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Thread: SpaceX

  1. #901
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    Oh wow, what an amazing thing to see! The video stream from the barge froze just as the landing burn was reflecting light off the barge's deck. You could hear all the SpaceX employees gasp ... then the stream resumed and there was a massive bloom of light, which I think many thought was a crash, judging by the groans and questioning sounds. Then all of a sudden, BOOM (figuratively), the legs were there, almost DEAD CENTER of the SpaceX logo, and the cheers were deafening (including at our house!). AWESOME!

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  2. #902
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    Quote Originally Posted by Swift View Post
    Spaceflightnow.com has some images, but no video yet
    There is a link to the video that shows the launch and landing in the thread "no of launches in 2016"

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  3. #903
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    As far as this flight is concerned, they were coming in a bit fast. Again--this means more airflow through and around the grid fins--in the same way a large ship actually becomes more maneuverable at high speeds--to allow the rudder to have more to bite into.

    With landings on land--you want calm winds--and you have more room so the stage can drift a bit. On land, you can get a goodly amount of shear:

    http://www.afloat.com.au/images/maga...Wind-shear.jpg

    At sea, you may not want the winds too calm--or the stage can wander away from the limited surface area of the barge.

    You want to be gripped in the flow--and plant--like a good linebacker. The winds were a bit lighter--but the stage came down faster--so good airflow over the grid fins again.


    The new claim of heavier payloads:
    http://nextbigfuture.com/2016/05/spa...h-payload.html

    I have to quibble with the 73% figure. Weren't they already advertising 40-53 tons anyway? Merlin engine toughness or no.

    I would think the non-landing Falcon Heavy Cores would have had the 22,800 kg (50,265 lb) into low earth orbit payloads--and that the weight penalty of landing gear and such would have pushed payloads DOWN to the old data at 13,150 kg (28,990 lb) to LEO.

    What gives?

    Quote Originally Posted by bknight View Post

    So again I ask if cleaning any residuals would be in the cleaning procedure.
    I imagine so. Got to be careful with rags:

    "In the case of the Ariane 44L with the blocked water line, it’s clear that the launch organization failed to implement the type of “sponge count” procedures that had been the norm for US launches for some time. The sponge count was inspired both by earlier failures and by surgical procedures that are designed to ensure that no tools or sponges are left inside the patient."

    http://www.thespacereview.com/article/1768/2
    Last edited by publiusr; 2016-May-06 at 09:15 PM.

  4. #904
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    Quote Originally Posted by publiusr View Post
    As far as this flight is concerned, they were coming in a bit fast. Again--this means more airflow through and around the grid fins--in the same way a large ship actually becomes more maneuverable at high speeds--to allow the rudder to have more to bite into.

    With landings on land--you want calm winds--and you have more room so the stage can drift a bit. On land, you can get a goodly amount of shear:

    http://www.afloat.com.au/images/maga...Wind-shear.jpg

    At sea, you may not want the winds too calm--or the stage can wander away from the limited surface area of the barge.

    You want to be gripped in the flow--and plant--like a good linebacker. The winds were a bit lighter--but the stage came down faster--so good airflow over the grid fins again.


    The new claim of heavier payloads:
    http://nextbigfuture.com/2016/05/spa...h-payload.html

    I have to quibble with the 73% figure. Weren't they already advertising 40-53 tons anyway? Merlin engine toughness or no.

    I would think the non-landing Falcon Heavy Cores would have had the 22,800 kg (50,265 lb) into low earth orbit payloads--and that the weight penalty of landing gear and such would have pushed payloads DOWN to the old data at 13,150 kg (28,990 lb) to LEO.

    What gives?



    I imagine so. Got to be careful with rags:

    "In the case of the Ariane 44L with the blocked water line, it’s clear that the launch organization failed to implement the type of “sponge count” procedures that had been the norm for US launches for some time. The sponge count was inspired both by earlier failures and by surgical procedures that are designed to ensure that no tools or sponges are left inside the patient."

    http://www.thespacereview.com/article/1768/2
    There's nothing wind shear is going to do that will improve grid fin function. The only thing it's going to do is cause shifts in attitude that the grid fins and engine(s) need to correct. The higher descent speed will give them more authority, but the Grasshopper tests demonstrated control at low airspeeds with and without the grid fins.

    The reasons for the landing failures were very clear: grid fin failure due to them running out of hydraulic fluid, loss of control due to a sticky throttle valve, an otherwise-perfect landing in which a leg didn't latch, and an experimental high-speed, low-margin landing attempt in which the rocket simply ran out of propellant. Inadequate grid fin control has not been a problem.

    The 73% increase is for the Falcon 9. It had a max payload of 13150 kg to LEO, after the upgrades it can lift 22800 kg to LEO. The 53 ton figure is for the Falcon Heavy, now without cross-feed but with effectively the same payload that previously required cross-feed. I don't know what you're trying to say about "non-landing Falcon Heavy Cores".

    The Merlins do multiple burns in rapid succession during launch, test burns on the pad prior to launch, etc. without cleaning. It's possible that the engines are simply plumbed to avoid exposing RP-1 to the problematic temperature ranges that cause coking.

  5. #905
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    A couple of views of the landing:
    https://www.youtube.com/watch?v=LHqLz9ni0Bo

    A lot of post landing flames, Including the green sputters of TEB.
    I wonder how much of these flames have the potential to enter the octaweb engine compartments and what that could do to plumbing and control gear.
    There must be a lot of (hot) airstream going the opposite way to what usually happens to rockets...

  6. #906
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    Teb?
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  7. #907
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    Quote Originally Posted by Trebuchet View Post
    Teb?
    TEA+TEB, Treb.

    Triethylaluminum + Triethylborane

    The SpaceX Falcon 9 heavy-lift rocket also uses a triethylaluminium-triethylborane mixture as a first and second stage ignitor.
    [...]
    Triethylborane is strongly pyrophoric, igniting spontaneously in air, burning with an apple-green flame characteristic for boron compounds.
    0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...
    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

  8. #908
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    Quote Originally Posted by baskerbosse View Post
    A lot of post landing flames, Including the green sputters of TEB.
    The green sputters of TEB were a bit of a surprise. I wonder if they're using it to maintain combustion stability at very low throttle settings, or if the burn was just short enough that there was still some left in the lines.


    Quote Originally Posted by baskerbosse View Post
    I wonder how much of these flames have the potential to enter the octaweb engine compartments and what that could do to plumbing and control gear.
    There must be a lot of (hot) airstream going the opposite way to what usually happens to rockets...
    There's been residual flames after every test fire, abort, and landing. I doubt the bottom side of the rocket is excessively flammable.

  9. #909
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    Quote Originally Posted by cjameshuff View Post
    The green sputters of TEB were a bit of a surprise. I wonder if they're using it to maintain combustion stability at very low throttle settings, or if the burn was just short enough that there was still some left in the lines.




    There's been residual flames after every test fire, abort, and landing. I doubt the bottom side of the rocket is excessively flammable.
    I think the TEA-TEB is for engine restart only, but you don't want any left when you transport the stage (being pyrophoric, slightest leak might set stuff on fire), so perhaps they are clearing leftovers out as part of post landing safing?
    I remember last recovery, they actually ran the engines a few seconds on dockside with similar green sputters!

    The residual orange flames seem quite a bit more and of longer duration this time. Perhaps a bit of a leak? (Also this time they deployed oil booms around the barge once they got to the harbour)
    While the engines are designed to take some heat, it's probably not desirable to have them on fire for any extended period of time. :-)
    At about 30:55 in the broadcast, you can even see a bit of solid material on fire falling:
    https://www.youtube.com/watch?v=L0bMeDj76ig

  10. #910
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    Quote Originally Posted by 01101001 View Post
    Thank you for today's learning experience! I always feel better if I've had one.

    ETA: My, that sounds like nasty stuff. Useful, but nasty.
    Last edited by Trebuchet; 2016-May-11 at 02:46 AM.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  11. #911
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    SpaceX's Dragon cargo ship returned to Earth on Wednesday after a one-month journey to the International Space Station, U.S. space agency NASA said.

    http://news.xinhuanet.com/english/20..._135351979.htm

    The unmanned spacecraft was released from the orbiting lab at 9:19 a.m. EDT (1319 GMT) and splashed down in the Pacific Ocean at 2:51 p.m. EDT (1851 GMT) about 261 miles (420 kilometers) southwest of Long Beach, California, where a recovery team will retrieve it.

    More than 3,700 pounds (1,700 kilograms) of cargo, science and technology demonstration samples were brought back from the space station, including research in the burgeoning field of nanotechnology.

  12. #912
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    Perhaps another reusable?

  13. #913
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    Quote Originally Posted by bknight View Post
    Perhaps another reusable?
    I think the plan is to reuse Dragons once they begin landing on terra firma.
    Salt water is nasty stuff.
    I may have many faults, but being wrong ain't one of them. - Jimmy Hoffa

  14. #914
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    Quote Originally Posted by Trebuchet View Post
    Thank you for today's learning experience! I always feel better if I've had one.

    ETA: My, that sounds like nasty stuff. Useful, but nasty.
    Boron fuels have an interesting history
    https://warisboring.com/the-strange-...947#.u5656lloq

    Also nasty: http://up-ship.com/blog/?p=22309

    dicyanoacetylene/FOOF rockets--if a nozzle could withstand it--might be the ultimate in chemical rocketry. http://up-ship.com/blog/?p=29498

    Then too:

    I wonder if this may pan out: http://nextbigfuture.com/2015/02/con...gh-energy.html

    I seem to remember the term "chemonuclear." Maybe a lithium based option: https://forum.nasaspaceflight.com/in...?topic=39844.0
    Last edited by publiusr; 2016-May-14 at 08:41 PM.

  15. #915
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    Quote Originally Posted by baskerbosse View Post
    A couple of views of the landing:
    https://www.youtube.com/watch?v=LHqLz9ni0Bo

    A lot of post landing flames, Including the green sputters of TEB.
    I wonder how much of these flames have the potential to enter the octaweb engine compartments and what that could do to plumbing and control gear.
    There must be a lot of (hot) airstream going the opposite way to what usually happens to rockets...
    According to a tweet by Elon Musk, the "(m)ost recent rocket took max damage, due to v high entry velocity." So that one will not be returning to space. http://www.floridatoday.com/story/te...mage/84454230/

  16. #916
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    So it was the burning through the atmosphere during free fall that killed it for further use? Well, at least it's a good benchmark and a demonstration that their landing principle can bring back a Falcon no matter how challenging the launch profile. The outer shell does look pretty overcooked in pictures, and possibly even torn open. Not because of the landing loads itself though, that appeared to be perfectly smooth.
    Last edited by Nicolas; 2016-May-18 at 08:36 AM.

  17. #917
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    The outer surface looks nicer to me than it did on the very first landing. I see a dirty but intact and smooth paint surface, whereas the first landed booster had bubbling and chipped paint showing bare metal in places. Compared to the two previous boosters the most obvious extra wear are the thermal blankets between the engines and the bottom body of the rocket. At least one was ripped, and the others were missing altogether. It's hard to say how much that means. For all we know that can be fixed by attaching them more strongly.

    The outer shell is the tank wall - if it was torn open, the rocket would have disintegrated. It's actually how the flight termination system works.

  18. #918
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    Quote Originally Posted by Nicolas View Post
    So it was the burning through the atmosphere during free fall that killed it for further use? Well, at least it's a good benchmark and a demonstration that their landing principle can bring back a Falcon no matter how challenging the launch profile. The outer shell does look pretty overcooked in pictures, and possibly even torn open. Not because of the landing loads itself though, that appeared to be perfectly smooth.
    As Elukka said, the outer shell is the skin of the tanks and the main structure of the vehicle. If there were tears in it, the stage wouldn't have been able to stand or be transported (which requires pressurization), let alone navigate to the ASDS while flying at supersonic airspeeds and perform a three-engine landing burn.

    The stage was basically intact. Assuming nothing was internally overstressed, it looks like the grid fins were the most damaged part (with a couple grid segments actually missing), and the interstage needs a new paint job. Some access panels seem to have popped off the base and probably provided the exit holes for the missing blankets, so there's probably a lot of soot blown into the base and damaged fasteners, but that landing just wouldn't have been possible if there was any damage to the engines serious enough to affect performance.

    Still, that landing was just at the vehicle's limits. That thing's a goldmine of information about what they're going to be able to do with these stages, how long they can expect various parts to work reliably, what they need to improve, etc.

  19. #919
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    Quote Originally Posted by Nicolas View Post
    So it was the burning through the atmosphere during free fall that killed it for further use? Well, at least it's a good benchmark and a demonstration that their landing principle can bring back a Falcon no matter how challenging the launch profile. The outer shell does look pretty overcooked in pictures, and possibly even torn open. Not because of the landing loads itself though, that appeared to be perfectly smooth.
    It looks like that's the case. SpaceX says that the booster experienced 5 times more heating than previous boosters during reentry. It was traveling about 30% faster.

  20. #920
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    I saw what looked like tears at 15 seconds in this video: http://www.floridatoday.com/story/te...nter/84382744/

    But as Falcon 9 first stage has no space in between the LOX and fuel tank (shared bulkhead), any tear visible on the outside would indeed mean a ruptured tank and loss of vehicle. So what is seen there must be only in/on the paint, like paint cracks or smoke marks.

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  22. #922
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    SpaceX postpones rocket launch after 'tiny glitch'

    http://www.spacedaily.com/reports/Sp...litch_999.html

    SpaceX on Thursday postponed the launch of an Asian communications satellite after detecting a "tiny glitch" in the Falcon 9 rocket engine, CEO Elon Musk said.

    "There was a tiny glitch in the motion of an upper stage engine actuator," Musk said on Twitter.

    "Probably not a flight risk but still worth investigating."

    The next attempt at launching from Cape Canaveral, Florida will be Friday at the earliest, the head of the California-based company said without specifying a time.

    The missions aims to propel the Thaicom 8 satellite to a distant orbit some 22,250 miles (35,800 kilometers) from Earth.

  23. #923
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    Good launch and successful landing of the first stage.

  24. #924
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    Launched and Landed! Again!

    The webcast did encounter a bug with about one minute to go for launch. Specifically, a wasp crawled across the lens!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  25. #925
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    Well done!

    It kind of looked like S2 fired pretty much exactly above 0,0. Wonder if that was intentional...


  26. #926
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    Quote Originally Posted by Trebuchet View Post
    Launched and Landed! Again!

    The webcast did encounter a bug with about one minute to go for launch. Specifically, a wasp crawled across the lens!
    I saw that bugger, probably looking for a nesting site.

  27. #927
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    There was some kind of material on the drone ship after the stage landed.... laying besides and between the legs. Does anyone know what that was? Also the 'rain' that you see at some points in space around the second stage... Is that pre chill oxygen used just before the re-ignition?


    Sent from my iPad using Tapatalk

  28. #928
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    Not a fluke--they've got all the problems figured out now.

  29. #929
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    Quote Originally Posted by WalrusLike View Post
    There was some kind of material on the drone ship after the stage landed.... laying besides and between the legs. Does anyone know what that was?
    Link for what you saw? I watched videos from the barge camera and the 1st-stage camera and didn't see anything as described. The was some white material, maybe insulation-wrapped intrument or pipe, at the bottom of the barge-camera video, but it was there before the landing, and much closer to the camera.
    0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 1 0 0 1 0 1 1 0 1 0 0 1 1 0 0 1 0 1 1 0 ...
    Skepticism enables us to distinguish fancy from fact, to test our speculations. --Carl Sagan

  30. #930
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    Sorry. Thanks for looking...

    https://youtu.be/zBYC4f79iXc

    30 min 15 seconds in.

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