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Thread: SpaceX

  1. #4921
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    Quote Originally Posted by Trebuchet View Post
    Things that bug me: Calling it "Starship". It's never going to another star. Some descendant of the current object MIGHT get to another planet. At best, it's a "Planetship". The current generation is, of course, a 10kmship.
    Well It is called Starship, not Starsship. So technically correct.

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    With sufficient thrust, water towers fly just fine.

  2. #4922
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    And they've hit the magic 10 with the latest Falcon 9 launch, congrats!

    Here's a question though, do you think Musk and SpaceX will stop at Starship or will they look to carry on to something more advanced, maybe assembled in orbit, maybe nuclear propulsion?

  3. #4923
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    Quote Originally Posted by Trebuchet View Post
    Things that bug me: Calling it "Starship". It's never going to another star. Some descendant of the current object MIGHT get to another planet. At best, it's a "Planetship". The current generation is, of course, a 10kmship.
    And the Boeing Starliner not only isn't used for star travel, it's not a liner. And the Beechcraft Starship never even leaves the atmosphere. And the Ford Starliner never even leaves the ground.

    It's a name, not a description.

  4. #4924
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    Quote Originally Posted by cjameshuff View Post
    And the Boeing Starliner not only isn't used for star travel, it's not a liner. And the Beechcraft Starship never even leaves the atmosphere. And the Ford Starliner never even leaves the ground.

    It's a name, not a description.
    The Eurostar travels through a black hole, maybe that counts?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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  5. #4925
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    Quote Originally Posted by Garrison View Post
    And they've hit the magic 10 with the latest Falcon 9 launch, congrats!

    Here's a question though, do you think Musk and SpaceX will stop at Starship or will they look to carry on to something more advanced, maybe assembled in orbit, maybe nuclear propulsion?
    I very highly doubt they'll pursue either of those. Braking into orbit requires about double the delta-v compared to direct entry and landing. NTR gives you...about double the delta-v. It's possible a NTR craft would actually be limited to a higher-efficiency trajectory, with methalox Starships getting to Mars in less time. A NEP system, on the other hand, barely has time to start being effective on a Mars transit, and solar-electric systems will give better performance for less mass at least out to Mars.

    Either way, you'd then have to shuttle people and materials between the craft and the surface with conventional vehicles, and perform all maintenance in orbit. That's a bunch of Mars launches, orbital rendezvous/transfer operations, and tedious microgravity work on a now-radioactive nuclear power system, compared to just landing and unloading a vehicle on the ground.

    And then there's cost...SpaceX's goal is for Raptors to cost less than $250k each to build. The structure is stainless steel. You could probably build and launch a fleet of Starships for the cost of one nuclear super-ship.

    Nuclear propulsion and orbital mega-craft just don't have many benefits for Mars, they're better suited to other destinations where most of the drawbacks are things that exist anyway...asteroids and moons (except Titan) have no atmospheres for braking, so entering orbit has no additional cost. Where nuclear power might make sense for Mars is powering propellant production and other industry on the surface.

  6. #4926
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    Congratulations on another launch landing of a Falcon 9.

  7. #4927
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    Quote Originally Posted by cjameshuff View Post
    I very highly doubt they'll pursue either of those. Braking into orbit requires about double the delta-v compared to direct entry and landing. NTR gives you...about double the delta-v. It's possible a NTR craft would actually be limited to a higher-efficiency trajectory, with methalox Starships getting to Mars in less time.
    >
    Nuclear propulsion and orbital mega-craft just don't have many benefits for Mars, they're better suited to other destinations where most of the drawbacks are things that exist anyway...asteroids and moons (except Titan) have no atmospheres for braking, so entering orbit has no additional cost. Where nuclear power might make sense for Mars is powering propellant production and other industry on the surface.
    DoD/DARPA's DRACO program is targeting an NTR demonstration mission by 2025, the goal being propulsion modules for reducing the response time of cislunar vehicles. With Starship likely doing cislunar via NASA, Sierra Space (a spinoff of Sierra Nevada Corp) being contracted for cislunar "outposts" for DoD, and DARPA itself picking Lockheed-Martin and Blue Origin to develop a testbed vehicle, the odds of the US deploying NTR lunar missions look high.

    A Starship HLS with fractional-size CH4/LOX tanks, an NTR prop tank, and NTR modules in place of the Raptor Vacuum engines?

  8. #4928
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    ASDS A Shortfall of Gravitas

    https://spacexfleet.com/where-is-a-s...itas-droneship

    News has been circulating around Twitter over the last 24 hours regarding SpaceX’s new droneship, A Shortfall of Gravitas being discovered in Louisiana. What we can tell you is that the barge that is expected to be converted into ASOG – Marmac 302 – is indeed at Port Fourchon, Louisiana, where we have been quietly tracking it.
    And, Octagrabber #3 is being built in Florida,

    https://twitter.com/SpaceXFleet/stat...07651814047744

  9. #4929
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    Quote Originally Posted by docmordrid View Post
    DoD/DARPA's DRACO program is targeting an NTR demonstration mission by 2025, the goal being propulsion modules for reducing the response time of cislunar vehicles. With Starship likely doing cislunar via NASA, Sierra Space (a spinoff of Sierra Nevada Corp) being contracted for cislunar "outposts" for DoD, and DARPA itself picking Lockheed-Martin and Blue Origin to develop a testbed vehicle, the odds of the US deploying NTR lunar missions look high.

    A Starship HLS with fractional-size CH4/LOX tanks, an NTR prop tank, and NTR modules in place of the Raptor Vacuum engines?
    NTRs are heavy and essentially only useful with liquid hydrogen propellant, or you don't even get that doubling of delta-v. A NTR LH2 tank isn't something you just stuff into a Starship somewhere...Starship already has a fairly high dry mass and its tanks are sized for dense propellants, the propellant mass ratio of the resulting vehicle would be awful. You're more likely to see something like a modified New Glenn upper stage.

  10. #4930
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    Quote Originally Posted by docmordrid View Post
    DoD/DARPA's DRACO program is targeting an NTR demonstration mission by 2025, the goal being propulsion modules for reducing the response time of cislunar vehicles.
    Why is that even needed? It doesn’t take very long to get to the Moon with a chemical rocket if you plan it right.

    With Starship likely doing cislunar via NASA, Sierra Space (a spinoff of Sierra Nevada Corp) being contracted for cislunar "outposts" for DoD, and DARPA itself picking Lockheed-Martin and Blue Origin to develop a testbed vehicle, the odds of the US deploying NTR lunar missions look high.
    Unless someone shows a strong need, which isn’t obvious to me, I doubt it. Anti-nukes would really get upset with nuclear rockets going between the Earth and Moon.

    NTR makes more sense for interplanetary flights where the delta-v advantage could really be useful.

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  11. #4931
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    Quote Originally Posted by Van Rijn View Post
    Why is that even needed? It doesn’t take very long to get to the Moon with a chemical rocket if you plan it right.



    Unless someone shows a strong need, which isn’t obvious to me, I doubt it. Anti-nukes would really get upset with nuclear rockets going between the Earth and Moon.

    NTR makes more sense for interplanetary flights where the delta-v advantage could really be useful.
    General Atomics got the contract...

    https://www.ga.com/general-atomics-a...-draco-mission

  12. #4932
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    Quote Originally Posted by docmordrid View Post
    General Atomics got the contract...

    https://www.ga.com/general-atomics-a...-draco-mission
    So? That doesn’t answer the question of why it is needed. I’ll believe a demonstration flight when I actually see it flying, and even if a demonstration flies, it would still be a big step to operational rockets. Mind you, I don’t mind seeing new work done on NTR, but I would expect it for interplanetary flights where it had a good advantage.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

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  13. #4933
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    StarLink 26

    Date: May 15, 2021
    Time: 1858 Eastern (2258 UT)
    Pad: LC-39A
    Booster: B1058.8
    Booster landing: ASDS Of Course I Still Love You
    Fairing recovery: MV Shelia Bordelon
    Recovery support: GO Quest

    The Capella 5&6 secondary payloads just got their license issues worked out and may move to StarLink 28.

  14. #4934
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    Quote Originally Posted by Van Rijn View Post
    Why is that even needed? It doesn’t take very long to get to the Moon with a chemical rocket if you plan it right.



    Unless someone shows a strong need, which isn’t obvious to me, I doubt it. Anti-nukes would really get upset with nuclear rockets going between the Earth and Moon.

    NTR makes more sense for interplanetary flights where the delta-v advantage could really be useful.
    Yeah, that part doesn't make much sense to me. Even Mars is really too close, and the atmosphere and direct EDL for chemically-propelled vehicles makes it hard for nuclear to compete. It seems best suited to asteroids and beyond...asteroids miners in particular might benefit from the simpler pointing requirements and relatively small size of high-temperature radiator arrays compared to solar arrays for power while working up close with their targets. The moon is close enough that response time is going to be dominated by mission planning and bureaucracy.

  15. #4935
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    Here's their thinking...

    https://www.darpa.mil/news-events/2021-04-12

    >
    Rapid maneuver is a core tenet of modern Department of Defense (DoD) operations on land, at sea, and in the air. However, rapid maneuver in the space domain has traditionally been challenging because current electric and chemical space propulsion systems have drawbacks in thrust-to-weight and propellent efficiency, respectively. DRACO’s NTP system has the potential to achieve high thrust-to-weight ratios similar to in-space chemical propulsion and approach the high propellent efficiency of electric systems. This combination would give a DRACO spacecraft greater agility to implement DoD’s core tenet of rapid maneuver in cislunar space (between the Earth and moon).

    “The performer teams have demonstrated capabilities to develop and deploy advanced reactor, propulsion, and spacecraft systems,” said Maj Nathan Greiner, USAF, program manager for DRACO. “The NTP technology we seek to develop and demonstrate under the DRACO program aims to be foundational to future operations in space.”
    >

  16. #4936
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    Quote Originally Posted by docmordrid View Post
    Rapid maneuver of what? You've got to launch the stuff, and that's going to account for most of the delay.

    And NTRs are not exactly agile. It takes a non-trivial amount of propellant to keep them from melting after a burn, careful spacing of sequential burns to safely operate the reactor as fission poisons build up/decay and its reactivity changes, and burns long enough that the startup and cooldown transients don't eat all your performance, plus the only propellant that makes sense is difficult to store for long periods. Missions with nuclear thermal rockets will be planned in great detail before they ever launch.

  17. #4937
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    Quote Originally Posted by docmordrid View Post
    Frankly, to me, it comes across as more of an excuse to work on NTR than anything realistic. It isn’t obvious to me what any other country could do in the foreseeable future that would require an NTR for response. Things might change in the late part of this century but when there is a concrete issue that would be time to evaluate options. For cislunar space I suspect uncrewed chemically propelled spacecraft, possibly left in orbit log term, would be a better option. Communication lag isn’t that bad, so some autonomous functions plus someone on Earth monitoring could get you rapid response without incredibly expensive hardware.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

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  18. #4938
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    Quote Originally Posted by cjameshuff View Post
    Rapid maneuver of what? You've got to launch the stuff, and that's going to account for most of the delay.

    And NTRs are not exactly agile. It takes a non-trivial amount of propellant to keep them from melting after a burn, careful spacing of sequential burns to safely operate the reactor as fission poisons build up/decay and its reactivity changes, and burns long enough that the startup and cooldown transients don't eat all your performance, plus the only propellant that makes sense is difficult to store for long periods. Missions with nuclear thermal rockets will be planned in great detail before they ever launch.
    It may be better to think in terms of "fast transit between where and where?"

    DoD has contracted with Sierra Space (SNC spinoff) to adapt Dream Chaser's Shooting Star logistics module as the core of a free-flying "orbital outpost." Locations include medium-Earth orbit, highly elliptical orbit, geosynchronous (including transfer) and cis-lunar orbits. Other attachments are mentioned, as well as it being optionally crewed which implies Sierra's LIFE expandable habitat (nominally 300 m3).

    My impression is these are multipurpose. Initially flag-planting given China's stated intent to do likewise in cis-lunar space once their Orion-like vehicle goes live and they do a lunar landing. Another reason, given increased cis-lunar traffic, could be Search and Rescue (SAR) - a Space Guard function.

    https://www.sncorp.com/press-release...ost-prototype/

    2020 article
    https://www.thedrive.com/the-war-zon...-space-station

    2019 article
    https://breakingdefense.com/2019/07/...space-station/

    While the near-term requirements are obviously aimed at prototyping an autonomous, robotic mini-space station to house experimentation, the “future desired capabilities” listed in the solicitation are much farther reaching. They include the capability to dock with unmanned and manned spacecraft and, even more surprisingly, “human rating.”

    Human-rating is short-hand for a set of requirements developed by NASA and the Federal Aviation Authority (which licenses launch and re-entry of commercial spacecraft) to ensure the safety of astronauts aboard a spacecraft. These include things like special insulation to protect crew from extreme temperatures and radiation.

    Even though the concept may be a long shot in DoD thinking, the fact that DIU is even considering the idea of a military presence in orbit is a pretty big deal. The idea will no doubt will be controversial if significant funding starts pouring into exploring it.
    Last edited by docmordrid; 2021-May-11 at 05:05 AM.

  19. #4939
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    Quote Originally Posted by docmordrid View Post
    It may be better to think in terms of "fast transit between where and where?"

    DoD has contracted with Sierra Space (SNC spinoff) to adapt Dream Chaser's Shooting Star logistics module as the core of a free-flying "orbital outpost." Locations include medium-Earth orbit, highly elliptical orbit, geosynchronous (including transfer) and cis-lunar orbits. Other attachments are mentioned, as well as it being optionally crewed which implies Sierra's LIFE expandable habitat (nominally 300 m3).

    My impression is these are multipurpose. Initially flag-planting given China's stated intent to do likewise in cis-lunar space once their Orion-like vehicle goes live and they do a lunar landing. Another reason, given increased cis-lunar traffic, could be Search and Rescue (SAR) - a Space Guard function.

    https://www.sncorp.com/press-release...ost-prototype/

    2020 article
    https://www.thedrive.com/the-war-zon...-space-station

    2019 article
    https://breakingdefense.com/2019/07/...space-station/
    I see no reason to think this has anything to do with the NTR project. In fact, you'd have great difficulty combining the two due to the reactor shielding required. And so what if you have some stations...what exactly is it you're in such a hurry to move between them?

  20. #4940
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    Quote Originally Posted by cjameshuff View Post
    I see no reason to think this has anything to do with the NTR project. In fact, you'd have great difficulty combining the two due to the reactor shielding required. And so what if you have some stations...what exactly is it you're in such a hurry to move between them?
    The emissions from a reactor are not an insurmountable problem. If they're designing a reactor which can be shut down after a "burn" and it has a forward shield the exposure within the shield's "shadow" may be manageable.

    AvWeek is talking about the reactor also being used in a "Deterrence Layer " of operations. Paywalled.

    https://aviationweek.com/defense-spa...ace-propulsion

  21. #4941
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    SN-15 moving to Pad B for a possible re-launch...

    https://twitter.com/bocachicagal/sta...24872617250817

  22. #4942
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    Quote Originally Posted by docmordrid View Post
    The emissions from a reactor are not an insurmountable problem. If they're designing a reactor which can be shut down after a "burn" and it has a forward shield the exposure within the shield's "shadow" may be manageable.

    AvWeek is talking about the reactor also being used in a "Deterrence Layer " of operations. Paywalled.

    https://aviationweek.com/defense-spa...ace-propulsion
    You can put the engine on a truss with a shadow shield protecting the habitat...but then you have to keep the station in the shadow as well for all operations in proximity to it. If there's two spacecraft in the vicinity, you have to keep them both in the shadow. And so on...

    It's a major operational complication that simply doesn't exist for chemical propulsion systems, and a major impairment to the "agility" of nuclear systems. They give you more delta-v, but everything else has to be done a thousand times more carefully. They are the opposite of agile. Out past Mars, the penalties might be worth the delta-v, but it's a very strange trade to attempt in cislunar space.

  23. #4943
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    From Fraser's post concerning Blue Origin's scheduled passenger flight.

    Over the years, Musk has offered projections on what a one-way trip to Mars with SpaceX could cost, with estimates varying from $200,000 to $500,000. There is also the proposed lunar flyby scheduled for 2023, where a Starship will transport Japanese fashion titan, billionaire, and art collector Yusaku Maezawa and a crew of selected artists around the Moon (aka. the Dear Moon campaign).
    That's a bit beyond my meager resources for a flight to the Moon

  24. #4944
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    Boca Chica

    Road/beach closure Friday; 1100 - 0100 Eastern.

  25. #4945
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    Gonna launch 15 again?
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  26. #4946
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    More likely move something, maybe parts for that monster Liebherr 11350 crane they're assembling.

    Earlier they hauled an elevator system to the orbital pad area. Probably for the tower, once it's stacked.

  27. #4947
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    I noticed the other day that the tower at KSC they use for manned flights has the same basic structure that they're building at Boca Chica. Makes sense.
    Interesting that they've put 15 straight back on a launch pad without going to the build site for refurb. Of course, maybe they need to do that in order to remove the engines.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  28. #4948
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    StarLink + Google Cloud...

    (Been expecting this since Google & Fidelity invested $1B in 2015)

    https://www.cnbc.com/2021/05/13/goog...nectivity.html

    Google wins cloud deal from Elon Musk’s SpaceX for Starlink internet connectivity

    KEY POINTS


    • Google announced that its cloud unit has won a deal to supply computing and networking resources to Elon Musk’s SpaceX to help deliver internet service through the latter’s Starlink satellites.

    • The Starlink satellite internet will rely on Google’s private fiber-optic network to quickly make connections to cloud services as part of a deal that could last seven years.

    >
    >
    SpaceX will install ground stations at Google data centers that connect to SpaceX’s Starlink satellites, with an eye toward providing fast internet service to enterprises in the second half of this year.

    The deal represents a victory for Google as it works to take share from Amazon and Microsoft in the fast-growing cloud computing market.
    >

  29. #4949
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    Quote Originally Posted by docmordrid View Post
    StarLink + Google Cloud...

    (Been expecting this since Google & Fidelity invested $1B in 2015)

    https://www.cnbc.com/2021/05/13/goog...nectivity.html
    This all sounds good until the cloud is hacked and computations are stolen, ransomed along with personal data.

  30. #4950
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    Quote Originally Posted by bknight View Post
    This all sounds good until the cloud is hacked and computations are stolen, ransomed along with personal data.
    Maybe I don;t understand your point but how would that be different or more impactful than any other data breach involving millions of accounts? No system is secure and the best us dumb humans can do is keep working to improve the security of these complex networks. At least there is significant funding to bolster the system.

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