled Propane, but IPA is a nice “training-wheels” propellant. It get’s decent performance, cools well, doesn’t leave deposits, doesn’t coke the cooling jacket, and doesn’t stink.

    All in all, a good mix.

    ~Jon

  3. Anonymous says:

    You guys have been progressing very quickly. Do you work at Masten full time? I think Armadillo only works Saturdays and Tuesday evenings.

  4. Jon Goff says:

    Anonymous,
    I’m full time, Ian and Pierce are mostly full time (full time while also finishing up their degrees at SJSU). But with the way schedules meet up we are mostly doing our testing on weekends too. One of these days we’ll move somewhere where engine testing doesn’t involve a 2 hr drive…

    But yeah, things are moving a lot faster as of late.

    ~Jon

  5. Anonymous says:

    Congratulations! Your progress seems very promising. And it’s a pleasure to be able to read of your development so frequently, while Armadillo’s updates have been getting less frequent as of lately…

    So, these 500lbf ones are supposed to be vernier engines for XA-1.0.
    Main engines for XA-1.0 will be bigger? Presumably using the same design…
    How scalable do you expect your design to be?

    And, what kind of engine configuration have you planned for XA-1.0 ?

    One/several vernier engines? And main engines?

    Just out of curiosity…

  6. Jon Goff says:

    Anonymous,
    So, these 500lbf ones are supposed to be vernier engines for XA-1.0. Main engines for XA-1.0 will be bigger? Presumably using the same design…How scalable do you expect your design to be?

    Well, I can’t go into too much detail about our future plans (partially because that’s our livelihood, and partially because not all the details have been firmed out yet). But the mains will likely be in the 2000-2500lbf ballpark, and with how well pintle engines have worked for us so far, there’s a good chance we’ll stick with them.

    As for scalability of pintles engines, they’ve been built and tested from as small as less than 1lbf hypergolic all the way up to a 650,000lbf LOX/LH2 engine, so I’m not really too worried. We’ll likely need to repeat a lot of the development, just to make sure that the design is still workable at that size, but a lot of the time that’s gone into engine development so far has been figuring out the whole liquid rocket engine learning curve. I wouldn’t be surprised if the next engine was easier to develop, actually.

    And, what kind of engine configuration have you planned for XA-1.0 ?

    If you look on our blog at this address: http://masten-space.com/blog/?p=57 you can see more or less what we’re looking at. A few of the minor details have changed (or were modified by the artists who did the rendering), but the overall idea is pretty close to our current plans for XA-1.0.

    ~Jon

  7. John Carmack says:

    In hindsight, I think it is probably fair to say that Masten took a better route on engine development than Armadillo did — “Do what XCOR did”. Torch igniters and chamber / saddle / jacket regen chambers.

    There were a few initial misconceptions that influenced our development process several times:

    We had concerns about deep throttling fixed liquid injector geometries, so we started off with the lox pre-burner designs and generally avoided conventional injectors.

    We were trying to avoid the possibility of hard starts, which the preburner should have helped, and we theorized that the throatless engines would have helped.

    It turns out that we have never seen a stability problem throttling fixed injectors. Isp gets bad, but everything does “just work”.

    It also turns out that you can hard start a preburner (a less violent, but still engine-breaking event), and even hard start a throatless engine.

    We were also probably overly-wed to aluminum fabrication because of our in-house skills and capabilities. Making chambers out of copper would have avoided several slagged engines.

    So now, over a year later, we have a torch igniter and a conventional injector head. Oh well, at least we got a lot of experience in the process. I don’t regret the work with ablatives, but if we ever stick with an engine size for more than six months, I expect we will probably make some regen chambers to replace the ablatives.

    I hope the Masten guys bring an engine to Space Access so we can peer inside it and estimate dimensions. 🙂

    John Carmack

  8. Jon Goff says:

    John,

    It turns out that we have never seen a stability problem throttling fixed injectors. Isp gets bad, but everything does “just work”.

    Yeah, I was also kind of amazed at how far we were able to push things with just a simple fixed injector design. I’m now kind of curious what has caused others so much grief with throttling stability.

    I hope the Masten guys bring an engine to Space Access so we can peer inside it and estimate dimensions. 🙂

    Heh. That’s actually kind of flattering. Since it looks like Tiff and I will be driving down (with little Jon), we may very well bring our CSJ style engine with us, but we’ll probably be pulling another trick from XCOR’s playbook and “sticking a sock in it”. Sorry John, maybe after someone has won both levels of the Lunar Lander Analog Challenge…. 😉

    It should be a fun competition this year and next.

    ~Jon

  9. Brian Dunbar says:

    I’m jealous. I’ve been slack because I’m up to my hips deploying softare. You’re out there doing Real Work.

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