23 thoughts on “SpaceX SES-9 Launch”

  1. I was watching, and when it lit up then stopped, I really thought we were going to see a rapid launch site reconfiguration. Startled the heck out of me.

  2. Rand,

    While I think there’s a good chance you’re right that they just need more practice with propellant supercooling to make it work reliably, we should remember that they’ve had to abandon many unconventional ideas over the years (fall-away first-stage insulation panels, parachute recovery, Falcon 1, Falcon V, ablative nozzles, etc). Having confidence that they’ll be successful as a company vs. confidence in any one specific technology idea they try are two very different things.

    ~Jon

    1. Well, it worked on the first flight, after playing with it a couple days. No particular reason to think it wouldn’t have worked this time if they hadn’t been delayed by the fouled range. I’d bet they’d never attempted to do a hold that long with full tanks. So they probably learned something yesterday.

        1. True. That seems to be why SpaceX now starts tanking ops relatively late in the countdown compared to what they used to do. I think the only likely way to make F9 FT, and the FH version based on it, “hold-tolerant” is to put some large-diameter tap-off plumbing on the propellant tanks near their tops to enable continuous cycling and rechilling of the propellant loads; offloading “warm” propellant at the top and replacing it with freshly chilled prop pumped in at the bottom. I have no idea whether or not something along these lines is actually a part of the current F9 FT design.

      2. Rand,
        Do we know if the first flight on v1.2 actually pushed the envelope as far as they need to on this flight? The Orbcomm payload was likely less than 20% the normal capacity of the F9 v1.2, and while they did a “full duration burn”, it didn’t have a payload, so do we know if they actually got full performance with it? Ie do we know that that first flight actually demonstrated the complete capabilities of the upgrade, or might it have been a less aggressive demo that they didn’t have to work as hard with the subcooling for?

        ~Jon

  3. The next time spacex tries landing on a barge they should have a painting of Michael Palin dressed as king of swamp castle on the side of the rocket. (The third one burned down, fell over, then sank into the swamp, but the fourth one STAYED UP.)

    1. Actually, with all the scrubs and aborts, it’s more like watching the beginning of Lancelot’s charge.

  4. What was telling was this last (3rd delay). Where from what I read a “low performance” sensor warning shutdown the engines while it was still on the pad. The warning was engendered from the delay in the countdown due to an appearance of a boat in the launch range which caused the LOX to heat along with a helium bubble to form. These all are real problems from using densified fuel and oxidizer that will have to be addressed, either through design or procedural changes, since delays (of all sorts) are unavoidable. Yet the schedule facing SpaceX going forward is daunting and unrelenting. Nobody said what SpaceX is attempting is easy.

  7. Is the idea that they are completely pushing the envelope with this flight because they are (a) using every bit of fuel they can to get SES as high and fast as possible, and (b) still hope to just barely make it down to the barge in one piece with what’s left?
    Do they need to go through all this for every flight? Don’t they have a lot more margin on most others?

    1. This is a high-performance mission, but I think they plan to subcool LOX (and kerosene) on every flight of this vehicle. They need it to maximize recovery chances, I suspect.

  8. I wonder if it would it be possible to hold in place a 2-3 piece external insulation layer around the vehicle via retractable gantries to aid in keeping the LOX cold until the last minute or so of the countdown?

    1. Do you mean something that gets pulled off laterally at launch? or like a sock that gets pulled off vertically? Either way, if it isn’t removed completely uniformly, could impart a lateral motion or, worse, prevent one side from accelerating vertically as fast as the other side at takeoff. The insulation would have to be as responsive as the hold-down clamps.

      1. I’m not certain but I think it has been done. One possibility is to apply a lightweight foam insulation over the LOX tanks. The insulation wouldn’t have to withstand flight loads like the Shuttle ET. It could be designed to break up and fall off not long after liftoff.

      2. Removed laterally. Picture a hollow cylinder of insulation of sufficient thickness. Now divide it into 3 sections, each making up 120 degrees of the full circumference of the rocket body. Each section is held in place against the Falcon 9 by a swing away arm. See the umbilical swing arms used on a Soyuz launch for what I am referring to. The insulation is held in place until the last 1-5 minutes of the countdown, helping maintain the proper temperature but not adding any weight to the vehicle since it is rotated away from it prior to launch.

  10. Propellant cooling, besides increasing the performance so they can have more margins, is also a good technology to test for when they go LCH4. A lot of the LCH4 proposals I have seen over the years chill the propellants in order to mitigate its atrocious density.

    The Russians also replaced RP-1 with Sintin at one point. But I don’t think the refining capability for it exists today. Especially not in the US.

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