Falcon 9 first stage successfully flies for the third time


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Capitalism in space: During a successful launch today of 64 smallsats, SpaceX successfully landed for the third time the rocket’s first stage.

This first stage flew twice before, in May and August. With this flight it is primed for a fourth flight, I will bet sometime in the next two months.

SpaceX was also going to try to recover half of the fairing, but as I write this there is no word yet on that effort. Also, the deployment of the 64 smallsats will start momentarily and take more than an hour. During the live stream, which you can watch as a replay at the link, it was very clear that one of SpaceX’s commercial goals with this launch was to promote the Falcon 9 as an affordable and viable vehicle for launching smallsats. SpaceX is anticipating the growth of that business, and wants to encourage smallsat manufacturers to buy their services. As I like to say, the competition is heating up.

The leaders in the 2018 launch race:

33 China
19 SpaceX
13 Russia
9 Europe (Arianespace)
8 ULA

China remains ahead of the U.S. in the national rankings, 33 to 31.

Update: What I neglected to mention, partly because I was writing this post while traveling, is that with SpaceX launch the company set a new annual record for the most launches in a year, which is also the record for the most launches in a year by any private company, ever.

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9 comments

  • geoffc

    They landed on JRTI just 30 miles offshore, since the NRO payload on the D-4H that is a couple of miles away from landing zone at Vandenberg, was considered to risky to allow the landing.

    And 24 hours and 5-10 min later we have an ISS flight of Dragon on CRS-16.

  • Kirk

    https://twitter.com/elonmusk/status/1069679948103847939

    Elon Musk: Falcon fairing halves missed the net, but touched down softly in the water. Mr Steven is picking them up. Plan is to dry them out & launch again. Nothing wrong with a little swim.

  • MDN

    I still don’t understand why they aren’t simply catching the fairings with a pair of helicopters. Their weight is well within the limits for a surplus Blackhawk, and it would seem trivial to design an aerodynamically steerable grab-hook that would hang on a 500-1000 foot tether so downwash would not disrupt the parafoils.

    BTW, watching the launch video from this morning there is an interesting event at about 25:20 where a small piece of the second stage broke off and fell past the engine nozzle. I wonder what it was and if this was a significant incident.

  • Kirk

    MDN, @25:21 in the video (T+05:25) a piece of Oxygen Snow breaks off and falls past the nozzle. I’ve never heard the plumbing fully explained, but during Merlin 1D Vacuum engine operation, a small amount of LOX is discharged from a pipe just above the big RP-1 regenerative cooling pipe (the one which tapers in size as it runs around the top of the nozzle). On some launches when the lighting is right, you can see the fluffy looking Oxygen Snow continually accumulating there, with pieces periodically breaking off and falling away.

    I predict that this will be one of those things which, now that you have noticed it, you will repeatedly observe on future flights.

    SpaceX marches on. The webcast link Bob gives above is now for tomorrow’s CRS-16 resupply launch, currently scheduled for 1:38:51 p.m. EST. The weather prediction is improving, now showing a 60% chance of acceptable weather, but NASA is having some late load issues (they’re dealing with mold contaminated mouse food). If the launch slips to Wednesday, then they will be targeting 1:16:18 p.m. EST, with weather predictions currently calling for 90% chance of acceptable weather.

    Here is the link for the official SpaceX livestream (now replay) of today’s launch: https://www.youtube.com/watch?v=Wq8kS6UoOrQ

  • Kirk

    The SPX/CRS-16 flight has been delayed until 1:16 p.m. EST Wednesday. Weather should be much clearer, so this will benefit observers wishing to see the first East Coast RTLS since the Falcon Heavy demo. (There have been two other CRS missions since the February FH launch, but both were second flights of Block 4 boosters which were expended.)

  • wayne

    Kirk–
    great factoids–thanks.

  • Kirk

    MDN, I was wrong when I described the snail-like pipe going around the top of the nozzle of the Merlin 1D vacuum engine as being for RP-1 regenerative cooling of the nozzle. It’s for nozzle extension cooling, and like its counterpart on the Saturn V’s F-1 engine, it’s carries the gas generator exhaust. (Compare this to the Merlin 1D sea level engines which lack the vacuum nozzle extension and exhaust their gas generators directly.)

    I was just looking at last year’s CRS-13 mission and saw a good example of O2 snow buildup (though I’m sure I’ve seen even better illuminated ones). Here is a link to T+07:30, just moments before a beautiful landing. Second stage footage picks up at T+08:22, and if you watch the view from the camera which shows the Earth to the left, you will see a small amount of LOX being vented toward the top, with O2 snow building above the gas generator exhaust piping. A piece of that snow breaks off at SECO at T+09:02.

    That 2017-12-15 launch was at 10:36 EST, compared to Today’s (Wednesday 12/05) 13:16 CRS-16 launch, but with beautiful weather on both days we should see just as impressive a landing today. I don’t know how a couple of hours of sun angle difference will affect the S2 Merlin illumination, but I’ll be watching to see if O2 snow buildup is as visible.

  • Kirk

    Thinking about that LOX venting, I’ve decided that it is most likely part of the pre-ignition engine chill down system, and they determined that it was more efficient (in cost and/or weight) to just vent a small amount of LOX during engine operation than to install a valve there.

    Here is a great photo of a Merlin 1D vacuum engine without its nozzle extension. The gas generator exhaust plumbing is clearly visible, as is the RP-1 regenerative cooling pipe above it.

  • Kirk

    And for completeness, here is a Merlin 1D sea level engine. (Perspective is a little weird with the octoweb suspended in the background, and it takes a moment to realize that the gas generator isn’t a different engine hanging from the octoweb.)

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