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Thread: Venera 8 de-orbit

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    Default Venera 8 de-orbit

    Some excitement coming up soon.
    A Venera - Cosmos 482 will de-orbit this year.
    The failed Venus probe never left Earth orbit so it has been slowly decaying over the last ~50 years.
    What is exciting about this spacecraft is that it is designed for re-entry so that means almost all of it is going to make it to the surface
    The Perigee is also in the southern hemisphere, so half a tonne of Russian spacecraft might be headed our way.
    I like the idea of it's parachute deploying, but that's unlikely.



    The Keplerian elements for this satellite:

    1 6073U 72023E 19059.84643830 +.00019993 +52867-5 +92491-4 0 9993
    2 6073 052.0545 224.5486 1431776 329.3988 023.0419 12.89841235440528
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    If Russian tech lands on my Australian property, do I have to give it back?
    They say the parachute will not deploy because the battery will be dead. I have an old Eveready 9V probably from the 1960/70's type 276-P (Australian made) that still measured a bit of voltage at very light load maybe 5years ago but is now dead.
    I think the warm, humid salty air here killed it, not found in space. Also the very low temperature in space can attribute to an extremely long shelf life that might not have been considered here.
    Last edited by Uncle Fester; 02-03-19 at 12:23 PM.
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    Every wondered why these satellites that decay in their orbit and re enter the earths atomspher nearly always have a southern trajectory?

    Seems like they are dumping as far from their lands as possible???
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    Quote Originally Posted by porkop View Post
    Every wondered why these satellites that decay in their orbit and re enter the earths atomspher nearly always have a southern trajectory?

    Seems like they are dumping as far from their lands as possible???
    No need to ponder over that, it is indeed intentional because there is far less land mass. There is a dedicated space cemetery somewhere in the south pacific:
    Last edited by Uncle Fester; 02-03-19 at 12:33 PM.
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    Yep, nomeat has pretty much hit the nail on the head.
    There are two reasons.
    The first is that there is less land mass so it makes more sense to bias re-entries in the southern oceans.

    But there is a more dominant reason, though less deliberate. The perigee of orbit.
    This takes a little bit of 3 dimensional thinking to understand it.

    When you launch a spacecraft, there are different orbits and the rocket has to make a couple of maneuvers to get into orbit.
    If you do nothing and just send your rocket up on a "Ballistic trajectory". It will never go into orbit, it will just come back to earth or if you have enough velocity, head out into deep space.

    A rocket launches on a ballistic trajectory and then changes that to an orbital insertion trajectory. It has to go up and then horizontal, though this is usually done in a linear fashion and not so binary

    If you look at altitude vs down range distance for a typical launch, there is a dip where the rocket goes up and then comes down before going on to a higher altitude.
    This seems counter intuitive but it is actually a lot more efficient. Burning more fuel sooner to get higher means you don't have to carry that weight to a higher altitude.
    But that energy is not lost, it's potential energy in altitude. The rocket can then use that potential to get a gravitational assist from the earth and speed up the rocket to achieve an orbital velocity.
    That that means is that the perigee happens by default about half an orbit from the launch site roughly the opposite side of the earth.
    Russia and China, that means usually the SE Pacific Ocean and for the NASA and ESA, the SE Indian Ocean.

    Of course the Earth rotates beneath the orbit of the spacecraft, so that perigee drifts west with each orbit about 1000km.
    If for example Skylab had come down one orbit earlier, most of it would have landed in South Australia.

    In the case of this Venera, it was in a parking orbit until the spacecraft was ready to leave Earth orbit for Venus. Instead it failed so there was no intention to put it into that particular orbit, it was just a function of the launch parameters.
    Yes I am an agent of Satan, but my duties are largely ceremonial.

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