Additional AV-017 Flight Experiment Information

I’ve mentioned, here and in my propellant depot paper, the post-flight cryogenic fluid management experiments ULA carried out on the AV-017 flight this past fall.  I don’t have time this morning to comment on it, but I just found out that they have now published some information about the tests carried out and the preliminary results.  Also, while digging up that first link, I noticed a new presentation on their sunshield technology that I don’t think I had linked to previously.  Hopefully I can get some time tonight to update this post with commentary, otherwise, if intrepid readers want to mention what parts most interested them (in the comments section), that would work too

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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.
Jonathan Goff

About Jonathan Goff

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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17 Responses to Additional AV-017 Flight Experiment Information

  1. Neil H. says:

    So the basic question: What do we know now as a result of this experiment that we didn’t know (or were unsure about) before, and what remains to be shown to convince NASA that propellant depots aren’t a high-risk technology which to be avoided at all cost?

  2. john hare says:

    Reading the two new links raised a question in my mind. Could you use the boil off to cool the sunshield in order to further reduce the radiation being transmitted to the tank? Or possibly reduce the number of layers of shield to reduce mass if that is desirable?

  3. Neil,
    When the final data gets in we’ll know a lot more about the solid body rotation settling. If this turns out to be workable for long durations, then it’s a powerful tool for an early depot, because it gives you settling without having to constantly be providing settling acceleration from venting or thrusters. There’s still some other stuff that needs flight testing, like the sunshield, and the actual cryo couplings, but at this point the biggest remaining risk is integrating the various pieces into a working depot demonstrator.

    As for convincing NASA…there are three views at NASA regarding depots–those who have had any relevant experience with depots, who are mostly supportive, those who work on HLVs that feel threatened by depots, who won’t be convinced even by a working depot, and lastly the rest of NASA. 🙂 The people on the fence would probably need to see some sort of Orbital Express-scale system demo in order to be convinced.

    ~Jon

  4. John,
    Maybe, but it would probably be pretty hard. You would need to somehow diffuse the gas out enough to not have it damage the sunshield, and to get even cooling while maintaining enough density to get a reasonable heat transfer rate…of course, if you injected the cold vented gas in between the innermost two layers right where they attach to the centaur, it might work…but I’m not sure if it buys you anything compared to using the GH2 for other purposes (like eliminating LOX boiloff, and short-circuiting heatflow from the high-temperature parts of the stage/depot.

    Not sure–my heat transfer fu is not that strong. Though if any of the ULA or NASA guys are reading, maybe they can comment.

    ~Jon

  5. Neil H. says:

    Thanks for the great answer, Jon!

  6. Tom D says:

    John and Jon,

    Using boil-off for extra cooling is fairly commonly done with the cryogenic dewers for infrared telescopes. It’s called a vapor cooled shield (VCS). It adds another layer of complexity to the design, but it may well be worth it. Before the development of very low vibration cryocoolers, an infrared telescope could only be used as long as the cryogen (such as liquid helium or solid hydrogen) used to cool the detector lasted (typically 6 to 18 months). The VCS significantly reduced the parasitic heat leak into the cryogen tank by using the escaping boiloff gases to cool the surfaces that the crogen tank “sees”.

  7. Mr. Walker says:

    “…HLVs that feel threatened by depots, who won’t be convinced even by a working depot…”
    The opposition to the depots is mostly political in nature. The depots enable the use of multiple vehicles and also enable flexibility into the architecture. Both of which the proponents of the Ares LVs and Constellation architecture do not want.

    Concerning the injection of cryogens into the shield, that would be something that would help in convective or conductive matters, but the shield is there to handle the radiative aspects of the design. The shield is not a radiator per se. It reflects and prevents incoming radiation and reflects the outgoing radiation from the stage to deep space.

  8. A_M_Swallow says:

    Propellant depots will not be considered a tested technology until a satellite has been fuelled and sent to lunar orbit, geostationary orbit or possibly a planet.

  9. Neil H. says:

    Jon, any ideas on whether there will be a press release or anything on this sometime? It’d be nice for propellant depots to get more publicity.

  10. Jonathan Goff Jonathan Goff says:

    Neil,
    My guess is not until the President has set his exploration agenda, and Congress decided what to do about it. ULA unfortunately has to answer to Boeing an LM, and I think both of them are very much in a “don’t-rock-the-boat” mentality. If ULA were a “free-man” so-to-speak, I bet they’d be speaking up more, but ultimately, they have to answer to their shareholders, who in this case don’t necessarily have only ULA’s interests in mind.

    It’d be sweet if at some point ULA could free itself from those constraints, but I doubt it’ll happen.

    ~Jon

  11. Nels Anderson says:

    I see what you mean about ULA taking a don’t-rock-the-boat stance: the written piece never mentions depots or anything like them.

    The first questions that arise in my mind are about the *numbers*: how low was the acceleration in the low-g test? How long did the slosh observed in that mode last? What was the rotation rate in solid-body mode? How long were these modes used?

    Although it’s not directly relevant to depots, I wonder whether the successful MRS test might indicate that the RL10 could conceivably be ignited on a two-phase mixture (the original J-2S was supposed to be able to do this). Is it significant that LO2 was depleted before LH2, i.e., would depleting LH2 first be risky?

    About the chill-down test, why is pulsed LH2 a new technique, if pulsed LO2 has been around for years?

    Gotta love the RL10: world’s first hydrogen engine, still going strong forty years on.

    Re the above discussion of using evaporate to chill the sunshade, chilling the sunshade with GO2 seems like it might be a good idea. Surely the best use of GH2, however, is to chill the LO2. That way every joule of heat absorbed by the GH2 is a joule extracted from propellants.

  12. Jonathan Goff Jonathan Goff says:

    Nels,
    They may be concerned about ITAR issues when it comes to discussing technologies like this (even though they really have absolutely nothing to do with missiles or how you would do weapons, ITAR still hangs over our head). But I agree, those are good questions that I would like to see answers to. I imagine that you might be able to back some of that info out if you tried hard enough, by looking at previous papers, estimating hydrazine reserves, trying to look up the thrust specs of their hydrazine thrusters, etc. But it would be cool just to have that published in a paper later this year. We’ll see.

    As for using GO2 to cool the sunshield…if you’re using the GH2 to cool the LO2, there isn’t going to be a lot (or any) GO2 to use for a sunshield…

    ~Jon

  13. Nels Anderson says:

    Yeah, you’re right–no GO2 to play with. But come to think of it, because of GH2’s high heat capacity, even after it’s warmed up to LO2 temperatures it still makes a better coolant than does GO2. So, how about cooling the sunshade with the GH2 *after* it’s cooled the LO2? GH2 is probably friendlier to sunshade materials too. And if you want to use warmed up GO2 for propulsion, the additional heating may be useful.

  14. Nels Anderson says:

    Final reference to “GO2” should read “GH2”.

  15. Jonathan Goff Jonathan Goff says:

    Nels,
    You could possibly do that, but with a decent sunshade, that’s no longer your biggest source of heat flow into the tanks–your electronics deck is. Cooling the connections between the hot and cold stuff is a better use of the GH2’s remaining heat capacity. Plus, you generally want to use that GH2 (that’s now quite a bit warmer) in a warm-gas RCS jet for stationkeeping purposes. If you send it out through the sunshield, it’s a lot harder to do that.

    ~Jon

  16. Robert Wallace says:

    This is fantastic. I pondered years ago what the Air Force’s take on space-based refueling depots was — but I was thinking on the Moon and in lunar orbit — following extraction from hoped for lunar ice deposits at the poles. Everything I have had a chance to read here all makes sense — and would make a great focus topic for a high school-level aerospace Science Technology Engineering and Math (STEM) Education enrichment module. You have all your physics principles present, numerous chemistry topics, tons of engineering analysis problems, and plenty of math required in your various trade-off analyses. NASA is kicking-off a Summer of Innovation Project in 2010 and the STEM content of Orbiting Refueling Depot Engineering offers a fantastic “vehicle” for integrated STEM knowledge transfer. Any thoughts gentlemen?

  17. PrairieKirk says:

    Well, it’s been a year now…, and I don’t know if this comment will even be accepted this far on.

    But thought I should let you all know that the links to the “published some information” and “presentation” in Jon’s 12 Jan 2010 post have gone dead.

    Anyone have a URL for where the papers might still be found?

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