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Posts posted by Rakaydos

  1. 20 minutes ago, JoeSchmuckatelli said:

    I don't know enough about rocket fuels - but would some kind of flexible hose between the two ships work (like mid-air or under-way refueling of aircraft or ships)?

    Or is the cryo aspect such that they need to figure out how to transfer cryogenic fuels through a hard-docked mechanism to keep the fuels at the proper temps?

    Cryogenics are a known difficulty with the process, yes.  But unlike zero G, we can test cryo docking  fittings in vaccum here on earth, which makes it cheap to iterate.

  2. Post industrialization climate change, mass media induced factionalization, and controlling the atom,  seems like a nasty triple threat that we are not entirely past ourselves, and the nature of the three means that most civilizations will have to deal with multiples at once, prior to expanding beyond their ability to wipe themselves out.

  3. On 2/19/2022 at 7:53 AM, kerbiloid said:

    The fossil fuel is a solar energy consumed by plant and accumulated as fossils.

     So, the most green fuel is coal. It's all made of the coastal sealife.

    A fossil fuel is one you dig out of the ground. A green fuel is one that does not contribute to climate change. So nuclear is fossil, but also green, because the waste, while diifcult to deal with, at least doesnt turn into CO2. Coal and oil, being as they are putting hundreds of years of CO2 sequestration into the air every day,  are very much not green, BECAUSE they are fossil fuels.

  4. 42 minutes ago, Spacescifi said:



    Depends on both acceleration and range.

    If you start with 50 missiles in mars low orbit and a battleship with the pellet plasma armature railgun in Earth low orbit, and the missiles max out at 20g continous, but the battleship maxes out at 3g then the missiles will be be at a disadvantage.


    Why? Because the battleship has the sniping pellet railgun turrets AND 20g continous acceleration missiles of it's own.

    And shipbased anti-missiles could carry all sorts of anti-missile packages that do not require them to even directly collide with the missiles.

    Shrapnel, machine guns, nuke ECM.... sure there are more still.

    ...and now we're evolving into space-fighter dogfighting.  Missiles shooting at other missiles to keep them from shooting at the motherships. But in a passing engagement at nearlight velocities.

    Which is rather my point. There's a reason modern navies dont field Battleships anymore, it's all about Carriers, and support ships to protect the carriers (Though, instead of taking advantage if the difference between water transportation and air transportation, it's taking advantage of not having to keep humans un-pancaked)

  5. 39 minutes ago, Spacescifi said:


    Won't matter if the battleship has multiple railgun turrets all firing at the same target.

    And a missile with a powerplant of it's own is a one-shot and done kind... unless it's a small ship itself

    Wont matter if multiple missiles are firing in a volley at the ship.

    Anything the ship can so, the missile volley can do better... once.

  6. 1 hour ago, Spacescifi said:


    You saw the power requirements of the railgun from sevenperforce?

    If fired once every second that is energy comsumption of New Jersey!

    A small missile is unlikely to be packing such a powerplant, especially since it is disposable.

    Unless there are more missiles than can reasonably be shot down the battleship with the pellet gun wins. Utterly.

    A missile doesnt have to power it continuously. All it needs is a few good shots, inside the killzone of the weapon.

    Notably, since a missile can be designed to handle higher gs than a crewed ship, and is physically smaller, the range at which a ship can reliably hit an evading missile is SMALLER than the range a missile can reliably hit an evading ship. 

    That gives the missiles an advantage in engagement envelope.

  7. 15 hours ago, Spacescifi said:



    Well yes and no.


    If a spaceship is only 300 kilometers away and I fire the lightsecond in 30 seconds pellet it is likely going to get hit with it.


    Weapons this fast force all combat into long range.

    And also means that anywhere from 300 to a thousand kilomters is a nigh guaranteed kill zone... likely farther than that.... but feel free to calculate the effective range of the relativistic pellet gun.

    All weapons that fast do is redefine "long range." Past the point where a torch drive CAN dodge your nearlight pellet, a missile (or dronefighter) will be able to follow the enemy maneuvers, enter the killzone, and make it's own attack.

    Notably, as point defense gets batter, missiles need more standoff range. If ship-style weapons are more effective, then the missile becomes a disposable fighterdrone, with it's own ship style weapon with the same killzone as ship weapons, but still fundamentally a missile, trading mission endurance for evasion and power, fired in the hopes of damaging the enemy before it's destroyed or runs out of power.

  8. 7 hours ago, kerbiloid said:

    Then you make it proportionally shorter, and it weights fine.

    And they still need a skirt. So, even Raptors 2 don't fit its diameter.

    Thus, Raptor 1 looks unable even to lift it, and the diameter looks overoptimistically.

    The cutouts have a visible gap to prevent the contact of the nozzle and the ring.
    The nozzles are attached to the combustion chamber, not to the ring.

    And anyway the cutouts weaken the ring and would not be planned, unless being forced to by the already existing tank design.

    I believe, the SpaceX engineers know what they do much better than we can estimate their engine quality.

    Then why call it "problems"?

    Of course, where the engines are put close to each other, they shade each other, so the cooling area gets decreases twice in the real rocket, rather than on the test stand.

    Looks like they faced the problem of Raptor 1 overclocking, making it possible to lift this rocket at all.

    Just a side note



    Not proportionately shorter, ACTUALLY shorter.

    The booster was always planned to have the load path from the outer ring of engines go straight up into the the structure of the tank, rather than rely on the puck to distribute the forces. This means that the engines were always going to stick out. This was never a flaw. Aeroshells are simple.

    The "engine melting" is not a problem of clustering. Regenerative cooling means that the outside of the engines is downright frosty while in operation. It's a problem of the INSIDE of the engine not  being evenly heated, so despite being evenly cooled, some copper starts boiling off before the theroetical maximum performance (just shy of "the entire copper lining boils at once") is reached.


    Also, the date on your article is 2 years old. Not news.

  9. 31 minutes ago, kerbiloid said:

    And that's also why expendable rockets are better than reusable ones.

    By making them, you train.

    Not if you cant afford to build 2 before the guy in charge retires. 

    Reusables at least get more capability over their lifespan. Build the same number as you would build expendables, you get the same benifits, but also get to fly an order of magnitude more.

  10. On 2/8/2022 at 8:48 PM, Spacescifi said:

    I know virtually nothing about why dishes are special (why not use a bell nozzle dish instead).

    Bell nozzles are about turning a point pressure (at the throat) into a directional flow. The more of the flow interacts with the bell, the better, so it's a very DEEP parabola.

    A parabolic antenna, on the other hand, is just a lense, taking a directional signal and focusing it at the focal point. a shallow chord of the parabola  is both sufficent, and lighter, even allowing for the stick to put your sensor (or transmitter) at the focal point.

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