High Eccentricity Orbits

From: Stephen E Bolton (sbolton@nbnet.nb.ca)
Date: Fri Jun 09 2006 - 17:26:23 EDT

  • Next message: Leo Barhorst: "LB obs 2006 Jun 09"

    Chris said:
    (79 x 1,550 km)
    it seems like it might be a mistake?
    Not a mistake. Highly eccentric orbit satellites, especially the Molniyas,
    often end their lives with many days or even weeks in the 70-80 km perigee
    regime. Lunisolar perturbations dip the perigee down to 70-80 km, while the
    apogee is up at 20 to 40 thousand km. On each pass, the satellite dows oops
    does heat up a lot, and loses a lot of velocity due to friction, dropping
    the apogee by many km per pass. But the apogee's so high, and the perigee
    velocity is so fast, that the satellite survives in orbit for an extended
    time - many tens of revolutions even. It's not uncommon for bits to fall off
    and generate short lived debris, but the main satellite does remain tracked
    in orbit until the apogee drops to a few hundred km and so the perigee
    velocity isn't fast enough to survive an atmosphere pass.
    Just unintentional aerobraking - kind of like the Mars Recon Orbit is doing
    intentionally at Mars right now.
    In reply:
    I had the good luck to observe a 100 km altitude pass of the Raguda-33 R/B
    in August of 1996 from my home in New Brunswick, Canada. Impressive to say
    the least - about a 4 degree tail of burning gas behind and VERY fast.
    In 2004 (?) I was at a conference in Toronto (the year may be wrong) and
    called Ted Molczan about dropping over for a visit. The Raduga-33 satellite
    was re-entering that night and visible from Toronto! But it was occurring at
    3 AM and I had a heavy day the next day so I passed.
    Had a chance to witness both the sat and the rocket body re-enter. Kick me.
    Steve Bolton
    Lat 45.432 N
    Long 65.976 W
    El 100m
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