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Thread: SpaceX

  1. #4771
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    Quote Originally Posted by DavidLondon View Post
    Thanks Van Rijn. Starship/New Glenn scale is more important. But there still may be a sub-orbital market.

    It is clear that SpaceX is ahead of the competition at the moment. And does seem to be benefitting from first mover advantage - as shown by it earning money sending astronauts to the ISS and the recent lunar lander decision. But, in a dynamic, innovating market like this, second movers can benefit from sometimes expensive learning lessons learnt by first movers and, given a longer term perspective, can catch up over time. Schumpeterian economics can probably help us here - some of the concepts were explored in my Post 29 of the Emerging Space Economy thread.

    On rocket technology, 3 questions come to mind.
    - How far is SpaceX ahead of the competition?
    - How well resourced are its nearest competitors? (including Blue Origin and Chinese based companies)
    - How easily can these competitors replicate the SpaceX successes over time?
    Stainless steel metallurgy is about 200 years old, amateurs on shoestring budgets were vertically landing rockets 20 years ago, and Bezos has a bottomless wallet, while China has nearly a fifth of the world GDP. And it's going to be extraordinarily difficult for either of them to replicate SpaceX's successes. There's no key new technological development enabling SpaceX, it's a matter of company culture and management. Willingness to experiment, to break things and learn, a habit of looking at things from base principles instead of from tradition and accepted wisdom, and some very effective application of modern tools and lessons learned from the software industry to managing large, complex projects.

  2. #4772
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    Quote Originally Posted by DavidLondon View Post
    >

    On rocket technology, 3 questions come to mind.

    - How far is SpaceX ahead of the competition?
    In terms of F9 style stage landings, at least 5 years. No one is working on a reusable Starship class vehicle. Expendable, yes - Long March 9.

    - How well resourced are its nearest competitors? (including Blue Origin and Chinese based companies)
    No one has the resources available to SpaceX except China or the DoD. First, their access to venture capital. If they do a funding round it's always over-subscribed, with funds competing for shares. Once StarLink goes live, the revenue estimates run $10-30 billion/year.

    - How easily can these competitors replicate the SpaceX successes over time?
    The problem with replicating Spacex is that they're a rapidly moving target. By the time ArianeSpace builds an F9 semi-reusable clone in 2028-2030 SpaceX will have moved on from the 9 meter fully reusable Starship.

  3. #4773
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    Quote Originally Posted by docmordrid View Post
    The problem with replicating Spacex is that they're a rapidly moving target. By the time ArianeSpace builds an F9 semi-reusable clone in 2028-2030 SpaceX will have moved on from the 9 meter fully reusable Starship.
    And even if they aim for a Starship equivalent, they're going to need a crash program...complete with crashes...to catch up. That's culturally unacceptable for the older government contractors in the US (which Blue Origin has largely imported their culture from), or for the Chinese or ESA.

  4. #4774
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    Crew Dragon Crew-2

    Date: April 22, 2021
    Time: 0611 Eastern (10:11 UT)
    Pad: LC-39A
    Booster: B1061.2 (Crew-1)
    Booster recovery: yes
    Spacecraft: C206.2 Endeavour (DM-1)

    Crew
    Commander: Shane Kimbrough (NASA)
    Pilot: K. Megan McArthur (NASA)
    Mission Specialist 1: Akihiko Hoshide (JAXA)
    Mission Specialist 2: Thomas Pesquet (ESA)

    NASA webcast
    https://youtu.be/WeIVJyufJrE

    Mission patch
    1618800726071.jpg

  5. #4775
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    Nuts. Too dang early in the morning here on the west coast!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  6. #4776
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    Quote Originally Posted by Trebuchet View Post
    Nuts. Too dang early in the morning here on the west coast!
    Too dang early here in EDT as far as I'm concerned.
    At night the stars put on a show for free (Carole King)

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  7. #4777
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    Quote Originally Posted by Swift View Post
    Too dang early here in EDT as far as I'm concerned.
    Replays are wonderful, and you KNOW what happened.

  8. #4778
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    A Liebherr LR11350 will be used to build the Starship orbital pad's massive integration tower. BIG SOB.

    https://youtu.be/MvCoJuZK7K4

  9. #4779
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    Quote Originally Posted by docmordrid View Post
    A Liebherr LR11350 will be used to build the Starship orbital pad's massive integration tower. BIG SOB.

    https://youtu.be/MvCoJuZK7K4
    Why so sad?

  10. #4780
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    Quote Originally Posted by bknight View Post
    Why so sad?
    SOB doesn't mean to cry. Short for "son of a b****"

  11. #4781
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    Quote Originally Posted by docmordrid View Post
    SOB doesn't mean to cry. Short for "son of a b****"
    Ok, then why the SOB?

  12. #4782
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    Dontcha wish you'd purchased the United Rentals franchise for Brownsville three or four years ago?
    I've taken to counting cranes per scene in NSF videos. Gotten as many as seven in a single scene.
    And that big crane currently being assembled inspired me to look up its owner, Fagioli. The stuff they're moving for SpaceX is pretty small potatoes compared to some of their other jobs. Same goes for the owner of "Tankzilla", Roll-Lift. Also a Liebherr.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  13. #4783
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    The last huge Liebherr unit I was involved with, had a small whoopsie... Not Liebherr's fault; the crane hook which was made by another company broke.

    https://www.youtube.com/watch?v=xYu0f57XAz0
    Last edited by Nicolas; 2021-Apr-20 at 09:25 PM.
    With sufficient thrust, water towers fly just fine.

  14. #4784
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    Wow. Those cranes at SpaceX aren't so big after all!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  15. #4785
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    When I first read the specs and saw a 400 ton main hook, I thought that was its lifting capacity. It's not. It's the weight of the main hook (including sheave block). took a few months to cool after casting. The crane lifts 5000 tons with its main hook, precisely. And that is the key word: precisely. There are many A frame heavy lift cranes of similar capacity, but they are brute force up/down stuff. This crane however, can lift 5000 tons and move/rotate it with extreme precision.

    I worked with the training simulator of this crane. The difference between me -total amateur at lift jobs- and the best operators when attempting to do the same thing is amazing. They are so much better, also on simulator without any practice.

    By the way, respect for Liebherr for not deleting this video, disabling the comments or even changing the title after the "event".
    https://www.youtube.com/watch?v=5HiaP90HW2U

    Short summary of how it failed: during a lift, the ship is dynamically balasted to stay on even keel under the lifted load. When the hook broke, the ship suddenly lost a 2600 ton force on one side, causing it to tilt to the other side. This caused the crane boom to tilt over vertical, at which point it fell backwards onto its own A frame and broke on impact. So the boom didn't "whiplash" backwards when the hook broke (the boom would have to bend a lot under load for that to happen); it was due to the ship overtilting.
    Last edited by Nicolas; 2021-Apr-20 at 09:35 PM.
    With sufficient thrust, water towers fly just fine.

  16. #4786
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    Quote Originally Posted by Nicolas View Post
    By the way, respect for Liebherr for not deleting this video, disabling the comments or even changing the title after the "event".
    https://www.youtube.com/watch?v=5HiaP90HW2U
    Did you link the correct video? This one doesn't seem to match your description.

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  17. #4787
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    The right video. It's titled "Liebherr - The lift that writes port history in Rostock". A few weeks later it would write more Rostock port history than they wanted, with the crane completely collapsing.
    With sufficient thrust, water towers fly just fine.

  18. #4788
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    Quote Originally Posted by Nicolas View Post
    The right video. It's titled "Liebherr - The lift that writes port history in Rostock". A few weeks later it would write more Rostock port history than they wanted, with the crane completely collapsing.
    Ah, that was needed context, I too had no idea what this was to show.

    This short video should be watched first (the collapse):

    https://www.youtube.com/watch?v=7AlI1myzpK4

    This discusses it more and has another short video showing another view:

    https://gcaptain.com/liebherr-addres...se-in-rostock/

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  19. #4789
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    Crew-2

    Scrubbed: downrange weather

    Date: April 23 (Friday)
    Time: 0549 Eastern

    https://twitter.com/Commercial_Crew/...32941172289536

  20. #4790
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    Quote Originally Posted by docmordrid View Post
    Crew-2

    Scrubbed: downrange weather

    Date: April 23 (Friday)
    Time: 0549 Eastern

    https://twitter.com/Commercial_Crew/...32941172289536
    Even worse time!!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  21. #4791
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    Quote Originally Posted by Trebuchet View Post
    Even worse time!!
    LOL, check the replay!!

  22. #4792
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    Sounds like a new toy for US Special Operations Command

    DoD: Man-Portable Starlink System

    https://rt.cto.mil/wp-content/upload..._SBIR_FULL.pdf

    SOCOM212-001

    TITLE: Man-Portable Starlink System

    RT&L FOCUS AREA(S): Microelectronics; Network Command, Control and Communications

    TECHNOLOGY AREA(S): Electronics; Information Systems; Materials; Space Platform The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

    OBJECTIVE: The objective of this topic is to develop applied research toward an innovative capability to develop a small form factor system that enables reliable access to the Starlink commercial internet system.

    DESCRIPTION: As a part of this feasibility study, the proposers shall address all viable overall system design options with respective specifications on the key system attributes. The current commercial Starlink system uses a 1m dish and requires significant amounts of power to operate. The key system attributes for the desired system are that it must be man portable and battery powered. The system should be designed to be as small as possible while providing enough link margin to achieve reliable internet connection over the Starlink constellation. The antenna and modem need to be miniaturized along with being integrated with a small commercial off the shelf Software Defined Radio (e.g. Epiq Z2) for the RF link.

    PHASE I: Conduct a feasibility study to assess what is in the art of the possible that satisfies the requirements specified in the above paragraphs entitled “Objective” and “Description.” The objective of this USSOCOM Phase I SBIR effort is to conduct and document the results of a thorough feasibility study (Technology Readiness Level 3”) to investigate what is in the art of the possible within the given trade space that will satisfy a needed technology. The feasibility study should investigate all options that meet or exceed the minimum performance parameters specified in this write up. It should also address the risks and potential payoffs of the innovative technology options that are investigated and recommend the option that best achieves the objective of this technology pursuit. The funds obligated on the resulting Phase I SBIR contracts are to be used for the sole purpose of conducting a thorough feasibility study using scientific experiments and laboratory studies as necessary. Operational prototypes will not be developed with USSOCOM SBIR funds during Phase I feasibility studies. Operational prototypes developed with other than SBIR funds that are provided at the end of Phase I feasibility studies will not be considered in deciding what firm(s) will be selected for Phase II.

    PHASE II: Develop, install, and demonstrate a prototype system determined to be the most feasible solution during the Phase I feasibility study on a man portable Starlink system.

    PHASE III DUAL USE APPLICATIONS: This system could be used in a broad range of military applications where the need for a man portable Starlink system is required for operation of a communication or data exfiltration system.
    >
    Last edited by docmordrid; 2021-Apr-22 at 01:14 AM.

  23. #4793
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    Crew Dragon Crew-2

    Date: April 23 (Friday)
    Joint NASA/SpaceX webcast begins: 0130 Eastern
    Time:**0549 Eastern (0949 UT)

    https://youtu.be/lW07SN3YoLI

  24. #4794
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    Quote Originally Posted by docmordrid View Post
    Crew Dragon Crew-2

    Date: April 23 (Friday)
    Joint NASA/SpaceX webcast begins: 0130 Eastern
    Time:**0549 Eastern (0949 UT)

    https://youtu.be/lW07SN3YoLI
    Nice replay. I don have a question about the entry and landing burns. What is the approximate throttle of each?

  25. #4795
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    Quote Originally Posted by bknight View Post
    Nice replay. I don have a question about the entry and landing burns. What is the approximate throttle of each?
    Generally full throttle. It's about changing velocity, which has gravity and time components. The longer you are fighting gravity the more propellants you use due to "gravity losses." Solution; make your velocity change as quickly as possible - pretty much stand on the brakes. The payload mass & trajectory determines the exact method.

    The entry burn is always 3 engines at full bore.

    For landings the idea is to hit 0 m/s just as it touches the pad or droneship, a "hover-slam," then cut the engine. Merlin's high thrust to weight ratio creates a problem; if you stop too soon the booster goes back up, even at low throttle. Oops.

    For higher energy trajectories, such as a Falcon Heavy center core or big commsat launch, they do a "super-slam" landing; stand on the brakes with 3 engines first, then land on 1 engine.
    Last edited by docmordrid; 2021-Apr-23 at 04:18 PM.

  26. #4796
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    Quote Originally Posted by docmordrid View Post
    Generally full throttle. It's about changing velocity, which has gravity ant time components. The longer you are fighting gravity the more propellants you use due to "gravity losses." Solution; make your velocity change as quickly as possible - pretty much stand on the brakes. The payload mass & trajectory determines the exact method.

    The entry burn is always 3 engines at full bore.

    For landings the idea is to hit 0 m/s just as it touches the pad or droneship, a "hover-slam," then cut the engine. Merlin's high thrust to weight ratio creates a problem; if you stop too soon the booster goes back up, even at low throttle. Oops.

    For higher energy trajectories, such as a Falcon Heavy center core or big commsat launch, they do a "super-slam" landing; stand on the brakes with 3 engines first, then land on 1 engine.
    Tanks

  27. #4797
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    It's interestingly different to Blue Origin's approach. They do a full hover than slowly touch down. Possibly related to throttleability of the engines.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  28. #4798
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    Quote Originally Posted by bknight View Post
    Nice replay. I don have a question about the entry and landing burns. What is the approximate throttle of each?
    For the reentry burn, a higher throttle means decelerating at higher altitude and then accelerating more post-burn, a lower throttle means getting lower at high speed during the burn, but a lower altitude at end of burn and lower peak airspeed after the burn. Their grid fins seem to take the worst heating several seconds after the burn, and it seems like they'd try to reduce that. However, they also do the burn with 3 engines, so maybe they have some other reason to use higher thrust during the burn. (Exhaust heating from the burn itself being lower at higher altitude, maybe?)

    For the landing burn, they want to reach 0 vertical velocity at 0 altitude. At the start of the landing burn, they want max thrust to keep gravity losses down (and like docmordrid said, they can start up 3 engines for the first part of the burn, though I think this may have become the standard landing approach now, rather than something they only do for high-energy missions), but I expect they try to keep the throttle somewhere in the middle of its range at the end of the landing. Maybe not precisely half-throttle, but with room in either direction to adjust for error. If they came in full-throttle or minimum-throttle, they'd have zero margin to adjust for coming in faster or slower than expected.

  29. #4799
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    Quote Originally Posted by Trebuchet View Post
    It's interestingly different to Blue Origin's approach. They do a full hover than slowly touch down. Possibly related to throttleability of the engines.
    The Falcon 9 booster lacks the throttle range to hover, but there's really nothing to gain from hanging around in the air just above the ground. A human-piloted vehicle might need to do that because of its pilot's very limited reaction speeds and inability to quickly and precisely judge distances, but under computer control, there's nothing to gain. The vehicle's going to need to approach the ground at non-zero velocity anyway in order to land, stopping and resuming descent just complicates the descent.

    Notice that even New Shepard, at least on its latest flights, doesn't actually hover during landing, it just descends more slowly. (And that slower descent doesn't seem to help its landing accuracy.)

  30. #4800
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    Quote Originally Posted by Trebuchet View Post
    It's interestingly different to Blue Origin's approach. They do a full hover than slowly touch down. Possibly related to throttleability of the engines.
    Probably a bigger difference is that F9 is an orbital class booster. The engines are designed to that end which means a much higher propellants / vehicle+payload ratio, which means the difference between take-off and landing mass is larger with F9 than with New Shepard.

    The following Falcon 9 numbers are from Spaceflight Insider. 1st stage empty mass 25,600 kg. Gross F9 launch mass for a max LEO launch adds up to about 540,670 kg. I don't know how much fuel an F9 1st stage has left, on average, prior to the landing burn, but for ballparking it I'll assume it's close enough to empty. That's a ratio of 540,670/25,600 or, rounding down, 21.

    The only number I could find for New Shepard, from Astronautix, aren't very detailed and I don't know if they are reliable. They say gross mass is 75,000 kg, which I assume means booster+capsule+fuel, i.e. launch mass. They say unfueled mass is 20,569 kg, and I've no idea if that's the booster+capsule or just the booster. Using these numbers gives a ratio of 3.65.

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