Email Detail

HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "url": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/P3RWLOZG47FZEPXER4YAFJIS7KLFOCWA/?format=api",
    "mailinglist": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/?format=api",
    "message_id": "[email protected]",
    "message_id_hash": "P3RWLOZG47FZEPXER4YAFJIS7KLFOCWA",
    "thread": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/thread/C2VTROKWXHRTM4FILIKRDCFXUA22JQHA/?format=api",
    "sender": {
        "address": "vk3jed (a) gmail.com",
        "mailman_id": "e049fcabdd4648088cd7ce227ab7c655",
        "emails": "https://mailman.amsat.org/hyperkitty/api/sender/e049fcabdd4648088cd7ce227ab7c655/emails/?format=api"
    },
    "sender_name": "Tony Langdon",
    "subject": "[amsat-bb] Re: Since We Are Off Topic Somewhat.... And drifting slightly",
    "date": "2008-02-16T06:32:00Z",
    "parent": "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/MA56VECODUBV7CGPR5AKGVJBLKYZ5AXA/?format=api",
    "children": [
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/IECHRIXHPTTCYPBJOBT3WAE7FYHBLY3F/?format=api",
        "https://mailman.amsat.org/hyperkitty/api/list/[email protected]/email/N7WHU3BY23JEMT7SQ3U5YGJMJBQOBBBM/?format=api"
    ],
    "votes": {
        "likes": 0,
        "dislikes": 0,
        "status": "neutral"
    },
    "content": "At 03:55 PM 2/16/2008, Greg D. wrote:\n\n>To go from a low circular orbit to a higher one, you fire your \n>rocket behind you to pick up more speed.  The \"point\" of the burn \n>becomes the perigee of the new elliptical orbit, and half-way around \n>is the new apogee.   Ok, so far, so good.  Now, if at the instant of \n>apogee you\n\nYep. :)\n\n>did nothing, you'd fall back down to perigee, and back again to \n>apogee on the next orbit.  But since you fired your rocket to speed \n>you up in the first place, to circularize the orbit you fire your \n>rocket at the point of apogee to slow you down, and in fact to a \n>slower speed than you started.  I would think that would make you \n>drop more steeply down on the next orbit, probably to a lower \n>perigee than you started.\n\nNope.  You fire the rocket to speed you up, which raises the perigee.\n\n>  Instead, I'd think you should fire in the same direction as the \n> first burn, to make things round, but that would make you go even \n> faster, which Mr. Kepler said was wrong.\n\nYou're forgetting that the speed of a satellite in a non circular \norbit varies as the satellite moves.  In fact, Kepler's Laws state \nthat in you were able to attach a string (with a very high elasticity \nand low tension!) between the satellite and the point around which it \nis orbiting, this string would sweep out an equal area every second.\n\n\n>My head is spinning (no pun intended)...  Where did I go wrong?\n\nTime for a thought experiment.  I'll enlist the aid of Q of Star Trek \n(Next Generation) fame to shrink the Earth to a point, and the \nsatellite to a very small size (maybe the size of a grain of \nsalt).  We'll put the satellite into a highly elliptical orbit, with \na perigee of 1 metre above this \"Earth singularity\", and an apogee of \naround 7000km (equal to 800km above the Earth's real surface).  As \nour satellite orbits this imaginary shrunken Earth, it picks up speed \nuntil it's travelling at some incredible speed at perigee (any \nmathematicians want to work it out, might even be relativistic, but \nlet's assume Newtonian physics apply at all times and velocities - Q \ncan make anything happen ;) ).  What happens at apogee is more \ninteresting.  We're now approximately 7000 km above the singularity, \nand at the instant of apogee, there is no vertical motion, the \nvelocity is horizontal, and only a few metres per _hour_ (since the \norbit is very narrow).  Now, at the moment of apogee, we accelerate \nour tiny satellite to around 27000 km/h horizontally in the forward \ndirection (Thanks Q for the push ;) ).  Hey presto, it's now in a \ncircular orbit, approximately 7000km above the Earth singularity.  I \ncan now get Q to put the Earth and Relativity back to normal, and we \nhave the satellite in a nice 800km circular orbit. :)\n\nHope that extreme, imaginary example helps illustrate what's going on. :)\n\nMetric was used, because that's the direction NASA and space science \nis headed.  I can work in either system myself... ;)\n\n73 de VK3JED\nhttp://vkradio.com\n\n",
    "attachments": []
}