Re: When does the orbiter significantly change its orbit?

From: Bjoern Gimle (
Date: Mon Aug 20 2001 - 22:37:13 PDT

  • Next message: Dale: "Re: oig messgae"

    > magnitudes (in feet per second).  I've seen some reference to the M50
    > frame somewhere before - is it an Earth fixed or inertial frame or what?
    > LVLH refers to the spacecraft orientation relative to its orbit
    direction -
    > I can't remember exactly what it stands for.
    > ...
    Local Vertical, Local Horizontal
    From Ken Ernandes' documentation:
    VEC2TLE provides two standard systems for specifying the orientation of the
    ECI coordinate axes:  1) True Equator, True Equinox of Date and 2) Mean
    Equator, Mean Equinox of 1950 (M50).  The former, as its name implies,
    orients the X-, Y-, and Z-axes to the actual directions of the Vernal
    and polar axes at the applicable time of the vector.  The latter orients the
    axes to the respective directions of the equinox and pole at the beginning
    the Besselian Year 1950.
    The Invar Sph HA/HP defy my guess - obviously it is not in LVLH, where
    angles close to 0,90,180 or 270 would be expected: yet the two sets are
    quite similar, like the vector directions.
    In the M50 system, the two sets would be more different; at least one angle
    closer to 0,90,180,270 and the other three more spread out over [0,359.9]
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to

    This archive was generated by hypermail 2b29 : Mon Aug 20 2001 - 22:52:36 PDT