Re: Integral Orbit

From: Tony Beresford (
Date: Fri Oct 18 2002 - 07:54:22 EDT

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    At 19:47 18/10/02, Russell Eberst wrote:
    >Recently the orbit of Integral has been quoted as:-
    >"Integral will be in a highly elliptical orbit with a perigee of 9,000km and
    >apogee of 155,000km."
    >I believe that first figure should be 90,000 and not 9,000.
    >Can anyone confirm which is correct?
    Russell, it says this in the description of launch operations, on
    the INTEGRAL website at
    This not only states the figures mentioned earlier of a 9000Km perigee,
    but the statement about usage says it passes thru the radiation belts
    at altitudes below 40,000Km. It couldnt do this if the perigee was
    90,000Km as you have been informed.
    Tony Beresford
    >About 50 minutes later, the upper stage is ignited. It is powered by a
    >restartable, liquid oxygen-synthetic kerosene propulsion system. The upper
    >stage puts the satellite into a highly eccentric transfer orbit with a perigee
    >altitude of about 700 kilometres. At the end of the upper-stage burn, the
    >satellite will separate. Then INTEGRAL's own propulsion system will bring
    >the spacecraft to its operational 72-hour orbit with an initial perigee height of
    >9000 kilometres and the apogee height of 155 000 kilometres. The perigee
    >height increases throughout the mission to about 13 000 kilometres after 5
    >years. In addition to the orbit shape, the inclination also changes drastically
    >to 85 after 5 years.
    >The high and eccentric orbit guarantees long periods of uninterrupted observation
    >with nearly constant background and away from trapped radiation in the Earth's >proton and electron belts. In this way, scientists can use 90% of the time spent in >the orbit provided by the Russian rocket for scientific observations above an >altitude of 40 000 kilometres. The orbital period with its 72 hours is a multiple
    >of 24 hours which guarantees an optimal coverage pattern from the ground stations. >This coverage is continuous for INTEGRAL's orbit for all                      >revolutions and allows repetitive working shifts on ground. 
                           In its four-stage configuration, Proton is
                           regularly used to launch spacecraft into
                           geosynchronous trajectories. 
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