Re: Apollo TLE

From: Antonín Vítek (
Date: Tue Jan 22 2002 - 02:07:13 EST

  • Next message: Tristan Cools: "RE: Re: OIG Catalog Action Report for the week ending January 19"

    Robert G Fenske Jr wrote:
    > On Mon, 21 Jan 2002, Mark Hartwell wrote:
    > > and while we're this far off topic ....
    > >
    > > IF there was a man made satellite in synchronous orbit around the moon
    > > (lunosynch?) wouldn't it be at the earth-moon distance ?  (as the moon
    > > keeps the same face towards the earth)
    >         No.  If the Moon had the same mass as the Earth that would be
    > the case (but then the Moon wouldn't be at the distance it is).  As it
    > is only 1/81 as massive, the orbit would be a lot closer.  I work out
    > the selenosynchronous (?) orbit to be about 93000 km from the Moon's
    > center.
    > Robert Fenske, Jr.    Sw     |The Taming the C*sm*s series:
    > Southwest Research Institute            /R---\  |
    > Signal Exploitation & Geolocation Div  | I    | |"The Martian canals were the
    > San Antonio,Texas USA  ph:210-522-3931  \----/  | Martians' last ditch effort."
    But this distance (93000 km) means that the satellite would be outside of Moon's
    sphere of influence and therefore such an orbit should be unstable.
    Only two possibilities of "selenostationary" orbit might be possible, ie. to put
    the spacecraft into the Langrangian points of the Earth-Moon system (not to mistake
    with Sun-Earth L.P. already used). Then those satellites should be stationed at the
    Earth-Moon line, one in front of the Moon, one behind the Moon, and due to the
    bound rotation of the Moon  the S/C will retain the selenocentric longitude. (Three
    other L.P. are on the orbit of the Moon, one oposite of the current Moon's position
    (180 deg difference in true anomaly), one leading, and the last triling the Moon,
    both with 60 deg. separation). But of course, those "selenostationary" orbits aro
    not selenocentric orbits, rather geocentric (but in fact barycentric, ie governed
    by the gravitational fields of both Earth and the Moon). How stabe are those L.P.
    orbits I am unable to guess.
    Antonin Vitek
    Main Library - Academy of Sciences of the Czech Republic
    Narodni 3, CZ-115 22 Praha 1, Czech Republic
    Phone: +420(2)21 40 32 55
    **** Note change in phone no. ****
    Fax:   +420(2)24 24 05 26         E-mail:AVITEK@LIB.CAS.CZ
    My satellite home page:
    Kytin 127, CZ-525 10 p. Mnisek p.B., Czech Republic
    Phone: +420(305)592865
    Coordinates: 14.2193 deg E, 49.8488 deg N, 442 m ASL
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to

    This archive was generated by hypermail 2b29 : Tue Jan 22 2002 - 02:24:17 EST